AGRC1032 Elements of Ecology

What are the steps to succession in Cooloola? What steps are included in progressive succession and regressive succession?

1. Colonisation of sand dunes by salt tolerant species (Imperata grass) 2. Establishment of small shrubs (Phebalium) 3. Small tree (Banksia, Allocasuarina) 4. Large trees (Acacia, eucalypts) 5. Small trees, open woodland Steps 1-4 Progressive (increase in biomass), corresponds to dune systems 1-4 Step 5 Regressive (decline in ecosystems), dune systems 5-6

Moisture: What are the ways in which uplifting of air occurs?

1. Convective precipitation: heated air rises (ex. monsoon in N Aus). 2. Convergence (cyclonic) precipitation: air is lifted up into a low pressure system. 3. Frontal precipitation: warm air is displaced by a cold front (ex. winter rain of S Aus) 4. Orographic precipitation: air is forced over mountains (ex. rainfall on E side of Great Dividing Range- rain shadow). Windward side has > rain, > vegetation, leeward side has < rain, < veg

What are the pathways for NO3-?

1. Immobilisation 2. Plant uptake 3. Leaching 4. Denitrification

What are the pathways for NH4+?

1. Immobilisation/mineralisation 2. Mineral fixation 3. Volatilisation 4. Plant uptake 5. Nitrification

Facilitation

(+/+) or (0/+) an interaction where one species can have positive effects on another species without direct and intimate contact - For example, the black rush makes the soil more hospitable for other plant species Opposite of symbiosis

Herbivory

(+/-) an interaction in which a herbivore eats parts of a plant or alga •It has led to evolution of plant mechanical and chemical defenses and adaptations by herbivores

What factors affect temperature?

1. Latitude: less insolation and more seasonality at higher latitudes. 2. Coastal vs. Continental due to water acting as a buffer (smaller temperature range) 3. Elevation: temperature decreases with increasing altitude.

Moisture: What are the pre-requisites for precipitation to occur?

1. Moist air 2. Condensation nuclei 3. Uplift to cool the air

Ecological succession in Glacier Bay, Alaska

1. The exposed moraine is colonised by pioneering plants including liverworts, mosses, fireweed, Dryas, willows, and cottonwood (Pioneer stage) 2. Dryas dominates the plant community (Dryas stage) 3. Alder invades and forms dense thickets (Alder stage) 4. Alder are overgrown by Sitka spruce, western hemlock, and mountain hemlock (Spruce stage) •Succession is the result of changes induced by the vegetation itself •On the glacial moraines, vegetation lowers the soil pH and increases soil nitrogen content

Parasitism

(+/-) one organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process •Parasites that live within the body of their host are called endoparasites •Parasites that live on the external surface of a host are ectoparasites •Many parasites have a complex life cycle involving a number of hosts •Some parasites change the behaviour of the host to increase their own fitness

Predation

(+/-) refers to interaction where one species, the predator, kills and eats the other, the prey •Some feeding adaptations of predators are claws, teeth, fangs, stingers, and poison •Prey display various defensive adaptations •Behavioural defenses include hiding, fleeing, forming herds or schools, self-defense, and alarm calls •Animals also have morphological and physiological defense adaptations

Commensalism

(+/0) one species benefits and the other is neither harmed nor helped •Commensal interactions are hard to document in nature because any close association likely affects both species

Interspecific Competition

(-/-) when both species compete for a resource

Assimilation efficiency: what does it measure?

(A/I) measures the efficiency of extracting energy from food Endotherms more efficient than ectotherms Carnivores are more efficient than herbivores

Net radiation calculation

(Incoming SW - Reflected SW) - (Emitted LW - Downward LW)

Production efficiency: what does it measure?

(P/A) measures how efficiently assimilated energy is incorporated into secondary production Invertebrates more efficient Endotherms less efficient

Ecosystem engineers

(or "foundation species") cause physical changes in the environment that affect community structure - For example, termite mounds can transform landscapes on a very large scale

declining population approach

- Focuses on threatened and endangered populations that show a downward trend, regardless of population size - Emphasises the environmental factors that caused a population to decline 1. Confirm that the population is in decline 2. Study the species' natural history 3. Develop hypotheses for all possible causes of decline 4. Test the hypotheses in order of likeliness 5. Apply the results of the diagnosis to manage for recovery

What are the three main concepts of biodiversity?

- Genetic diversity - Species diversity - Ecosystem diversity

What are major threats to biodiversity?

- Habitat destruction - Introduced species - Overharvesting - Global change

What are some human-caused changes in the environment?

- Nutrient enrichment - Accumulations of toxins - Climate change - Ozone depletion

Explain the mark-recapture method

- Scientists capture, tag, and release a random sample of individuals (s) in a population - Marked individuals are given time to mix back into the population - Scientists capture a second sample of individuals (n), and note how many of them are marked (x) - Population size (N) is estimated by N = sn/x

What are the two components of species diversity?

- Species richness is the total number of different species in the community - Relative abundance is the proportion each species represents of the total individuals in the community

What configurations can the human population exist in to maintain stability? What is the demographic transition?

- Zero population growth = High birth rate - High death rate - Zero population growth = Low birth rate - Low death rate Demographic transition is from the first state to the second state.

What components of hydrology define the structure of freshwater wetlands?

-Physical aspects of water & its movement: precipitation, surface & subsurface flow, direction & kinetic energy of water, chemistry of water -Hydroperiod involves duration, frequency, depth, & season of flooding Hydroperiod length varies among wetlands

How much has Earth's climate risen in the past century?

0.74ºC Warming in the second half of the century has been double that of the first half.

How can you measure NPP in terrestrial ecosystems?

1) Measure CO2 assimilation rates (difference in CO2 in and CO2 out in chambers) Works best for small plants Expensive for large plants 2) Measure pools of organic matter (Carbon in standing biomass + litter + soil + consumption) Difficult to measure root biomass Estimate standing biomass in trees use allometry DBH = a * biomass ^b 3) Estimate from photosynthetic efficiencies- In the simplest form: absorbed PAR by crop * photosynthetic efficiency of crop * climate function = NPP 4) Estimate from satellite/drone data with normalised difference vegetation index (NDVI) Measure reflectance of NIR (700-1200 nm) and visible (400-700 nm) light APAR estimated from NDVI, used for further calculations (also used for precision agriculture and ecosystem health)

How many photos can be taken per trigger?

1-10. 3 is the standard

What is evidence of how human activities have influenced climate change?

1. A decline of 10‐15% of the Arctic sea ice extent and a 40% decrease in its average thickness 2. Retreat of glaciers and sea‐ice 3. Snow depth at the start of October has declined 40% in the last 40 years in the Australian Alps 4. Significant observed changes in global precipitation and cloud cover 5. An increase in coral bleaching due to increased water temperature 6. Increased ocean acidification (by 30%) as CO2 is absorbed by the oceans 7. Changes in mating and migration times of birds 8. Pole‐ward and altitudinal shifts of plants and animals (especially in the Alpine zone) Less ice and snow = less reflection and loss of albedo Hadley cell will slow down

Where are global nitrogen pools?

1. Atmospheric 2. Mantle 3. Crust 4. Ocean as nitrate

What is hydrology affected by?

1. Climate 2. Geomorphology 3. Seasonal patterns of streamflow and runoff Water balance of wetlands: Water balance = Precipitation + inflow - runoff - drainage - evapotranspiration

How much has snow depth decreased?

10% on average since the 1960's Spencers Creek Snowy Mountains • 40% decrease in snow depth in spring since 1962

Major sources of greenhouse gases in Australia

29.3% agriculture 27.7% manufacturing 13.8% mining 12.2% commercial services 8.7% gas and storage 8% electricity, gas, water 0.4% construction

What happens to solar radiation when it reaches the Earth?

50% penetrates the earth 30% reflected back (from high albedo surfaces) 20% absorbed by the atmosphere, warming the planet

How is the statistical probability of a flood measured?

50-year flood The level (depth) of flood likely to occur on average once per 50 years (return interval, Tr) P = 1/Tr 0.02 = 1/50 = 2% probability

How much of the Earth's surface do marine environments cover? How are they connected, what are they influenced by, and what are they characterized by?

70%, >10km deep in some places. Small surface area compared to total volume. All seas are interconnected by currents, influenced by wave actions & tides, characterized by salinity Marine environment exhibits stratification & zonation

Composition of atmosphere

78% N2: largely inert, sourced from bacteria and volcanoes 21% O2: chemically active (oxidation), increased by photosynthesis 0.035% CO2: decreased by photosynthesis, absorbs both long and short wave radiation. Causes global warming.

Moisture: Where is most of the water contained?

97.5% of water is in the oceans. 68.7% of the fresh water is in glaciers. 30.1% fresh water in groundwater. Very little fresh water is in surface water, and even less in the atmosphere.

Carbon footprint

= amount of GHGs and specifically CO2 emitted by something (as a person's activities or a product's manufacture and transport) during a given period (Merriam‐Webster dictionary) • Australia ranks #15 in the world • In Copenhagen Accord, Australia pledged to reduce 5‐25% compared to 2000

Why is biological contamination of water an issue?

>2 Mt sewage & industrial / agricultural waste discharged daily into waterways around the world Biological contamination of water is one of the most significant forms of water pollution worldwide Result of ca. 2.5 billion people on Earth living without adequate sanitation Water may contain infectious organisms able to cause diseases in humans / animals, typically result of contamination with human and/or animal wastes Bacteria, viruses, protozoa, helminths Pathogens of human origin regarded as greatest risk Both drinking water & recreational water (swimming pools, lakes, rivers, beaches) are potential sources of water-borne pathogens Largest cryptosporidiosis outbreak occurred in Sydney area in 1998 Cryptosporidiosis outbreak occurred in Victoria in 2013

Organic contaminants

>20,000 organic contaminants Chemical industry (organic micropollutants) Spillages, leaks - e.g. leakage from underground storage tanks Gas works, electrical industries, etc. Derelict industrial sites Accidental release, off-site transport of pesticides Leachates/runoff from biosolids Industrial effluents - e.g. dioxins, furans Waste disposal - landfill leachates, wastewater effluents Industrial By-products: PCDDs (dioxins) PCDFs (furans) Industrial Products: PCBs Pesticides: DDT Chlordane Heptachlor Aldrin Endrin Dieldrin Toxaphene Mirex Hexachlorobenzene (HCB)

Ocean warming: How much heat is being absorbed by the oceans, and what has this caused?

>80% of added heat has been absorbed by the oceans. This has led to sea level rise, has been largest in the Arctic, and has caused melting of the Arctic ice cap. Ice is melting about 15.1%/decade and is becoming thinner. The Antarctic Peninsula is warming faster than the global average. This warming is associated with the retreat of glaciers and breakup of ice sheets

What are terrestrial ecosystems?

A biological community interacting with a land area via climatic processes

What is a survivorship curve? What are the types?

A graphic way of representing the data in a life table. - Type I: low death rates during early and middle life, then an increase in death rates among older age groups (human) - Type II: the death rate is constant over the organism's life span (rodent) - Type III: high death rates for the young, then a slower death rate for survivors (oyster)

What is a population? What is it described by?

A group of individuals of a single species living in the same general area. It is described by its boundaries and size.

How do rain, wildfire, predators and prey interact?

A lack of rain leads to drought and increases the probability of wildfires. Large-scale wildfires reduce groundcover, and prey species have less places to hide from predators. This results in an increase in the number of predators in the area, and a reduction in the prey population. Lots of rain increases prey populations and groundcover, so they have places to hide. This is a "boom" in the prey population. Following heavy rain, wildfires can occur due to increased vegetation. • Rainfall: Increases productivity, increases populations of rodents and other consumers • Wildfire: natural, lightning ignition, follows heavy rain events; decreases animal populations • Invasive predators: reduce prey by direct consumption • These factors interact: - heavy rains increase rodents, risk of fire and numerical response by predators; - the fire × predation interaction drives mammal populations to low levels; - predation, webs of fear come and go in pulses

What is the logistic growth model? What does it incorporate?

A population cannot sustain exponential growth for long, so we can limit this with the carrying capacity, K. This is the max population size an environment can support, and it varies with abundance of natural resources. dN/dt = rmax*N*((K-N)/K)

What is an estuary? What do its currents vary with?

A semi-enclosed part of the coastal ocean where freshwater joins saltwater The unidirectional inflow of freshwater streams and rivers interacts with the inflowing/outflowing saltwater tides, setting up a complex of currents that varies with: Structure of estuary (size, shape, volume) Season Tidal oscillations Winds

Extinction vortex

A small population is prone to inbreeding and genetic drift can go into an extinction vortex • The key factor driving the extinction vortex is loss of the genetic variation necessary to enable evolutionary responses to environmental change • Small populations and low genetic diversity do not always lead to extinction

What are the horizons of podzol and what is their composition?

A1 horizon: at the top, consists of dark organic matter A2 horizon: sand mostly stripped of iron oxide B horizon: contains iron oxide

TEAM: What are some ways to analyze the data?

ANOVA T test Chi^2 test Species diversity: Shannon and Simpson Index See if there is a difference in relative abundance of species between sites, arrays, etc.

How much solar radiation on the earth's surface is usable for photosynthesis?

About 50% is in the usable 400-700nm range (PAR). The green spectrum cannot be utilized.

How is evaporation measured?

About 90% of rainfall is returned to the atmosphere through evapotranspiration Pan evaporation Integrates temperature, humidity, rainfall, solar radiation, & wind effects Potential value, PE • PE > E but correlated • Body of water does not have metal sides • Uniform light penetration in a pan • Generally multiply pan evaporation by correction factor Lysimeters give excellent measure of evapotranspiration

What variables affect water movement to streams?

Actual water movement to stream is heterogeneous across a landscape Soil type Topography Contour curvature (Convex and Concave) Land cover (Vegetation) Pattern of precipitation (intensity) Land use (surface permeability)

What are the major contributors of CO2 emissions?

Agriculture: Land clearing is major contributor to CO2 emissions • C gain in soil pool is greater than C emissions through agricultural management - C‐sequestration • Contribution of reducing atmospheric CO2 in agricultural practice could provide C‐credits to growers - C‐emissions trading Conversion of forest to agriculture reduce soil C Conversion of cropping land to forest increases soil C, but slow

What is the effect of temperature on decomposition?

All microbial processes are temperature sensitive Cold = Thick litter layer, slow decomposition Warm = Thin litter layer, rapid decomposition

How does energy allocation vary in terrestrial ecosystems?

Allocation varies by plant life-form, environment condition, and plant age (biomass increases with age).

How have humans impacted wetlands?

Alteration to water balance (Damming, diversion, irrigation water extraction) Introduced fauna (carp, tilapia, gambusia) Introduced flora (Salvinia, water hyacinth) Waterway barrier affect fish migration Water quality changes (Salinity, fertiliser runoff, sediment) Changes to water flow (channelization, bank stabilisation)

What is a reproductive table or fertility schedule?

An age-specific summary of the reproductive rates in a population. Usually only focuses on females. It describes reproductive patterns of a population. Age groups on the left side of the table. On the top of the table are proportion of females weaning a litter, mean size of litter (males and females), mean number of females per litter, and average number of female offspring. Proportion of females weaning a litter * mean number of females = average number of female offspring

What is a life table? How do you create one?

An age-specific summary of the survival pattern of a population. • It is best made by following the fate of a cohort, a group of individuals of the same age • Age groups are on the left hand side of the table • Males and females are separated, each with: # alive at start of year, proportion alive at start of year, # deaths during the year, death rate, and average additional life expectancy

Community ecology

An assemblage of populations of various species living close enough for potential interactions

Murray River Channel & Mouth Environmental Icons

An open Murray Mouth More frequent estuarine fish spawning and recruitment Enhanced migratory waterbird habitat in the Lower Lakes and the Coorong Increase the frequency of higher-volume flows in spring, which are ecologically significant Overcome barriers to migration of native fish species between sea & Hume Dam Maintain channel stability

Aposematic coloration

Animals with effective chemical defense often exhibit bright warning colouration. Predators are particularly cautious in dealing with prey that display such colouration.

