| I'm interested in the processes that translate
individual-level behavior to metapopulation- or population-level behavior.
I want to explore how the spatial heterogeneity of habitat quality affects
individual behavior, and what effect conspecific density has on habitat
use? Concepts such as Fretwell and Lucas' ideal free distribution and
it's extension into pelagic fisheries, MacCall's Basin model, predict
population behavior dependent on habitat quality and conspecific density.
How are predictions of this density-dependent habitat selection affected
when large-scale environmental gradients are super-imposed on small-scale
heterogeneity? or when directionality is added to individual movement?
Does the interaction of environmental quality and conspecific density
tend toward any spatial structure of characteristics such as age, size
or condition?
The gag population in the northeastern Gulf of Mexico represents a system
in which these questions of space, environmental heterogeneity and density
may be addressed. After leaving the nearshore nursery grounds, juveniles
and pre-reproductive females spend a few years moving about on the shallow
shelf before joining the reproductive population in deeper water. The
shallow shelf is characterized by low-quality soft-bottom habitat with
sporadic patches of higher, but variable quality hard-bottom. As gag
move out across the shelf they take up residency in hard-bottom areas
for months at a time. It appears that individual choice of location
is affected by habitat quality and conspecific density. In turn, these
factors lead to differences in fish size and condition. The role of
these differences in overall individual fitness and population dynamics
is unclear.
I want to explore how individuals' decisions about habitat utilization
affect the reproductive potential of individuals and the population.
Is movement across the landscape random or directed? Do assumptions
on this question lead to different expectations of population distribution
and dynamics? Does variation in individual growth, size at age, and
condition, established early on, carry through to reproductive output
or is early variation reduced through time as individuals encounter
higher and lower quality habitat?
e-mail address: zbiesing@ufl.edu
Page created September 6, 2005
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