chapter 11 Flashcards
the pattern of density and spacing of individuals in a population.
Spatial structure
the range of abiotic conditions (e.g., temperature, humidity, salinity) under which a species can persist.
fundamental niche
: the range of abiotic & biotic conditions under which a species can persist
realized niche
measure of the total area covered by a population (e.g., temperature and drought define the range of sugar maple).
geographic range
creates geographic ranges that are composed of small patches of suitable habitat.
Small-scale variation in the EVR
The Lewis’ monkeyflower lives at high elevations, whereas the scarlet monkeyflower lives at low elevations.
When planted outside their natural elevations, the two species grew poorly and experienced lower survival.
what does this suggest?
plants are limited by unsuitable environmental conditions.
general rule about population growth
populations can grow larger in more suitable habitats.
what does understanding the realized niche of a species help with
species aids in species conservation and can help to limit the spread of invasive species.
the process of determining the suitable habitat conditions for a species.
Ecological niche modeling
range of ecological conditions that are predicted to be suitable for a species (differs from the realized niche, which describes conditions in which a species currently exists).
Ecological envelope
what do researchers use to predict potential geographic range of a species when few individuals exist?
researchers can use historic distributions of species.
Temperature change can cause
a shift in the geographic range of species.
) What is the difference between pop. distribution and population dispersion?
Population dispersion is the spacing of individuals with respect to one another within a population.
species that live in a single, often isolated, location.
Endemic
species with very large geographic ranges that can span several continents.
Cosmopolitan:
total # of individuals in a pop. that exist w/in a defined area (e.g., total number of lizards on a mountain).
Abundance
The total abundance of a population provides a measure of
whether a population is thriving or on the brink of extinction.
the number of individuals per unit area or volume; calculated by dividing abundance by area
Density
where does the largest density of indiviiduals typically occur?
near the center of a population’s geographic range.
What mechanisms could cause evenly spaced distributions of individuals w/in pops.?
E. territorial animals
the spacing of individuals with respect to one another within the geographic range of a population.
Dispersion
when individuals are aggregated in discrete groups (e.g., social groups or clustering around resources).
Clustered dispersion
when each individual maintains a uniform distance between itself and its neighbors (e.g., defended territories, croplands).
Evenly spaced dispersion
when the position of each individual is independent of other individuals; not common due to non-random environmental heterogeneity
Random dispersion
the movement of individuals from one area to another.
Dispersal
the seasonal movement of individuals back and forth between habitats.
migration
counting every individual in a population.
Census
surveys that define the boundaries of an area or volume and then count all of the individuals in the space.
Area- and volume-based surveys
surveys that count the number of individuals observed as one moves along a line.
Line-transect surveys
method of population estimation in which researchers capture and mark a subset of a population from an area, return it to the area, and capture a second sample of the population after time has passed.
Mark-recapture survey
The American bullfrog is native to eastern NA, but it has been moved by humans and thrives in western NA. What does this suggest about the cause of the bullfrog’s historical range limit?
It was caused by an environmental barrier.
the absence of a population from suitable habitat because of barriers to dispersal.
Dispersal limitation
a strip of favorable habitat located between two large patches of habitat that facilitates dispersal (e.g., a narrow band of trees that connects forests).
Habitat corridor
when a large population is broken up into smaller groups that live in isolated patches.
Subpopulations
what happens When dispersal is infrequent
each subpopulation fluctuates independently.
population model that builds upon the basic metapopulation model and accounts for the fact that not all patches of suitable habitat are of equal quality.
Source-sink metapopulation model
in high-quality habitats, subpopulations that serve as a source of dispersers within a metapopulation.
Source subpopulation
in low-quality habitats, subpopulations that rely on outside dispersers to maintain the subpopulation within a metapopulation.
Sink subpopulation:
a population model that considers both differences in the quality of the suitable patches and the quality of the surrounding matrix (e.g., habitat corridors).
Landscape metapopulation model