Climate Change

Any change in climate over time that persists for an extended period of time due to natural variability or human activity.

Describe large rivers (6-10+)

As stream order increases further (6th to 10th order & higher) Channel is wider and deeper Flow volume increases, current slows Sediments accumulate on bottom Autotrophic & riparian production increases FPOM is basic energy source Dominant consumers = bottom-living collectors Slow, deep water & DOM support minimal phytoplankton &

Describe mid-order streams (4 to 6)

As streams increase in width to medium-sized creeks and rivers (4th to 6th order) Importance of terrestrial detrital input decreases More surface water is exposed to sun, temperatures rise Elevational gradient declines & current slows GPP > respiration Dominant consumers = collectors & grazers Predators shift to warm-water species

What might clumped dispersion be influenced by?

Availability of resources and behavior.

How are births and deaths expressed as the average number of births and deaths per individual during the specified time interval?

B = bN D = mN Where b = annual per capita birth rate m = annual per capita death rate N = population size Revise the equation to: dN/dt = bN - mN

Global nitrogen fluxes

BNF = biological nitrogen fixation lightning combustion fertilizer production * Agricultural BNF BNF in ocean - cyanobacteria *

What is BOD and DO?

BOD - biochemical oxygen demand a measurement of the quantity of oxygen utilised by the decomposition of organic material over a specified time period (usually 5 days) standard measurement for wastewater samples and is used to quantify the readily-decomposable organic matter content of wastewater Unit: mg O2/L High organic matter content → high BOD DO - dissolved oxygen Oxygen has limited solubility in water, so as BOD increases, DO decreases Unit: mg O2/L Wastewater discharge example: BOD peaks within a short distance from point of discharge, then gradually decreases Rapid BOD increase due to microbial decomposition of available (discharged) organic materials Oxygen in water not adequate to support high rate of microbial decomposition, so DO decreases (inverse relationship with BOD)

Wildlife Picture Index (WPI)

Based on species occupancy of a site and not relative abundance such as number of events. Goes up or down with biodiversity.

What is life like on sandy and muddy shores? What are the types of fauna?

Because of the properties of sandy and muddy shores, most life is forced to live beneath the sand -Provides no attachment surface for seaweeds / associated fauna Life on sandy & muddy beaches consists of -Epifauna: organisms living on sediment surface -Infauna: organisms living in sediments (usually within tubes or burrows) -Meiofauna - organisms living between sand & mud particles (size 0.05 to 0.5 mm)

How can we predict the consequences of climate change?

Before the industrial revolution, there was 280 ppm CO2 in the atmosphere. Now it is 410 ppm. General Circulation Models (GCMs) can simulate the influence of increased greenhouse gases on global climate and predict that: • Average global temperature will increase 1.1-6.4ºC by 2100 • Warming will be greatest in winter months at Northern latitudes • Global precipitation will increase • Climate variability will increase (more storms, greater snowfall, rainfall variability)

Describe the benthic community and the meaning of benthos.

Benthic refers to the floor of the sea, benthos refers to organisms that live there No light = no photosynthesis Benthic community strictly heterotrophic (except in vent areas) & depends on OM drifting to bottom from more shallow zones High-temperature, deep-sea hydrothermal vents occur along volcanic ridges in ocean floor Vents form when cold seawater flows down through cracks in basaltic lava floor deep into underlying crust Waters react with hot basalt, become enriched with minerals Hot water re-emerges through "chimneys" Benthic communities support high diversity of species Benthic bacteria in sediments synthesize protein from dissolved nutrients & become source of protein, fat, oils for other organisms Rich diversity of deep-sea life is associated with hydrothermal vents -Organisms live within a few meters of the vent -Primary producers are chemosynthetic bacteria that oxidize sulfur compounds such as hydrogen sulfide (H2S) to release energy -Primary consumers include giant clams, mussels, & polychaete worms that filter or graze on bacteria

What is the benthic zone like? How is the substrate characterized?

Benthic zone - comprised of organic debris sinking through profundal zone / washed in from littoral zone In lakes & ponds, decomposition occurs mainly in benthic zone Substrate characterised by high biological activity - Sharp drop in O2 in profundal water just above bottom - Organic muck very low in O2 & dominant organisms are anaerobic bacteria - Muck rich in H2S & CH4 forms when available OM > OM used by bottom fauna - Periphyton (aufwuchs) are organisms associated with benthos that attach to /move on but do not penetrate submerged substrate

Two major divisions of marine environments?

Benthic zone: bottom region Pelagic zone: whole body of water

What trade-off do organisms face when there are limited resources?

Between survival and reproduction/paternal care. Ex. Kestrels with a larger number of eggs have a lower survival rate. Plants can produce few seeds that are large with more energy for seedlings to become established, or more small seeds.

What is biodiversity of forests influenced by?

Biodiversity of forests is influenced by Age of stand - older stands are more complex and have different vertical niches Once canopy closes, less light penetration, less ground cover and undergrowth, less biodiversity Location of plantation - is it established on cleared pasture or a forest replacement Landscape mosaic - maintaining patches or strip (0.5 ha is enough) or riparian buffers (lifeboats)) Adjacency of plantation - if a plantation is established next to native forest, biodiversity is higher (biodiversity may be good or bad - pest vs predators) Harvesting schedule - creating a mosaic of harvested areas and stand age important Species mixture - patches or mixed species plantation support higher biodiversity

How are coastal wetlands biologically important?

Biological importance Important for estuarine food chains and primary productivity Important food source for juvenile fish and crustaceans Mediates a balance of nutrients and organic matter between salt marsh and other interacting systems including mangroves, seagrass beds and open water systems acts as an ecological buffer between freshwater and marine ecosystems. Habitat for both marine and terrestrial organisms, some of which are endangered and protected.

What do ecosystems consist of?

Biotic (plants/flora and animal/fauna) and abiotic components

Density-dependent populations: what type of feedback do they have and what factors affect population size?

Birth rates fall and death rates rise with population density. This is negative feedback. Factors that affect birth and death rates are competition for resources, territoriality, disease, predation, toxic wastes and intrinsic (physiological) factors.

How is per capita rate of increase (change in population size) calculated?

Births + immigrants - deaths - emigration Sometimes ignore immigration and emigration so it is just births - deaths

What causes variation in population size (population dynamics)?

Births, deaths, immigration (the influx of new individuals from other areas), and emigration (the movement of individuals out of a population)

How can you estimate population densities and total population sizes?

By extrapolation from small samples (sample/area * total area), an index of population size (ex. # of nests), or the mark-recapture method

How is the ecology of a stream ecosystem determined?

By its stream flow (water discharge occurring in natural channel)

How do you classify aquatic ecosystems? What is the major defining feature?

By the features of the physical environment. Salinity

How does ocean acidification occur? What does it affect?

CO2 + H2O <--> H2CO3 Increased acidity resulting from an increase in CO2 is deleterious to calcifying organisms. Many calcifying organisms are photosynthetic primary producers so acidification could reduce NPP (positive feedback).

Air temperatures: How have CO2 concentrations changed?

CO2 is higher than it has ever been in the past 400,000 years. From fossil fuel burning and other anthropogenic activities. Air temperature in Australia is increasing everywhere and not decreasing anywhere.

Frontal precipitation in Australia

Causes winter rain in S Australia. Subtropical ridge is further south in summer so high pressure blocks cold air from the south. In winter the subtropical ridges move north so cold air moves across S Australia causing warm air to rise (frontal precipitation).

How has precipitation changed?

Changes have not been spatially or temporarily uniform. Oct- Apr (summer) Northern wet season wetter than average Apr- Nov (winter) Southern wet season drier than average because hadley cell is slowing down

How does climate change affect wetlands?

Changes of hydroperiod (ET, rainfall, pattern and intensity) Coastal wetlands affected by rising sea level and storm intensity (erosion/salinity) Wetlands of significance are protected under the Ramsar 1971 convention "wise-use" permitted: Manage site to maintain ecological character Have procedures in place to monitor quality

How are forests harvested?

Clearcut or selective logging? Pros and Cons Dispersed retention (need around 15% of native trees) Aggregated retention (clumps or strips, "lifeboats") Patch size important, strips can be along water courses Burning to clear site common, but detrimental Retention of leaves, branches, slash and snags important for nutrient cycling and habitat

What is the primary cause of the latitudinal gradient in biodiversity?

Climate

Main weathering factors of soil?

Climate (rainfall) Relief (topography) Organisms (lichens; symbiosis of algae and moss) Parent materials Time

What interacts to define landforms? What processes define them?

Climate and geology Erosion - dissection Fire - dissection Waterflow - dissection Land clearing - dissection Oasis (water comes to surface in a desert area) - dissection Deposition - new habitat formed

Describe the patterns of dispersion.

Clumped: individuals aggregate in patches Uniform: individuals are evenly spaced (ex. nesting penguins) Random: position of each individual is independent from others

How are coastal wetland ecosystems classified?

Coastal wetland ecosystems characterised by halophilic (salt-loving) flora and fauna species

Sediment pollution

Common in Australian systems, due to erosion or dredging Reduce light penetration Reduce habitat for microorganisms Reduce population of algae/aquatic plants Reduce fish populations

Common metal contaminants

Common metal contaminants of waters include Pb, Zn, Cu In the past, Pb was used in water pipes, gasoline, and paints Although drinking water in Australia typically contains less than the guideline limit (10 μg/L) Pb concentrations in excess of this value are occasionally reported In February 2012 drinking water samples from 4 outback towns in in SA reported Pb >10 μg/L As toxicity in Bangladesh Sources include tailings, emissions, smelter complex materials and residuals, acid mine drainage Cyanide heap leaching used in Au mining has potential to release large quantities of cyanide to the environment if improperly managed Acid formed by AMD dissolves metals in waste rock and tailings, releases them to ground and surface water

What are the benefits of higher diversity?

Communities with higher diversity are - More productive and more stable in their productivity - Better able to withstand and recover from environmental stresses - More resistant to invasive species, organisms that become established outside their native range

What are threats to coastal wetlands?

Competing land use (clearing, marina, landfill, aquaculture) Increased fine sediment and nutrient loads in stormwater runoff and agriculture. Nutrients and sediments emanating from diffuse sources (e.g. intensive agriculture and urban stormwater) in catchments can be particularly large and difficult to control. Drainage and/or filling for agricultural, urban or industrial development - the latter are closely tied to population density. Drainage for mosquito control. Degradation by pollutants such as acid drainage, nutrients, metal contaminants. Change in hydrology may alter salinity and species distribution River regulation, barrages, infrastructure and floodplain structures can modify flow volumes and hydrological regimes including natural flooding, drying and tidal-flushing patterns. Rising sea level and storm intensities

Life history

Comprises the traits that affect its schedule of reproduction and survival - The age at which reproduction begins - How often the organism reproduces - How many offspring are produced during each reproductive cycle • Life history traits are evolutionary outcomes reflected in the development, physiology, and behaviour of an organism

What do soils consist of and what is its importance?

Consist of mineral and organic fractions Store and supply nutrients Store and supply water Anchorage Habitat Regulates stream flow Different characteristics at different depths (horizons)

Engineered wetland

Constructed wetland is artificially flooded land Creates poorly drained soil and wetland flora/fauna Primary purpose if flood control and pollution control Good for control of non-point contamination Geochemistry of wetland soils 1. Loss of oxygen 2. conversion of NO3- to nitrogen 3. Reduction of Mn and Fe minerals 4. Reduction of sulfate to H2S 5. Reduction of carbohydrates to methane Can be used to eliminate pollutants, e.g. municipal wastewater and stormwater, mining drainage, agricultural wastewater Detention time and loading rate critical for success of treatment wetlands

What is the Network of Ecosystem Warming Studies?

Coordinated international effort to study the response of ecosystems to climate warming. • experiments focus on the response of soil respiration, net nitrogen mineralization, and aboveground NPP • 32 research sites in 4 biomes: high (latitude/altitude) tundra, low tundra, grassland, forest • Across all sites, experimental warming (0.3 - 6.0 ºC) for 2 - 9 years duration • Results show considerable variation in response to warming • Increases seen in: ‒ Soil respiration rates: 20% (larger in forest ecosystems) ‒ Net nitrogen mineralization rates: 46% ‒ NPP: 19% (larger in low tundra ecosystems)

What do mixing of waters of different salinities and temperatures in an estuary create?

Creates a counterflow that works as a nutrient trap • Inflowing rivers are usually nutrient-poor except for phosphorus • Nutrients & oxygen are carried into the estuary by the tides • If vertical mixing occurs, these nutrients are not swept back out to sea but circulate up and down

Artificial

Dams, canals

Describe the composition of dead material.

Dead material very heterogenous in composition • Some material labile (easy to decompose), other material recalcitrant

What organisms decompose plant and animal material?

Decomposition required a variety of organisms/enzymatic pathways • Bacteria decompose mainly animals and soft plant tissues • Fungi decompose mainly plant material and recalcitrant tissues Litter is broken down by shredders (Mites, springtails, woodlice, earthworms) into residue. Residue is broken down by decomposers (mites, nematodes, fungi, bacteria) into humus. Humus is broken down by decomposers (fungi, bacteria) into minerals. Bacteria, nematodes and fungi are also eaten by predators.

K-selection

Density dependent selection; selects for life history traits that are sensitive to population density

R-selection

Density independent selection; selects for traits that maximize reproduction

How is carbon distributed in the soil? What affects the amount of carbon in the soil?

Depth distribution of C • More C in surface layer • Less C in deeper layer Amount of soil C depends on a combination of: • Precipitation • Temperature Temperature increases, more biomass, reaches maximum (25ºC) High moisture leads to only ananaerobic, more OM accumulates (slow decomposition) Low moisture --> aerobic --> faster decomposition

Global precipitation patterns

Deserts form at the dry descending air part of the Hadley Cell. Most precipitation at the equator/ITCZ. Coriolis effect = dry descending air at 30º N and S causes areas of deficits and deserts. The ITCZ can move according to seasons. Tropical rainforests at ITCZ, temperate forests at 30º, boreal at 60º

What has loss of wetlands led to?

Despite global recognition of ecosystem service provision by wetlands However, loss of wetlands has reached a point at which environmental & socioeconomic values are in jeopardy Waterfowl habitat Groundwater supply and quality Floodwater storage Sediment trapping water quality (nutrient retention)

Why isn't nitrogen an almost unlimited resource?

Diatomic nitrogen gas has triple bonds! Plants and animals cannot break the triple bond, but nitrogen fixing bacteria on legumes can.

How is water quantified in streams and lakes?

Discharge of water (m^3/s) = Stream flow x cross section m/s x m2 Cumulative data of the discharge = hydrograph

Mid-latitude climates

Dry subtropical • Climate is dominated by the STR but higher latitude • Larger temperature range • Arid and semi‐arid • Dominant landscapes in SA and much of NSW Moist subtropical • Eastern side of continents • Often water surplus • Larger temperature range • Influenced by STR - winds flow over oceans on to land becoming moist Mediterranean/Marine • Dry/warm summers, wet/mild winters • West side of continents • Occurs due to STR moving pole‐ward in summer • In winter, STR moves towards equator - rainfall increases as fronts move in • Important in S. coastal regions of WA and SA, VIC, TA Moist Continental • Strong winter/summer • Good rainfall • None in southern hemisphere • Eastern N America and Eurasia • Dominated by warm moist tropical air in summer and cold air in winter

Insolation: Latitude

Due to the angle of incidence at which sunlight hits the earth's surface. Average annual surface net radiation decreases as you move to higher latitudes because the angle is greater and radiation is spread over a larger area, having to travel through more of the atmosphere, being reflected back along the way. Highest net radiation is at the equator. Equator has an energy surplus, polar regions have an energy deficit. This imbalance of energy drives earth's atmospheric circulation patterns.

Why is Australia's interior so dry?

Due to the subtropical ridge/ subtropical high pressure belts. Central Australia is below the STHPB.

How does nutrient composition and the horizons of the soil in each dune system differ? How does vegetation differ?

