exam 4 Flashcards
Community
a group of interacting plants and animals inhabiting a given area
Dominance
if a species if found to predominate (or have a large proportion of the total number of individuals) it is defined as a dominate species
Species richness
number of species
Species evenness
relative abundance of individuals among the species
Simpson’s index
(number of individuls of a species/number of inidivudals of all species) which ranges between 0(as richness and evenness increase, value approaches ) in comparison to 1(no diversity)
Shanon Index
no diversity (one only species) is 0! Max diversity is ln (total number of species)
Rank-abundance curves
graph that has rank abundance (species rank from most to least abundant) on x axis and relative abundance on y axis… THUS THIS GRAPH CANNOT EVEN INCREASE AT ANY POINT…
Keystone species
species that has dispoorportionately large effect on its environment reltive to its abundance. They maintain a critical role in the ecological community EVEN when in small abundance
Basal species
Basal species – species that feed on no other species! Typically plants
Intermediate species
Intermediate species – species that are both predator and prey
Top predator
Top predator – it is eaten by no other species… usually is a cannibal as well?
Food web connectance
(number of links/maximum possible number of links or speciescount^2)
linkage density
links/species
chain length
length from basal to top predator
compartmentalization in food webs
extent to which a food web contains relatively islolated subwebs
Diffuse interactions
when the abundance of the species is influenced by a number of competing species, the removal of single species may have minimal or insignificant effect on the chain
Indirect interactions (interpretation from analysis of food webs)
effects have big effects on whole communities! Direct interactions occur when anything is eaten or eats. Indirect interactions occur between organisms that don’t eat or be eaten directly by eachother but are impacted through other organisms… like how grass will help the top predatoor
Apparent competition
A form of competition between species or group of organisms indirectly competing with another species or group of organisms, which both of them serve as prey of a predator…. For example if food source for an organism(1) goes up, so that organism’s predator goes up, thus hurting another species(2) that that predator usually eats… competition between the two consumers(1 AND 2)!
Trophic cascade
species interactions lead to changes in pop sizes of various species?? CHANGE IN TOP PREDATOR
Zonation
spatial changes in community structure as one moves across the landscape…different zones
Role of resource availability on plant community species diversity- species interactions on a large scale
competition leads to changes in seedling survival, mean growth rate, and flowers produced per plant… THERES A TRADEOFF BETWEEN TOLERANCE TO LOW RESOURCE AND CMPETITIVE ABILITY
Relationship between habitat diversity and species diversity in animal communities
(e.g., Foliage height diversity and bird species diversity)
greater habitat diversity leads to more species diversity. WITH MORE FOLIAGE HEIGHT DIVERSITY (more vertical layers of vegetation) THERE IS MORE BIRD SPECIES DIVERSITY
Succession
Succession - temporal changes in community structure…changes in dominance
Primary vs secondary succession
Primary – succession on a previously unoccupied site
Secondary - succession following disturbance that has removed previous vegetation
Allogenic environmental change
abiotic factors NON LIVING
Autogenic environmental change
biotic factoors ORGANISMS
WHICH GROW FIRST SHADE TOLERANT OR INTOLERANT IN SUCCESSION?
intolerant! then tolerant
Importance of mutualistic relationship between plants and N-fixing bacteria in
early stages of primary succession in terrestrial environments
IN PRIMARY SUCCESSION, NOT MUCH NITROGEN TO START SO N FIXING BACTERIA LIKE RHIZOBIUM IS VERY NEEDED AND HELPFUL
Tilman Model of Succession
during initial stages of primary succession, light availability is high and nitrogen is low, as time progresses, light availability declines and nitrogen availability increases. This leads to changes in plant species over time due to different needs
Grime Model of Succession
separates out which plants tend to be around during SECONDARY succession, starts with R then C then S species!
