Collaborative Research: Recruitment dynamics and population connectivity in Bahamian octocorals
Lasker, Howard Principal Investigator
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Recruitment, the addition of new individuals to populations, has played a prominent role in analyses of the population dynamics of marine benthic species. Understanding whether recruits come from local populations (closed populations) or from other sources (open populations) and from which sources (connectivity) is essential to understanding of the dynamics of benthic populations and to the conservation and management of benthic species. Assessing whether populations are closed or open is methodologically difficult and most such analyses have been inferential in nature. The harvest of the Caribbean gorgonian, Pseudopterogorgia elisabethae in the Bahamas, has created a massive manipulation of population density and has provided a unique opportunity to directly determine whether P. elisabethae populations are closed and on what scale. Connectivity of P. elisabethae populations is being assessed from the effects of the harvest on recruitment and population age structure. In this project, assessments of recruitment and connectivity in recovering populations will be continued and enhanced DNA microsatellite based measures of connectivity will be undertaken using new markers which will be developed. A high resolution bio-physical model of larval dispersal in the Bahamas will be developed and the results of the empirical studies will be compared with the simulation of dispersal. Bio-physical models are a potentially powerful in assessing patterns of connectivity and this research project provides a unique opportunity to validate the biophysical model and compare the different methodologies used to assess connectivity in marine communities. Parallel studies of five additional, closely related, species that are not harvested will provide information on the role of reproductive strategies in determining recruitment across species and habitats and the relative importance of larval supply, and post-settlement processes in establishing distribution patterns. The broader impacts of the study are in large part based on addressing one of the fundamental questions of marine ecology, whether marine populations are open or closed and assessing the utility of different methodologies in making that determination. The question is of particular concern for coral reef species, which are increasingly at risk and require the development of sound conservation policies. In addition, the study focuses on a commercially important species that is currently being harvested in the Bahamas and could be harvested throughout the Caribbean. The study will be of broad interest to stakeholders such as governmental and non-governmental organizations interested in the conservation and management of coral reefs. Educational aspects of the project fall into two categories. Firstly, the project will involve the participation and training of graduate and undergraduate students from both the U.S. and the Bahamas. Secondly, the research will form the basis of a case study to be developed for the National Center for Case Study Teaching in Science. The case study will be used in University at Buffalo undergraduate classes and through the Center's website will be available to instructors throughout the world.