Ecological indicators for assessing and communicating seagrass status and trends in Florida Bay

Authors

Christopher J. Madden, Everglades Division, South Florida Water Management DistrictFollow
David T. Rudnick, Everglades Division, South Florida Water Management DistrictFollow
Amanda A. MacDonald, Everglades Division, South Florida Water Management District
Kevin M. Cunniff, R.C.T. Engineering, Inc.Follow
James W. Fourqurean, Department of Biological Sciences and Southeast Environmental Research Center, Florida International UniversityFollow

Abstract

A suite of seagrass indicator metrics is developed to evaluate four essential measures of seagrass community status for Florida Bay. The measures are based on several years of monitoring data using the Braun-Blanquet Cover Abundance (BBCA) scale to derive information about seagrass spatial extent, abundance, species diversity and presence of target species. As ecosystem restoration proceeds in south Florida, additional freshwater will be discharged to Florida Bay as a means to restore the bay's hydrology and salinity regime. Primary hypotheses about restoring ecological function of the keystone seagrass community are based on the premise that hydrologic restoration will increase environmental variability and reduce hypersalinity. This will create greater niche space and permit multiple seagrass species to co-exist while maintaining good environmental conditions for Thalassia testudinum, the dominant climax seagrass species. Greater species diversity is considered beneficial to habitat for desired higher trophic level species such as forage fish and shrimp. It is also important to maintenance of a viable seagrass community that will avoid die-off events observed in the past. Indicator metrics are assigned values at the basin spatial scale and are aggregated to five larger zones. Three index metrics are derived by combining the four indicators through logic gates at the zone spatial scale and aggregated to derive a single bay-wide system status score standardized on the System-wide Indicator protocol. The indicators will provide a way to assess progress toward restoration goals or reveal areas of concern. Reporting for each indicator, index and overall system status score is presented in a red–yellow–green format that summarizes information in a readily accessible form for mangers, policy-makers and stakeholders in planning and implementing an adaptive management strategy.

Comments

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Madden, C.J., D.T. Rudnick, A.A. McDonald, K.M. Cunniff, J.W. Fourqurean. 2009. Ecological indicators for assessing and communicating seagrass status and trends in Florida Bay. Ecological Indicators 9(6): S68-S82. doi:10.1016/j.ecolind.2009.02.004.