Habitat Fragmentation Lecture Notes

These flashcards cover key concepts related to habitat fragmentation, including definitions, biological consequences, and the dynamics of habitat patching.

What is habitat fragmentation?

The process in which a habitat is broken into smaller, isolated patches, often due to human activity.

What is a patch in the context of habitats?

A small area of habitat that is isolated from other patches of the same or different habitat.

What is a corridor in habitat conservation?

A natural or created passage that connects isolated habitat patches, facilitating movement of species.

What is the matrix in habitat fragmentation?

The surrounding environment that influences the patches, typically different from the habitat type of interest.

How does habitat fragmentation affect biodiversity?

It can lead to a loss of biodiversity beyond just the area lost, due to isolation of patches.

What are some characteristics of a typical anthropogenic landscape?

It consists of many small, isolated patches of one habitat type within a matrix of another habitat type.

What is habitat heterogeneity?

Variation in habitat due to factors like elevation, slope, and disturbances, leading to a mosaic landscape.

What are some biological consequences of habitat fragmentation?

Initial exclusion, crowding effect, insularization and area effects, isolation, edge effects, and species invasions.

What is the initial exclusion effect?

Loss of habitat due to fragmentation leading to mortality or emigration of some individuals or species.

What is the crowding effect in fragmented habitats?

A short-term increase in population densities of mobile animals due to immigration of displaced individuals.

What does the species-area relationship (S = cAz) indicate?

It explains the relationship between the number of species (S) and the area (A) of a habitat.

What does the equilibrium theory of island biogeography suggest?

Species richness on an island is a dynamic equilibrium influenced by immigration and extinction rates.

How does isolation affect genetic diversity?

It decreases genetic diversity due to lack of gene flow, leading to inbreeding depression.

What are edge effects in habitat fragments?

Differences in physical and biological variables at the edges of habitat patches compared to core areas.

What are some physical edge effects?

Changes in microclimate, such as increased sunlight and wind, resulting in drier, warmer conditions.

What are biological edge effects?

Changes in predation and parasitism rates, often leading to increased predation in edge habitats.

How does the ratio of edge to core area depend on habitat size?

Smaller areas have a higher percentage of edge relative to core; larger areas have a lower percentage of edge.

What is the average size of forest patches in the U.S.?

The average size is approximately 34 hectares.