Ecology Exam 3

give an example of an argument made by a climate change skeptic and how you would respond using what you've learned in class

"The plant has been hotter than this before" yes, but the rate at which the planet is warming is faster than ever recorded and CO2 emissions have increased by 90%

what are the major, natural reservoirs of C, N, and P? in which ecosystems is P limiting? N?

Carbon: limestone, fossil fuels, oceans, plant & animal biomass Nitrogen: atmosphere (78% N2 gas), soils, sediments, biomass. Limiting plant nutrient Phosphorous: Rock (weathering) and Soil minerals (erosion). Limiting in aquatic ecosystems

What is the edge effect? why is it a cause for concern? give a specific example

Changes in population/community structures that occur at the boundary of 2 habitats. Areas with small habitat fragments exhibit especially pronounced edge effects that may extend throughout the range. the smaller the habitat patch, the greater the influence on the entire patch from the edge. Resource avialibility and distribution of animals may decrease with an increasing edge in the forest, since the edge has thick dense habitat that many animals can not forage through. decrease in Wood Thrush population who use core habitat and increase in proportion of Brown-headed Cowbird-parasitized nests who use edge

how can species populations, not individuals, respond to long term changes in environmental conditions? give two specific examples

Earlier or later arrival in migratory species in long term response. Ex. Townsends warbler arriving .4 days later per year, yellow-billed cuckoo arriving .2 days earlier per year. Populations may move to higher altitudes and see a species range shift. Either adapt, move, or die

though individual species respond to changes in climate, these changes can lead to cascading changes in community and even ecosystem structure. give an example

Expansion of invasive species because of climate change, change ecosystem structure. May exapnd range of mosquitos carrying diseases. EX, 3-fold increase in shrub density leads to changes in kangaroo rat and pocket mice population size, changing the community stucture

what is a dead zone and how is it formed

In spring, warm freshwater runoff from the Mississippi River creates a floating barrier layer in the Gulf, cutting off the saltier water below from contact with oxygen in the air. N and P from fertilizer and sewage in freshwater layer cause huge algae bloom. As algae die, they sink into saltier water below and decompose. Decomposers use up oxygen in deeper water. Deep water becomes a dead zone. Fish avoid the area or die in massive numbers. Invertebrates that make up the base of the food web also die.

indirect effects of multiple invasive species (understand results of an ANOVA, understand how to trace and test for indirect effects among members of a community)

Intraspecific: competition among individuals of the same species• Interspecific: competition among individuals of different species ANOVA (Analysis of Variance)• Used to compare more than 2 means: is there a significant difference between/among the means of 3 or more independent groups• Null hypothesis: all means are equal IF ANOVA is significant...• We know means are not equal, but which treatments differ from one another?Post-hoc comparison provides series of pair-wise comparisons and produces p-values to tell which treatments differ from one anotherOnly do post-hoc comparisons if ANOVA significant• Tukey's HSD post-hoc comparison commonly used series of t-tests between means

what is the main difference between primary succession and secondary succession

Primary succession: development of communities in habitats that are initially devoid of plants and organic soil; pioneer species (mosses, lichens, drought tolerant grasses) produce organic matter to create soils. Secondary succession: development of communities in habitats that have been disturbed, may contain few or no plants, but still have organic soil

which terrestrial ecosystems have the highest primary productivity and why

Tropical rainforests Dominant plant forms determined by annual temperature and precipitation, high temperatures and intermediate precipitation leads to high primary productivity

what would drive a community to go from one stable state to another? give an example of alternate stable states of a community and explain the factor that would lead to the tripping point between states

alternatice stable states: community is disturbed so much that the species composition and relative abundance of populations in the community change. New community stucture is resistant to further change. Passing the threshold would lead to a new stable state with a new equilibrium. EX. Coral reefs that were maintained by herbivores, loss of herbivoes leads to algal barren new ecosystem and new stable state

Equilibrium

colonization rate= extinction rate

how can increasing species diversity help maintain community stability over time? use the term functional redundancy in your answer

diverse community allows an ecosystem to continue functioning even with ecolsystme changes since different species are resistant to different factors. If there is species diversity and climate gets colder, instead of an entire ecosystem crashing, some speices may crash, while others will thrive, keeping the ecosystem funtional. Functional redundance allows for compensation for the function of species lost during environmental fluctuations. AKA other species can pick up the slack from the species lost

how can pioneer species affect which species become established in later successional stages? give examples

early succession species can modify the environment in ways that affect whether late successional species can become established. Facilitation: presence of one species increases the probability that a second speceis can become established. Ironwood trees as nursery plants to cacti

climate has changed dramatically in the past in fact, the earth has been way hotter than it is now. So what then are major causes for concern regarding current climate change?

