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PREDICTIONS IN AN INVADED WORLD - PART II: USING NICHE MODELS TO PREDICT DISTRIBUTIONS OF MARINE/ESTUARINE SPECIES AT THE ESTUARY SCALE
Citation:
REUSSER, D. AND H. LEE, II. PREDICTIONS IN AN INVADED WORLD - PART II: USING NICHE MODELS TO PREDICT DISTRIBUTIONS OF MARINE/ESTUARINE SPECIES AT THE ESTUARY SCALE. Presented at 5th International Bioinvasions Conference, Cambridge, MA, May 21 - 24, 2007.
Description:
To better understand the potential geographical distributions of nonindigenous species (NIS), we are evaluating the ability of niche models to predict the presence of existing native and NIS species within individual estuaries based on landscape characteristics. One model being evaluated is nonparametric multiplicative regression (NPMR), and approach that inherently incorporates interactions among environmental factors which are likely to occur over large environmental/latitudinal gradients. From the 219 estuaries in California, Oregon, and Washington, a subset of 28 estuaries were selected for model development based on the criterion that at least 100 species had been reported in the estuary in the regional database Pacific Coast Ecosystem Information System (PCEIS). The presence or absence of 9 native, 9 NIS, and 2 cryptogenic benthic species within each estuary was then determined based on available distributions in PCEIS. A set of 13 quantitative landscape characteristics for each estuary was extracted for each of the 28 estuaries or its watershed from PCEIS, and the estuarine-scale models developed for the 20 species. Preliminary results indicate NPMR can reasonably predict the regional distribution of these species, though its sensitivity to incorrectly stating a species is absent from an estuary needs to be evaluated. Most species were modeled using 2 to 3 landscape variables. Similar to the habitat scale, latitude was the most frequently included variable, being selected in 11 species' models. At the estuary scale, however, mean air temperature was included as frequently, with five instances where both latitude and mean air temperature were included in the same model. An unexpected result was that the ratio of estuarine area to watershed area was included in 8 models. Looking at the overall ability to predict distributions at the estuary scale, these results indicated that NPNR will predict equally well for both native and nonindigenous species.