lecture vocab Flashcards
zonation vs. succession
zonation: variance in community structure across the landscape
succession: the gradual and (seemingly) directional change in community strcture through time from field to forest
primary succession
the series of changes that take place when there is no soil present. Ex: after a volcano, glacier retreat, etc.
secondary succession
the series of changes that take place when there is soil present. Ex: disturbance of established vegetation after a fire, flood, timber harvest, etc.
disturbance
a discrete event in time that disrupts an ecosystem, community, or population, changing substrates and resource availability.
Alt: an event that changes a community, removes organisms from it, or alters resource availability
characterizations of disturbances (3)
- magnitude:
- intensity: physical force of the event
- severity: impact on the system of interest
- spatial: area over which the disturbance occurrs
- frequency: how often it occurs (small scale more frequent than large)
- duration: Press (chronic) or Pulse (mt. st. helens)
decomposition
the breakdown of chemical bonds of organic molecules, releasing energy, carbon dioxide, water, etc
major microbial decomposers of plant/animal material
- bacteria
- fungi
- detritivores
note: all heterotrophs function to some degree as decomposers
How does the type of carbon compounds present in dead organic matter influence its quality as an energy source for decomposers (3)?
- glucose, other simple sugars: high quality sources of carbon, small molecules, high-energy bonds
- cellulose & hemicellulose: moderate quality, structurally complex, more energy req’d to break bonds
- lignin: low quality, very large and complex molecules, slow to decomp; only decomposed by basidiomycetes
mineralization vs. immobilization
- mineralization: the transformation of nutrients contained in organic compounds into inorganic forms
- immobilization: the uptake and assimilation of minerals by microbial decomposers
- net mineralization: difference between the two
initial C:N of plant litter v.s. decomp
High ratio mean not much nitrogen available for decomposers, so it’s all immediately immobilized, and decomp rate slows.
phosphorus cycle
- main reservoirs are rock and natural phosphate deposits
- released by weathering, leaching, erosion, mining
- only small fraction of total in soil available to plants
nitrogen (and its cycle)
- is major element found in both RuBisCo and chlorophyll
- max rate of PS is correlated w/ leaf nitrogen content
carbon cycle
- pool contains 55,000 Gt total, most of which is in ocean (38,000) as bicarbonate and carbonate ions
- Earth total is 100 milion Gt, but most is buried in sedimentary rock
nonequilibrium model
describes communities as constantly changing after being buffeted by disturbances
traits of early successional species (pioneers) (4)
- high growth rates
- smaller size
- high degree of dispersal
- high rates of per capita population growth
traits of late successional species (4)
- lower rates of dispersal and colonization
- slower per capita growth rate
- larger
- longer-lived
facilitation / inhibition, in succession
each stage of succession brings changes that enable or prevent certain species from moving in. Ex: better soil, less light, more competition.
Facilitation: shade helps dogwoods
Inhibition: Madrone bark contains a chemical that keeps other plants from growing near it.
Autogenic environmental change
a direct result of the presence and activities of organisms w/in the community
ex: vertical light profile is a direct results of the vegetation structure
allogenic environmental change
brought about by a change in the physical environment
Ex: sediment deposition in aquatic environment -> marsh -> grassland
Intermediate Disturbance Hypothesis
the concept that species diversity is greatest in areas experiencing a moderate amount of disturbance.