Dune system 1: small A1 and B horizon 2: small A1, slightly larger B horizon 3: small A1, small A2, large B horizon 4: each horizon about even size, A1 and A2 are larger 5: Very large A2 , small A1 and B horizons 6: Even larger A2, smaller A1 and B horizons System 4 has the most nutrient-rich soil (N and P), and as plants become more dense in later systems, the soil is stripped of the nutrients. System 4 has the most nutrients, so it also has the highest species richness. Older dunes have less species richness, but have relatively tall tress competing for sunlight.

How would you calculate NPP, respiration and GPP using phytoplankton in a clear and dark bottle?

During incubation of the light, phytoplankton will photosynthesise O2 and also consume some O2 by respiration. The phytoplankton in the dark bottle will only respire O2. Initial bottle = 6 mg O2 /L ; Clear bottle = 8 mg O2 /L ; Dark bottle = 5 mg O2 /L (Clear - Initial) = (8-6) = 2 mg/L/hr = (GPP - R) = NPP (Initial - Dark) = (6 - 5) = 1 mg/L/hr = Respiration (Clear - Dark) = (8 - 5) = 3 mg/L/hr = (NPP + R) = GPP

Lake turnover and nutrient cycling

During turnover, nutrients released by decomposition on bottom are carried upward to surface layers - In spring, phytoplankton have access to nutrients & light - A bloom develops, depleting nutrients & reducing plankton populations

How are coastal wetlands economically important?

Economic Saltmarshes are farmed as grazing leases for cattle production. Important food source for commercially important fish Value of ecosystem services for the water treatment function of wetlands. Salt mining Human values Recreation

What can hydrographs help measure?

Effects of surfaces Areas of permeable rocks & soil allow more infiltration, less surface runoff Vegetation intercepts rain, increases evapotranspiration; urban areas have impermeable surfaces & more runoff.

How does temperature affect endotherms?

Endotherms have a constant body temperature, and temperature affects their metabolism, determining heat exchange. The larger the body size, the less area for heat dissipation. Geographically, average body size increases with decreasing annual temperature (increasing latitude). A smaller body size is more energetically efficient in both birds and mammals.

What is the energy base for organisms on sandy and muddy shores?

Energy base for life on sandy shore is accumulation of organic matter in sheltered areas Bacterial decomposition most rapid at low tide Detritivores ingest OM as means of obtaining bacteria (nematodes, copepods, polychaete worms) Filter feeders obtain food by sorting food particles from tidal water Predatory gastropods & crabs live at or below low-tide line -Tides bring in small predatory fish -Gulls and shorebirds hunt as tide ebbs

What are the types of temporary aquatic systems? What classifies a water body as permanent?

Ephemeral: Only filled after unpredictable rainfall and runoff. Surface water dries within days to weeks of filling and can support only short-lived aquatic life. Episodic: Annual inflow is less than the minimum annual loss in 90% of years. Usually dry but filled after rare and large, unpredictable rainfall events. Surface water persists for months to years, and often supports longer-lived aquatic life. Intermittent: Alternately wet and dry, but less frequently or regularly than seasonal waters. Surface water persists for months to years, and often supports longer-lived aquatic life. Seasonal: Alternately wet and dry every year, according to season. Usually fills and dries predictably and annually. Surface water persists for months, long enough for some plants and animals to complete the aquatic stages of their life-cycles. Permanent: Predictably filled, although water levels may vary. Annual inflow exceeds minimum annual loss in 90% of years. During extreme droughts, these waters may dry. Usually supports diverse aquatic life, much of which cannot tolerate desiccation.

Describe temperature stratification

Epilimnion -surface layer of warm, less dense water Metalimnion - middle zone in a thermally stratified waterbody which contains the thermocline Thermocline = horizontal plane where the greatest rate of change in temperature occurs. May also be called the metalimnion Hypolimnion - Cool dense layer of water comprising deepest layer of in a thermally stratified waterbody

What are Australia's major climate zones?

Equatorial Tropical Subtropical Desert Grassland Temperate

How many humans can Earth support?

Estimated 10-15 billion. By 2050, there will be about 7.8-10.8 billion. Possible limitations are food, space, nonrenewable resources and buildup of wastes

Why are Australian native trees less suited for mixed native/exotic plantations?

Eucalypts take up too much of the nutrients and they are the only ones that survive

What is the problem with exotic plantations?

Exotic plantation forests have low species diversity (pine vs native) Monoculture Pine plantation lower in hollow-dwelling birds, arboreal marsupials, nectarivorous, frugivorous and canopy-feeding birds Animal diversity is correlated with amount of native vegetation occurring within the plantation Plantation forests have lower coarse woody debris (snags), home to animals Plant and animal diversity increases with plantation age

What does hydromulch contain and how does it work?

Fibres (sugar cane, recycled paper, straw) Binders (starch, guar gum, bitumen) Seed mix Organic matter (topsoil, compost) Fertiliser, water and dye 1. Seeds germinate, grass, legumes, groundcover dominate first 2. tree and shrub seedlings grow slower, will shade out ground cover later 3. May need to manually plant long-lived trees.

How does Australian flora promote fire?

Fine leaves which burn easily and fast Flammable oils in leaves and twigs Heavy litter fall Open canopy promotes drying of undergrowth Stringybark to spread fire into crown Hard woody seedpods Epicormic buds and lignotubers Insulating bark This leads to regular low intensity fires Fire will normally not destroy vegetation composition, just return nutrients to soil and thin undergrowth. Perennial grasses regrow, undergrowth re-establishes from seeds or lignotubers, tree regrow from lignotuber or re-shoot. Non-fire adapted species (often weeds) will die-out by may re-establish from seed bank

What are the steps of nutrient cycling? What do plants and animals mostly consist of, and what do they decompose into?

First step in nutrient cycling is decomposition of organic matter Final step in nutrient cycling is mineralization • Decomposition pathways differ between source materials Plants: consist of carbohydrates; decompose to starch, hemicellulose, proteins, cellulose, lignin, waxes Animals: consist of protein; decompose to protein, keratin, bones, chitin, teeth C, O, H, N, S, P, Ca, Mg, K, Na, B, Fe, Mn, Zn, Cu........

How can food webs be simplified?

Food webs can be simplified by - Grouping species with similar trophic relationships into broad functional groups - Isolating a portion of a community that interacts very little with the rest of the community

Coral reefs

Found in warm, shallow tropical & subtropical waters Formed by unique accumulation of dead skeletal material built up by carbonate-secreting organisms -Living coral -Coralline red algae -Green calcareous algae -Foraminifera -Mollusks Reef-building corals have symbiotic relationship with photosynthetic algal cells (zooxanthellae) Symbiotic, photosynthetic dinoflagellate algae (zooxantellae) live in the tissues of coral gastrodermal layer Limited to depths < 45 m Precipitation of calcium from water is necessary to form coral skeletons -Occurs when water temperature & salinity are high, CO2 is low Oases of productivity within relatively nutrient-poor, lower-productivity sea

Estuarine

Fresh and seawater input, coastal flats

Palustrine

Freshwater floodplain, marshes, swamps

Dystrophic

From Greek word "dystrophy", meaning ill-nourished Receive large amounts of OM from surrounding landscape High levels of humic materials (stain water brown) Generally occur on peaty substrates (bogs, heathlands) Typically have highly productive littoral zones Littoral vegetation dominates the lake's metabolism, providing both DOM and POM

Fundamental vs. Realized Niche

Fundamental niche is what can be potentially occupied by that species, but the realized niche is what that species actually occupies. Ex. the presence of one barnacle limits the realized niche of another. The golden spiny mouse and common spiny mouse are both nocturnal, but the golden spiny mouse becomes diurnal if the common spiny mouse is present.

Biogeochemical cycles: How will rising atmospheric CO2 concentrations influence the exchange of carbon between the atmosphere & terrestrial ecosystems?

Global carbon cycle links the atmosphere, hydrosphere, biosphere, and geosphere on a global scale • 50 % of the carbon released through human activities remains in the atmosphere • Of the remaining 50%: • 26% is taken up by terrestrial ecosystems • 24% is taken up by the oceans • forms carbonic acid, which increases surface acidity

What happens in the change from erosive headwaters to depositional floodplain in lotic systems?

Gradual change from erosive headwaters to depositional floodplain Closer to the mouth of river = less slope Slower water movement Deeper More particle deposition Less light penetration Fewer submerged plants Increase in suspended biota Frequent floods Frequent shift of flow pattern

What is life on rocky shores influence by?

Grazing predation, competition, wave action Waves: Provide consistent supply of nutrients Carry away organic material Move seaweed fronds (evenly distribute light) Dislodge plants & invertebrates to provide areas for colonization, reducing interspecific competition Heavy wave action can reduce activity of predators

Subterranean

Groundwater and hyporrheic zone

What are benefits of wetlands?

Groundwater replenishment Diversion of riverflow/stormwater/quality of water Bird habitat Recreation Local temp control Flood regulation Fish stock Midges/mosquitoes Filter for debrish/rubbish/nutrients

Metapopulations

Groups of populations linked by immigration and emigration High levels of immigration combined with higher survival can result in greater stability in populations

Shannon Diversity Index (H)

H = -(pAlnpA + pBlnpB + ...) Where A, B, etc are the species and p is the relative abundance of each species

Describe how nitrogen fertilizer is made.

Haber/Bosch process • N2 + H2 • high pressure (200 atm) • high temperature (500 °C) • Input of N to terrestrial systems more than doubled • Massive increase in agricultural productivity • 1/3 of protein in human population from this process (2 billion people)

Why does fragmentation occur? What are the consequences?

Habitat loss and fragmentation mainly due to land clearing Fragmentation = continuous habitat segmented into patches Highly modified surrounding environment = matrix Species richness: Less habitat Less habitat diversity Species composition affected: Generalists increase Specialists decrease Species interaction: Loss of keystone species = major change in ecosystem functioning

What are some plant adaptations to fire?

Heat/fire resistant bark Seed pods (banksia) - release seeds Seeds (acacia) - lots of tiny seeds regenerate Lignotubers - germinate with crown at ground level Tussocks (grass tree) - has scales

How is population density distributed in terrestrial ecosystems? What are the levels of distribution?

High population density in centre of distribution Density tends to zero at edge of patch Zero density can be temporary until conditions improve (geophytes, rainfall, competition) Cosmopolitan = global Pandemic = continental Endemic = localized at single sites or multiple sites (disjunct)

Eutrophic

High surface-to-volume ratio (shallow lakes) Often surrounded by nutrient-rich deciduous forest / farmland, high nutrient levels (N, P) Poor light penetration Low dissolved O2 High algae growth Low water clarity Silt or clay bottom with large quantity of OM Typically have overgrowth of aquatic vegetation, high net primary productivity

Temperature: Elevation

Higher elevations have colder temperatures, and glaciers can form there even in tropical areas. Mt. Kilimanjaro is about 6,000 m tall, and every 1,000 m there is a 6.6ºC decrease.

What are Giving-Up-Densities and how are they tested?

How long an animal stays and eats food before they "give-up" and hide from predators. In other words, how comfortable they are. Exclusion cages, cage controls and open controls were placed in burnt and unburnt areas.

How do dead zones develop?

Human activities can have negative impacts on water quality in freshwater and marine ecosystems Inputs of nitrogen and phosphorus These are normally limiting for NPP in aquatic ecosystems This can lead to low oxygen levels (anoxia), which causes the death of marine organisms, forming dead zones How does a dead zone form? -Input of unnaturally high levels of nitrogen & phosphorus into an aquatic ecosystem (lake, ocean) -NPP of phytoplankton & other autotrophs increases -Autotrophs die, sink into the benthic zone, are consumed by bacteria -Increased bacterial respiration reduces oxygen levels -Winds move surface waters away from coast -Surface waters replaced by deeper oxygen-depleted water -If oxygen levels are very low (anoxia), organisms die

What societies fared better 40 years ago?

Hunter-gatherers were more knowledgeable about their environment and had better survival, while subsistence agriculture had crop failure.

What is ecology in wetlands driven by?

Hydrology Biogeochemistry Vegetation succession Wetlands are water saturated for part of a year

How does hydrology influence vegetation?

Hydroperiod influences plant composition (effects on germination, survival, mortality at various stages of life cycle) Effect is most pronounced in basin wetlands Basin with adequate depth to have standing water throughout drought, dominant plants are submergent If the basin goes dry at some point, tall or mid-height emergent species dominate If a basin is shallow and floods only briefly, grasses, sedges, and forbs produce a wet meadow If a basin is deep enough in its center & large enough, zonation of vegetation may develop Reflects response of plants to hydroperiod: Long hydroperiod supports submerged plants & deep-water emergent plants (cattails, bulrushes) Short hydroperiod supports shallow-water emergents & wet-ground plants (rushes, sedges) Periods of drought & wetness can induce vegetation cycles associated with changes in water levels

What are the hypotheses of the boom and bust cycle between the lynx and hare? Which ones are most likely?

Hypothesis 1: The hare's population cycle follows a cycle of winter food supply. • If this hypothesis is correct, then the cycles should stop if the food supply is increased • Additional food was provided experimentally to a hare population, and the whole population increased in size but continued to cycle • These data do not support the first hypothesis Hypothesis 2: The hare's population cycle is driven by pressure from other predators • In a study conducted by field ecologists, 90% of the hares were killed by predators • These data support this second hypothesis Hypothesis 3: The hare's population cycle is linked to sunspot cycles • Sunspot activity affects light quality, which in turn affects the quality of the hares' food • There is good correlation between sunspot activity and hare population size --> The results of all these experiments suggest that both predation and sunspot activity regulate hare numbers and that food availability plays a less important role

TEAM: Why do we have to standardize trap nights?

Ideally, 60 cameras for one site (every 2 km^2) should be set out for 30 days. However, sometimes cameras are left out for less than 30 days, and if we do not factor this into our events per 100 trap nights equation, then this can skew the data. Some sites and arrays may differ in the number of trap nights, so you have to standardize the data. Example: If you had the cameras running for 10 days in array 1 with 5 events and 20 days in array 2 with 10 events. You would assume the abundance is double in array 2 but they are exactly the same: events per 100 trap nights array 1 = 5/10 =2 events per 100 trap nights array 2 = 10/20 = 2

Equilibrating energy gradients: what does imbalance cause?

Imbalance causes a global pattern of heat distribution from the equator to poles. Air rises when warmed at the equator and lowers when cooled at the poles, leading to high pressure at the surface.

How has climate change affected species interactions (Caribou and Mountain Pine Beetle)?

In Caribou of W. Greenland, reproduction of depends on synchronizing calving with resource abundance. Plant species emerged 14.8 days earlier, and calving by only 1.28 days. Caribou repro is cued by day length, so there was little change. Plants are correlated with mean Spring temperature, which rose by 4.6ºC, so there was a larger chance. The rate of calf mortality increased and annual calf production decreased because of this mismatch. The Mountain Pine beetle has risen to epidemic levels over the past 10 years because increased drought from increased temperatures made trees more susceptible, and beetles expanded. Beetle flight season starts one month earlier and lasts twice as long, and sometimes there are even 2 generations per year.

Convective precipitation in Australia

In Jan, NE winds bring wet maritime air. In July, SE winds bring dry continental air. This causes monsoons in N Australia.

How does climate change occur naturally?

In Jan, the angle of incidence is greater in the S hemisphere, so there is more insolation (summer). The angle of incidence is less in the N hemisphere, so there is less insolation (winter). The tilt of earth's axis varies from 22.5-24º over a cycle of 4,000 years, which has been responsible for the ice ages.

Nutrients as an environmental factor: What are essential mineral nutrients for plants and animals? What are plant and animal adaptations?

In aquatic ecosystems, nutrients are mainly dissolved, move to plant. In terrestrial ecosystems, nutrients are mainly in soil. Nutrient availability can be high or low. Plant: Roots, vascular elements, Microbial symbiosis, parasitism, carnivory Animal: Herbivory, carnivory

Temperature as an environmental factor: Land vs. water? Plant vs. Animal Adaptations?

