PLS 162 Final Exam

biotic homogenization in urban systems and the mechanisms that lead to it

-Biotic homogenization: combination of biodiversity loss and gain to increases in similarity among communities through time and across space. -Higher similarity of weedy species across California's high population density areas -Very low similarity of rare species

peri‐urban versus intra‐urban agriculture

-Peri-urban: takes place in urban periphery -Intra-urban: takes place in inner city; most cities and towns have vacant and under-utilized land areas that can be used for agriculture

urban agriculture

Agricultural activities located within or on the fringe of a city; grow or raise, process and distribute a diversity of food and non-food products (livestock for eggs, meat, wool; mushrooms, spices, fruit trees, ornamental plants, medicinal herbs); uses largely human and material resources, products and services found in and around that urban area

stowaway

Attached to or within a vector

Urban Exploiters

Dependent on human resources, released from predators. Homogenized fauna - most similar city to city. Ex- starlings, finches, sparrows, rats → Bird species dominance in urban vs. non-urban land covers The steeper the curve means the community is dominated by fewer species. Urban is dominated by fewer species than forest. Maybe due to the efficiency of foraging techniques by the dominant species in urban areas,

ecosystem services

Ecosystem services are the benefits that people can derive, directly or indirectly, from an ecosystem

OUT of UHI

Latent heat flux is decreased because cities lack surface water and vegetation Anthropogenic flux: cities release large amounts of heat Convective flux: the magnitude and sign depend on wind flow and relative temperatures

Benefits of expanding the tree canopy

Provides shade which lowers ambient temperature and reduces energy use (can reduce consumption by 25%)

Metapopulation

The interconnected populations of a particular species

List and justify several mitigation strategies that could be use to reduce the UHI. In your justification make sure to explain changes to specific energy fluxes resulting from your interventions.

Urban greening may mitigate UHI in desert cities (but need to be counterbalanced with the need to conserve water) Increase reflective surfaces, permeable surfaces, shade, orientation of buildings with prevailing wind direction (to increase heat exchange), green roofs and walls Decrease heat storage, direct radiation on man-made materials, anthropogenic heat generation, air pollution, urban canyons

why is CO2 measured at Mauna Loa?

it's far from direct city pollution

Cities are useful to study because...

they have elevated CO2 levels which is what the future of the globe may have someday

Associated biodiversity

unplanned/ unintentionally managed organisms: weeds, native plants with crops, wildlife, pests, pollinators, biocontrol, soil biodiversity

Explain the impact of the UHI on plant phenology and how it extends beyond the footprint of the city.

"Vegetation greenup" -- outside the urban center, the vegetation blooms earlier and goes dormant later because of increased temperatures Related to urban density more than physical size of the city Also impacts warmer spring temperatures, delayed dormancy, and warmer autumn and winter temperatures The strength of urban influence decays exponentially with distance from the perimeter of the urban land cover Greenup and spring temperature increase were unrelated to urban sprawl but more likely a function of population density

Soil pores

"holes" between soil particles; ratio of the volume of the pores to the volume of the soil; size of pores important; macropores transport gas and water due to gravity; medium pores hold water, big pores cannot hold water against gravity, small pores hold water so tight the plant can't extract

goal and limitations of intercropping

-Crop rotational diversity enhances belowground communities and functions in an agroecosystem -Intercropping promotes high diversity systems, which have high genetic variation, number of species, ecosystem habitat types, functional diversity -Intercropping has high alpha (local) diversity and low beta (across communities) diversity (strip planting has the opposite)

Understand why equitability and homogeneity are not the same

-Homogeneous distribution of amenity does not necessarily mean equitable distribution of service → services/disservices may be received at a location or a scale different from the location or scale of the management decisions or actions -Equitability = dealing fairly and equally with all peoples concerned -Homogeneity = composed of parts or elements that are all of the same kind -SO, equity means that the mitigation strategy would be fair, while homogeneous means that it is the same strategy for all areas regardless of whether the areas differ or not, -Seek equitability in the distribution of the service NOT homogeneity in the distribution of the amenity.

density-diversity paradox

-If species can survive in the urban sprawl (exploiters), then they do well and flourish and populations increase dramatically (red line) -Urban areas remove top predators, biodiversity depends on scale (Avoiders stay away from cities and cause drop in species richness) -Paradox exists because of reduced spatial and/or temporal variation in: food, water, habitat, temperature, changing trophic dynamics like the loss of top predators, and the increase in invertebrate prey, and competition.

