NOAA's Undersea Research Center at the University of North Carolina Wilmington
Project Summary: 2005–14B

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2005 Project Summaries

Project Summary for 2005–14B: A colony–based study of coral survivorship across environmental gradients of the Florida reef tract

The biological diversity of reefs of the Florida reef tract makes this ecosystem ecologically, economically, aesthetically, and biogeographically unique. However, recent declines in coral cover have prompted researchers to declare Florida’s reefs in a state of emergency. The potential for future declines in water quality in response to increased exploitation and increased freshwater flows from Everglades restoration activities raise concerns for the health of these communities. The location of patch reefs in proximity to urban centers of the Florida Keys and exposed to water flows across tidal channels highlights the need for a monitoring program developed explicitly for these largely unexplored habitats of the Florida Keys National Marine Sanctuary.

In this proposal, funds are requested to continue and expand an ongoing monitoring program of patch–reef habitats that was initiated in 2001 with funding from NURC. This research is based on the repeated sampling of marked colonies of coral species with diverse life history charactersitics (Porites astreoides, Siderastrea radians, and S. siderea) within permanent patch–reef sites. The goals of the proposed activities are to:

• expand research within patch–reef habitats under–represented in ongoing monitoring efforts and most likely to be affected, due to their location, by changes in water quality,
• document demographic data like coral population structure, recruitment, and colony-based parameters such as growth, partial, and total mortality in relation to environmental (distance to shore and connections to coastal bays) and resource protection (Special Protection Areas) gradients, and
• provide the parameters needed to develop size–based population models for five coral species that can be used to evaluate the long–term survivorship of coral populations.

During the first year of this research, we will:

• add two reef-building coral species (Montastraea cavernosa and M. faveolata) to the survey protocol,
• establish new sites in Biscayne National Park and the Middle Keys,
• continue monitoring of sites established in the Upper Keys region in 2001, and 4) complete population models for S. siderea, S. radians, and P. astreoides based on demographic data collected from 2001 — 2004.

During the second year of this research, we will:

• resurvey all sites,
• develop initial models for M. faveolata and M. cavernosa based on data obtained between 2004-2006, and
• validate models for S. siderea, S. radians, and P. astreoides by comparing model projections of population structure with field observations using goodness–of–fit tests.

Preliminary information collected between 2001 — 2002 revealed inshore–offshore gradients in coral population structure and demographic parameters that were not what would be expected under the assumption of lower habitat value closer to shore. In fact, coral cover and colony growth were higher, while partial and total mortality were lower on inshore patch reefs compared to offshore habitats. In light of these patterns, expanded research is needed to determine whether some of the long–accepted hypotheses about the causes of the recent decline in coral health in the Florida Keys may need to be reevaluated.

The addition of two reef–building coral species (Montastraea cavernosa and M. faveolata) to the survey protocol, new survey sites in Biscayne National Park and the Middle Keys, and continued monitoring of established sites will determine whether these initial patterns are consistent across temporal and spatial scales, and will establish a comprehensive baseline on the status of these communities against which future changes can be assessed.

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