high rates = 0 late successional species
low rates = diversity declines as late successional species take over
fire regimes of pacific northwest (3)
- High (lethal): 100+ years, stand-replacing
- Mixed (moderate): 25-75 years, mix of severities
- Low (non-lethal): 5-15 years, low intensity
plant adaptations to fire (5)
- thick bark
- canopy seed banks - serotinous cones
- soil seed banks
- sprouting - adventitious buds / lignotubers
- rapid development
human-caused disturbances
- air pollution
- fire (prevention/ignition)
- introduced plants, insects, diseases
- forest management / harvest
- urbanization
- road construction
- mining
- climate change
traits of acid rain (3)
- pH < 5.3
- mostly sulphuric acid and nitric acid
- mobilizng aluminum in soils
non-target effects
accidental effects of things like spraying w/ insecticides
take home message of east/west forests (nationwide)
- West: plenty of probs, but forest is still able to recover from disturbance; maintains many of its historical, balanced interactions; relatively healthy on different scales
- East: historical interactions are gone; forests are no longer able to tolerate native insects and fire; unhealthy on all scales
effects of disturbances on ecosystems (4)
- influences all aspects of ecosystems
- changes ecosystem structure (plant biomass, animal/plant species composition, vegetation succession)
- influences processes such as decomp, nutrient cycling, water flow, primary productivity
- not necessarily good or bad, unless are “changes of concern”
retranslocation / reabsorption
reuptake of chlorophyll and minerals from leaves to roots before leaves fall for winter
biogeochemical cycle
- the cyclic flow of nutrients from the nonliving to the living and back to the nonliving components of the ecosystem
- two types: gaseous and sedimentary
- could not exist w/o water cycle
- structure
- inputs
- internal cycling
- outputs
bacteria
dominant decomposers of dead animal matter; aerobic or anaerobic
fungi
major decomposers of plant matter
detritivores
decompose leaves, twigs, etc, classified by body width:
- microfauna: protozoans, nematodes; water in soil pores
- mesofauna: mites, potworms; soil air spaces
- macrofauna: snails, millipedes, earthworms
- megafauna (>20mm): dominated by earthworms & snails
litter bags
used to examine the decomposition of plant litter
wet fall / dry fall
- wet: nutrients released by precipitation
- dry: nutrients brought in by airborne particles & aerosols
rhizosphere
narrow region of soil that is directly influenced by root secretions and associated soil microorganisms
soil microbial loop
- plants supplement carbon to microbial decomposers n the rhizosphere
- microbes are preyed on by microbivores that release minerals and nutrients back to the soil
- result: enhancement of mineral cycling & an increase in nutrient availability to plants
gaseous biogeochemical cycle
- main pools of nutrients: atmosphere, oceans
- nitrogen, carbon dioxide, oxygen
- sulfur (hybrid of gaseous/sedimentary)
sedimentary biogeochemical cycle
- main pools of nutrients: soil, rocks, minerals
- inorganic mineral sources are released to living animals through weathering and erosion
- phosphorus
- sulfur (hybrid)
net ecosystem productivity
NPP - consumer & decomposer respiration
NPP = carbon uptake (photosynth) - carbon loss (respiration)
the two main food chains are…
and the difference between them is
grazing and detritus…
the source of energy for the first-level consumer
(living plant biomass (primary production)
vs. dead organic matter / detritus)
population
a group of individuals of the same species living in a given area at a given time
community
a group of interacting plants and animals in a given area
ecosystem
Biota + environment + interactions
landscape
mosaic of two or more ecosystems exchanging water, energy, nutrients, and organisms
biome
major regional ecological community of plants and animals
biosphere
thin layer about Earth in which all living organisms exist
chemoautotrophs
energy for the transformation of CO2 into organic molecules is supplied by the oxidation of inorganic molecules
photoautotrophs
energy for the transformation of CO2 into organic molecules is supplied by the Sun
photosynthesis
the process by which short wave energy from the Sun is used to fix CO2 into carbohydrates and release O2
6CO2 + 12H2O -> C6H12O6 + 6O2 + 6H2O
net photosynthesis
= gross photosynthesis - Respiration
measured in moles CO2 per unit leaf area (or mass) per unit time
PAR
photosynthetically active radiation… the availability of light
LCP
light compensation point… the pont at which the net rate of PS is zero
(when gross PS = respiration)
light saturation point
amount of light at which plants achieve the maximum rate of photosynthesis
mesophyll cells
specialized leaf cells in which photosynthesis occurs
stomata
openings on the surface of a leaf through which CO2 enters and O2 and H2O exit
transpiration
water loss through stomata
water-use efficiency
the ratio of carbon fixed (photosynthesis) per unit of water lost (transpiration)
carbon fixed : water lost
photosynthesis : transpiration
P.S. & respiration VS. leaf temperature
both rise with an increase in temperature, but rate of P.S. rises more quickly
net energy balance
the difference between the absorbed energy a plant receives and that which is reflected back to the environment (Rn = net radiation)
carbon balance
the balance between the uptake of CO2 (photosynthesis) and loss (respiration), including all biomass, not just “net” photosynthesis
total carbon uptake =
(uptake of CO2 in photosynthesis/leaf area) * (total leaf area)
-
(loss of CO2 in respiration/time) * (total mass of living tissue)
carbon allocation choices (3), and under ideal conditions, allocation to _____ promotes fastest growth
- leaf - photosynthetic
- root - uptake of water & nutrients
- stem - support and encounter of sunlight
allocation to leaf tissue promotes fastest growth under ideal conditions, by increasing photosynthetic surface
SLA
specific leaf area (cm2/g), a measure of biomass allocation
phenotypic plasticity
the ability of an organism to change its phenotype in response to changes in the environment
C4
photosynthetic pathway that fixes more carbon relative to water loss (compared to C3), but uses more energy
CAM
crassulacean acid metabolism; photosynthetic pathway in hot desert plants, in which they only open stomata at night, collecting and storing CO2 in malate, then proceeding with photosynthesis in the day.