Be familiar with sources of lead in the environment and their history. What is the distribution of that lead at the parcel and city scale and what features of the landscape at each of those scales may account for the measured distribution?

-Leaded Gas 1920-1986 released to atmosphere -Lead-based paint 1884-1978 -Large amount of lead in environment today; very widely dispersed, soil is a major source, urban environments are hotspots, lead is a public health issue and an environmental issue -Endangers child health, urban city farms, more people now having personal gardens -Urban Gardening increases access to nutritious food but also more susceptible to lead poisoning (playing in dirt, breathing in dest, NOT in food itself) -Lead concentration high near buildings and major roadways; older homes; differ by neighborhood and soil type

How does composting work, and what is it made of?

-Organic waste collected from households to biosolids as resources to create compost; diverts residential waste from landfill -Microorganisms break down organic material and heat is generated; high temps sanitize waste and kill off pathogens -Creates a uniform mixture of humified organic matter, mineral matter and microorganisms, with reduced mass and water content -Raw manure: organic matter (feces, urine, feed) and inorganic nutrients (soil, water, microorganisms)

how are Metapopulations and source-sink dynamics linked to island biogeography theory

-Patches are either sources or sinks, while arrows between them indicate interactions between patches -Example of comparing Baltimore and Phoenix bird richness and family income → Relationship is stronger in phoenix because of regional plant diversity. -Greater diversity with alterations in elevation, land use (current and former), income, and housing age. → Phoenix is surrounded by desert (xeric) and higher income households have the means to landscape their property to better fit bird habitats. While Baltimore is mesic and therefore vegetation is roughly the same across the city regardless of income.

Understand the timeline of urban agriculture and the role it has played at different times and in different places in the world

-Rooftop gardens long history from Middle Ages -Victory Gardens after the war-- people incentivized to grow their own food due to food scarcity -Terraces in Aztec culture in order to minimize runoff and maximize space

"important" ideas around ecosystem services

-Separate the "thing" from the amenity -Amenities can provide more than one service -There are disservices -Services can be acquired by hybrid solutions in cities -There are interactions and tradeoffs among services -People play a central role -Amenities and services are not evenly distributed across the landscape

What are the major types of urban agriculture?

1. Food security: abandoned land, wastelands 2. Food supplement: urban home gardens, container gardens, small animal production 3. Mixed food security/ commercial: peri-urban, zero-grazing, crop-livestock systems 4. Commercial: per-urban and urban, irrigated lands, farms

Think through how different green infrastructure strategies can influence other ecological processes discussed this quarter.

1. Multifunctionality: integrate ecological, social and economic functions; park provides benefits to human recreation, supplementary wildlife habitat, public sense of place 2. Connectivity: support species dispersal, metapopulation dynamics 3. Integration 4. Communicative and social-inclusive processes: ecologists and sociologists and economists all come together to be decision-makers and planners 5. Long-term strategy: long term benefits are better than short term gains

Streetscape

1. Planter boxes: rain gardens with vertical walls and open or closed bottoms, collect and absorb runoff, ideal for space limited sites in dense urban areas and in streetscaping 2. Bioswales: vegetated, mulched, or xeriscaped channels; provide treatment and retention, slo, infiltrate and filter stormwater flows; linear features well suited for being along roads and parking lots 3. Green streets and alleys: store, infiltrate and ET stormwater, permeable pavement, bioswales, planter boxes and trees woven into street or alley design

City-wide and Regional

1. Urban tree canopy: trees reduce and slow stormwater by intercepting precipitation, transpire water and reduce runoff; must work with private landowners because this is where most available space for trees is 2. Greenway networks: An interconnected network of green space that conserves ecosystem values and functions and provides benefits to humans 3. Land conservation: protecting open spaces and sensitive natural areas within and adjacent to a city; provides recreation

