9 – Population Dynamics

Which factors increase population size?

Immigration and births.

Which factors decrease population size?

Emigration and deaths.

True or False: Dispersal can only decrease the size of a population but it cannot increase it.

False (Dispersal includes both immigration, which increases size, and emigration, which decreases it).

True or False: A population is declining if it displays a net reproductive rate of less than one.

True.

What is the primary difference between Type 1 and Type 2 survivorship curves?

Type 1 represents declining survival rates as individuals age (high survival when young)

Type 2 depicts constant mortality across all age groups.

In general, how does fragmentation affect habitat area?

Fragmentation increases edge area.

In ecological interactions, what defines a "numerical response"?

A change in the population density of a predator species in response to variations in prey abundance.

In a fragmented forest, which patches generally maintain higher population sizes?

Patches that are closer to a source patch.

How do macroinvertebrates colonize upstream locations despite the "drift paradox"?

They disperse upstream during their flight-capable life stage.

Define "Intrinsic rate of increase (r)".

A measure of population growth potential.

What is a "Fecundity schedule"?

A description of reproductive output at different ages.

What characterizes a "Metapopulation"?

Groups of subpopulations connected by migration.

In a species that produces many more offspring than will survive, which survivorship curve would you expect?

Type III curve.

Which factor influences local population size specifically within metapopulations?

Patch size.