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Spatial Patterns of Subtidal Benthic Invertebrates and Environmental Factors in the Nearshore Gulf of Maine
Citation:
HALE, S. S. Spatial Patterns of Subtidal Benthic Invertebrates and Environmental Factors in the Nearshore Gulf of Maine. Chapter 13, Advancing an Ecosystem Approach in the Gulf of Maine. American Fisheries Society Symposium. American Fisheries Society, Bethesda, MD, 79:167-183, (2012).
Impact/Purpose:
Knowledge of the spatial patterns of subtidal benthic invertebrates and their relation to physical-chemical variables is necessary to calibrate benthic indices of environmental condition and to be able to conduct ecosystem-based management. The results provide important information to environmental managers who may need to apply different management techniques to different areas within the Gulf of Maine.
Description:
The spatial patterns of subtidal benthic invertebrates and physical-chemical variables in the nearshore Gulf of Maine (Acadian Biogeographic Province) were studied to provide information needed to calibrate benthic indices of environmental condition, determine physical-chemical factors affecting species distributions, and compare recent data with historical biogeographic studies. Knowledge of the distribution of species and how that is affected by biotic, environmental, and anthropogenic factors is essential to conduct ecosystem-based management. Five years (2000-2004) of data from reference stations of the National Coastal Assessment were used. Multidimensional scaling done on Bray-Curtis similarity matrices of species relative abundance showed faunal transitions around Cape Ann, Cape Elizabeth, and Penobscot Bay. The ordination of environmental data (temperature, salinity, sediment percent silt-clay, depth) correlated well with the ordination of benthic abundance data (R = 0.75, p < 0.03). Temperature was the most important factor affecting broad species distribution patterns, followed by salinity, but the relative importance of environmental factors varied with geographic scale. A multivariate regression tree showed a faunal split at 16 °C, followed by a split based on sediment percent silt-clay of 49%. Species richness increased with increasing salinity but showed no relationship with latitude or percent silt-clay. Based on small changes in slope of a species accumulation plot, Bray-Curtis similarities of at least 54.0, and 40% overlap among clusters, it appears a single benthic index is feasible for the entire nearshore Gulf of Maine. Additionally, these results provide a foundation for ecosystem-based management, valuation of ecosystem services, conservation, and ocean planning. They provide a baseline to help address broad-scale and long-term issues such as global climate change, species invasions, and ocean acidification.