MEPS 253:123-136 (2003)  -  doi:10.3354/meps253123

Critical evaluation of the nursery role hypothesis for seagrass meadows

K. L. Heck Jr.1,*, G. Hays2, R. J. Orth3

1Dauphin Island Sea Lab, University of South Alabama, 101 Bienville Boulevard, Dauphin Island, Alabama 36528, USA
2Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 225 Sinsheimer Avenue, Santa Cruz, California 95064, USA
3Virginia Institute of Marine Sciences, College of William and Mary, 1208 Greate Road, Gloucester Point, Virginia 23062, USA

ABSTRACT: The vast majority of published papers concerning seagrass meadows contain statements to the effect that seagrass beds serve as important nurseries for many species. We reviewed more than 200 papers that were relevant to the nursery role hypothesis. We used both vote counting and meta-analytic techniques to evaluate whether the body of previous studies that report seagrass meadows to be nursery grounds actually contain data that support this proposition. We restricted our analyses to papers that compared seagrass beds to other habitats, and examined data on a variety of well-studied species concerning their density, growth, survival and migration to adult habitat. Within this group of papers, we considered potential factors that could influence the nursery function (e.g. location, or laboratory vs field studies). We also evaluated case histories of well-documented large-scale seagrass losses on the nursery function. Major results were consistent with the expectations that abundance, growth and survival were greater in seagrass than in unstructured habitats. Abundance data also suggested that seagrass beds in the Northern Hemisphere might be more important as nursery areas than those in the Southern Hemisphere. Surprisingly, few significant differences existed in abundance, growth or survival when seagrass meadows were compared to other structured habitats, such as oyster or cobble reefs, or macroalgal beds. Nor were there decreases in harvests of commercially important species that could clearly be attributed to significant seagrass declines in 3 well-studied areas. However, there were decreased abundances of juveniles of commercially important species in these areas, suggesting a strong link between seagrass abundance and those of juvenile finfish and shellfish. One important implication of these results is that structure per se, rather than the type of structure, appears to be an important determinant of nursery value. Clearly, more rigorous studies that test all aspects of the nursery role hypothesis are clearly needed for seagrass meadows as well as other structured habitats. The results of such studies will allow better decisions to be made concerning the conservation and restoration of marine habitats.

KEY WORDS: Nursery role · Seagrass meadows · Meta-analysis

Full text in pdf format 
Export citation: Endnote - Reference Manager
Mail this link - Contents Mailing Lists - RSS
- -