11th ICRS Abstract book - Nova Southeastern University

20-9
Resilience in A Small Coral World: Disturbance in Networks
Stuart KININMONTH* 1 , Glenn DE'ATH 1 , Hugh POSSINGHAM 2
1 Australian Institute of Marine Science, Townsville, Australia,
Queensland, Brisbane, Australia
Oral Mini-Symposium 20: Modeling Concepts and Processes on Coral Reefs
2 University of
Coral reefs are declining worldwide due to increasing local and regional stress from
fishing, coastal development, run-off and climate change. While disturbance is an
essential part of coral reef dynamics, its frequency and intensity has increased. As the
health of a reef changes due to stress and disturbance its capacity to recover is partly
determined by the connectivity through larval transport. This exchange of larvae
between reefs creates a complex system of interactions that can be modelled. Using graph
theory models, we discover that ecological connectivity patterns are highly clustered and
well connected. This gives rise to the description of the connectivity pattern of coral reefs
as ‘small world’ where individual reefs appear to be improbably well connected. We
examine the hydrological and genetic patterns of the central section of the Great Barrier
Reef to find a mesoscale small world. We examine the history of disturbance from
cyclones, Crown-of-Thorns starfish and bleaching within the coral reef network and
discover that the spatial and temporal character of the disturbance differentially affects
the network connectivity. Long term monitoring records of reef decline, stasis, or
recovery cycles are incorporated into the graphical model. Our model demonstrates the
need to understand the functional aspects of coral reefs in order to adequately provide
conservation measures.
20-10
Models Of Coral Community Structure, Environmental Variation, And Connectivity
Carrie KAPPEL* 1 , Daniel BRUMBAUGH 2,3 , Craig DAHLGREN 4 , Alastair HARBORNE 5 ,
Katherine HOLMES 2 , Fiorenza MICHELI 6 , Peter MUMBY 5 , Claire PARIS 7
1 National Center for Ecological Analysis and Synthesis, University of California Santa Barbara,
Santa Barbara, CA, 2 Center for Biodiversity and Conservation, American Museum of Natural
History, New York, NY, 3 4Marine Protected Areas Science Institute, National MPA Center,
Santa Cruz, 4 Perry Institute for Marine Science, Jupiter, FL, 5 Marine Spatial Ecology Lab,
School of BioSciences, University of Exeter, Exeter, United Kingdom, 6 Hopkins Marine Station,
Stanford University, Pacific Grove, CA, 7 Marine Biology and Fisheries, Rosenstiel School of
Marine and Atmospheric Science, University of Miami, Miami, FL
A suite of physical and biological environmental factors and processes have been shown
to structure coral reef communities at local scales. Recently, studies have begun to
address the role that other factors, such as temperature, pH, and dispersal potential, play
in shaping communities at global and regional scales. Conservation planning and
implementation typically take place at the seascape scale (10s – 100s km), creating a
need to understand what drives variation in communities at intermediate scales and a
demand for easily measured surrogates for biodiversity. We used distance-based
redundancy analysis (dbRDA) to assess the role of physical and biological factors in
explaining patterns of coral community structure at the seascape level. We examined the
relationship between community structure, as measured in detailed field surveys of coral
species distributions at nested spatial scales across the Bahamas archipelago, and the
measured or modeled environmental variables: depth, vertical relief, wave exposure,
grazing intensity by herbivorous parrotfishes, connectivity (based on simulations of larval
dispersal for typical spawning and brooding corals), history of hurricane and bleaching
disturbances, macroalgal cover and total coral cover, local human population density and
tourism intensity. Several of these factors, including incoming coral larval supply (i.e.
subsidies) and macroalgal cover were significant predictors of coral community structure.
We also examined species-specific patterns of abundance across the archipelago. We
used linear mixed-effect models to explain variation in common individual coral species
from the genera Montastraea and Agaricia, relating their abundance to physical and
biological variation and connectivity among our sites. For individual species, number of
retained larvae (i.e. self-recruitment) was often a significant predictor of abundance.
Together these analyses highlight the importance of connectivity, the history of
disturbance, and physical and biological processes like grazing and wave exposure in
explaining patterns of coral abundance and community structure across the Bahamian
seascape.
20-11
Exploring Past And Future Human Impacts On Reef Fish Ranges Via Distribution
Models
Jana MCPHERSON* 1 , Julia BAUM 2 , Derek TITTENSOR 1
1 Biology Department, Dalhousie University, Halifax, NS, Canada, 2 Marine Biology Research
Division, Scripps Institution of Oceanography, La Jolla, CA
Our study uses species distribution models to identify human-induced changes in the
composition of reef fish communities. Species distribution models traditionally combine spatial
information on species’ occurrence with measures of environmental conditions to delineate
individual species’ ranges. They are widely used in terrestrial ecology to predict shifts in
species’ distributions in response to habitat alterations and climate change. We apply these
models to coral reefs using data compiled by the Pacific Reef Fish Collaboration (PaReFiCo),
an international effort to study humanity’s impacts on reef ecosystems. PaReFiCo’s data consist
of underwater visual sightings of reef fish species from more than 8000 transects conducted at
83 islands across the Pacific Ocean. In order to determine both natural and human-induced
constraints on individual species’ ranges, potential explanatory variables in the models include
not only traditionally used environmental predictors (e.g. temperature, habitat type) but also
indicators of anthropogenic stressors (e.g. coastal population density). We are thus able to
explore past as well as future human impacts on individual species’ occurrence. Layering of
individual species’ models provides insight into human-caused changes in community
composition.
20-12
The New Commons: Why Coral Reef Scientists Should Get Out More
robert SEYMOUR* 1 , Roger BRADBURY 2
1 mathematics, UCL, London, United Kingdom, 2 ANU, Canberra, Australia
How do we understand complex ecosystems such as coral reefs? More importantly, what do we
understand them for? The current “big idea” in the Life Sciences is Systems Biology, a
movement that aims to reverse the paradigm of reductionist research in which more-and-moredetailed
properties of smaller-and-smaller components of biological systems are isolated and
dissected. Systems Biology aims to pursue a reverse, integrationist agenda, in which whole
system properties “emerge” from component processes. It is these emergent properties that
promise significant payoffs to humans. Ecology is stuck in a rut with the classical “systems
analysis” paradigm: ecosystems are conceived as assemblages that just “do what they do”, and
we try to understand this “doing” through a description of local interactions between
components. Can we develop a Systems Biology paradigm for ecosystems? This talk will argue
that we can, and should. Thus, in the absence of obvious naturally evolved ecosystem
“functions”, we should develop views as to what the “function(s)” of such an ecosystem might
mean. Taking such a view forms a high-level conceptual basis for modelling, and can be used to
provide a conceptual bridge between high-level functional properties and low-level mechanistic
processes. This greatly facilitates modelling and analysis. Such “functions” cannot, and should
not, avoid being related to human activity. We must escape from the guilt paradigm in which
ecosystems would revert to a harmonious state if only humans would leave them alone. Instead,
management should aim to buffer homeostatic properties associated with these functional
properties (to maintain “health”). In this endeavour we should think more like medical
physiologists and agricultural scientists, using manipulative techniques where necessary. Thus,
the future of the Commons must be that of a highly managed landscape, subject to controlled
development.
172