| Autor: |
LEFTWICH, KEVIN N., ANGERMEIER, PAUL L., DOLLOFF, C. ANDREW |
| Zdroj: |
Transactions of the American Fisheries Society; Sep1997, Vol. 126 Issue 5, p725-734, 10p |
| Abstrakt: |
We examined the predictive power and transferability of habitat-based models by comparing associations of tangerine darter Percina aurantiaca and stream habitat at local and regional scales in North Fork Holston River (NFHR) and Little River, Virginia. Our models correctly predicted the presence or absence of tangerine darters in NFHR for 64% (local model) and 78% (regional model) of the sampled habitat-units (i.e., pools, runs, riffles). The distribution of tangerine darters apparently was influenced more by regional variables than local variables. Data from Little River and 37 historical records from Virginia were used to assess transferability of our models developed from NFHR data. In general, the models did not transfer well to Little River; all models predicted that either no (regional model) or few (local model) habitat-units in Little River would contain tangerine darter even though the species was observed in 83% of the habitat-units sampled. Conversely, the regional model correctly predicted presence of tangerine darters for 95% of the historical records. Principal components analysis showed extensive overlap in NFHR and Little River habitat which suggests that the two streams are ecologically similar. The suitability of Little River for tangerine darters was shown more clearly by principal components analysis than by our models. Because different limiting factors may apply in different systems, the elimination of potentially important ecological variables may compromise model transferability. A hierarchical approach to habitat modeling, with regard to variable retention, may improve transferability of habitat models. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
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