Parcel scale (Residential and Commercial/ municipal)

1. downspout disconnection: reroute rooftop drains from flowing into storm sewer to rain barrels or permeable surfaces; results in storing stormwater or allowing soil infiltration 2. rain water harvesting: collect and store runoff and provide a source of water; valuable in arid regions where it could reduce demands on limited water supplies 3. rain gardens: installed in unpaced regions, shallow, vegetated basins that collect and absorb runoff; infiltration and ET 4. permeable pavement: infiltration, treat, and/or store rainwater, made of porous, pervious or permeable pavers, cost-effective where land is high and flooding is a problem 5. green roofs: vegetation enables rainfall infiltration and ET of stored water; cost-effective in dense urban areas where land values are high; reduce water runoff during small storms

What are the characteristics of urban soils?

1. pH: alkaline relative to "natural" soils due to calcium from de-icing roads, irrigation with calcium enriched water, weathering of cement releases calcium 2. Low fertility: people remove topsoil/ leaves/ organic matter which changes the available Nitrogen, Phosphorous and nutrients; organisms are thus less common in soil due to less aeration and more compaction; changes in soil chemistry effects nutrient cycling 3. Vertical and spatial variability 4. Surface crust on bare soil-- usually hydrophobic 5. Restricted aeration and water drainage 6. Interrupted nutrient cycling 7. Presence of anthropeic materials (pollutants, pipes, construction debris) 8. Changed soil temperature 9. More inorganic soil and less organic soil, air and water than forest soils

four different types of ecosystem services

1. supporting 2. provisioning 3. regulating 4. cultural

Critically evaluate the advantages and disadvantages of producing food in urban areas compared to rural areas

Advantages: huge growing market for ag products, comparative advantages to supply (perishability, short distance to market, less transportation costs), provides livelihood, can improve urban environment Disadvantages: disease, lack of space, difficult to make a profit, poor management, contaminated roadside soils, air and water

Define albedo and understand how it is measured and reported, rank different materials according to relative albedo, link albedo back to the energy balance

Albedo is a fraction of solar energy (shortwave radiation) reflected from Earth back into space; reflectivity of the Earth Light surfaces have high albedo, dark surfaces have low albedo Reflection is greater in the forest because energy isn't absorbed as much as it is in the urban system

release (and example)

Commodity, bio-control, erosion control; ex: Kuzu. initially brought to US from japan for shade use, then was used as an attempt to reduce agricultural soil erosion. Extremely costly to remove

How might the UHI vary among cities in different biome types (e.g. Baltimore vs. Phoenix)?

Different biomes have different air temperatures, heating and cooling rates, and therefore heat island intensity Phoenix: drought tolerant, less water, no ET; UHI more likely caused by increased man-made surfaces and canyon geometry Baltimore: water dependent: UHI more likely caused by relative decreases in vegetation density

mitigation strategies for urban environmental problems

Example: Urban heat problem in Baltimore City. -Heat exposure, measured as land surface temperature, can vary a lot within a city -Temperature is lower where there is more woody vegetation -Heterogeneity of urban heat and household income → hotter areas also have lower median household income. These patterns of heterogeneity in heat and income can be used as tools to develop mitigation strategies → identify hotspots that have high temperatures and vulnerable populations. (you can change criteria to broaden or narrow the areas included based on available funding)

What ecosystem services can urban agriculture provide?

Food production, microclimate improvement, improvement of urban soils, waste and nutrient recycling, biodiversity, global warming, environmental awareness, reduces transportation, stabilizes environmentally fragile land

GHG _________ radiation, leading to ________

GHG absorb radiation, leading to warming; differ in concentration in the atmosphere and atmospheric lifetime and heat trapping effectiveness

ecological and social tradeoffs of expanding the urban tree canopy and how these tradeoffs differ among cities with different characteristics

Heat is the leading cause of "natural disaster" mortality in the U.S since heat increases the formation of ozone and exacerbates other air quality concerns for human health. Managing for heat and air pollution. Shade trees and all vegetation in general → reduce A/C use and ambient temperature which → reduces demand from power plants, causes area sources to emit less, and slows down reaction rates, resulting in → less energy consumed, lower CO2 NOx and VOC levels, leading to lower ozone levels Ecosystem services provided by trees: reduce air pollution, sequester CO2, saves energy and avoids emissions due to shading, reduces stormwater runoff, and increase market value because aesthetically pleasing.

