lallala new Flashcards
guild
group od organisms that make their living in a similar way
relative spp abundance
one of most fundamental aspects of community structure
dominance:
- biomass
- area
- #ind
regularities = most spp are moderately abundance, few are abundant
- unimodal distribution of rare-common
spp abundance lognormal distribution
- abundance is relative, normally 1spp 2x other = log2 scale
- each interval twice one previous
- larger sample show more lognormal dist
spp diversity
spp richness = #spp in community
- r=basic measure of spp
spp eveness = relative abundance
- more evenly common = more resistant and functioning ecosystem
integrative index of spp diversity
- shannon index
characterize species diversity in a community. Shannon’s index accounts for both abundance and evenness of the species present.
ranking abundance curves
- plot relative abundance of spp against tank in abundance.. or
- relative abundance
- dominance
- diversity
Plankton paradox
- live in simple environments and compete for same nutriences
- many spp coexist
- no evidence of competitive exclusion
Tilman 1977: 2 competing diatom spp (algae)
- coexistence depends on Si:P ratio which varies across lake
- Asterionella limited by Si
- Cyclotella limited by P
Disturbance and diversity equllibriam
model prediction: ppn densities do not change once equilibrium reached
- distrubance can affect spp diversity due to departure from avg conditions
- equilibrium = stability maintained by opposing forces, i.e if ppn altered by event it will return to equilibrium quickly
Disturbance
- fq and intensity
Connel 1975/187
disturbance:
intermediate levels = high diversity
high/low levels = low diversity
termperate grassland disturbance and diversity
disturbances = fire, drought, bison, prarie dogs (dig burrow)
- removal of veg causes increased light availability and modified soil properties. These patches allow for the colonization of different plant species.
- foster higher diversity by maintaining intermediate levels
Disturbance and intermediate disturbance hyp
- not uniformly true
- unimodal relationships are rare
distrubance on diversity depends on:
- biology of organisms
- details of disturbance
landscape
- heterogenous area composed of distinct patches
elements = distinct patches within landscape
landscape origin
geological process, climate, organisms, and fire contribute to landscape creation
- glaciation
- volcanism
- erosion
- sedimentation
In Canada and US glacial ages made landscapes
- periodic glaciers
- interrupted nu interglaciers (warmer periods between periodic
Glacier impact on landscape
- rock and soil moved great distances
- forward movement scores landscape
global scales = massive water storage
global sea levels = rise and fall
ephemeral nature = coral atolls and mangrove swamps
land bridges
North America glaciers
- vegetative colonizers from glacial retreat exposed areas come from glacial refugia and nanatak
- glacial refugia= areas never glaciated
- nunatak = mountain peaks surrounded but not covered
organisms and landscape structure
- Forest becomes agricultural
- abandoned farms retreat to forest
Netherlands: heathland revert to forest, agriculture varies the least
Blanket bog Ireland
Forest moved to lowlands due to heather flower colonizing bare soil, turning it more acidic, peat builds up.
Leaching occurs and land is cleared for agriculture. Then peat builds up and heather grows becomes Bog,
so agriculture moves to forest lowlands
Forest in between two
Fire and landscape structure
tropical savanna-boreal forest
- fire supress increase in biomass
- climate changes
-diference in agree structure of vegetation
- topographical differences
landsape structure
size, shape, composition, # and position of patches
patches = relatively homogenous area differing from surrounding
- patches form mosaic of landscape structure
matrix = element within landscape that’s most spatially continues
landscape impacts on processes
- move organisms
- landscape influence critter location
- rodents in smaller patches move more
- habitat fragmentation - spp richness, extinction probability, effect on trees - dist of spp
- heal ppn density
- nutrient cycling and aquatic wetland chemistry
Landscape fragmentation
- habitat fragmentation - spp richness, extinction probability, effect on trees
- effects boreal birds
1.small/isolated patches increase spp turnover, community more dynamic
2. spp turnover increase in smaller area and more resilient community
3. resident spp decrease in older forest, more transient spp increase
4. old forest decrease, new forest increase
corridors
corridors: habitat strip connecting similar habitat patches in fragmented areas
- lack of data that it increase movement
matrix and animal movement
matrix = dominate connected ecosystem
- structure influences ecological processes
- non-forested = maculata stay on stream
- forested = maculata left stream
- partial forest = C.aeubalilis left stream
landscape and lake chem
- lake position explain responses to drought
- upper lakes drop more than lower b/c of less GW flow
- mass of Ca2+ and Mg2+ highest in lakes unchanged at top b/c of isolation and more inflow at bottom
troposphere
earths surface to 9-16km
stratosphere
troposphere-50km
- ozone most concentrated
mesosphere and thermoshere
extend above stratosphere
greenhouse effect
earth surface trap heat w/ greenhouse gases
- h20,co2,ch4,nitrous oxide, cfc
- 30% incoming solar radiation reflected into space via clouds and particles
- 70% absorbed then re-mited as infrared, absorbed by ggs, or radiated back to eath
southern oscilation
oscilation in atmosphere prssure than extends across pacific ocean
- cause la ninas and elnino
el nino
brown chrismas
- occur along equatior
1. air over warmer western specific
2. sink as it reaches eastern pacific
3. moves west again and collects moisture, rising a warm
marine ppn effects:
- decrease upwellings of nutrient rich water
- decrease primary productions
- decrease fish
la nina
- periods of lower sea surface temo
Alberta’s atmosphere: human influence
praries increase in temp, short, warm winters, hot long summer. intense storems
- water flow decrease, supply challenge increase
- forest down, grassland up
