51) Use the following abstract from Theoretical Population Biology to answer the question.
Abstract:
We derive measures for assessing the value of an individual habitat fragment for the dynamics
and persistence of a metapopulation living in a network of many fragments. We demonstrate that
the most appropriate measure of fragment value depends on the question asked. Specifically, we
analyze four alternative measures: the contribution of a fragment to the metapopulation capacity
of the network, to the equilibrium metapopulation size, to the expected time to metapopulation
extinction and the long-term contribution of a fragment to colonization events in the network.
The latter measure is comparable to density-dependent measures in general matrix population
theory, though some differences are introduced by the fact that “density dependence” is spatially
localized in the metapopulation context. We show that the value of a fragment depends not only
on the properties of the landscape but also on the properties of the species. Most importantly,
variation in fragment values between the habitat fragments is greatest in the case of rare species
that occur close to the extinction threshold, as these species are likely to be restricted to the most
favorable parts of the landscape. We expect that the measures of habitat fragment described and
analyzed here have applications in landscape ecology and in conservation biology.
Copyright © 2003 Elsevier Inc. All rights reserved. (Otso Ovaskainen and Ilkka Hanski. 2003.
How much does an individual habitat fragment contribute to metapopulation dynamics and
persistence? Theoretical Population Biology 64:481-95.)
One measure for the value of the patch was given by the long-term contribution of a fragment to
colonization events in the network. How do the properties of a landscape and the properties of a
species affect the value of a patch? The value of the fragment depends _____.
A) on the properties of the landscape and the properties of the species
B) only on the properties of the landscape and not on the properties of the species
C) not on the properties of the landscape but only on the properties of the species
D) on neither the properties of the landscape nor on the properties of the species
52) A population of white-footed mice becomes severely overpopulated in a habitat that has been
disturbed by human activity. Sometimes intrinsic factors cause the population to increase in
mortality and lower reproduction rates to occur in reaction to the stress of overpopulation. Which
of the following is an example of intrinsic population control?
A) Owl populations frequent the area more often because of increased hunting success.
B) Females undergo hormonal changes that delay sexual maturation, and many individuals suffer
depressed immune systems and die due to the stress of overpopulation.
C) Clumped dispersion of the population leads to increased spread of disease and parasites,
resulting in a population crash.
D) All of the resources (food and shelter) are used up by overpopulation, and much of the
population dies of exposure and/or starvation.