In aquatic ecosystems, temperature amplitude is low (small temperature fluctuations) In terrestrial ecosystems, temperature fluctuations are greater Need to prevent heat and cold damage Plant: leaf shedding/dormancy, transpiration, osmotic adjustment (more sap to prevent freezing), leaf adaptations (waxy coating). Animals: hibernate, sweat, seasonally changing fur, movement

Secchi depth

In field studies, sediment pollution or relative turbidity may be estimated using a secchi disk Depth at which the black and white plate is no longer visible from the surface is referred to as secchi depth Current rates of sediment erosion in Lockyer & Mid Brisbane catchments, much of which is subsequently transported to Moreton Bay, estimated 30X greater than rates of erosion prior to colonisation

Turbulent water flow

In natural condition river banks and beds contain impediments to laminar flow Woody detritus Cobbles Boulders Aquatic plants

Where is P most limiting?

In older ecosystems. Also limiting in intermediate (along with N). N limiting in younger ecosystems.

Shallow-rooted plants in estuaries

In shallow estuaries, rooted aquatic plants are important Rooted aquatic plants support many epiphytic organisms & are important sources of food for vertebrate grazers

When does random dispersion occur?

In the absence of strong attractions or repulsions

What is the significance of the riparian zone?

Inclusion of riparian zone as part of river ecosystem may be necessary Vegetation in riparian zone may be connected to water-saturated zones (parafluvial / hyporheic) via root system

Where does sunlight end up?

Incoming solar radiation 1370 W/m^2 at the top of the atmosphere Average over the surface is 340 W/m^2 315 W/m^2 absorbed by atmosphere 660 W/m^2 absorbed by earth 400 W/m^2 reflected back

What allows demographic transition to occur?

Increase in health care quality with improved access to education.

How have human activities affected climate change?

Increases in average global temperature, melting of snow and ice, rising sea level. It is very likely due to an increase in greenhouse gas emissions.

How has climate change affected regional patterns of diversity (zooplankton)?

Increases in sea surface temperatures from 1958-1999 has led to zooplankton changes in the East North Atlantic and European shelf areas. Warmer-water species moved North by 10º latitude and colder water species retreated North.

What does an increase in CO2 concentration cause?

Increasing CO2 concentration • Increase temperature • Increase photosynthesis • Increase biomass production • Increase litter & root production • Increase soil organic matter • Increase microbial organisms • Increase soil C

What are threats to aquatic ecosystems?

Increasing water temperature Changing rainfall patterns and intensity Water pollution Sediment Changes in water level Invasive plant and animal species

What is the Allee effect?

Individuals have a more difficult time surviving or reproducing if the population size is too small

Worldwide, coastal hypoxic zones are usually concentrated in which areas?

Industrial areas

Chemical pollution

Inorganic - metals / metalloids, radionuclides Organic - carbon-based compounds such as hydrocarbons, polychlorinated biphenyls (PCBs), detergents, insecticides, etc. Nutrient pollution is a form of chemical pollution

Carbon dioxide atmospheric cycle

Inputs: organic material decomposing, fossil fuels (major), land use change (deforestation) Sink: oceans (also land) CO2 concentrations are rapidly increasing.

What is interspecific interaction? What types are there?

Interactions between species that can have a positive, negative or no effect on survival and reproduction. Competition, predation, symbiosis (mutalism, commensalism, parasitism), herbivory, facilitaion

What is ITEX?

International Tundra Experiment (ITEX) = coordinated international effort using standardized methods. • Global network of Arctic and alpine research sites • Experimental & observational studies use standardized protocols to measure responses of tundra plants and plant communities to increases in temperature • Investigators from 13 countries working at 28 sites • ITEX studies used open top chambers to passively warm plant‐level air temperature by 1 - 3ºC = range of observed and predicted tundra region warming • Responses were rapid, detected in whole plant communities after two growing seasons • increased height and cover of deciduous shrubs and grasses • decreased cover of mosses and lichens • decreased species richness and evenness

How has climate change impacted ecosystem processes?

It has affected Net Primary Productivity (NPP) and decomposition. 1982-1999: NPP up by 6% 2002-2009: NPP down by 0.55 petagrams of Carbon due to regional drying that constrains plant growth. In N hemisphere, NPP increased for 65% of vegetated land, and in the S hemisphere, NPP decreased for 70% of vegetated land (increased evaporation and reduced water availability).

Methane CH4: How has it changed in the past century? What are the contributors? How much more potent is it than CO2?

It has doubled in the past 100 years. 60% from agriculture 20% fossil fuel burning 20% natural (wetlands, volcanoes) It is 28x more potent than CO2.

Are communities ever in equilibrium?

It was once thought that communities would reach equilibrium, but now the non-equilibrium model is more accepted.

What are essential nutrients and where do they come from?

K, N, Ca, P, O2, Na, H2, C Come from when Earth was formed- we can't make more!

What does lyngbya respond to? What doesn't affect it?

Lab studies show growth response of Lyngbya to Fe, pH, EC, P, DOC Why no effect of nitrogen on growth? Fe: required for photosynthesis and N fixation in Lyngbya P: required for growth pH: affects availability of nutrient DOC (dark coloured): soluble carbon, may complex trace elements and contains N, P, stimulates Lyngbya photosynthesis EC:? Acid Sulfate Soil releases acid and minerals. Pine and tea trees contribute to this. Avoid pine tree plantations near waterways.

Oligotrophic

Lake has low surface-to-volume ratio (big, deep lakes) Little nutrient input / low nutrient levels Good light penetration High dissolved O2 Low algae growth High water clarity Rock, gravel, or sand bottom (very little OM) Typically have little/no aquatic vegetation, low net primary productivity Usually low no. of organisms but high species diversity

What are some lentic ecosystem characteristics?

Lakes are relatively short-lived Sediment deposition converts lakes/lagoons into swamps and dry land Changes from low nutrient status to high nutrient status

Lacustrine

Lakes formed by river channel migration (billabongs)

Insolation: Surface characteristics

Land vs. Water 1. Sun penetrates water to greater depths than the surface. Water heats slower, land heats faster. 2. Heat capacity of water is greater so it stays warm longer than land does. 3. Water mixes 4. Water has evaporation and a greater loss of latent heat, land has less loss of latent heat. Albedo = % radiation reflected back • Snow 80-95 % albedo • Light roof 35-50% • Grass 25-30% • Dark roof 8-18% • Concrete 17-27% • Water bodies 10-60% • Crops 10-25% • Forests 10-20% • Moon 6-8%

Nitrous Oxide N2O: When did it start increasing? How much more potent is it than CO2?

Large increase at the industrial revolution. Especially in 1910 with the invention of N fertilizers. 265x more potent than CO2.'

What are two key factors that affect community biodiversity?

Latitude and area

What scales do nutrient cycling involve?

Length • Micrometers (within microbes) • Metres (within landscapes) • Kilometres (between continents) Time • seconds • days

How do you further classify lentic and lotic freshwater systems?

Lentic/standing water by stratification: light temperature oxygen Lotic/flowing water by: flow rate permanence

How do environmental conditions differ between terrestrial and aquatic ecosystems?

Light Nutrient availability Water availability Oxygen Temperature

How do light, temperature and oxygen influence distribution and adaptations of life in lakes and ponds?

Light decreases with water depth, affected by silt and phytoplankton growth. Temperatures vary seasonally & with depth O2 can be limiting, especially in summer (Respiration by decomposers consumes large quantities of O2)

How does light affect forest ecology?

Light quantity and quality changes with forest age Quantity (light intensity) decrease from canopy to forest floor Quality changes (PAR absorbed by foliage), shift to far-red spectrum Low R:FR ratio suppressed germination Increased etiolation Smaller leaf area Understory plants tolerate low light intensity, seedlings have large reserves (Moreton Bay chestnut), long lifespan Shade intolerant plants only establish after canopy gaps, fast growing, few reserves, short lifespan (pioneer species)

Light as an environmental factor: how does it differ and what are animal and plant adaptations?

Light transmission (quality/spectrum and quantity/intensity) differs between air and water. Light of all spectrums penetrate clean water ~200m. Only the blue light spectrum penetrates deep water. Plant: Pigmentation, leaf orientation. New leaves are red to protect against the sun, and they are tilted down when the light is bright. Animal: Pigmentation, fur

Insolation: Cloud cover

Little cloud cover over desert/equator = more insolation 30º N and S of the equator = deserts

Horizontal stratification in lakes: what are the zones?

Littoral zone: shallow-water zone in which light reaches bottom Limnetic zone: open water that extends to depth of light penetration. Habitat of plankton & free-swimming organisms (nekton) such as fish

Competitive exclusion

Local elimination of a competing species that can occur after interspecific competition. The competitive exclusion principle states that two species competing for the same limiting resources cannot coexist in the same place

What type of radiation do greenhouse gases absorb?

Long wave radiation (333 W/m^2) in the infrared spectrum

If only 10% of energy moves from one trophic level to the next, where do the other 90% go?

Lost as heat Energy flow is unidirectional in the grazing food chain is not unidirectional in the detrital food chain Food Chain first level - primary producers second level - primary consumers (herbivores) higher levels - secondary consumers (carnivores)

What are the types of freshwater ecosystems?

Lotic: flowing water (rivers, streams) Lentic: non-flowing water (ponds, lakes, wetlands)

What can cause low and high NPP?

Low water availability => less evaporative cooling (dissipating heat) => low NPP gas exchange decreased => low NPP High PAR and low water availability => photo-oxidative stress => low NPP High PAR and low temperature => photo-oxidative stress => low NPP Short daylength or low light intensity => low NPP Low nutrients => chlorosis of leaves => low NPP C4 plants have higher NPP

What is Lyngbya?

Lyngbya is a blue-green alga (cyanobacterium) living in shallow coastal waters N-fixing Photosynthetic Produces toxin Fish avoid areas with Lyngbya Smothers seagrass and coral Turtles avoid areas with Lyngbya Harmful to humans Increased incidence in northern Moreton Bay, often after heavy rainfall

Describe the sulfur cycle inputs and outputs.

Main S inputs: • Air pollution (SO2 emissions from coal & oil) • Bushfires (release of S in vegetation) • Fertiliser (gypsum, superphosphate, sulfur) • Volcanic eruptions • Seaspray (aerosols) Main S losses: • Volatilization as organic S compounds (onion, cabbage) • Leaching • Bushfires • Precipitation as metal sulphides in anoxic conditions • Crop removal

Describe P in soil of Australia.

Majority of bedrocks (parent materials for soil) in Australia are over 1 million years old Globally soils contain around 0.02 - 0.15% P Australian soils typically lower: 0.01 - 0.03 % P

What replaces salt marshes in tropical areas? How do they develop?

Mangroves Mangrove forests cover 60- 75% of tropical coastline Develop in absence of wave action, sediments accumulate, muds are anoxic Extend to highest vertical tide range where there may only be periodic flooding Dominated by mangrove plants with other salt-tolerant plants, mainly shrubs

What life do mangroves support?

Mangroves support a unique mix of terrestrial & marine life Birds nest in upper branches (herons, egrets) Littorina snails live on prop roots & trunks Oysters & barnacles attach to stems, prop roots Crabs burrow into the mud during low tide & live on prop roots during high tide Mudskippers live in burrows in mud Sheltered waters of roots provide a nursery & haven for larvae / young of many species

Global warming potential (GWP): What is it? Give values for N2O and CH4.

Measure of the energy absorbed by various gases relative to CO2 • capacity for different gases to contribute to warming Over one year, CH4 GWP is 12.4x, and N2O is 121x. For 20 years, CH4 is 84x, N2O is 264x. For 100 years, CH4 is 28x, N2O is 265x.

Mineral vs. organic fertilizers

Mineral doesn't rely on microbial activity to work, but organic does Organic might take longer for nutrients to go into the soil and be less economic. You may have to apply more organic fertilizer to get the same amount of nutrients.

Bogs and Fens in Australia

Mires dependent on precipitation for water supply/nutrients & dominated by Sphagnum are bogs Mires fed by groundwater (source of nutrients) form fens dominated by sedges

Describe mixed species plantation forests.

Mixed species plantation forests have highest species diversity of plantations Polyculture Mixed species plantation tend to grow faster, are more pest resistant, ecologically more valuable Agroforestry is a form of mixed species plantation (Coffee/cacao in Casuarinas)

What is the effect of aeration on decomposition?

Most microbial processes are aerobic; increase aeration increases decomposition.

What is the most common water contamination problem?

Most prevalent water quality problem worldwide is eutrophication due to excess nutrient loading Major sources: agricultural runoff, sewage, industrial effluents and atmospheric inputs from the burning of fossil fuels / bush fires N & P are important plant nutrients When transported from landscape to waterways can promote excessive algal growth

What has the highest productivity in aquatic ecosystems? What determines productivity?

Most productive aquatic ecosystems are shallow coastal waters. Photosynthetically active radiation (PAR) declines exponentially with water depth. Coastal waters also highest in nutrients.

Where does energy come from?

Mostly sunlight, some chemical (photosynthesis is the main source of energy in terrestrial ecosystems).

How will we predict the fate of future CO2 emissions? What happens if NPP increases? If NPP decreases?

Must determine how rising CO2 / climate change will influence carbon exchange between the atmosphere and terrestrial ecosystems. If NPP increases and therefore net removal of CO2 --> negative feedback If NPP decreases (or decomposition increases) and therefore net addition of CO2 --> positive feedback

Biological nitrogen fixation

N2 --> organic nitrogen

Denitrification

NO3‐ --> N2O and N2 nitrate to nitrous oxide and nitrogen gas

What is the available energy for autotrophs in an ecosystem?

NPP I = W + A = W + P + R (A = P + R) I = ingestion W = waste A = assimilation P = production R = respiration

What are the advantages of native forest plantations? What is an issue?

Native plantation forests have higher species diversity than pine, but lower than native forest Monoculture Native forest provide habitat and resources for native animals Plant and animal diversity increases with plantation age Tree hollows only form after >150-300 years, but trees are harvested before then

What are keys to forest management?

Native species rather than exotic species (Eucs vs pine) Mixed species rather than single species (polyculture vs monoculture) Leave mature tree with hollows Avoid clearfelling Maintain lifeboat niches (strips/patches) Maintain as much cover/slash on site Encourage controlled burn in sites with frequent natural fires Encourage understory species (Stand structural diversity) at some sites

Inorganic contaminants

Natural and anthropogenic sources of inorganic chemical contaminants, including: Geologic materials Mining & smelting activities Agriculture Wastewater treatment facilities Fossil fuel combustion Industrial activities Waste disposal Warfare Nuclear power generation Others

Can transpiration be estimated?

Need information about vegetation Potential evapotranspiration (PET) Usually measured indirectly

What are the two horizontal provinces within the pelagic zone?

Neritic province: water that overlies continental shelf Oceanic province: water that overlies abyssal plane

What is the difference in the rate between carbon exchange of the atmosphere, surface waters, and land?

Net Ecosystem Productivity (NEP)

Explain NPP as it relates to photosynthesis. Why do plants consume photosynthates?

Net primary production (NPP) = gross primary production (photosynthates) - respiration losses NPP supports hetertrophs (e.g. herbivores) Plants respire approx 50% of their photosynthates

Is there a clear start and end point between primary and secondary succession?

No

Is there ever a climax community?

No; succession is ever present due to disturbance.

What are the steps of regressive succession? What may mask regression?

Nutrient availability decreases - stored in biomass, lost by leaching Competition for water Plant requirement for water and nutrients greater than available resources = regression => Results in vegetation decline (species richness) and favours specialists Frequent fires may mask regression = cyclic renewal of community composition

Why do trees grow faster after a fire? What is the effect of fire and cattle grazing?

Nutrients returned to soils Less competition for light, water and nutrients Removal of pest species Low tree density (open woodland): dense groundcover, fire kills tree seedlings, maintains open woodland, tree bark fire-resistant, old trees not affected Cattle grazing in forest: less groundcover, fire doesn't spread easily, encourages undergrowth (not grazed), causes intense fires and severe damage Rainforest too wet to burn, encroaches wet sclerophyll forest. Burning kills rainforest species but not sclerophyll species. Fire required to maintain sclerophyll forest.