adaptations to minimize water loss (6)
- smaller, thicker leaves
- stomatal size
- cell wall thickness
- density of vascular system
- hairs, wax, resins
- increase carbon allocation to roots
mesic
wet
xeric
dry
frost hardening
the conversion of cold-sensitive cells into hardy ones
plant adaptations to cold environments
- frost hardening
- fomation/addition of protective compounds (antifreeze)
- winter deciduous
winter-deciduous species
… reduce costs associated with cold tolerance by shedding their leaves
needle-leaf evergreen
… maintain photosynthetic tissue over winter, investing in protective molecules and/or physical structures
shape of evergreen trees, which helps them ____
conical; reduce snow loads
tundra plant adaptations (4)
- must survive variable extremes in temperature (broad temperature optima)
- leaf retention (broad-leaved evergreen), stress tolerant
- clumps tend to retain heat emitted by dark soil
- dish-like flowers trap heat in spring
macro/micronutrients
needed in large/small amounts
photoperiodism
physiological response of organisms to length of day or night
phenology
the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate, plus habitat factors (ex: elevation)
ex: first frost, first swallow, first leaf, etc
shade tolerance of req’d plants
Very tolerant: W. hemlock
Tolerant: WRC, Spruce (2), Mt. Hemlock, Grand fir, Subalp fir
Intermediate: W. White Pine
Intol: Doug fir, Ponderosa, Lodgepole
ecology
the study of the relationship between organisms and their environment (biotic & abiotic)
resources
abiotic or biotic factors that can be consumed, making them less available for other (eg. food, water, mates); can undergo competition
conditions
abiotic or biotic factors that can influence an organism but can not be consumed (eg. temperature, day length, acidity); may alter competitive ability
habitability
the ability of the physical environment to support life
climate
the long-term average pattern of weather (local / regional / global)
“what you expect”
weather
the combination of temperature, humidity, precipitation, wind, cloudiness, and other atmospheric conditions occurring at a specific place and time
“what you get”
climate factors (5)
- radiation and albedo
- energy budgets
- wind (global circ, high/low pressure systems)
- temperature (effects of latitude/elevation, greenhouse effect)
- moisture (types of precip, seasonal distribution, latitudinal distribution, orographic precipitation, humidity, precipitation)
orographic precipitation
aka relief rainfall; caused when masses of air pushed by wind are forced up the side of elevated land formations, such as large mountains
forms of radiation
- ultraviolet & visible: short wave, from the sun,
- infrared (heat): long wave, from the earth, a function of temperature
albedo
- proportion of shortwave radiation that is reflected (0-1)
- white surfaces have highest albdos, dark surfaces the lowest
wind/circulation cells (3)
- Hadley (0-30°)
- Ferrell (30-60°)
- Polar (60-90°)
sinking air is…
high pressure, stable, good weather
rising air is…
low pressure, unstable, bad weather
temperature inversion
air temperatures increasing w/ height, usually due to warm, high pressure system moving on top of a cold, low pressure system
clearcuts are _____ and ______ than forests
hotter and colder
temperature and precipitation are both _____ in the tropics and ____ at the poles
higher / lower
mitigation of urban heat islands (3)
- increase vegetative cover
- use porous concrete surfaces
- change the albedo of surfaces
four features of temperate forests
- most are dominated by broad-leafed deciduous trees
- dormant during winter
- new leaves in spring
- photosynthesis in wet summer
why do conifers dominate PNW ecosystems? (3)
- short, cool, dry summers
- mild winters
- precipitation mostly in winter (75% between Oct-Mar)
10 indicators of global warming
- inc. humidity
- inc. air temps in troposphere (near surface)
- inc. temps over land
- inc. air temps over oceans
- inc. sea surface temps
- inc. sea level
- inc. ocean heat content
- dec. sea ice
- dec. glaciers
- dec. snow cover
human-scale indications of Global Climate Change (7)
- open arctic passageways (melting glaciers/ice caps)
- ski areas closing (dec. snow cover)
- heat waves (inc. air temps)
- inc. coastal flooding (inc. sea level)
- tropical plants moving north
- insect infestations (warmer winters)
- dec. in ocean pH (higher CO2 absorption)
5 basic soil forming processes
CROPT
- Climate
- Relief/topography
- Organisms/biotic activity
- Parent material
- Time
LAI
- leaf area index = the area of leaves per unit ground area
- leaf area = surface area of one or both sides
- cumulative leaf area and LAI increase as you move from top of forest canopy to the ground
sunflecks
