Conservation Science Chpater 10

What is meant by the term habitat fragmentation?

is the transformation of contiguous habitat into a patchwork of small, isolated remnants

What is the focus of the scientific discipline called landscape ecology?

focuses on effects of spatial patterning on interactions among species and their environment.

• In the hierarchy of ecological disciplines, landscape ecology falls between community ecology and ecosystem ecology

The planning of an “ideal” network of protected areas was said to consist of what four fundamental questions about the individual areas that make up the network?

1. How many protected areas should there be?

2. How big should each one be?

3. What shape should each
   one be?

4. How near to other protected areas should they be?

Which two famous ecologists were responsible for formulating the theory of island biogeography?

Robert H. Macarthur and Edward O. Wilson

The equilibrium theory of island biogeography is based on a balance between the rates of which two processes regarding habitat patches? (i.e., the number of species predicted to occupy a patch is determined by the rate of _____ and the rate of _____.)

colonization and extinction

According to the equilibrium theory of island biogeography, the rates of extinction and colonization depend on which two main characteristics of a patch of habitat?

the size and relative location/isolation

To what phenomenon does the term faunal relaxation refer?

the decrease in diversity after reducing the size of a patch

To what phenomenon does the term extinction debt refer?

The number of species predicted to become extinct after a reduction in patch size

Be familiar with (and able to succinctly explain) the SLOSS debate

• is an enduring focus of conservation science (“single large or several small” pieces of land debate)

• A single large area will have higher species richness than the small areas if the species composition is highly nested

• Data sometimes show that collections of small habitat fragments harbor more species than a single large patch

• The SLOSS debate often become moot of the priority is not just to preserve the greatest number of species

What geometric property of habitat patches does fragmentation affect? (Hint: Think in terms of edge and interior.)

Fragmentation increases proportion of edge habitats relative to interior habitat

provide/recognize examples of edge effects that are due to abiotic environmental conditions as well as to changes in interspecific interactions

changes in biotic interactions, such as increased exposure to predators

For a patch of a given area, what shape will have the smallest edge-to-interior area ratio

a circle

What do ecologists mean by the term metapopulation?

A collection of spatially isolated subpopulations of species that interact at some level

In a metapopulation model, the extinction risk of an entire metapopulation depends on a balance between the rates of which two factors?

extinction and colonization

four major simplifications that are inherent in most models of metapopulation dynamics (as listed in lecture and detailed in the textbook)

Patches are considered as either “occupied” or “unoccupied”

Complexities of population growth within subpopulations are typically ignored

Probability of colonization does not differ among patches

Probabilities of extinction does not differ among patches

What do the variables f and f* refer to in a metapopulation model?

rates of extinction and colonization affect the fraction of patches occupied (f)

In terms of a metapopulation model, in order for f* to be greater than zero, the probability of which factor has to be greater than the probability of which other factor?

the probability that the patch of colonization is bigger than the patch of extinction

In the language of a metapopulation model, why does the destruction of habitat increase the probability of extinction? (Hint: think in terms of colonization success.)

Destroying habitat increases the distance between patches, thereby reducing colonization success (c)

Metapopulation models have taught conservation scientists the following important lessons

1. unoccupied patches can still be essentail for the survival of a metapopulation

2. reduced dispersal success can cause a metapopulation to go extinct

3. the metapopulation can be extinct before the last patch is gone.

4. arrangements and connectivity of patches matter in the success of a metapopulation.

What do conservation scientists mean by the term dispersal corridor?

strips of habitat that link larger habitat patches

all meta population equations