Population Ecology distribution and abundance Flashcards
Population
Group of individuals from the same species that co-occur in space at the same time
density
of individuals per unit area
Distribution
-size shape and location of area occupied
Absolute density
The number of individuals of a population per unit area
Ecological Density
Number of individuals of a population per unit area SUITABLE HABITAT
ie moose per hectar of forest
Metapopulation
-population of many species that do occur in spatially isolated patches
-subpopulations living on such patches by exchange of individuals making up the metapopulation
5 essentials of a metapopulation
- metapopulations are populations of subpopulations
- subpopulations connected by movement of individuals from one subpop to another
- subpop can go extinct and recolonize over time
- subpopulation extinction greatest for small subpop
5.y-dependent and density-independent population dynamics occur within each population
Rocky Mountain parnassian butterfly
-specific niche requirement distributed in patches
-subpop size coorelates with meadow size
-immigration from small pop to large ones
what is decreasing size of rocky mountain parnassian butterfly?
fire suppression and warming climate, forest encroachment
The distribution of a population is limited by
physical environment and species niche requirements
what are the abiotic and biotic factors that make up Habitat suitability
Abiotic
soil comp, ph , temp, precip
biotic
-interactions(territoriality etc) , herbivores, preds, pathogen
what influences population distribution and abundance
habitat suitability
historical factors
dispersal limitations
WHy arent polar bears in antarctica?
They cannot travel through warm areas because of physiological limitations, cannot disperse to suitable habitat
Dispersal
Permanent movement of individuals
Natal Dispersal
Juveniles disperse to another location permanently
Greenwood animals vs birds dispersal
-Sex based dispersal
-Female BIRDS more likely to undergo natal dispersion–> because males are territorial
-males more likely–> mammals more likely to be polygynous , reduce risk of relative females
Seed dispersal modes
Gravity
Explosive
by wind
water
animals
heavy fruits fall from tree and roll
short
short distances
short to long distance
short to long
transporting long to short
Examples of seeds being dispersed by animals
cougars, pacus, lizards
cougars eat herbivores
pacus–> fish that eat fruit
lizards–> eat seeds and shit in rocks which is suitable environment
Dispersion can alter
species distributions and local pop density
immigration
movement into a local pop
emmigration
movement out of a local pop
pred responses to variation in prey density
functional RESPONSE
-increase or decrease feeding rate
NUMERICAL RESPONSE
-increase or decrease pred pop in respnse to change in prey density
2 drivers of numerical responses
reproduction response
dispersal(aggregative response)
reproduction response ( a driver of numerical response)
example of animal
-time lag between peak prey and pred
-non synchronized dynamic
wolves
aggregative response
what type of animal do dis
no time lag between peak prey and pred
synchronized
bird of prey
the 3 Dispersal patterns
RANDOM-
REGULAR-
Clumped-
Random distribution
-equal chance of living anywhere.
-neutral interactions between organisms, and local environment–>
-random disturbance, uniform distribution of resources
Regular Distribution
-uniformly spread
-negative interactions between individuals or depletion of resources–>
-uniform distribution of resources
-uniform depletion of resources
Clumped distribution
higher probability of being in some areas, Attraction between individuals or a common resource
-patchy resources
-dispersal limitation
Large scale Distributions are
How individuals are distributed over scales where there is significant environmental change
Large scale distributions tend to be
clumped
the wider a species large scale distribution, usually
The broader the niche
-bird pops
Why arent all species in all the places?
principle of allocation
-takes extra energy to survive and reproduce in regions on edge of niche
-surviving on edge not efficient
Africanized bee
aggressive, efficient,
large colonies bc of excess food
massive swarms
outcompete other bees
too cold for them to travel north and south of range
or dispersal lag–> not enough time to colonize new area, will happen eventually
Mountain pine beetle
usually limited by cold temps(-40)
however recent outbreaks linked to favorable weather in summer and winter
dry summer good for beetles as tree defences crippled
also climate control
range expansion due to climate change
theoretically dispersal allows species to move along climate,
only if climate change slow enough to keep up’
–>solution, speed up climate change as much as possible
population density decreases with
and why?
increasing organism size
body scaling
metabolic demand and resource availability
–>large organism take up hella space and resources
why do birds and mammals occupy similar body body mass ranges?
mammals live in more dense populations as birds are more mobile and can forage over large areas
density decreases with increasing biomass in a process called
why?
self thinning
competition between plants
what is different and similar with plant size spectum as opposed to animals
relationship more dynamic in plants life stages in plants – self thinning
body scaling and resource demands vs. availability have similar patterns
Commonness and rareness of species influenced by:
geographic range
habitat tolerance
local pop size
common species have
no aspects of rarity
somewhat vulnerable species have
one aspect of rarity
more vulnerable species have
two aspects of rarity
rare species have
three aspects of rarity
IUCN red list
LC,NT,VU,EN,CR,EW,EX
—————————->
SARA Species at risk act
risk categories
special concern :sensitive to human disturbance
Threatened: likely to be endangered if limiting factors not reversed
Endangered: at immediate risk of extirpation or extinction
exterpation: no longer exist in canada
Extinct: no longer exists anywhere
Data deficient- not enough info
