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Modeled Larval Connectivity Patterns in two Coral Reef Regions : the Western Caribbean and the Kenyan-Tanzanian Shelf

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Title Modeled Larval Connectivity Patterns in two Coral Reef Regions : the Western Caribbean and the Kenyan-Tanzanian Shelf
Names Mayorga Adame, Claudia Gabriela (creator)
Batchelder, Harold P. (advisor)
Spitz, Yvette H. (advisor)
Date Issued 2015-09-21 (iso8601)
Note Graduation date: 2016
Abstract Tropical coral reef ecosystems are very important from both the ecological and economical
points of view. However, they are also particularly fragile, and have been
declining in recent years in most regions of the world, since they are highly susceptible
to anthropogenic stressors operating at global scales (e.g., global warming
and ocean acidification) and local scales (e.g., pollution/eutrophication, fishing, overcommercialization
for recreation). Coral reef ecosystems are complex communities
with very high species diversity. Most reef species have a bipartite life history with
a planktonic larval stage and a benthic associated adult life. Therefore most adult
reef organisms are distributed in metapopulations connected by pelagic larvae that
disperse subject to the ocean currents. Knowledge of population connectivity among
individual reef habitats within a broader geographic region of coral reefs has been
identified as key to developing efficient spatial management strategies to protect
marine ecosystems. The study of larval connectivity of marine organisms is a complex
multidisciplinary challenge that is difficult to address with direct observations.
This research examines the temporal and spatial, physical and ecological processes
influencing connectivity of two important coral reef genera among isolated reef habitats
within two regions: the Kenyan-Tanzanian and the Western Caribbean coasts.
High resolution ocean circulation models were developed for each region and coupled
to individual based models (IBM) that track particles (virtual larvae) released from
each reef habitat. The connectivity patterns for two coral reef species groups having
contrasting larval behavior and development duration where characterized in the
two study regions: Acropora, a genus of branching corals with passive larvae and
fast development (pelagic larval duration (PLD)<12 days), and Acanthurus, a genus
of highly mobile, herbivorous fish, with long PLD (>50 days). Additional simulations
were done to represent better the complexity of the Acanthurus larval life:
one experiment included an idealized ontogenetic vertical migration behavior; another
experiment examined how temperature-determined larval duration influenced
trajectories and settlement patterns. The more complicated behavioral and development
models were evaluated by comparing connectivity matrices to the passively
transported case. To investigate interannual variations in connectivity patterns and
percentage of successful settlement experiments were done for two contrasting years
2000 and 2005. Environmental seasonal and interannual variability in the ocean circulation
models was analyzed to detect the mechanisms controlling connectivity in
the two regions. The connectivity patterns and the mechanisms causing them were
compared among the two study regions. Results are interpreted in the context of
marine spatial management, describing the implications of the modeled connectivity
patterns for currently established Marine Protected Areas. The connectivity patterns,
and the processes controlling connectivity for different taxa, provide policy
relevant scientific information that enables managers and decision-makers to make
more informed choices regarding the size, spacing and optimal spatial design of marine
protected networks.
Genre Thesis/Dissertation
Access Condition http://creativecommons.org/licenses/by-nc-nd/3.0/us/
Topic Larval Connectivity
Identifier http://hdl.handle.net/1957/57502

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