brief increases in solar irradiance that occur in forest understories when sunlight is able to directly reach the ground. They are caused by either wind moving branches in the canopy or as the sun moves during the day; can account for 70-80% of solar energy reaching the ground in forest environments
regolith
the unconsolidated debris overlaying hard, unweathered rock
mechanical weathering
the destruction of rock materials into smaller particles by the action of water, wind, temperature, and organisms (esp. plant roots)
chemical weathering
the destruction of rock materials into smaller particles due to chemical alteration by water, oxygen, and acids
soil formation: climate
- affects the physical, chemical, and biotic breakdown of parent material
- leaching moves solutes throught the soil
- temperature influences the rates of biochemical reactions
soil formation: relief/topography
affects erosion, deposition, influence of climate (via gradient of slope)
soil formation: organisms/biotic factors (3)
- plant roots hasten process of weathering and pump nutrients from the soil depths up to the surface
- photosynthesis returns some of sun’s energy to the soil as organic carbon
- decomposition turns dead plants/animals back into organic matter, incorporated into the soil
soil formation: parent material
the material from which soil develops; primary determinant of soil properties
soil formation: time
well-developed soil may require 2,000 - 20,000 yrs to form
soil properties: color
- easily defined, useful characteristic
- organic matter (humus): dark or black
- iron oxides are yellowish-brown to red
- manganese oxides are purplish to black
- quartz, kaolin, gypsum, and carbonates are whitish and grayish
nitrogenase
only biological enzyme that can break up N2 triple bond
soil properties: texture
… is the proportion of different-sized soil particles present; affects pore space and the movement of air and water in/through the soil
- Gravel > 2.0mm
- Sand = .05 - 2.0mm
- Silt = .002 - .05mm
- Clay < .002mm
soil moisture: field capacity
when water fills all of the pore spaces and is held by capillary forces, at which point it is called capillary water
soil moisture: saturated
when there is more water than the pore space can hold and excess water drains from the soil
soil profile and horizons
profile: the sequence of horizontal layering
horizons: the horizontal layers of soil material
a general soil profile consists of…
- O horizon: organic material (litter)
- A horizon (topsoil): mineral soil and organic material leached from above accumulation (contains E)
- B horizon (subsoil): accumulates mineral particles and contains less organic matter than above layers
- C horizon: unconsolidated material that lies under the subsoil
- Bedrock
soil order
the broadest level of soil classification, of which there are 12; brought about by regional differences in geology, climate, and vegetation
potential energy
stored energy that is available for performing work
kinetic energy
energy in motion, performs work at the expense of potential energy
work
the storage of energy and the arranging or ordering of matter
first law of thermodynamics
energy is neither created nor destroyed, it is merely transferred or transformed
second law of thermodynamics
when energy is transferred or transformed, part of the energy assumes a form that cannot pass on any further; this reduction in potential energy is referred to as entropy;
the constant input of solar radiation provides the means to counteract entropy
GPP
gross primary production; total rate of photosynthesis, the energy assimilated by autotrophs
NPP
net primary production; the rate of energy storage as organic matter after respiration (R);
NPP = GPP - R
productivity
the rate at which organic matter is created by photosynthesis
biomass
the amount of organic matter present at any given time
standing crop biomass
mass of organic matter / area
g/m2
site index
measure of the productivity of a site based on how tall trees will grow over a specified period of time; higher = more productive;
ex: 50-year site index of 120 means that at age 50, the dominant trees would be expected to be 120 feet tall
R:S
root-to-shoot ratio
- 0.21, tropical rain forest - mostly shoots
- 1.2, arid shrublands - more roots than shoots
- 4.5, desert - LOTS more roots than shoots
secondary production / productivity
production by consumer organisms over time / rate at which heterotrophs produce biomass per unit area per unit time;
secondary production is constrained by primary production
HANPP
human appropriation of terrestrial NPP
consumption efficiency
defines the amount of available energy produced by any given trophic level (Pn-1) which is consumed by the next-higher level (In)
In / Pn-1
cow / alfalfa
carbon sequestration