Ozone impacts on vegetation

High O3 = high damage for plants (lower biomass, decreases leaf area, inhibits stomatal control)

corridor (and example)

Human infrastructure linking areas → ex. Transportation: Rail road tracks through the location of people and disturbance.

Energy fluxes that make up the energy balance and how these fluxes are different between urban and non-urban systems

Influx of energy in forest and urban systems are the same-- shortwave radiation from the sun and longwave radiation from the atmosphere Reflection is greater in the forest-- more energy is absorbed in the urban system due to the warmer surfaces and anthropogenic sources of additional heat Forests also lose more energy via water evaporation and vegetation transpiration Warmer surfaces lose more longwave energy and exchange more energy via convection Urban systems have more stored energy due to anthropogenic inputs

containment

Introduced with a specific commodity

IN and OUT of UHI

Longwave radiation exchange: lost during nighttime cooling-- at night, the surface temperature decreases as heat is radiated away from the surface, buildings inhibit cooling which results in the urban area being warmer than surrounding regions at night Shortwave radiation exchange" cities have low shortwave reflectivity (albedo) Radiation rebounds in the city and cannot leave the system as easily which is why urban areas don't cool as fast during the night

Disservices from tree canopy

Maintenance, water use, infrastructure, and safety Alot more challenging for a city like Phoenix to plant more trees because of the xeric (low moisture) environment. Trees require more water than the ecosystem can provide. More reasonable for mesic (high moisture) environments since water is not a stressor

O3

NOT directly emitted but created by chemical reactions between NOx and VOCs in the presence of heat and sunlight

Sources of O3

NOx sources: industrial/ commercial/ residential fuel combustion, motor vehicles, utilities VOC sources: motor vehicles, industrial/commercial processes, point-- power plants, non-point-- vehicles, dry cleaners; trees naturally produce VOCs (Isoprene emissions cause the blue haze of the smoky mountains)

dis/amenities

Objects perceived as a benefit, valuable to people and society. People manage amenities, and services. PERCEIVED

Urban heat island

Occurs when a city is warmer than the surrounding rural area due to human activities; We modify the environment by creating large vertical surfaces and by using dark materials which increases the radiation absorbed

3 different spatial scales in the urban landscape to achieve the goals of green infrastructure

Parcel scale, streetscape, city-wide and regional

Island Biogeography Theory application to urban systems

Patch size (island) and distance to a source population are predicted to influence the number of species present in the patch -species richness increases with patch size Application of IBT to cities: "islands" of habitat within them Caution matrix is not uniformly hostile like ocean surrounding and island, and the arrangement of suitable patches plays a big role Large uniform patch is the MOST optimal

green roofs

Plants and soils on a roof improve cooling by reflecting more and evaporating water

Explain and discuss the agroecological principles for sustainable urban ag.

Productive agriculture systems that have conservation of natural resources, biodiversity and ecosystem services as a basis for improvement, use of nature for food production and decrease inputs 1. Recycling: recycle biomass, optimize nutrient availability 2. Build natural soil capital: secure favorable soil for plant growth by managing organic matter and enhancing biotic activity 3. Minimize losses: due to flows of solar radiation, air and water by microclimate management, water harvesting, and soil management through increased soil cover 4. Biodiversity: species and genetic diversification 5. Promote beneficial biological interactions: promotes key ecological processes and services

difference between dis/amenities and dis/services

Separate the "thing" (amenity) from the service. Amenities can provide more than one service, and there are disservices. Services can be acquired by hybrid solutions in cities, and there are interactions and tradeoffs among services. People play a central role → amenities and services are not evenly distributed across the landscape; Services and disservices are influenced by perception PHYSICALLY DERIVED

source-sink dynamics

Source population supplies immigrants to the sink populations since the sink population requires immigration to persist

Urban Adaptors

The "edge" or transitional species- need habitat but can deal with some disruption. Wide tolerances, and do better in urban areas because of subsidized resources and/or release from predators. Ex- raccoon, deer, fox, skunk → San Joaquin kit fox: Endangered species that does better in Bakersfield than in nearby preserves. Eat same food as humans, which results in longer life spans, more pups, higher calorie food, and minimal variation in food supply seasonally.

