SUNY ESF - EFB 320, Exam 2

Fundamental Niche

The range of abiotic conditions under which species can persist.

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.

Ecological Envelope

The range of ecological conditions that are predicted to be suitable for a species.

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 geographic ranges that can span several continents.

Abundance

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

Density

In a population, the number of individuals in a unit of area or volume.

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 Surveys

Surveys that define the boundaries of ana rea or volume and then count all the individuals in the space.

Line-Transact Surveys

Surveys that count the number of individuals observed as one moves along a 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 the 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 reporduces.

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.

Demography

The study of populations.

Growth Rate

In a population, the number of new individuals that are produced in a given amount of time minus the number of individuals that die.

Intrinsic Growth rate (r)

The highest possible oer capita growth rate for a population.

Exponential Growth Model

A model of population growth in which the population increases continuously at an exponential rate.

J-Shaped Curve

The shape of exponential growth when graphed.

Geometric Growth Model

A model of population growth that compares population sizes at regular time intervals.

Doubling Time

The time required for a population to double in size.

Density Independent

Factors that limit population size regardless of the population’s density.

Density Dependent

Factors that affect population size in relation to the population’s density.

Negative Density Dependence

When the rate of populatuon growth decreases as population density increases.

Positive Density Dependence

When the rate of population growth increases as population density increases. Also known as Inverse Density Dependence or the Allee Effect.

Carrying Capacity (K)

The maximum population size that can be supported by the envrionment.

Logistic Growth Model

A growth model that describes slowing growth of populations at high densities.

S-Shaped Curve

The shape of the curve when a population is graphed over time using the logistic growth model.

Inflection Point

The point on a sigmoidal growth curve at which the population achieves its highest growth rate.

Age Structure

In a population, the proportion of individuals that occurs in different age classes.

Life Tables

Tables that contain class-specific survival and fecundity data.

Stable Age Distribution

When the age structure of a population does not change over time.

Net Reproductive Rate

The total number of female offspring that we expect an average female to produce over the course of her life.

Generation Time (T)

The average time between the birth of an individual and the birth of its offspring.

Cohort Life Table

A life table that follows a group of individuals born at the same time from birth to the dearth of the last individual.

Static Life Table

A life table that quantifies the survival and fecundity of all individuals in a population during a single time interval.

Population Dynamics

Variation in population size over time or space.

Overshoot

When a population grows beyond its carrying capacity.

Die-off

A substantial decline in density that typically goes well below the carrying capacity.

Population Cycles

Regular oscillation of a population size over a long period of time.

Delayed Density Dependence

When density dependence occurs based on a population density at some time in the past.

Damped Oscillations

A pattern of population growth in which the population size initially oscillates, but the magnitude of the oscillations declines over time.

Stable Limit Cycle

A pattern of population growth in which the population size continues to exhibit large oscillations over time.

Deterministic Model

A model that is designed to predict a result without accounting for random variation in population growth rate.

Stochastic Model

A model that incorporates random variation in population growth rate.

Demographic Stochasticity

Variation in birth rates and death rates due to random differences among individuals.

Environmental Stochasticity

Variation in birth rates and death rates due to random changes in envrionmental conditions.

Metapopulation

The collection of subpopulations that live in isolated patches and are linked by dispersal.

Habitat Fragmentation

The process of breaking up large habitats into a number of smaller habitats.

Basic Metapopulation Model

A model that describes a scenario in which there are patches of suitable habitat embedded within a matrix of unsuitable habitat.

Source-Sink Metapopulation Model

A population model that builds on the basic metapopulation 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 metapopulation.

Sink Subpopulations

In low-quality habitats, subpopulations that rely on outside dispersers to maintain the subpopulation within a metapopulation.

Landscape Metapopulation Model

A population model that consdiers both differences in the quality of the suitable patches and the quality of the surrounding matrix.

Rescue Effect

The phenomenon of dispersers supplementing a declining subpopulation that is heading toward extinction.