Patterns of species diversity during succession
species diversity increases then decreases …UPSIDE down parabola… in plants it starts with herbs which have the most species diversity, then shrubs nd tree stages which make species diversity go down
Intermediate Disturbance Hypothesis
INTERMEDIATE FREQUENCY OOF DISTURBANCE HAS highest diversity, high frequency and low frequency both have lower diversity
Influence of resource availability of patterns of diversity through succession
starts with small birds and small mammals, slowly gets up to deer and foxes and other kinds of birds
zonation vs sucession
zonation is over landscape changes, sucession is over time chnges
chronosequence
series of sites within an aarea that are at different stages of succession…. Allows ecologists to look at different seral stages!
Order of trees in succession?
pine then oak! This is due to AUTOGENIC changes in light
peak of diversity occurs when during succession?
during the middle stages of succession after the arrival of later species but before the decline of early species
slower population growth rates leads to species diversity remaining higher for longer periods of time before dominance of new species’ take hold!!
true
Landscape mosaic
patchwork of different types of land cover
Habitat fragmentation
reduction in total habitat/community… creates habitat patches of various size and shape….they’re isolated usually!
Matrix
Matrix – surrounding communities around patches
Patch
Patch- areas of more or less homogenous cover in relation to the matrix, as opposed to a landscape in total which is heterogenous
Border
Border – the place where the edge of one patch meets the edge of another adjacent patch or matrix…
Corridor
Corridor- strips of habitat or cover that is similar to the patches which they connect and increase the connectivity of the landscape… they connect two patches through a usually thin space… INCREASES CONNECTIVITY
Edge
Edge – place where two communities meet
Ecotone
Ecotone – transition zone between two structurally different communities
Edge species
Edge species – species that lives ONLY along edges between communities
Edge effect
Edge effect – the fact that borders are often populated by a rich diversity of life
PAtch size effect on edge and interior habitats
bigger patches are more likely to have more kinds of plant species and thus created more habitats for species.
Influence of patch size on species composition (edge vs interior species)
bigger patch size means greater populations of individuals and greater numbers of species (species richness). Bigger patch sizes can hold larger animals like bears who have bigger home ranges. More predators along boundaries than interior!
Patch size and habitat heterogeneity relationship?
positive correllation
Home range size impact
Home range size - larger animals tend to need more home range/patch size
Connectivity
Connectivity – the degree to which the landscape facilitates or impedes movement among patches… influenced by the proximity of the patches to one another
Structural connectivity
Structural connectivity - the physical arrangements of patches
Functional connectivity
Functional Connectivity – takes into account physical arrangement AND the organism/species being studied to determine connectivity! For example a two spaces may not be structurally connected but functional connected for species of butterflies and birds. (THIS IS SPECIES AND LANDSCAPE SPECIFIC)
Connectivity and species diversity
decreasing species richness with increasing distance to nearest neighboring patch… more connectivity more diversity
Corridors and species diversity
– more corridors, more diversity… also corridors are often human made (strips of forests after development)but they really do help to create gene flow between subpopulations
Theory of island biogeography
Immigration and extinction rates – equilibrium species richness – the number of species on an island represents a dynmic equilibrium between the immigration of new colonizers and the extinction of previously established ones… the equilibrium is achieved when the immigration rate = the extinction rate….
Influence of island size and distance from mainland
greater the island size, greater species richness… greater the distance from mainland, less immigrants, decrease in equilibrium number of species (also meaning less species richness)
in Metapopulation theory:
Equilibrium proportion of patches occupied – colonization and extinction of patches – the point where the rate of patch colonization and the rate of patch extinction are equal to zero. By colonization, they men the movement of individuals from occupied patches to unoccupied patches
Island biogrography vs metapopulation
island biogeography looks at isolated populations and meta looks at them as wholes who colonize
Influence of patch size and isolation on rates of colonization and extinction
increasing patch size functions to decrease the rate of extinction so higher P (proportion of occupied patches). Increasing distance from neighboring patches functions to decrease the rate of colonization, so MORE ISOLATION (MORE DISTANCE) means LOWER P
Metapopulation theoryh graph
When this is graphed out, the extinction rate is linear, and the colonization rate is a negative parbola. The point where they cross is the equilibrium… at values of P (proportion of patch occupied) above .5, the rate of change for the metapop is negative nd the vlue of P declines
plants in boundary environments tend to shade-intolerant (need sun) and can tolerate dry conditions; animals in boundary environments tend to require 2 or more habitats for survival (for example, need low shrubbery for nesting and tall trees for food so you go back and forth between
yep
Why are boundaries so diverse?
