Bahamas Estuarine
Food Webs
  Estuary
function is dependent on tidal flow inherent to these ecosystems,
and thus disruption of tidal exchange has drastic consequences
for food web structure and function. Roads in the Bahamas
typically are built along the shoreline, thereby impeding
tidal flow. Our work (with Albrey Arrington, Perry
Institute for Marine Science) is focused
on the impacts of this reduced tidal flow, largely from a
food web perspective.
Species composition of estuaries along a gradient
of fragmentation was the starting point for this line of research.
This led to diet studies, in which food web interactions are
depicted directly through stomach content analyses. Stable
isotope analyses are also a primary tool we are employing.
We have collected samples from 8 different estuaries specimens
to evaluate what food web properties are most sensitive to
estuary fragmentation. For example, working with David
Post (Yale University), we are using stable isotopes to
examine food chain length. Food chain length is dependent
on both community- (predator-prey interactions) and ecosystem-level
(primary production, nutrient cycling) properties, and thus
may reflect the changes induced by fragmentation.
Essential to the study of local food web structure
is an understanding of the connectivity of estuaries to the
marine environment. I am especially interested in the movement
of fishes in and out of the estuaries, and how this is affected
by fragmentation. Both plastic dart tags and telemetry will
be used to track fish movements, providing information on
both small- (among adjacent mangroves and seagrass beds) and
large-scale (to and from coral reefs) movement patterns.
These data provide background information necessary
for past and upcoming ecosystem restoration
projects in which, in collaboration with Andros Conservancy
and Trust and the Bahamas Environmental Research Center, we
are restoring tidal flow to severely fragmented estuaries.
Following the restoration initiatives, we are tracking changes
on food web structure, and these data will be used to plan
for future projects.
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