Describe the differences in relative humidity between urban and non-urban systems and why.

The amount of water that can be held in the air is a function of the air temperature; warmer temperature = higher saturation of water concentration Relative humidity is reduced in urban areas because of the increased air temperatures, NOT because the air "dries out" The same amount of water vapor is in the air but warmer air holds more water at saturation There also is reduced water vapor released through ET in urban regions This causes more precipitation in urban areas

Regulating

The benefits from regulating ecosystem processes; Examples → Climate regulation (Urban heat island), Pollination( urban agriculture and green roofs), Riparian zones (regulate export of nitrate), Vegetation (microclimate, erosion, water, air, and soil quality), Storm water (green roofs)

Dis/services

The benefits that society derives from ecosystems. Each service relies on fundamental ecological processes that can be recognized and measured by scientists.

Cultural

The non-material benefits Examples → Spiritual and religious, recreation (parks and public areas like the New York City high line), Ecotourism (Bats in Austin, Texas), Central park in NYC (sense of place and identity)

Island Biogeography Theory

The theory of island biogeography provides a model for determining how many species an island can support. The predicted number of species present on the island is based the size of the island and its distance from the source.

Provide several reasons why human population density and biodiversity are often positively correlated

There is a positive correlation because people choose to settle in places with high biodiversity. Plants and animals preferentially settle near humans or are introduced to humans -People and organisms have the same preferences for environments: -High abundance of resources, near water, and diversity of habitats.

Livelihood

UA generates income, especially for women

source-sink dynamics in urban regions

Urban = sink surrounding rural = source

What characteristics of urban soils benefit and hider urban agriculture?

Urban soil: non-ag, manmade surface layer; undisturbed but altered by urban environment, anthropogenic soils; compacted and low in organic matter, high biological activity, N cycling, accumulation of heavy metals

Green Infrastructure

a cost-effective, resilient approach to managing wet weather impacts that provides many community benefits. A single-purpose gray stormwater infrastructure (conventional piped drainage and water treatment systems) is designed to move urban stormwater away from the built environment, green infrastructure reduces and treats stormwater at its source while delivering environmental, social and economic benefits.

Food desert

accessibility = affordability

pH

acidity or alkalinity (0-14) of soil measured in H+ ion concentration; 6-6.5 favorable for trees, influences organisms in soil and availability of minerals

Nutrients

available Nitrogen, Phosphorous and nutrients vary with amount of organic matter

Organic matter

deposited on surface as plant litter or root breakdown; provides cation and anion exchange capacity, water holding capacity, mineralized essential elements, a substrate and fuel for detritus food web, and pore space; decomposing materials then move downward through the soil and pass the absorbing roots, create soil structure

escape (and example)

e.g garden plants, species used for bait → ex. Horticulture: the source of 85% of US invasives. Most commonly caused by human choices(aesthetics and culture) introduced more than plants (bacteria, fungi, insects through soil)

Types of green roofs

extensive and intensive

Sources of PM

fire, wind erosion, agriculture, smokestacks, car emissions, construction; includes: dust, soil, soot, smoke; health problem for respiratory system; most polluted cities are in places with a long growing season

Extensive roof

functional for storm-water management, thermal insulation and fireproofing, shallow substrate depth, low-growing plant communities with little or no irrigation requirements; more functional than accessible 1. Complete: each component, including roof membrane, is installed as an integral part of the roof 2. Modular: vegetation trays cultivated ex situ are installed above the existing roofing system 3. Pre-Cultivated vegetation blanket: growing medium, plants, drainage mats, and root barriers are rolled onto existing roofing