Where does the law of mass apply?

On a global scale. Hard to confirm on a local scale due to storage of nutrients and obscure pools.

TEAM: Why do we have to standardize the number of events? What constitutes a separate event?

One animal may trigger several photos, so we only count photos that are 5 minutes or more apart from each other as events. This way one animal does not skew your data.

Insolation: Season

One year for earth to rotate the sun. One day for earth to rotate on its axis, with a 23.5º tilt. In Jan, the angle of incidence of incoming solar radiation is greater in the southern hemisphere, directly on the tropic of capricorn = more insolation (summer). In the northern hemisphere the angle is less = less insolation, away from tropic of cancer (winter).

What are types of marine ecosystems?

Open water Coastal Saline

What causes red tides? What make up the largest biomass in temperate and tropical oceans?

Open-water autotrophs Dinoflagellates live in regions of downwelling, concentrate near surface in areas of low turbulence Dinoflagellates cause "red tides" when concentrated (right) Diatoms dominate regions of upwelling Downwelling occurs when winds cause surface waters to converge, pushing surface water downwards Dinoflagellates tend to converge near the ocean surface in areas in areas of downwelling and may colour the water red or brown Often toxic to vertebrates Can make shellfish unsafe for human consumption Nanoplankton make up largest biomass in temperate & tropical ocean waters Cyanobacteria Haptophytes: photosynthetic algae Coccolithophores (right): major source of primary production

Peatlands/Mires

Organic matter is produced faster than it can be decomposed in peat environments -Generally form under oligotrophic or dystrophic conditions -Found in tropical & subtropical as well as boreal regions Peatlands or mires are wetlands characterized by accumulation of organic matter -Mires fed by groundwater (source of nutrients) form fens dominated by sedges -Mires dependent on precipitation for water supply/nutrients & dominated by Sphagnum are bogs Blanket mires & raised bogs (moors) are mires that develop in upland situations Peat mat becomes its own reservoir of water, forming perched water table -Decomposed, compressed peat forms a barrier to downward movement of water, a perched water table

Decomposition and ammonification

Organic nitrogen --> NH4

Describe stratification of lakes

Oxygen, temperature, & light varies with depth strongly influences distribution & adaptations of life in lakes & ponds Horizontal stratification: • Littoral zone: shallow-water zone in which light reaches bottom. Aquatic life is the most rich and abundant here. Emergent vegetation dominate shallow areas, anchor in bottom sediments. Floating plants are present. Also Zooplankton & microcrustaceans, invertebrates (snails, dragonflies), Vertebrates (fish, birds). • Limnetic zone: open water that extends to depth of light penetration. Habitat of plankton & free-swimming organisms (nekton) such as fish. Floating plants dominate the deeper, open water. Submerged plants live in depths too great for floating plants. -photosynthesis primarily in limnetic zone -Phytoplankton (autotrophs) are primary producers in open-water ecosystems - main form of phytosynthetic life in limnetic zone - Zooplankton (heterotrophs) feed on phytoplankton, form important link in energy flow in limnetic zone -Fish comprise most free-swimming organisms in limnetic zone

How does the P, N and C composition change down the chronosequence?

P starts high then decreases due to leaching (highly tied to soil) N increases due to nitrogen fixing bacteria in plants esp. legumes C increases and then decreases

Soil and landscape dynamics as abiotic factors: What is parent material? What are the types of parent material?

Parent material is the geological material that weathers to soil Igneous: from fire (volcanoes, granite, basalt) Sedimentary: from pressure (sandstone, mudstone) Metamorphic: from heat and pressure (igneous or sedimentary such as schist and limestone changes to marble). Soil formation is a slow process!

What are the types of camera traps?

Passive - no bait Baited Standardized - same fields of view (vertical is best, but horizontal can also be used if you put a screen behind it). Targeted - target one species with a door or burrow

What are concerns of organic contaminants?

Personal care products and pharmaceuticals represent emerging water quality concern E.g. birth control pills, painkillers & antibiotics Long-term impacts on ecosystems is unclear Many organic chemicals in personal care products & pharmaceuticals mimic natural hormones Can disrupt an organism's endocrine system Studies have documented feminisation of male fish in waters affected by endocrine disrupting chemicals

What is the photic zone? Aphotic zone?

Photic- Limnetic or littoral zone (top layer) where photosynthesis takes place. Aphotic- Profundal zone: respiration = photosynthesis

Photosynthesis: what is it conducted by, what does it transform?

Photosynthesis is conducted by photoautotrophs Photosynthesis consists of chemical and energy transformation: • Radiant energy is transformed into chemical energy (energy transformation) • Chemical compounds are transformed to new products (chemical transformation) Plants produce chemical energy (i.e. photosynthates) from light energy (= gross primary production) Plants both produce phytosynthates and consume photosynthates

How is water quality assessed?

Physical characteristics e.g. temperature, TSS, turbidity, odour, colour Chemical characteristics e.g. pH, EC, DO, nutrient concentration (particularly N & P), BOD, & respective concentrations of a range of pesticides and other organic compounds, metals/metalloids, & radon; Microbiological characteristics e.g. faecal coliform & other harmful bacteria (Pseudomonas, Klebsiella & Legionella spp.), viruses, pathogenic protozoans (Cryptosporidium & Giardia spp., Naeglaria fowleri), some mycobacteria, & helminths (nematodes, e.g. Trichurus spp) Biological characteristics e.g. relative abundance of selected macroinvertebrates (mayfly, stonefly, caddisfly), fish, & plants

How are coastal wetlands physically important?

Physical importance Protection of coastlines from the erosive effects of storms and extreme tides. Traps and binds sediment aiding in the process of land making. Hydrologic support - water quality and maintenance of groundwater.

How do you measure terrestrial ecosystem productivity? What drives productivity? What has the greatest productivity?

Plant biomass NPP = GPP - R Ecosystem level NEP = GPP - R (ecosystem) = GPP - R (plants + consumers) = NPP - R (consumers) Water and heat drive productivity Tropics have the highest productivity

What is the difference between a forest, woodland and plantation?

Plantation = planted trees, not naturally established. Often involves site preparation, fixed planting density, ongoing management. Single species Forest = woodland consisting of single stemmed trees > 2 m tall with >20% canopy cover Can be natural or plantation Canopy density distinguishes woodland from forest Many different classification systems for forests, e.g. based on tree height, climate, dominant tree type, canopy cover Woodland: 20-50% canopy closure Open forest: 50-80% canopy cover Closed forest: > 70% canopy cover

How does nutrient cycling in plants and animals occur?

Plants (retranslocation): Mobile elements are moved from old leaves to young leaves, Old leaves shed Animals (resorption): Minerals are resorbed by kidneys and intestines Faeces produced

How are plants affected by climate change?

Plants respond to CO2 levels. In Western USA, tree mortality increased in parallel with droughts. Eastern USA Mesic forests; trees growing faster due to increase in growing season length. In Costa Rican tropical rainforests, growth rates of 6 tree species are declining due to an increase in nighttime temperatures (increased respiration).

Where do plants and animals obtain nutrients from?

Plants: atmosphere, water Animals: food and water • Available nutrients are not the same as total nutrients • Most essential elements have limited availability • Nutrient recycling essential • Nutrients can be stored

What type of soil is at Cooloola?

Podzols that start with beach sand (silica/quartz), and as plants root in the sand, their organic material decomposes and forms humus.

Point source vs. non-point source

Point source - a single, identifiable source of pollutants such as a pipe or drain Can also include pollutants contributed by tributaries to receiving water body Non-point source - pollutants originating from multiple sources over a relatively large area Sometimes referred to as 'diffuse' pollution

What does the exponential growth model describe?

Population growth in an idealised, unlimited environment •It is useful to study population growth in an idealised situation •Idealised situations help us understand the capacity of species to increase and the conditions that may facilitate this growth

What is exponential growth? What is rmax equal to under these conditions? What does an exponential growth curve look like? What happens if you change the instantaneous growth rate?

Population increase under idealised conditions. •Under these conditions, the rate of increase is at its maximum, denoted as rmax •The equation of exponential population growth is dN/dt = rmax*N The curve is J-shaped (on a graph of population size vs. number of generations). If you decrease r(inst), the curve moves to the right and it is less steep; it takes more generations or more time to reach the maximum population size.

Describe feedbacks to climate warming

Positive feedback: • ice-albedo: ice caps and sheets melt, less light is reflected and more light is absorbed, leading to an increase in warming • Arctic methane: permafrost melts, releasing stored CH4, increasing warming • Forest fires: decreased rainfall and increased drought leads to increase in biomass from burning/emissions, causing warming Negative feedback: • Water vapor: more evaporation and more clouds reflect light, leading to cooling If the net value is positive, warming is the result.

What triggers lyngbya blooms?

Possible causes: Anthropogenic sources (pollution/runoff) Warming of water Land-use change Pollution/Runoff most likely cause

How can runoff be estimated?

Precipitation less Potential Evaporation P - PE = estimated runoff P-PE > 0, leaching/runoff P-PE < 0, no runoff, water stress

What limits primary productivity in marine environments?

Primary productivity in marine environments limited to regions where availability of light & nutrients can support photosynthesis, plant / algal growth Shallower waters of photic zone Thermocline prevents nutrient movement from deeper to surface waters Rate at which nutrients are returned to surface, & thus productivity, is controlled by: Seasonal breakdown of thermocline & subsequent turnover Upwelling of deeper nutrient-rich waters to surface Coastal regions exhibit highest productivity Shallower waters (continental shelf) have increased vertical mixing from turbulence and seasonal turnover Coastal upwelling brings deep, nutrient-rich water to surface

Iteroparity/ Repeated reproduction

Produce offspring repeatedly

Turbidity

Quantity of sediment in water can be determined by measuring the turbidity, or quantity of solid particles that are suspended in water causing light rays shining through the water to scatter Turbidity makes water appear cloudy or even opaque in extreme cases Measured in nephelometric turbidity units (NTU) In Australia, drinking water quality guidelines specify aesthetic guideline value of 5 NTU & target value of <1 NTU for effective disinfection

What types of coastal storms occur? What do they affect?

Rainfall Heavy, frequent Cyclone Tsunami Storm surge (+ high tide) Dam failure Topography Water infiltration Vegetative cover Surface retention Land use

Forest Types

Rainforest -tall closed forest -canopy cover >70% -tree height >30m -climate >1000 mm rainfall -climbers, palms, ferns, trees, epiphytes -understory poorly developed -dense canopy, little groundcover Wet Sclerophyll -tall open forest -canopy cover 50-80% -tree height >30m -climate >1000 mm rainfall -eucalypts, tree ferns -understory complex, RF species Dry Sclerophyll -open forest -canopy cover 50-80% -tree height 10-30m -climate >1000 mm rainfall -eucalypts -understory shrubs and grasses -fire resistant Woodland -open woodland -canopy cover 20-50% -tree height 2-30m -climate <1000 mm rainfall -eucalypts or acacia -understory shrubs and grasses -fire resistant

Explain the fire resistance of each type of forest and how regeneration occurs.

Rainforest: densely spaced tress and moist all year, so species are not fire resistant. Little groundcover so fire doesn't spread very well. Fire converts it to wet sclerophyll. Regenerates when trees fall. Seeds have short viability, no seed bank is present. Wet sclerophyll forest: Leathery leaves that are not fire resistant, but it needs fire to regenerate, otherwise it converts to a rainforest. With frequent fires, converts to dry sclerophyll. Seed growth is best after fire; light exposed, ash has nutrients. Dry sclerophyll: trees are less tall and they have lignotubers and epicormic roots for fire resistance. Seed germination does not require fire and there is a continuous supply of seedlings. Open woodland: Least canopy cover, understory has shrubs and grass. Seedling recruitment only during wet years. Fire resistant. No fire is required for regeneration, so there are various age groups of trees.

What are characteristics of mangroves?

Range from short forms to timber-size trees 30 meters tall All have shallow, widely spreading roots Tangle of prop roots & pneumatophores slows tidal waters, allowing sediments to deposit -Prop roots provide support -Pneumatophores take in oxygen

What are the requirements to revegetate a roadside or mine site? What is the requirement for seed mixes in QLD?

Re-establish a native ecosystem Limit erosion Self sustaining Cheap 5 Acacia species, 3 tree species, 2 shrub species, 3 perennial grasses, 2 legumes, optional groundcover

Age structure

Relative number of individuals at each age. Can be used to predict a population's growth rate trends and help plan for the future.

Secondary succession

Replacement of existing vegetation - plants and grasses, bushes, shrubs and small trees, forest

Hydrologic cycle

Represents circulation of water & links all aquatic ecosystems. Evaporation, condensation, and precipitation. • Water evaporated from oceans condenses in clouds, forming precipitation which falls on land then either evaporates, runs off, or infiltrates into soils • Runoff follows a path determined by geomorphology, flowing from streams to rivers -May collect in basins or floodplains to form ponds, lakes, inland waterways • Rivers eventually flow to estuaries & then into oceans

Semelparity/Big Bang Reproduction

Reproduce once and die

What are types of freshwater wetlands?

Riverine (river) Palustrine (swamp) Lacustrine (lake)

Riverine

Rivers and streams

How do rivers and streams originate?

Rivers and streams originate from water catchments Rivers start upland as small creeks: Fast flow, low volume, erosion, no deposition of sediment Lowland river by confluence of creeks: Slow flow, larger volume, little erosion, deposition of sediment Stream order increase with complexity of river

What is the main source of river water? How does water force differ between rivers, lakes and estuaries?

Runoff Direction, fluctuation, residence time Rivers have unidirectional and horizontal movement with gravitational water forces. Water residence time is days-weeks. Runoff is the source, stratification is rare, and transparency is low. Estuaries are bidirectional and horizontal, with tidal water forces. Variable fluctuations with residence time of weeks-months. Runoff, marine, precipitation water sources. Stratification is common (salinity) and transparency is variable. Lakes have vertical movement and wind-induced forces, with small/seasonal water level fluctuations. Residence time is months-years, and sources are runoff and groundwater. Stratification is common (thermal). Transparency is high (algae, dissolved color).

What physical feature has the most influence on organismal distribution in estuaries?

Salinity Estuarine organisms must maintain position & adjust to changing salinity Many inhabit benthos, attach themselves to bottom, bury in mud Mobile inhabitants can swim against or move with tide Planktonic organisms are at mercy of currents, can be swept out to sea Most estuarine species are fully marine and cannot withstand lower salinities Sessile / slightly motile organisms have optimum salinity range When salinities exceed optimum range in either direction populations decline

What else affects water density?

Salinity and suspended particles can also affect water density Warm water may remain at a depth below cooler water if the warm water has a high salt concentration Example: shallow lakes with salt water concentrated by evaporation on Rottnest Island Inversely stratified for part of the year - rainfall runoff overlies warmer but highly dense salt water

Where do salt marshes occur? How are they determined?

Salt or tidal marshes occur where coastlines are protected from wave action, in tropical areas dominated by mangroves Within estuaries & deltas, by barrier islands & dunes Salt marsh structure determined by salinity Complex of distinctive, demarcated plant communities

What are salt pans?

Salt pans are depressions that are flooded at high tide; at low tide they stay filled with saltwater If pans are shallow enough water may completely evaporate, leaving concentrated salt Salt pans are interspersed among meandering creeks that carry tidal waters back to sea Exposed banks of creeks have dense populations of mud algae, diatoms, & dinoflagellates that photosynthesize year-round

What are some coastal wetland plants?

Saltgrass Suaeda Samphires Reeds Casuarinas Mangroves

Marine

Saltwater/oceans

Describe sand and muddy shores. How do they develop?

Sandy shores develop via weathering of rock inland & along shore, carried by rivers and waves then deposited as sand along ocean shore Size of the sand particles deposited influences nature of beach, including -Water retention during low tide -Ability of animals to burrow through it Mudflats develop in sheltered areas of the coast where outgoing tidal currents are slow & leave behind a residue of organic material

How do lakes originate?

