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Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon
Citation:
DEWITT, T. H., A. F. D'Andrea, B. D. Griffen, P. M. ELDRIDGE, AND T. G. O'Higgins. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon. Presented at A Conference on Ecosystem Services (ACES), Naples, FL, December 08 - 11, 2008.
Impact/Purpose:
Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia).
Description:
Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing shrimps (Neotrypaea californiensis and Upogebia pugettensis), can occur at great densities (exceeding 300 m-2) and high biomass (up to 200 g m-2, dry wt), and can occupy more than 75pct of the extensive tide flats in middle and lower estuarine reaches. As ecosystem engineers, burrowing shrimps physically and biogeochemically modify the sedimentary habitat through bioturbation (sediment mixing) and bioirrigation of their burrows. Bioturbation by N. californiensis can negatively affect the abundance of some bivalve shellfish (particularly oysters). On the other hand, bioturbation and bioirrigation by both species greatly accelerates carbon and nitrogen cycling, and filter feeding by U. pugettensis removes phytoplankton and seston from the water column. Both species are prey items for fish, crabs, birds and occasionally, grey whales, and the shrimps are harvested commercially and recreationally as bait. One focus of our research has been to measure and model the density-dependent effects of both shrimp species on carbon and nitrogen cycling, filter feeding, and food web dynamics within the Yaquina estuary, located on the central coast of Oregon (USA). We have also developed methods for mapping the abundance and distribution of shrimp populations, and have used those maps to interpolate the ecological functions of burrowing shrimps to whole-estuary scale. We are currently working on translating these ecological functions into ecosystem services and estimating the value of those services. As noted above, the shrimps have both positive and negative impacts on ecosystem services, some of which are dependent on the spatial distribution of human activities (i.e., molluscan aquaculture, recreational clam digging, bait harvesting). In this presentation, we will summarize our progress toward estimating the contributions of burrowing shrimps to the ecosystem services of Yaquina estuary, and highlight the challenge of reconciling the beneficial and detrimental impacts that ecosystem engineering species can impart on ecosystem services.