population distributions Flashcards
spatial structure
the pattern of density and spacing of individuals in a population
fundamental niche
the range of abiotic conditions under which a species can persist
-includes the range of temperature, humidity, and salinity conditions that allow a population to grow, survive, and reproduce
realized niche
the range of abiotic and biotic conditions under which a species does persist
-determines the geographic range of populations that compose a species
geographic range
a measure of the total area covered by a population
ecological niche modeling
the process of determining suitable habitat
-can help predict probability of successful reintroductions for nearly extinct species, the area where new pests might spread after introduction
-challenging when few individuals living in the wild
ecological envelope
the range of ecological conditions that are predicted to be suitable for a species from ecological niche modeling
-similar to the realized niche but is a predictions of where a species could POTENTIALLY live
an cause a shift in the geographic range of species
temperature
population characteristics
-geographic range
-abundance
-density
-dispersion
-dispersal
endemic (geographic range)
species that live in a single, often isolated, location
cosmopolitan (geographic range)
species with very large geographic ranges that can span several continents
abundance
the total number of individuals in a population that exist within a defined area
- number of sunfish in a lake
density
the number of individuals per unit area or volume
-calculated by dividing abundance by area
dispersion
the spacing of individuals with respect to one another within the geographic range of a population
clustered dispersion
when individuals are aggregated in discrete groups
-clustering around resources or social groups
evenly spaced (uniform) dispersion
when each individual maintains a uniform distance between itself and its neighbors
- defended territories or croplands
random dispersion
when the position of each individual is independent of other individuals
- not common due to nonrandom environmental heterogeneity
dispersal
the movement of individuals from one area to another
-migration
census
counting every individual in a population
area and volume based surveys
surveys that define the boundaries of an area or volume and then count all of the individuals in the space
line transect surveys
surveys that count the number of individuals observed as one moved along a line
-this data can be converted into area estimates of a population
mark recapture survey
a method of population estimation in which researchers capture and mark a subset of a population from an seas return it to the area, and capture a second sample of the population after time has passed
lifetime dispersal distance
the average distance an individual moves from where it was born to where it reproduces
-provides an estimate for how fast a population can increase its geographic range
populations with high abundance also have
large geographic ranges
the density of a population is negatively correlated to
the body size of the species
habitat corridor
a strip of favorable habitat located between two large patches of habitat that facilitates dispersal
dispersal limitation
the absence of a population from suitable habitat because of barriers to dispersal
ideal free distribution
when individuals distribute themselves among different habitats in a way that allows them to have the same per capita benefit
subpopulations
larger populations are broken up into smaller groups of conspecifics that live in isolated patches, called subpopulations
three models
-basic meta population model
-source sink metapopulation model
-landscape population model
basic meta population model
a model that describes a scenario in which there are patches of suitable habitat embedded within a matrix of unsuitable habitat
source-sink meta-ovulation model
a population model that builds on the basic meta population model and accounts for the fact that not all patches of suitable habitat are of equal quality
source subpopulations
in high-quality habitats, subpopulations that serve as a source of dispersers within a meta population
sink subpopulations
in low-quality habitats, subpopulations that rely on outside dispersers to maintain the subpopulation within a meta population
landscape meta population model
a population model that considers both differences in the quality of the suitable patches and the quality of the the surrounding matrix
