ch 10 population distributions

spatial structure

spatial structure

the pattern of density and spacing of individuals in a population

fundamental niche

the range of abiotic conditions under which species can persist. includes temperature, humidity, salinity, light, pH, nutrient availability, and oxygen conditions

realized niche

the range of abiotic and biotic conditions under which a species persists

ecological niche modeling

the process of determining the suitable habitat conditions for a species. leads to ecological envelope

ecological envelope

the range of ecological conditions that are predicted to be suitable for a species. similar to realized niche, but is only a prediction.

geographic range

a measure of the total area covered by a population

endemic

species that live in a single, often isolated location

cosmopolitan

species with very large geographical ranges that can span several locations

abundance

the total number of individuals in a population that exist within a defined area

density

the number of individuals in a unit of area or volume, in a population. density = abundance / area

dispersion

the spacing of individuals with respect to one another within the geographic range of a population

clustered dispersion

a pattern of population dispersion in which individuals are aggregated in discrete groups

evenly spaced dispersion

a pattern of dispersion of a population in which each individual maintains a uniform distance between itself and its neighbors

random dispersion

a pattern of dispersion of a population in which the position of each individual is independent of the position of other individuals in the population

dispersal

the movement of individuals from one area to another

census

a count of every individual in a population

survey

counting a subset of the population

area and volume based surverys

surveys that define the boundaries of an area or volume and then count all the individuals in the space

line transect surveys

surveys that count the number of individuals observed as one moves along the line

mark-recapture survey

a method of population estimation in which researchers capture and mark a subset of a population from an area, return it to an area, and then capture a second sample of the population after some time has passed

lifetime dispersal distance

the average distance an individual moves from where it was hatched or born to where it reproduces

dispersal limitation

a substantial barrier that prevents dispersal between suitable habitats

habitat corridor

a strip of favorable habitat located between two large patches of habitat that facilitates dispersal

ideal free distribution

when individuals distribute themselves among different habitats in a way that allows them to have the same per capita benefit