Chapter 2: Ecosystem diversity

Biodiversity

The full range of living things in a particular area or region; it can be described at various levels, including genetic differences, different species or types of ecosystems in a larger area

Ecosystem

A self-sustaining unit consisting of the interactions between the species present and their environment

Genetic diversity

The combined differences in DNA of all the individuals in a species

Biotic factor

A living component of an ecosystem, including animals, plants and bacteria

Abiotic factor

A non-living component of an ecosystem, including the physical landscape, minerals and weather conditions

Community

Groups of different species in an area and their interactions

Food web

A diagram of interconnecting food chains that shows how different organisms feed on each other, thereby transferring energy and matter through an ecosystem

Species richness

The number of species in an ecosystem

Species evenness

The number of individuals of each species in an ecosystem

Percentage cover

The percentage of an area occupied by a species

Quadrat

A frame used to set a standard area for sampling

Simpson’s diversity index (SDI)

The combined ratio of individuals in each species to the total individuals in an ecosystem – a quantitative measure of biodiversity

Habitat

A location that meets all of the conditions for an organism’s survival

Microhabitat

A smaller location within a habitat

Transect

A narrow section taken straight across an area, along which observations or measurements are made

Random sampling

A sampling method that ensures each part of the sample area has an equal chance of being counted

Systematic sampling

A sampling method that occurs at fixed intervals, typically along an environmental gradient

Environmental gradient

A gradual change in an abiotic factor over distance

Stratified sampling

A sampling method that divides an area into strata for separate sampling

Stratum

A layer or subsection of a whole

Holdridge model

A system of large-scale zoning of vegetation correlated to simple climatic data

Specht's classification

Classifies ecosystems according to dominant vegetation type and canopy/foliage cover