the process through which CO2 from the atmosphere is absorbed by trees, plants, and crops through P.S., and stored as carbon in biomass and soils
Darwin’s theory of evolution is a two step process…
- the production of variation in some characteristic among individuals within the population
- this characteristic results in differences among individuals in their survival and reproduction
explains both diversity and similarity
convergent evolution
the independent evolution of a similar characteristic in two different species, and NOT derived from a recent, common ancestor
biogeography
the study of the spatial or geographical distribution of organisms, both past and present;
historical biogeography: origin, dispersal, extinction of groups
ecological biogeography: distribution of contemporary organisms
critical functions of vegetation (6)
- produces oxygen via PS
- role in nutrient cycling & energy flows
- affects soil characteristics
- provides habitat and food for wildlife
- produces food, wood, fuel, other materials for humans
- psychologically important for humans, who evolved in direct contact w/, and dependence on, vegetation, for food, shelter, and medicine
physiognomy
the general form or appearance of something
6 major biomes
Determined primarily by precipitation, then by temperature
- Aquatic (marine / freshwater)
- Forest (deciduous / conifer / …) - > 75cm rain/year
- Grassland - 25-80cm rain/year
- Savanna - codominance of grasses and trees
- Tundra - cold, short growing season
- Desert - < 30cm rain/year
biome subdivisions
- Life Zones: based on observed differences in plant/animal communities that change w/ physical characteristics
- Ecoregion: have similar latitudinal and continental locations that are defined by the processes that produce them. The divisions are more specific than biomes, taking into account biogeographical divisions.
leaf longevity: deciduous
leaves live for only a single year or growing season.
winter-deciduous: leaves lost in response to cold
drought-deciduous: leaves lost in response to dry conditions
leaf longevity: evergreen
leave live beyond a year
**broadleaf: **characteristic of environments with no distinct growing season; growth continues year-round
**needle-leaf: **characteristic of environments w/ a very short growing season or nutrient limitation
climate diagram
describes the local climate at representative locations around the world
Grasslands
- occur in midlatitudes in midcontinental regions where annual precipitation is reduced
- temperate grassland experiences recurring drought
- dominated by herbivorous species
- soils: Mollisols - relatively thick, dark-brown/black surface horizon rich in organic matter
Deserts
- occupy 25-35% of Earth’s landmass
- temperate deserts lie in rain shadow of mountain barriers or are located far inland
- most are found in Northern Hemisphere
- Sahara (North Africa) is world’s largest
- vegetation, species, etc vary in response to differences in
- moisture
- temperature
- soil drainage
- alkalinity
- salinity
- cold and high elevation hot can be considered shrub steppes or desert scrub, dominated by Artemisia
Forests
north->south: conifer, broadleaf decid., temperate evergreen
- humid midlatitudes dominated by broadleaf deciduous forests
- mild, moist Southern Hemisphere dominated by temperate evergreen forests
- Conifer forests found mostly in broad circumpolar belt across northern hemisphere; low temps limit growing season to a few months a year
N.A. Rocky Mountain forest zones and trees
- Subalpine forest: Picea englemanni, Abies lasiocarpa
- Middle elevations: Pseudotsuga menziesii
- Low elevations: Pinus ponderosa, Pinus contorta
this percentage of global fresh water is used for _______
70%, agriculture
aquatic ecosystems are classified based on their
____ and _____
salinity, movement
2 major and 4 minor types of aquatic systems
Marine: open-water, coastal
Freshwater: Lotic (rivers), Lentic (lakes)
wetlands are…
transitional lands between aquatic and terrestrial systems where the water table is at or near the surface of the land, covered by shallow water
wetlands have one or more of the following three attributes:
- the land supports plants, which are adapted to wet soil conditions
- the base land is predominately undrained wet soil
- the base is impermeable and is saturated with water or covered by shallow water at some time during the growing season of the year
ecological, economic, and social benefits of wetlands (7)
- fish/wildlife/plant habitat
- fish/shellfish nurseries of commercial and recreational importance
- hold & slowly release flood water & snow melt
- recharge groundwater
- store/transport sediments
- recycle nutrients
- recreation & wildlife viewing opps for ppl
additional note: high carbon + low nitrogen + tannic water = slow decomp.