Intensive roof

garden-like, functional and aesthetic, increased living space, deep substrate depth, often require irrigation, larger plants, garden-level maintenance

Soil Structure

how soil particles are grouped (shape, size, strength, arrangement); created by organisms and root growth, affects root penetration, water intake and movement, aeration, can be changed through compaction or plowing; effects water and gas movement (single grain move fast, platy soil moves slow)

BENEFITS of green roofs

increased reflection, ET cooling, insulation of building, protects roof membrane, reduces membrane max temperature, retain precipitation/ delay runoff, plants provide shade, transpirational cooling, hold soil, look pretty, reduces overall stormwater runoff damage

Sources of CO2

industrial processes and vehicle emissions

CO2 absorbs _______ and traps heat in atmosphere

longwave radiation (heat)

Compaction

loss of soil aggregates; less aeration due to less macropore space; re-sorting and packing of soil particles changes soil structure

Food insecurity

low income spend 40-60% of income on food each year

CO2 and plant production

may increase plant biomass but plants compensate by "down regulating" and doing same photosynthesis is less time to conserve water

Bulk Density

mixture of air, water, minerals and organic matter; mass of dry soil/ volume of soil; increases with depth and compaction -- more bulk density means less porosity!

Ozone is generated... and disperses

near ground in the troposphere and disperses to outside regions in high concentrations

Diurnal changes of CO2

night heating, morning and evening commute times

Planned biodiversity

organisms that are intentionally managed/ introduced into agroecosystems; crops, livestock, pollinator, biocontrol

Seasonal changes of CO2

photosynthesis during growing season, plant respiration in growing season, winter heating homes and driving more, deciduous trees lose leaves in winter so there's less photosynthesis

Provisioning

products and consumables Examples → Food (urban agriculture and community gardens), Freshwater (watershed health?)

Soil texture

relative proportions of various sizes of soil particles; sand largest, silt, clay smallest; impacts infiltration rates; can only change by mixing with other soils from a different texture class 1. Soil: low water holding capacity, good aeration, high drainage rate 2. Loam: high water holding capacity, med aeration, slow to med drainage rate 3. Clay: high water holding capacity, poor aeration, very slow drainage rate

pathways of non‐native species introduction into cities

release, escape, containment, stowaway, corridor, tunnels, unaided

Soil aeration

respiration and photosynthesis; oxygen is crucial for root respiration; air moves through large pores; oxygen diffuses through the soil, following a concentration gradient, with increasing soil depth, natural increase in CO2 concentration and decrease in O2 concentrations

Urban avoiders

sensitive to changes in the environment, persecuted, rare, or low reproduction rate. Ex- large mammals/predators (mountain lion- when resources are rare like during a drought, then there are more frequent interactions with humans) Animals with specialized habitats → like wetlands or ground nesting species → Coyote territories in Chicago- spatial separation: Urban population of coyotes is increasing, their territories are in habitat patches within the urban matrix, but they avoid contact with humans by shifting activities to nighttime and they don't incorporate human food into their diet

Properties of soil in urban systems

structure, texture, soil pores (aeration), pH, bulk density, organic matter, nutrients

Role of Soil in urban systems

support (growth medium for roots), water, aeration, nutrients

Silva cells

suspended pavement system; reduce soil compaction and enhance aeration and water infiltration, stormwater management and tree growth

Temperature of a city is proportional to

the amount of vegetation

Supporting

the basic functionings that make all life possible, necessary for all the other ecosystem services. Examples → nutrient cycling and storage (nitrogen, decrease in Soil Organic Carbon over time), Soil formation (increase in earthworms in cities better for decomposition)

Sources of CO

vehicle emissions; deadly to humans in high concentrations, harmless to plants, cars produce 90% urban CO, higher concentrations in urban areas; high at intersections and low near parks

Retention

water held permanently

Detention

water temporarily held by roof or holding pond

UHI changes the _______ of an area

weather of an area-- the cycle causes an increase of pollution in the suburbs and higher relative humidity in rural areas