LECTURE NOTES - Week 4

Population

A group of individuals of the same species that live in the same area at the same time and interact with one another.

Abundance

The number of individuals of a species or population (population size).

Distribution

The geographic area where the individuals of the species are present.

Genet

The product of a single fertilization event (a single genetic individual).

Ramet

Actually or potentially independent members of a genet.

Absolute population size

The actual number of individuals in a population.

Relative population size

The number of individuals in one time interval or place relative to the number in another.

Area-Based Counts

Used to estimate population abundance of immobile or limited mobility organisms.

Density Estimation Formula

D = n/(2w₀L), where D is estimated density, n is the number of objects observed, w₀ is distance from the line where detectability is assumed perfect, and L is length of transect.

Capture Mark-Recapture Method

Method to estimate population size using R/M = C/N, where R is individuals recaptured, M is marked individuals, C is total captured, and N is estimated population size.

Dispersal

The movement of individuals into (immigration) or out of (emigration) an existing population.

Metapopulation

A group of geographically isolated populations linked together by dispersal.

Endemic Species

A taxa that is native to a certain limited area, found only in one location and nowhere else on the planet.

Cosmopolitan Species

A taxa whose range extends across all or most of the world in appropriate habitats.

Biotic Factors

Factors affecting species distribution and abundance, including food resources, vegetation structure, and competition.

Abiotic Factors

Non-living environmental factors impacting species distribution, such as temperature, water availability, and nutrients.

Rescue Effect

A phenomenon where high rates of immigration can help to prevent extinction in lower quality habitat patches.

Species Distribution Models (SDMs)

A tool that predicts a species’ geographic distribution based on environmental conditions.

Wallace’s Line

A boundary that reflects the distinct separation of species distribution, affecting biodiversity.

Capture-Mark-Recapture Assumptions

Key conditions such as closed population, no mortality between capture and recapture, and the marking techniques not affecting survival.