Sediment damming up water behind them (oxbow lakes, pools, billabongs) Human activity (Dams, quarries, & surface mines) Craters of extinct volcanoes Glacial erosion and deposition (tarns)

Which environments favor which type of reproduction?

Semelparity favored in unpredictable environments, iteroparity favored in more stable environments.

How does turbidity stratification occur?

Shallow waters with high conc. of suspended particulates may stratify Rapid temperature change within few centimetres' depth Result of heat absorption by particles / dark-coloured dissolved materials near surface Many Australian waterbodies are shallow & turbid Stratification due to turbidity may be more common than classical thermal stratification model described in most textbooks

What are the aquatic invertebrate feeding groups?

Shredders: feed on bacteria/fungi growing on CPOM (CPOM > 1 mm diameter) & break down material Filtering & gathering collectors: feed on FPOM (0.45 um< FPOM < 1 mm) produced by shredders Grazers: feed on the algal coating of substrates Gougers: burrow into waterlogged fallen trees Predatory insect larvae & fish: feed on grazers & detrital feeders

What two approaches are there to conservation?

Small population approach and declining population approach

What might uniform dispersion be influenced by?

Social interactions such as territoriality, the defense of a bounded space against other individuals.

What are controlling factors for NPP?

Soil nutrients Temperature Precipitation Photosynthetic period Pest pressure Photosynthetic pathway

Greenhouse effect

Solar energy absorbed by the atmosphere

What are two main climatic factors correlated with biodiversity?

Solar energy and water availability • They can be considered together by measuring a community's rate of evapotranspiration

Albedo

Solar energy reflected back into the atmosphere

Oxygen as an environmental factor: what is its solubility in water? What is the issue with it? Plant and animal adaptations?

Solubility of oxygen in water is low Concentration of oxygen in atmosphere is higher. Oxygen is toxic (free radicals) Oxygen is required for ozone Catch 22 - what is more toxic: oxygen or ozone? Plant: produce O2, photosynthesis to produce O2, metabolic machinery to detoxify O2 Animal: consumer O2, lungs/gills, detoxify O2

What are the effects when coastal wetland ecosystems are lost?

Sometimes referred to as environment's "kidneys", wetlands store freshwater & nutrients, trap sediments before entering marine environment Losses of coastal wetlands have a pronounced effect on salt marshes & estuarine ecosystems Many economically important organisms are negatively impacted Fish, prawns, oysters, crabs, etc. >75% of fish species require estuarine wetlands to complete life cycle Important habitat for migratory waterfowl

What are the steps in progressive succession?

Species diversity increases N and P content increase in soil Number of trees increases Vegetation height increases Soil profile development increases

Species diversity

Species diversity is the variety of species in an ecosystem or throughout the biosphere • The Commonwealth Environment Protection and Biodiversity Conservation Act 1999 defines six different levels of threatened species - Extinct - Extinct in the wild - Critically endangered - Endangered - Vulnerable - Conservation dependent

How do water quality standards of drinking water and water used for agriculture, recreation, etc. differ?

Standards are higher for drinking water

Stream order

Streams become larger on course to rivers, joined along way by many other streams Classified according to stream order Stream order only increases when streams of the same order merge First order: small headwater stream with no tributaries Second order: two first order streams join Third order: two second order streams join With increasing order number: Decreased slope Function change, erosive → depositional

How can you further classify the ecosystem types?

Substrate Depth & flow of water Type of dominant organisms

Ecological footprint

Summarises the aggregate land and water area needed to sustain the people of a nation •It is one measure of how close we are to the carrying capacity of Earth •Countries vary greatly in footprint size and available ecological capacity

What is the importance of aquatic ecosystems?

Support biodiversity and wildlife habitat Support biological productivity (fisheries/aquaculture) Water supply Recreation Electricity generation Climate regulation Flood control Transportation

What are the zones of rocky shorelines?

Supralittoral or supertidal (spray) zone -Gradual transition from lichens & land plants to marine life that is somewhat dependent on tidal waters -Supralittoral fringe Where saltwater comes only once every two weeks on spring tides Marked by black zone, named for thin black layer of cyanobacteria growing on rocks with lichens & green algae above high-tide line Essentially a non-marine community Littoral or intertidal zone zone -Covered / uncovered daily by tides Barnacles most abundant in the upper reaches Oysters, blue mussels, limpets, and common periwinkle (also found in the black zone) live in middle & lower portions of littoral zone Brown algae (rockweeds) occupy lower half of littoral zone (may be replaced by blue mussels if the surface is covered with sand/mud) -Infralittoral fringe Lowest part of littoral zone Uncovered only at spring tides & exposed for only short periods of time Consists of forests of large brown alga (Laminaria) Small plants & animals live among its holdfasts Infralittoral or subtidal -open water

What are stream quality measures?

Temperature Flowrate Sediment load (turbidity) Aeration (dissolved oxygen) pH Salt (electrical conductivity) Nutrients (N, P) Rivers are never stratified due to mixing

What are the most important determinants of climate type?

Temperature and precipitation. Others: insolation, cloud cover, air masses, atmospheric pressure, winds.

Compared to rocky shore species, organisms living in sandy/muddy beaches experience minimal fluctuations in what?

Temperature, because a few centimeters below surface sand temperature remains almost constant throughout year Sand surface temperature may be much higher during the day Salinity, because at 25+ cm depth salinity is little affected, even if freshwater runs over surface

Long-term NPP (temporal variations)

Temporal effects of: • climate (temp/rainfall) • age effects on GPP (photosynthesis) controls NPP in terrestrial ecosystem

Characteristics of terrestrial wetlands

Terrestrial wetlands are transitional zone between freshwater & land - Cover 6% of Earth's surface, found in every climatic zone - Most are local in occurrence Wetlands range along a gradient from permanently flooded to periodically saturated soil

Terrestrial vs Aquatic ecosystem nutrient cycling

Terrestrial: due to plant uptake Aquatic: due to wind and temperature mixing

What has been the belief regarding large mammals and their population stability over time? What population cycle has been observed?

That large mammal populations remain stable over time, but this has been challenged by long-term studies. Boom and bust population cycles have been observed. Lynx populations follow the 10 year boom and bust cycle of hare populations.

Earth's energy budget

The balance of incoming short‐ wave (high energy, high temperature, high radiation) and outgoing long‐wave (low energy, low temperature, low radiation) radiation. Largely determines Earth's climate.

What is the logistic growth curve shaped like? What is an example of an organism that follows this curve?

The curve is sigmoid (s-shaped) • The growth of laboratory populations of paramecia fits an S-shaped curve • These organisms are grown in a constant environment lacking predators and competitors Some populations overshoot K before stabilizing their density.

Energy

The driver of climate systems and weather. Radiation balance drives atmospheric circulation and oceanic circulation.

Coriolis Effect: how is air and water deflected, and where is deflection the strongest?

The earth rotates beneath moving air and water. Air and water are deflected to the RIGHT in the NORTHERN hemisphere and to the LEFT in the SOUTHERN hemisphere. Deflection is strongest at the poles, weaker at the equator.

What causes the ITCZ to move?

The earth's tilt and solar orbit. In the S hemisphere in winter, the ITCZ is N of the equator. In autumn and spring, ITCZ is at the equator. In summer, it is S of the equator.

Hadley cells

The key to understanding wind cells. Intense heating at the equator causes air to rise and pressure to be low at the Inter-Tropical Convergence Zone. The hot air is pushed towards the poles and sinks to the surface again at 30º N and S, creating subtropical high pressure belts. Air returns back to the ITCZ as trade winds, deflected by the coriolis effect from NE in N hemisphere and from SE in S hemisphere. On the pole-ward side of the subtropical high pressure belts, the coriolis effect turns diverging air into a westerly wind, creating the 30-60º N and S Mid-latitude Westerlies (weather systems move W to E). Over the poles, cold air forms high pressure systems.

Temperature: Latitude

The most important factor affecting temperature. Solar rays are concentrated at the equator and spread out over a larger area at the poles so the poles are cooler. Influences day length: equatorial regions constant, poles have large differences in day length. In Jan, coldest in Siberia, N. Canada, Greenland, and warmest in S. Africa and Central Australia. Oceans are warmer than water in the N hemisphere. In July, N. hemisphere continents warmed, S. hemisphere not very cold (except Antarctica) in winter. Greatest temperature ranges in continental regions, smallest in equatorial regions due to maritime influence.

Density

The number of individuals per unit area or volume.

Dispersion

The pattern of spacing among individuals within the boundaries of the population

Demography

The study of the vital statistics of a population and how they change over time Death rates and birth rates are of particular interest to demographers

What is phenology? How is it affected by climate change?

The timing of seasonal activities (migration, reproduction, hibernation). Activities that once took place in the spring now occur earlier. Ex. Great Tits of the UK now lay eggs 14 days earlier than they did in the 1960's. Onset of reproduction depends on temperatures in the period before egg laying. As the index of Spring warmth increases, the egg laying date becomes earlier. Shifts in phenology are larger at higher latitudes. Amphibians shifted toward early breeding times more than other taxonomic groups. Butterfly emergence/migratory arrival advanced 3x faster than the first herbaceous plant flowering- impacts plant/insect interactions.

Insolation: What is it and what is it influenced by?

The total amount of solar radiation energy received on a given surface area during a given time period. Influenced by: Latitude, atmospheric composition (aerosols), presence of clouds (height, thickness, temp), season (orbital position of the earth relative to the sun), surface type (water vs. soil) and albedo.

Ecological niche

The total of a species' use of biotic and abiotic resources, or that organism's ecological role. Ecologically similar species can coexist in a community if there are one or more significant differences in their niches.

How can we improve our predictions? Describe the types of studies.

There are 2 major sources of uncertainty; poor understanding of factors controlling distribution and abundance of species, and of how climate in a given region will change in response to increased GHG's. Two types of studies: 1. Examine response of systems to experimental warming and associated environmental factors (manipulation experiments). 2. Use models of ecological systems to evaluate the response to future climate scenarios Studies show response to warming but these are done over only a short period of time. Comparison between studies is difficult because of the diverse techniques used to produce warming experimentally.

Ocean circulation and energy movement: What is the major driving force of ocean currents?

There is a close relationship between atmospheric (wind patterns) and ocean circulation (currents). The major driving force of ocean currents is wind blowing over the ocean surface. Ocean currents reflect average wind conditions over a period of years and are modified by presence of land. Pole‐ward‐moving currents on the western‐sides of oceans (i.e. eastern coasts of landmasses) carry warm water towards the poles. Equator‐ward‐moving currents on the eastern‐sides of oceans (i.e. western coasts of landmasses) carry cool water towards the equator Therefore, oceans transfer energy from equatorial regions to the poles.

How are ectotherms affected by temperature?

They are directly affected by temperature, and their metabolism rises exponentially with temperature. Warming may have a larger impact on ectotherm metabolism in a warm environment (tropics and N temperate zone, not the Arctic) because even though an increase may be small, the environment was already warm. Increased metabolic rate increases demand for food and makes them more vulnerable to starvation. It also reduces energy allocated for reproduction.

What do landscapes consist of? How do they vary? What do they affect?

They consist of patches, which vary in size, shape, and connectivity. Patches affect habitat size, species richness, and extinction Corridors can be engineered

Global climatic zones: what do climatic regions reflect, and what are the types of climatic zones?

They reflect geographic position, proximity to oceans, altitude, and origin of prevailing air masses. 1. low- latitude climates (close to equator) 2. mid- latitude climates 3. high-latitude climates (close to poles)

How can we regulate the human population?

Through social changes. -female fertility reduced by contraception, birth later in life -children less focused on survival and more on trades -education -sexual selection based on income/wealth, intelligence, education, kindness

Moisture: 3 precipitation patterns?

Timing of precipitation during the year is the key to climate. 1. Uniform throughout the year (ex. Singapore) 2. Max during the summer (ex. Harbin, China, Cairns) 3. Max during the winter (ex. Palermo)

What is a walktest used for?

To position the camera (it shows a red light when it detects movement). Use this to make sure your detection zone is set where you want it.

How high do you set a camera? Which direction should you face it?

To the core body mass of the animal (ex. dog is 50 cm at the shoulder). 1-1.5 m for small species, 2-3 m for medium, 5+ m for road surveys targeting carnivores. Face South if possible.

How is precipitation measured?

Traditionally measured using various types of rain gauges Can also use radar to measure rainfall rate Useful to measure rainfall over large areas without dense network of gauges

What determines presence of species?

Transient presence (e.g migratory animals, fire) Environmental conditions (Climate) Breeding sites Competition (predation) Disease pressures

Intertidal zone

Transition between terrestrial & marine environments Intertidal region is bound on one side by height of extreme high tide & on other by height of extreme low tide Conditions within boundaries change hourly with ebb/flow of tides At high tide aquatic, at low tide terrestrial Seashore inhabitants are essentially marine organisms adapted to withstand some degree of exposure to air for varying periods of time Temperature fluctuations, solar radiation, desiccation

What are Australia's major biomes?

Tropical grasslands, shrublands Tropical forests Subtropical and temperate forests Deserts and dry shrublands Temperate grasslands and shrublands Mediterranean forests and shrublands

How does productivity vary in marine environments?

Tropical open waters are low in productivity because the thermocline is essentially permanent, slowing upward movement of nutrients Phytoplankton growth is fairly constant, controlled by the cycling of nutrients in the photic zone Antarctic waters have high productivity because of the continuous upwelling of nutrient-rich water around the continent Growing season is limited by short summer Temperate ocean productivity is strongly related to seasonal variation in nutrient supply, driven by seasonal changes in the thermocline

How is carbon distributed in ecosystems?

Tropical: C breaks down quicker than it is formed, above and below ground biomass is even. Boreal: most C below ground

High-latitude climates

Tundra/Arctic/Antarctic • Very low temps • No true summer • Little precipitation

What is carbon turnover? How long does it take?

Turn‐over = complete replenishment of element in a pool • Marine biota C turns over every 2‐3 weeks • Atmospheric C (primarily CO2) turns over every 3‐4 years • Vegetation C turns over in 11 years • Soil C turns over in 25 years • Rock & sediments C turns over in millions of years

Trophic state progression

Under natural conditions, trophic progression (oligotrophic → eutrophic) requires centuries Artificial eutrophication accelerates process to a scale of years

When would you use a white flash vs. IR camera?

Use WF when you need to ID an animal with different colors (especially at night). It can startle some animals. Use IR if you want to use it near roads. It doesn't startle animals and the battery lasts longer. It also has a faster shutter speed.

Describe headwater streams (1st to 3rd order)

Usually swift, cold, & in shaded forest regions Low primary productivity Dependent on terrestrial input of detritus, >90% of OM input Dominant organisms = shredders & collectors Grazers minimal as result of low autotrophic production Predators mostly small fish Ratio of GPP to respiration <1

Primary succession

Vegetation development on parent material (soil development) - bare rocks, mosses and lichens, plants and grasses

What are vertical cameras better for? What about horizontal cameras?

Vertical are best for smaller animals. Horizontal are best for larger animals.

Insolation: Atmospheric composition

Volcanic ash. dust, and sulfur dioxide (smog)

Describe the human population growth rate.

Was stable until 1650, then took off. It started slowing in the 1960's. The global population is now over 7 billion.

Temperature: Coastal vs. Continental

Water has an important influence on surface temperatures. Water and land have different thermal properties and influence the energy budget. Water has a moderating effect on the coast, while inland areas that are a greater distance from the ocean have greater temperature variation.

When is water most dense?

Water is most dense at 4 deg. C In temperate Australia differences in density of water along vertical water column are minor In tropical Australia high air temp. & water temp. >30 deg. C may result in substantial differences in water density Stratified waterbodies in tropical regions typically have a shallow epilimnion Require more energy to mix stratified layers compared to waterbodies in temperate regions

Water as an environmental factor: Why is it essential? Plant and animal adaptations?

Water required for maintenance of turgor In aquatic ecosystems, water is non-limiting In terrestrial ecosystems, water can be limiting or in excess Plant: cuticle, specialized root systems, osmotic adjustment, specialized stomates Animal: drinking, collecting dew

The rate at which water flows through stream channel influences what?

