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Benthic Species Richness of U.S. Pacific Estuaries
Citation:
Frazier, M., H. Lee, D. Reusser, AND Walt Nelson. Benthic Species Richness of U.S. Pacific Estuaries. U.S. Environmental Protection Agency, Washington, DC, 2013.
Impact/Purpose:
WED and USGS scientists develop models to predict the patterns of biodiversity of the animals that live in the sediments of U.S. Pacific coast estuaries. These organisms are critical to estuary function and changes in their biodiversity will have cascading effects on these valuable habitats. These models can be used to develop effective conservation strategies and to detect changes in biodiversity due to environmental perturbations such as pollutants or climate change.
Description:
Understanding the spatial distribution of biodiversity is of paramount importance due to the potential consequences of its loss on human welfare. We demonstrate that biodiversity of soft-bottomed estuarine benthic organisms can be predicted with relatively high accuracy at multiple spatial scales by a few environmental variables. The variables associated with benthic species richness were: river influence, minimum sea surface temperature (minSST), sediment % fines, estuarine habitat type, and salinity zone. According to cross-validation techniques, statistical models using these variables explained 58-65% of the variation in the number of taxa observed at smaller scales (0.1 m2 sample area) and 74% of the variation at larger sample scales (i.e., cumulative number of taxa observed in 10 samples from an estuary). Estuary-scale variables (river influence and minSST) were better predictors than local sample variables, suggesting that macroecological processes establish the limits for biodiversity which are then modulated by local drivers. In particular, the extent that an estuary is dominated by river processes (vs. ocean processes) can be used to obtain a fairly accurate estimate of biodiversity. Estuaries dominated by river processes had fewer taxa than those dominated by ocean processes. The average SST of the coldest month, as measured outside the mouth of the estuary also explained a sizeable portion of the variation in richness. These models can be used to predict benthic taxa richness in sediment samples from estuaries located on the U.S. Pacific coast. This information can be used to develop effective conservation strategies and to detect changes in biodiversity due to environmental perturbations such as pollutants or climate change.