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Donor and recipient regions: The biogeography of macrobenthic invaders
Citation:
REUSSER, D. AND H. LEE, II. Donor and recipient regions: The biogeography of macrobenthic invaders. Presented at 6th International Conference on Marine Bioinvasions, Portland, OR, August 24 - 27, 2009.
Impact/Purpose:
Aquatic invaders are a major threat to ecological integrity and biodiversity of marine, estuarine, and freshwater ecosystems around the world.
Description:
Aquatic invaders are a major threat to ecological integrity and biodiversity of marine, estuarine, and freshwater ecosystems around the world. These invaders have been successful in passing through four discrete phases in their invasion of a new environment: (1) transport, (2) release, (3) population establishment, and (4) range expansion. Examination of the regional and biogeographic spatial distributions of existing nonindigenous species identifies species that have the characteristics to pass through these phases in at least one location and, thus, represent a potential invasion risk to other geographic areas. Distributions of nonindigenous species in the Northeast Atlantic (European coast) and Northeast Pacific (western seaboard of the United States) were collected, collated, and analyzed to identify high-risk invaders. Approximately 200 nonindigenous invertebrates in marine and brackish waters have been reported from either the Northeast Atlantic and/or Northeast Pacific. The donor regions of these nonindigenous species were then analyzed. Rather than being donor regions to each other, the two regions share invaders from other biogeographic regions, in particular the Northwest Atlantic (U.S. East Coast) and the West Pacific (New Zealand to Japan). This asymmetric invasion pattern suggests that western sides of oceans tend to be donor regions while eastern sides of oceans tend to be recipient regions. A sufficient species overlap exists among these nonindigenous species in the Northeast Atlantic and Northeast Pacific indicating the environments in these two regions are similar enough to be used as “surrogates” for each other. Thus, the nonoverlapping invaders in each region represent an initial suite of species that have a high potential for invading either the Northeast Atlantic or the Northeast Pacific. Assuming that invaders with broader geographic ranges have characteristics promoting transport and establishment into new environments, the nonoverlapping invaders were then prioritized by the number of ecoregions in their new biogeographic region they had spread to. Species with the widest invaded range were identified as the most likely invaders. As invasion biology struggles to become a predictive science, we suggest that an analysis of regional and global patterns of invasion is one approach to identifying species with a high invasion potential.