extremely likely (>95% probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over decades to millennia. Temperature change is increasing at a rate faster than ever recorded

after a disturbance event, species richness tends to increase rapidly. however, as succession nears its final seral stage (climax community) the rate of new species being added to the community slows. why does species richness level off a s the climax community become established?

facilitation increases the establishment of new species. After several species are present, inhibition (one species decreases the probability that a second species will become established) levels off species richness by increasing competition, predations, and parasitism

what is a climax community

final seral stage of succession, organisms that will dominate the biome

what are pioneer species? what characteristics do they have?

first to arrive after disturbance, arrive quickly, ability to disperse long distances (like grasses and weeds)

why are gentoo penguins considered climate change winners in the Antarctic peninsula? why are horned puffins climate change winners in the high arctic? see video link from lecture

gentoo penguins are adapted to survive and reproduce withough ice, over other competing penguins. THey are highly plastic. horned puffins like open water for feeding, so open water and less sea ice increase there food availability and population size.

what roles does habitat diversity relate to species diversity

high habitat diversity leads to high species diversity

explain how climate change can be highly regional in its effects give a specific example from lecture. why is this important to understand

increases in extreme winter weather in parts of the US are linked to accelerated warming of the Arctic. This allowed colder winter weather to flow down to the US. Cold winds are being pushed down. Different regions will expereince climate change differently, but overall the earth is showing a trend of warming. It is important to look at the trends of the planet as a whole, and not just small regions

what is a phenological mismatch? how can this occur as a result of climate change? give an example

interacting species change the timing of regularly repeated phases in their life cyles at different rates. Lack of phenological shift leads to increased camouflage mismatch in scottish mountain hares. Snow is melting sooner with warmer temperatures and the hares are not adapting quick enough and end up still white with a snowless dark background

how could you use what you know about edge effects, species area relationships, and the equilibrium theory of island biogeography to assist in designing a nature reserve system?

large reserve size, one large reserve instead of many small, close reserve proximity, high reserve connectivity, even distribution with reserve shape

define the intermediate disturbance hypothesis

local species diversity is maximized when ecological disturbance is neither too rare nor too frequent. ... At high levels of disturbance, due to frequent forest fires or human impacts like deforestation, all species are at risk of going extinct.

what makes ecosystem-scale experiments relatively rare in ecology? give an example of an ecosystem scale experiment

long term with lots of data to be collected, difficult. Ice storm experiment: Gathering pre- and post-ice storm data on impacts on hardwood forests (2016-2017)

what is the equilibrium theory of island biogeography? draw a figure showing the relationships between island size, distance, and species richness. be able to explain the relationships

number of species decrease as area decreases. noticed that the number of species also decreases the further an island patch is from a source.

what is the species area relationship?

number of species increases with increasing area

floristic relay

predicting events that will allow occupation by early vs late successional species across a landscape

define primary productivity

rate at which solar or chemical energy is captured and converted into chemical bonds by photosynthesis or chemosynthesis

under what conditions would an ecosystem be dominated by early successional species, rather than reaching the final climax community stage

repeated disturbances to the community

what two factors determine community stability? what is the difference between them?

resistance and resilience. Resistance is the measure of how much a community changes in response to a disturbance(threshold)Resilience is the time it takes after a disturbance for a community to return to its original state (recovery)

is species richness always greatest at maximum habitat heterogeneity? why or why not? support your response with evidence from the intermediate disturbance hypothesis

speices richness is greatest at intermediate habitat heterogenaity. At low levels of disturbance, competitive exclusion limits diversity, at high frequent and large levels of distrubance, high stress rates leads to high extinction rates and low species richness

which aquatic ecosystems have the highest primary productivity and why

swamps and marshes Light availability and nutrients (N and P) high in swamps and marshes

define phenology. give an example of a documented change in phenology associated with climate change

timing of seasonal activities of animals and plants 18 butterfly species in the UK arriving earlier over the past 23 years

what are the effects of fragmentation of large contigous habitat patches into small patches

total amount of habitat decreases, number of habitat patches increases, average patch size decreases, amount of habitat edge increases, patch isolation increases. Number of species increases with increasing area, so decreases with fragmentation

can primary productivity occur in the absence of photosynthesis, explain

yes, hydrothermal vent communities use chemosynthesis, which is the conversion of carbon into sugars and nutrients by chemoautotrophic bacteria in dark places. They use hydrogen gas, hydrogen sulfide and methane as sources of energy, rather than light

Secondary production

•Movement of energy from producers to consumers