Water temperature O2 content Rate of nutrient spiraling Physical structure of benthic environment Organisms living in the stream

River Red Gum Forests

Waterbird breeding sites, important native fish habitat Feeding, breeding & nursery habitat for native frogs (+ crayfish, turtles) Ecological objectives include improvement & maintenance of river red gum forests, wetlands & floodplain vegetation communities Ramsar-listed wetlands of international importance esp. waterfowl

Weather vs. Climate

Weather is short term meteorological events and is a combination of temperature, precipitation, wind, cloudiness, atmospheric conditions. Climate is long term atmospheric conditions at a local, regional and global level.

Low-latitude climates

Wet Equatorial • 10ºN to 10ºS • Warm all year (ITCZ) • Annual water surplus • Rainfall often > 2500 mm • Tropical rainforests Wet-dry tropical • 5‐30º N & S • Wet and dry seasons • On periphery of ITCZ • When ITCZ moves further away climate becomes dominated by the STR, hence the dry season • Drought‐resistant plants Dry tropical • Climate is dominated by the STR • Larger temperature range (proximity to water bodies, clear skies allows intense heating) • Arid and semi‐arid

How are wetland habitats lost?

Why drain, clear or fill wetlands? Land for crop production Landowners may consider wetlands an economic liability (no return & little tax revenue) Wildlife supported by wetlands may threaten crops (Urban) development River regulation/water diversion Excavated for fuel, peat, soil >80% of Australians live within 50 km of coastline Coastal wetlands are threatened & disappearing rapidly >60% of original coastal & near-coastal wetlands in NSW have been cleared, drained or filled 70-80% of all wetlands in southwest WA have been cleared, drained or filled

What are risks to soils?

Wind and water erosion Soil acidification Nutrient rundown Soil contamination Soil salinization

How does vegetation and diversity change across a salt marsh?

Zones of distinctive vegetation reflect microtopography -Seaward edge has salt-tolerant vegetation forming strip between open mud to high marsh behind (Hollow tubes from leaf to root for oxygen diffusion) -High marsh stands at level of mean high water & supports grasses, herbs, reeds, sedges, shrubs -Salt marsh diversity increases with increasing latitude (differs from mangrove diversity which is highest in lower latitudes of tropics)

Movement corridor

a narrow strip of quality habitat connecting otherwise isolated patches •Movement corridors promote dispersal and help sustain populations •In areas of heavy human use, artificial corridors are sometimes constructed

Batesian Mimicry

a palatable or harmless species mimics an unpalatable or harmful species

Symbiosis

a relationship where two or more species live in direct and intimate contact with one another. Includes parasitism, mutualism, commensalism.

Biodiversity hot spot

a relatively small area with a great concentration of endemic species and many endangered and threatened species •Biodiversity hot spots are good choices for nature reserves, but identifying them is not always easy •Designation of hot spots is often biased toward saving vertebrates and plants •Hot spots can change with climate change

Estuaries

a semi-enclosed part of the coastal ocean where freshwater joins saltwater The unidirectional inflow of freshwater streams and rivers interacts with the inflowing/outflowing saltwater tides, setting up a complex of currents that varies with: -Structure of estuary (size, shape, volume) -Season -Tidal oscillations -Winds Mixing of different salinities = nutrient trap Salinity impacts life

What is a chronosequence? Which dunes are the oldest?

a series of sites on the same parent material/environmental conditions that are at different stages of succession (that differ in time since they were formed) Dunes farther from the ocean are larger and older (about 1.5 million y/o as opposed to 40 y/o near the ocean)

Hydrophytic plants: what are they, how are they grouped?

adapted to grow in water or on soil that is periodically anaerobic as a result of excess water Three wetland plant groups: Obligate: require saturated soils (submerged plants, pond lily, emergent cattails & bulrushes) Facultative: can grow in either saturated or upland soil (trees such as River Red Gum, Coolabah, Black Box) Occasional: are usually found outside of wetland environments but can tolerate wetlands Wetlands are delineated by their vegetation If the plant is considered a obligate hydrophyte, the area is a wetland If the area is wet but no obligate hydrophytes present, it is not a wetland but a temporarily flooded land

top-down model

also called the trophic cascade model, proposes that control comes from the trophic level above •In this case, predators control herbivores, which in turn control primary producers

disturbance

an event that changes a community, removes organisms from it, and alters resource availability •Fire is a significant disturbance in most terrestrial ecosystems •A high level of disturbance is the result of a high intensity and high frequency of disturbance

Mutualism

an interspecific interaction that benefits both species •A mutualism can be - Obligate, where one species cannot survive without the other - Facultative, where both species can survive alone

Dominant organism of the pelagic zones?

autotrophs = phytoplankton herbivores = zooplankton Autotrophs restricted to upper surface waters (light availability) Shallow coastal autotrophs Attached algae: brown algae, red algae Open-water autotrophs Phytoplankton absorb nutrients directly from water, small body size gives a greater surface-to-volume ratio Seawater is dense, little need for support structures Littoral & neritic waters, regions of upwelling richer in phytoplankton than mid-oceans

Effective Population Size

based on the population's breeding potential Ne = (4Nf*Nm)/(Nf+Nm) Nf = # females Nm = #males

Secondary succession

begins in an area where soil remains after a disturbance

Density-independent populations

birth rates and death rates don't change with population density

What is the benthic zone?

bottom region & primary place of organic material decomposition Common to littoral & profundal zones

Food web

branching food chain with complex trophic interactions

Cryptic coloration

camouflage, makes prey difficult to spot

Biomanipulation

can help restore polluted communities •In a Finnish lake, blooms of cyanobacteria (primary producers) occurred when zooplankton (primary consumers) were eaten by large populations of roach fish (secondary consumers) •The addition of pike perch (tertiary consumers) controlled roach populations, allowed zooplankton to increase and ended cyanobacterial blooms

What are types of coastal wetlands? Rank these in order of salinity.

coastal freshwater wetland, coastal saltwater wetland salt marshes Coastal freshwater wetland < coastal saltwater wetland < salt marshes < marine ecosystem

In which climates are SOC and biomass C the greatest?

cold = SOC --> low decompostion warm and wet = biomass C --> high productivity

Mature community

complex, more stable

Genetic diversity

comprises genetic variation within a population and between populations

What is instantaneous growth rate?

dN/dt = r(inst)N where rinst is the instantaneous per capita rate of increase

nonequilibrium model

describes communities as constantly changing after being buffeted by disturbances

Riverine wetlands

develop along shallow and periodically flooded banks of rivers and streams - water flow is unidirectional

Basin wetlands

develop in shallow basins, from upland depressions to filled-in lakes and ponds - water flow is vertical

Sustainable development

development that meets the needs of people today without limiting the ability of future generations to meet their needs •The goal of the Sustainable Biosphere Initiative is to define and acquire basic ecological information for responsible development, management, and conservation of Earth's resources • Sustainable development requires connections between life sciences, social sciences, economics, and humanities

Resource partitioning

differentiation of ecological niches, enabling similar species to coexist in a community

Ecosystem Services: give examples

encompass all the processes through which natural ecosystems and their species help sustain human life • Some examples of ecosystem services - Purification of air and water - Detoxification and decomposition of wastes - Cycling of nutrients - Moderation of weather extremes

What does life in the profundal zone depend on?

energy & nutrients from limnetic zone, temperature, & O2 availability O2 may be limiting in lower parts due to depletion during OM decomposition Life is abundant in profundal zone when nutrients & oxygen are available

Net primary production

energy stored after respiration (R)

Evapotranspiration

evaporation of water from soil plus transpiration of water from plants

Keystone species

exert strong control on a community by their ecological roles, or niches • In contrast to dominant species, they are not necessarily abundant in a community • Field studies of sea stars illustrate their role as a keystone species in intertidal communities • Observation of sea otter populations and their predation shows how otters affect ocean communities

Trophic Structure

feeding relationships between organisms in a community •It is a key factor in community dynamics

Population dynamics

focuses on the complex interactions between biotic and abiotic factors that cause variation in population size

Swamps

forested wetlands

Biological magnification

increasing concentration of a harmful substance in organisms at higher trophic levels in a food chain or food web where biomass is lower •PCBs and many pesticides such as DDT are subject to biological magnification in ecosystems •Herring gulls of the Great Lakes lay eggs with PCB levels 5,000 times greater than in phytoplankton

Food chains

link trophic levels from producers to top carnivores

What are the sensitivity settings for a camera trap?

low (for slow animals), low/med, med, med/high high (fast animals)

What is the land use effect with urbanization?

more discharge (more impervious surfaces) shorter lag to peak Flash flooding

What are the quiet period settings? Why is this useful?

no delay, 15 sec, 30 sec, 1 min, 3 min, 5 min. If you set a delay it can reduce the number of photos that you have to go through.

Riparian/bottomland woodlands

occasionally / seasonally flooded by river waters Riparian vegetation crucial to health of freshwater wetlands Slowing down velocity of flood water Increased infiltration of water into soil Trapping of nutrients, sediment and pollutants Organic matter source for food chain Habitat in snags, branches, litter Shading river bank and lowers water temperature Stabilises riverbank (should be at least 50 m wide) Threatened by poor management (vegetation removal, cattle, stream development)

Fringe wetlands

occur along the coasts of large lakes - water flow is in two directions Flows carry nutrients/sediments in and out

Primary succession

occurs where no soil exists when succession begins

What is the flow of a food chain?

primary producers (plants) --> primary consumers (herbivores) --> secondary consumers (carnivore) --> tertiary consumers --> quaternary consumers

Bottom-up model of community organization

proposes a unidirectional influence from lower to higher trophic levels •In this case, presence or absence of mineral nutrients determines community structure, including abundance of primary producers

Dynamic stability hypothesis

proposes that long food chains are less stable than short ones

Area effects: Species-Area Curve

quantifies the idea that, all other factors being equal, a larger geographic area has more species •A species-area curve for forest remnants in north-east New South Wales supports this idea

How is per capita rate of interest calculated? What is it called when r = 0?

r = b - m When r = 0 this is known as zero population growth (ZPG). You can revise the equation to: dN/dt = rN

What are the picture interval options?

rapidfire, wait 1,3,5,10 sec

Tide pools

represent distinct habitats from exposed rock and open sea Conditions within each pool fluctuate widely between high & low tides (changes most marked in shallow pools) -Increase in pool temperature during the day -Salinity may increase (result of evaporation) or decrease (result of freshwater source) -Oxygen may be high during the day & low at night -pH changes in response to CO2 concentration

Conservation biology

seeks to preserve life, integrates several fields - Ecology - Physiology - Molecular biology - Genetics - Evolutionary biology

Pioneer community

simple composition, less stable

What are two factors affecting community structure?

species diversity and feeding relationships

Hundred Heartbeat Club

species with fewer than 100 individuals remaining on earth

Small population approach

studies processes that can make small populations become extinct

Energetic hypothesis

suggests that length is limited by inefficient energy transfer - For example, a producer level consisting of 100 kg of plant material can support about 10 kg of herbivore biomass (the total mass of all individuals in a population) This hypothesis is the most supported

intermediate disturbance hypothesis

suggests that moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance •High levels of disturbance exclude many slow-growing species •Low levels of disturbance allow dominant species to exclude less competitive species

Character displacement

tendency for characteristics to be more divergent in sympatric populations (occur in same area) of two species than in allopatric populations of the same two species. An example is variation in beak size between populations of two species of Galápagos finches

Critical load

the amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity •Nutrients that exceed the critical load leach into groundwater or run off into aquatic ecosystems •Agricultural runoff and sewage lead to phytoplankton blooms in the Atlantic Ocean •Decomposition of phytoplankton blooms causes "dead zones" due to low oxygen levels

What is Human appropriation of terrestrial NPP (HANPP)? Why is it an issue?

the amount of terrestrial NPP required for the food and fiber products used (consumed) by humans This is approximately 20% of terrestrial annual NPP 53% contributed by harvest 40% by land-use-caused productivity changes 7% by human-induced fires Humans comprise about 0.5 percent of the total heterotrophic biomass on Earth

Minimum viable population (MVP)

the minimum population size at which a species can survive •The MVP depends on factors that affect a population's chances for survival over a particular time

Zoned reserve

the model recognises that conservation often involves working in landscapes that are largely human dominated •A zoned reserve includes relatively undisturbed areas and the modified areas that surround them and that serve as buffer zones •Zoned reserves are often established as "conservation areas" •Costa Rica has become a world leader in establishing zoned reserves •Urban ecology examines the conservation of species in the context of cities

Ecological succession

the sequence of community and ecosystem changes after a disturbance Early-arriving species and later-arriving species may be linked in one of three processes - Early arrivals may facilitate appearance of later species by making the environment favourable - They may inhibit establishment of later species - They may tolerate later species but have no impact on their establishment

What is population ecology?

the study of populations in relation to environment, including environmental influences on density and distribution, age structure, and population size

Species diversity

the variety of organisms that make up the community

Dominant species

those that are most abundant or have the highest biomass • Dominant species exert powerful control over the occurrence and distribution of other species - For example, sugar maples have a major impact on shading and soil nutrient availability in eastern North America; this affects the distribution of other plant species •One hypothesis suggests that dominant species are most competitive in exploiting resources •Another hypothesis is that they are most successful at avoiding predators •Invasive species, typically introduced to a new environment by humans, often lack predators or disease

Introduced species

those that humans move from native locations to new geographic regions •Without their native predators, parasites, and pathogens, introduced species may spread rapidly •Introduced species that gain a foothold in a new habitat usually disrupt their adopted community • Sometimes introduced on accident •Humans have deliberately introduced some species with good intentions but disastrous effects - For example, release of the cane toad (Bufo marinus) in Queensland to control sugar cane beetles

Gross Primary Production

total energy produced by primary producer

Zoonotic Pathogens

transferred from other animals to humans •The transfer of pathogens can be direct or through an intermediate species called a vector •Many of today's emerging human diseases are zoonotic • Identifying the community of hosts and vectors for a pathogen can help prevent disease - For example, recent studies identified two species of shrew as the primary hosts of the pathogen for Lyme disease • Avian flu is a highly contagious virus of birds • Ecologists are studying the potential spread of the virus from Asia to North America through migrating birds

Müllerian mimicry

two or more unpalatable species resemble each other

Ecosystem diversity

variety of habitats, living communities, and ecological processes in the living world •More than 50% of wetlands in the contiguous United States have been drained and converted to other ecosystems

Marshes

wetlands dominated by emergent herbaceous vegetation - wet grassland, reeds, sedges, grasses, cattails

Biosphere project

• 12,700m2 closed environment • Contained ocean coral reef, marsh, forest, and farm • Aimed self‐contained, self‐ supporting ecosystem --> failed in 2 years because soil released CO2

Terrestrial biosphere model (Potsdam Institute for Climate Impact Research)

• 5 general circulation models on exchange of C between land and atmosphere • great uncertainty in predicted patterns of carbon exchange due to large differences in climate projections for each model

What is the effect of pH on decomposition?

• All microbial processes are pH sensitive • In acidic or alkaline soil, degradation is slowed and species composition changes

Global Energy balance: Do atmospheric constituents absorb specific wavelengths of energy? Without these gases absorbing energy, what would the temperature on Earth be?

• Atmospheric constituents such as CO2 and water vapour absorb specific wavelengths of energy. • Radiation emitted from Earth is of low intensity in wavelengths that correspond to the absorption wavelengths of these gases • Without these gases the average temperature on Earth would be ‐18ºC • 341 Wm‐2 incoming solar radiation is balanced by 239 Wm‐2 of outgoing long‐ wave and 102 Wm‐2 of reflected solar radiation • Disruption of this balance results in global warming or cooling.

Methods of classifying Australian climatic zones: Temperature/humidity

• Based on a set of definitions relating to summer and winter conditions: • Hot humid summer - Darwin, Cairns • Warm humid summer • Hot dry summer, mild winter • Hot dry summer, cold winter • Warm summer, cold winter • Mild/warm summer, cold winter For example: "Hot humid summer": • average January max temperature ≥ 30°C • average 3pm January water vapour pressure ≥ 2.1 kPa (this is the upper humidity limit for comfort)

Biogeochemical cyles: What is the main factor controlling exchange of Carbon?