coastal ecosystems include… (2)
- seashores: rocky/sandy beaches (rocky is better)
- habitat for barnacles, algae, oysters, sea stars, snails
- estuaries: partially enclosed bodies of water where fresh and salt water mix
- challenging environment (esp. salinity)
- high nutrient content
- Puget Sound sometimes classified aas estuary due to large river inflows
phenology
the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation)
in the 19__s, mangroves may have covered as much as __% of the word’s coastlines; replaced by ______
mangroves are a type of ______
70s; 75%; shrimp farms; estuary
some facts about bull kelp (4)
- brown algae
- dominant “overstory” species in Puget Sound
- fastest growing kelp in the world
- some are 120’ tall
riverine / riparian
of, relating to, or situated on the banks of a river
adaptations of Populus and Salix (willow) to thrive in riparian zones
- instant germination & rapid root growth, critical for seedling establishment
- meristamatic flexibility
- seeds are tiny w/o much to live on until PS starts
7 benefits of rivers
- water, sediment, and nutrients for agriculture
- habitat for diverse flora and fauna
- routes for commerce
- commercial and recreational fisheries
- aesthetic and cultural resource
- recreation
- hydropower
6 factors leading to eutrophication
- phosphates in water from detergents, fetilizers
- nitrogen from fertilizers
- waterfowl feces (in smaller lakes)
- sewage input
- all lead to increase in plant material -> increase in animals -> increase in decaying vegetation and animals
- … which leads to increased decomp and respiration
wildlife includes…
non-domesticated animal species, plants, fungi, and other organisms that grow or live wild in an area
environmental stability is…
the ability to sustain the exploitation of natural capital to meet growing human needs, such as:
- agriculture
- forestry
- fisheries
- industry
natural capital is…
the range of natural resources provided by ecosystems that humans draw upon as essential resources
sustainable resource use is a ____ between ___ and ____
w/ 3 key terms…
balance, supply, demand;
key terms:
- yield: amount of resource harvested per unit time
- rotation period / harvest interval: period of time for the resource to return to pre-harvest levels
- sustained yield: req’s resource to recover to preharvest levels
ecosystem services are…
the processes by which the environment produces resources (natural capital) to benefit humans
sustainability can be indirectly limited by…
adverse consequences of resource use: waste & by-products of production; pollution limits/disrupts ability of ecosystems to provide essential resources/services
agricultural ecosystems effectively have no ____ ____
nutrient cycle;
- fertilizers must be added
- pests & plant diseases spread rapidly through monocultures
sustainable forestry aims to achieve a balance between ______ and _____
net growth, harvest
-
rotation time depends on:
- tree species
- site conditions
- type of management
- intended use of harvested trees
removal of trees increases amount of ______ reaching soil surface, promoting _____ of remaining soil matter;
leads to increase in net ______, but lack of plants to take up nutrients means they are lost to ______ in ground and surface water
radiation, decomposition
mineralization, leaching
ecological restoration is…
the process of assisting the recovery of and management of an ecosystem that has been degraded, damaged, or destroyed
critical items for restoration success (5)
- assess initial conditions
- set clear and achievable goals
- select appropriate indicators
- develop hypotheses to test
- monitor and evaluate
r species selection factors (8)
- rapid development to maturity
- high r or net reproductive rate
- small body size
- few reproductive events
- many small offspring
- relatively short life span
- high mortality rate / low offspring survival rate
- minimal parental care / investment
r & K, and what are humans?