Allows species from both communities PLUS species adapted specifically to edge
Two influences of edge effect
edge effect influenced by size of boundary and the degree of contrast between the two adjoining communities (the greater the contrast between adjoining patches, the greater the diversity of species)
as patch size increases, the ratio of edge to interior…
decreases. A small patch is all boundary/edge, eventually an interior will form as it grows though. A very long thin habitat is ALL BOUNDAARY
as patch size increases, edge species richness decreases and interior species richness increases
yep
if the number of species on an island is greater than the equilibrium species richness, then the extinction rate is higher than the immigration rate (because more species means more competition so more extinction), thus there is a decline in species richness.
mhm
Ecosystem
Ecosystem – the biotic community and its abiotic environment functioning as a system
food web/chain
Food web/chain- Diagram defining the relationship between different feeding groups (groups of organisms that derive their food resources in a similar manner = trophic groups)…web is all, chain is one lineage?
Primary productivity –
photosynthesis – respiration… net is for ALL AUTOTROPHS in the system
Compensation depth
net photosynthesis is equal to zero… photosynthesis = respiration
Optimal net primary productivity weather?
COOL AND WET
Autochthonous
organic carbon produced within an ecosystem (from quatic plants, algae, phytoplankton.
allochthonous
inputs from outside the ecosystem… derived from dead organic matter from terrestrial ecosystems that enter water
In smaller streams more auto or allo?
ALLO
Secondary productivity
heterotrophic productivity (from one trophic level to the next)
Consumption efficiency (CE)
Consumption efficiency (CE) – ratio of energy ingested to production of the next lower trophic level (I/Pn-1 OR Ingestion/production at the next lower level
Assimilation efficiency (AE)
Assimilation efficiency (AE) – efficiency of the consumer to extract energy from the food it consumes (A/I or Assimilation/Ingestion)
Production efficiency (PE)
Production efficiency (PE) – efficiency of the consumer to incorporate assimilated energy into new tissue (P /A or production/assimilation
Difference between endotherms and ectotherms in PE –
ectotherms are more production efficient.
Transfer efficiency (TE)
Pn / Pn-1 is the trophic efficiency or transfer efficiency from one level to the next
in aquatic, respiration rate is relatively constant with depth, gross productivity declines with depth as function of decling llight
yeah
two types of biogeochemical cycles
gaseous and sedimentary
Retranslocation
taking nutrients back out of leaves to retain nutrients
General model of decomposition (mass loss):
General model of decomposition (mass loss): %OMR = e-k*t where k is decom coefficient and t is time… if k is greater, then greater rate of decomposition
Controls on decomposition rate: litter quality (lignin) and climate
more lignin means slower decomposition rate…also want warm wet conditions foor decomp!
Mineralization
As dead organic matter is consumed by decomposers, nutrients are transformed from an organic to an inorganic (or mineral) form
Immobilization
If the dead organic matter does not provide sufficient nutrients for the decomposers, they will take-up mineral nutrients from the soil.
Net Mineralization Rate
The difference between the rates of mineralization and immobilization
General patterns of mass loss, N, C:N and lignin through the process of decomposition General patterns of mass loss, N, C:N and lignin through the process of decomposition
more ligin, slower decomposition ; decline in C:N during decomp due to respiration, INCREASE in nitrogen portion as carbon is released
More simple litter that is glucosey will break down easier
true
Aerobic vs anaerobic
aerobic conditions allow for faster decomp
Epilimnion
Epilimnion- surface warm and low density water
Metalimnion
Metalimnion – thermocline (rapid decrease in water temp)
Hypolimnion
Hypolimnion – bottom cold high density water
Thermocline
Thermocline – rapid change in temp moving down
Influence of thermocline dynamics on both seasonal and geographic patterns of NPP
thermocline forming leads to higher net primary, until nutrient uptake starts to make it decrease! Also thermocline causes big increases in NPP for temperate and polar waters but not tropical
decomp is a form of nutrient recycling!
yerp