• Between atmosphere and surface waters = diffusion • On land = NPP (uptake of carbon) and decomposition (loss of carbon)

How does carbon vary in the atmosphere?

• Biannual fluctuation in CO2 • Vegetation uptake of CO2 in summer • Spatial variability in CO2 at cm scale • Until Industrial Revolution, CO2 concentration was steady • Exponential increase has occurred since then • In 2017, CO2 concentration is 407ppm • Highest in the last 800,000 years • Previously cycled between 200‐325ppm • Concentration of CH4 and HCFCs are small....but, environmental impact is huge compared with CO2 • CH4 = 21 x • HCFCs = 140 - 11700 x

What factors control decomposition and nutrient cycling?

• C:N ratio • lignin content/chitin content • temperature • pH • aeration • water availability • Decomposition experimentally determined by litter bags

What is the effect of the C:N ratio?

• C:N ratio differs for organic matter • Fate of nutrients on OM defined by C:N ratio • High C:N (>33) = N immobilized (ex. plants) • Low C:N (<15) = N mineralised (ex. pig manure) Soil organisms are energy limited 1. Degradation of C in litter for energy Released nitrogen assimilated 2. When microbes run out of energy, they decompose, release N 3. Recalcitrant C left over, + mineral N 1. Plant organic matter High C/N (Litter C, litter N) CO2 emitted 2. Microbial organic matter low C/N (Microbial C and microbial N) CO2 emitted 3. Stable C and mineral N

What will be the effect of climate change on boom-bust cycles and wildfires? What species are the most at risk? What management procedures are possible to alleviate this?

• Climate change will exacerbate boom-bust cycles and wildfires; irruptive rodent species will be at most risk, and then carnivorous marsupials • Vegetation cover may decline due to climate change, the strongest negative effect on prey populations in this desert system is top-down suppression from introduced predators • Management: strategic (time, place) reduction of invasive predators, or increased protection for vulnerable prey - is there a broader role for predator proof shelters in fire-prone landscapes?

What are sources of carbon?

• Combustion of fossil fuels • Respiration • Bushfires • Volcanoes

Soil nitrogen cycle

• Concentration of soil N follows organic matter content • N highest in topsoil, decreases in subsoil • Soil N important for crop growth • Plant available N = ~2% of soil N Gains: fertilizers, legumes, manure add to NH4+, which is converted to NO2-, then NO3-. NO3- is leached, or undergoes denitrification to N2, N2O, NO, NH3. It is also immobilized as organic matter. Losses: animal and plant uptake, gaseous losses

slash and burn agriculture

• Cut down existing vegetation • Burn to release minerals • Plant crops

What are the types of carbon in the ocean? Which type is the most abundant?

• Dissolved organic carbon (DOC) • Dissolved inorganic carbon (DIC) • Particulate organic carbon (POC) 98% of ocean‐C is DIC, which contains 3 forms: • Bicarbonate (HCO3‐) ~ 90% • Carbonate (CO32‐) ~9% • Free CO2 <1% • Composition of these forms are pH dependant

How have anthropogenic effects contributed to carbon in the atmosphere?

• Effects of human activities are evident • Fossil fuel combustion • Cement production • Deforestation Caused by • More anthropogenic CO2 emission in northern hemisphere • More CO2 sink in northern hemisphere reduce the difference between north and south Until mid‐20th century • Forest harvesting • Conversion to agricultural land • Frequent wildfire --> reduce carbon sink Late‐20th century • Regrowth of 2nd generation trees in forest • Abandoned agricultural lands • Suppression of wildfire --> increase carbon sink

What are the environmental impacts of P in fertilizer?

• Eutrophication - High concentration of P induce large biomass of algae in aquatic ecosystems It is difficult to remove P from wastewater. • Major bloom of cyanobacteria (turn water colour to green) occurred at the Barwon‐Darling river in late 1991 • Cause of the bloom was • Low water flow • High total phosphate concentration

Carbon in terrestrial ecosystems

• GPP (gross primary productivity) = photosynthesis (biological C‐fixation) • NPP (net primary productivity) = GPP - respiration • NPP = Δ biomass + litter • Δ litter = ? (complicated) • soil OM, soil C & respiration...

What are forms of nitrogen?

• Gaseous form - N2O, NOx, NH3 (ammonia), N2 • Soluble form - NH4+ (ammonium), NO2‐, NO3‐ (nitrate reduced by microbes to nitrous oxide), dissolved organic N • Insoluble form - Amino acids, organic N (R‐C‐NH2)

Habitat loss

• Human alteration of habitat is the greatest threat to biodiversity throughout the biosphere • In almost all cases, habitat fragmentation and destruction lead to loss of biodiversity • For example - In the Atherton Tablelands west of Cairns, 32,000km2 of rainforest have been cleared since the last century - About 93% of coral reefs have been damaged by human activities

How is human welfare related to biodiversity?

• Human biophilia allows us to recognise the value of biodiversity for its own sake • Species diversity brings humans practical benefits • Species related to agricultural crops can have important genetic qualities - For example, plant breeders bred virus-resistant commercial rice by crossing it with a wild population • In Australia, 25% of prescriptions contain substances originally derived from plants - For example, the rosy periwinkle contains alkaloids that inhibit cancer growth • The loss of species also means loss of genes and genetic diversity • The enormous genetic diversity of organisms has potential for great human benefit --> Ecosystem services

Nutrient enrichment

• In addition to transporting nutrients from one location to another, humans have added new materials, some of them toxins, to ecosystems • Harvest of agricultural crops exports nutrients from the agricultural ecosystem • Agriculture leads to the depletion of nutrients in the soil • Fertilisers add nitrogen and other nutrients to the agricultural ecosystem

What are the main forms of sulfur?

• In agricultural soils 90% of sulfur is organic sulfur • Main forms of sulfur in soil are: • sulfate (SO42‐) in oxic environments • sulphide (S2‐) in anoxic environments • Sulfur cycles through water, soil and atmosphere

What are inputs and outputs of carbon in terrestrial ecosystems? Where are soil carbon pools?

• Input = organic matter • Output = erosion, soil CO2 respiration, DOC leaching • Soil carbon pools are: • plant roots • microbes • soil organic carbon (SOC)

What is the effect of lignin content on decomposition?

• Lignin in plants (and chitin in insects) is recalcitrant to decomposition • Lignin is slow to decompose, accumulates in humus • Requires numerous enzymes to degrade

Where is most carbon in the ocean stored?

• Most of C in ocean water is stored in intermediate and deep water • Carbon in surface water (~200m) depends on wind speed, temperature, CO2 concentration in water • Carbon moves to deeper layers by - Solubility pump - Biological pump (detritus, CaCO3) • Carbon in deep ocean is stable (turnover > 1000years)

How is carbon found in the atmosphere?

• Mostly as CO2 - Major greenhouse gas • Methane (CH4), Hydrochlorofluorocarbons (HCFCs), are trace

Atmospheric nitrogen cycle

• N2O in troposphere is stable (~150 years) • Once N2O move up to stratosphere, it becomes unstable and transforms to NO • NO in stratosphere causes a chain reaction of N transformation and deplete ozone layer • Lightning strikes can also produce nitrate • Atmospheric N is deposited as: • Organic N (DON) or • Inorganic N (DIN) via precipitation events

What is the problem with nitrogen?

• NH3 volatile in dry alkaline soil • NO3 leaches, toxic, water contamination, algal blooms • N2O loss in waterlogged soil, GHG • Low N fertiliser use efficiency ~ 20 - 40% Fertiliser use efficiency (%) = plant uptake/ fertilizer applied *100

Nitrification

• NH4+ --> NO3‐ ammonium to nitrate

What is the difference between the P and N cycle?

• No gaseous phase in P cycle • No biological pathways to bring new P • Major source of new P is weathering of primary minerals

How is geographic distribution of species affected by climate change?

• Non-migratory bird species in N America and Europe have moved North over the past 50 years. • Plant species distribution has shifted and become more limited. In the Arctic, shrub and grass species are advancing where only lichen and mosses were previously. • Shifts in plant elevational boundaries in mountain areas. In S California from 1977-2007, there was a 0.4ºC increase in mean temperature, so snow decreased and average elevation of dominant species increased by 65 m. In Antarctica previous un-vegetated areas are becoming encroached by alien plant species.

Describe biological pumps

• Organic matter production consumes nitrate and CO2 in surface water • Surface water depleted in CO2, increases CO2 gradients and uptake of CO2 from atmosphere • Organic matter (organisms) die and sink to ocean bottom • C sequestered in deep ocean

Describe P use in Australia

• P fertilisers have been applied since 1930s • Generously applied to overcome P deficiencies (and it was cheap) • P fertiliser inputs are three times greater than preindustrial inputs (Bennet et al. 2001)

What are sinks of carbon?

• Plants (Photosynthesis) • Soil (organic matter) • Marine sediment (precipitation as insoluble minerals) • Atmosphere (gaseous) • Water (dissolved) -> largest pool is the ocean

Explain the significance of phosphorous.

• Plants and animals require P to live • Part of DNA, RNA, lipids, ATP • One of 6 macronutrients essential for healthy plant growth • P low in old soil • P immobile in soil • Difficult to take up by plants

Where is nitrogen in nature?

• Required for proteins/enzymes • 78% of atmosphere • 75,000 Mg/ha

Methods of classifying Australian climatic zones: Vegetation (modified Köppen)

• Six major groups and 27 sub‐groups of climate zones • Based on the concept that native vegetation is the best expression of climate • Six major classes (modified for Australia): • Equatorial • Tropical • Subtropical • Desert • Grassland • Temperate

C sequestration potentials

• Soil (change of land use, management [e.g. tillage]) • Oceans (fertilisation) • Biomass/biofuel (crops) • Geology (carbon capture and sequestration) • Biochar (charred biomass)

Latitudinal gradients

• Species richness is especially great in the tropics and generally declines along an equatorial-polar gradient • Two key factors in equatorial-polar gradients of species richness are probably evolutionary history and climate • Temperate and polar communities have started over repeatedly following glaciations • The greater age of tropical environments may account for the greater species richness • In the tropics, the growing season is longer such that biological time is faster

Why is carbon important?

• Structural backbone of plants (cellulose) and animals (proteins, CaCO3 skeleton) • Energy source for animals (sugar) • Storage form of energy (glycogen, starch) • Easy to transform

Methods of classifying Australian climatic zones

• Temperature/humidity • Seasonal rainfall • Vegetation (Köppen) • Different methods of classification are used depending on the intended use of the output

Convective precipitation and the Easterly Trough

• The Easterly trough is an area of low pressure on the inland side of the Great Dividing Range sandwiched between coastal moist air and continental dry air • Formed by the intense heating of the land during the summer months • As land warms trough moves towards the coast, causing showers and thunderstorms to form

Methods of classifying Australian climatic zones: Seasonal Rainfall

• Use the differences between summer and winter rainfall to identify six major zones • Summer dominant - North • Summer - SE, QLD • Uniform - SE, Victoria • Winter - S • Winter dominant - W, Perth • Arid - Central

Describe solubility pumps

• Warm water (equator) holds little CO2 • Cold water (polar) holds more CO2 • Ocean currents transport water to poles • Cold water sinks under warm water • Cold, CO2 enriched water sequestered in deep ocean

Orographic precipitation in E Australia: How does this affect the vegetation?

• Windward side - higher rainfall > plant growth more vigorous, trees • Leeward side - lower rainfall > plant growth less vigorous, shrubby •Trade Winds are associated with enhanced rainfall over tropical and sub‐tropical parts of the eastern seaboard (i.e. elevated areas of the Great Dividing Range) • Australia's wettest location (Mt Bellenden Ker, 1545m ASL) lies on the Great Dividing Range in the path of the Trade Winds between Cairns and Innisfail = average annual rainfall = 7708 mm.

What are pathogens and how can they affect communities?

• include disease-causing microorganisms, viruses, viroids, and prions • Pathogens can alter community structure quickly and extensively • Pathogens can have dramatic effects on communities - For example, coral reef communities in the Caribbean are being decimated by white-band disease • Human activities are transporting pathogens around the world at unprecedented rates • Community ecology is needed to help study and combat them

What are some conflicting demands?

•Conserving species often requires resolving conflicts between habitat needs of endangered species and human demands •For example, in Australia's south east there is conflict between the need for habitat preservation for platypus, native fish, birds and mammals and demand for grazing and resource extraction (coal seam gas, for example) •Managing habitat for one species might have positive or negative effects on other species

Rising CO2 levels

•Due to burning of fossil fuels and other human activities, the concentration of atmospheric CO2 has been steadily increasing •Most plants grow faster when CO2 concentrations increase •C3 plants (for example, wheat and soybeans) are more limited by CO2 so they grow faster than C4 plants (for example, corn) • Greenhouse gas effect --> warming of atmosphere due to trapping of heat

What are limits on food chain length?

•Each food chain in a food web is usually only a few links long because energy input decreases. •Two hypotheses attempt to explain food chain length: the energetic hypothesis and the dynamic stability hypothesis

Global Change

•Global change includes alterations in climate, atmospheric chemistry, and broad ecological systems •Acid precipitation contains sulphuric acid and nitric acid from the burning of wood and fossil fuels • Air pollution from one region can result in acid precipitation downwind - For example, industrial pollution in the midwestern United States caused acid rain in eastern Canada in the 1960s • Acid precipitation kills fish and other lake-dwelling organisms • Environmental regulations have helped to decrease acid precipitation - For example, sulphur dioxide emissions in the United States decreased 31% between 1993 and 2002

Toxins

•Humans release many toxic chemicals, including synthetics previously unknown to nature •In some cases, harmful substances persist for long periods in an ecosystem •One reason toxins are harmful is that they become more concentrated in successive trophic levels •Biological magnification

Depletion of the ozone layer: what is the cause, and what are the consequences?

•Life on Earth is protected from damaging effects of UV radiation by a protective layer of ozone molecules in the atmosphere •Satellite studies suggest that the ozone layer has been gradually thinning since the mid-1970s •Destruction of atmospheric ozone results mainly from chlorofluorocarbons (CFCs) produced by human activity •CFCs contain chlorine which reacts with ozone to make O2 •This decreases ozone in the atmosphere •The ozone layer is thinnest over Antarctica and southern Australia, New Zealand, and South America •Ozone levels have decreased 2-10% at midlatitudes during the past 20 years •Ozone depletion causes DNA damage in plants and poorer phytoplankton growth •An international agreement signed in 1987 has resulted in a decrease in ozone depletion

Nature reserves

•Nature reserves are biodiversity islands in a sea of habitat degraded by human activity •Nature reserves must consider disturbances as a functional component of all ecosystems •An important question is whether to create fewer large reserves or more numerous small reserves •One argument for large reserves is that large, far-ranging animals with low-density populations require extensive habitats •Smaller reserves may be more realistic, and may slow the spread of disease throughout a population

Overharvesting

•Overharvesting is human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound •Large organisms with low reproductive rates are especially vulnerable to overharvesting - For example, elephant populations declined because of harvesting for ivory

Area Effects: Island equilibrium model

•Species richness on islands depends on island size, distance from the mainland, immigration, and extinction •The equilibrium model of island biogeography maintains that species richness on an ecological island levels off at a dynamic equilibrium point

Fragmentation of habitats

•The boundaries, or edges, between ecosystems are defining features of landscapes •Some species take advantage of edge communities to access resources from both adjacent areas •The Biological Dynamics of Forest Fragments Project in the Amazon examines the effects of fragmentation on biodiversity •Landscapes dominated by fragmented habitats support fewer species due to a loss of species adapted to habitat interiors

How is catchment water balance measured?

𝑷−𝑬=𝑹𝒔+𝑹𝒈+∆𝑺 P = precipitation E = evaporation Rs = surface water runoff Rg = groundwater runoff S = storage