r = growth rate constant
K = carrying capacity; upper limit of pop. growth
humans are K-selected, but our growth curve looks like r-selected because we keep increasing the carrying capacity
K species selection factors (8)
- slower development to maturity
- higher competitive ability
- larger body size
- repeated reproduction events
- fewer, larger offspring
- longer life spans
- lower mortality rates, high offspring survival rates
- high parental investment
density independent factors (5)
- affects all pops regardless of pop size - usually abiotic
- unusual weather patterns (rain, temp)
- natural disasters
- human actions: damming, altering native veg
- pollution
(r-selected, often)
density dependent factors (3)
- effect depends on the size of the population, usually biotic factors
- availability of abiotic and biotic resources
- food, space, shelter, mates
- parasitism, predation, disease, competition
(K-selected, often)
factors that limit dispersal (3)
- mobility
- habitat
- necessary resources (biotic / abiotic)
- interactions w/ other animals
- predation, competition, disease
island biogeography theory (3)
the # of species found on an island (the equilibrium #) is determined by:
- the balance between extinction & immigration
- proximity: islands closer to mainland are more likely to receive immigrants
- size: chance of extinction greater on smaller islands
factors influencing island communities (9)
- degree of isolation
- length of isolation
- size of island
- climate
- location relative to ocean currents
- initial plant/animal composition if originally attached
- species composition of earliest arrivals
- serendipity/luck
- human activity
habitation loss may or may not _____, but….
fragment; loss is most important, despite usual emphasis on fragmentation
structural vs. functional corridors
structural: a narrow strip of land whose composition differs from that on either side
functional:
- conduit: passage, not reproduction
- habitat: duh
- filter: windbreaks, hedgerows
- barrier: roads, riparian buffers (water qual.)
- source: local reprod. exceeds mortality
- sink: local mortality exceeds reprod
wildlife responses to urbanization (3)
- exploiters
- Norway rat (introduced)
- American crow
- adapters
- Raccoon
- Eastern gray squirrel (introduced)
- avoiders
- Western gray squirrel
- Keen’s myotis
an urban ecosystem is…
a biological community where humans represent the dominant or keystone species and the built environment is the dominant element controlling the physical structure of the ecosystem
the two main functions of an ecosystem
- energy flow
- nutrient and material cycling
urbanization alters structure by altering… (3)
- the composition of the biological community including species, numbers, biomass, life history and distribution in space of populations
- the qty and distribution of the abiotic materials such as nutrients, water, etc
- the range of conditions of existence such as temperature, light, etc.
urbanization alters function by altering… (3)
- the rate of biological energy flow through the ecosystem
- the rate of material or nutrient cycling
- the biological or ecological regulation incl reg of orgs by env and reg of env by orgs
impacts of urbanization (9)
- soils & drainage
- water flow
- light availability
- albedo & winds (climate)
- land cover (vegetation)
- species/community composition
- nutrient cycling
- waste concentration
- energy demand concentration
ecology IN the city
examines ecological structure and function of habitats or organisms within cities
ecology OF the city
systems approach applied to urban areas;
one-way flows of energy and materials;
sources are continuously depleted, and sinks are continually overfilled
LEED vs. LBC
- LEED = Leadership in Energy and Environmental Design; based on inputs
- LBC = Living Building Challenge; based on outputs
- Bullitt Center is LBC
SEA
- Street Edge Alternatives project
- pilot program, completed 2001
- designed to provide drainage that more closely mimics the natural landscape prior to development than traditional piped systems
- reduced the total volume of stormwater leaving the street by 99%
3 features of regional climate that lead to formation of desert ecosystems
- dry, descending air masses
- rain shadows of coastal mountain ranges
- remoteness from oceanic moisture
* largely confined to two worldwide belts at 15° - 30° N & S
diffusion is…
… the movement of a substance from areas of higher to lower concentrations
ecology is…
the scientific study of the relatioship between organisms and their environment
the ITCZ is…
the Intertopical Convergence Zone, where trade winds meet, characterized by high amounts of precipitation.
Air piles up, warm humid air rises and cools. When the dew point is reached, clouds form and precip. falls as rain.
(The dry cool air then descends, warms, gathers moisture, causes deserts)
