| Abstract: | Ecological a??niche modelinga?? using presence-only locality data and large-scale environmental variables provides a powerful tool for identifying and mapping suitable habitat for species over large spatial extents. We describe a niche modeling approach that identifies a minimum (rather than an optimum) set of basic habitat requirements for a species, based on the assumption that constant environmental relationships in a species‘ distribution (i.e., variables that maintain a consistent value where the species occurs) are most likely to be associated with limiting factors. Environmental variables that take on a wide range of values where a species occurs are less informative because they do not limit a species‘ distribution, at least over the range of variation sampled. This approach is operationalized by partitioning Mahalanobis D2 (standardized difference between values of a set of environmental variables for any point and mean values for those same variables calculated from all points at which a species was detected) into independent components. The smallest of these components represents the linear combination of variables with minimum variance; increasingly larger components represent larger variances and are increasingly less limiting. We illustrate this approach using the California Gnatcatcher (Polioptila californica Brewster) and provide SAS code to implement it. |
| Genre: | Article |
| ProdID: | 1016477 |
| Citation Author: | Rotenberry, J. T.; Preston, K. L.; Knick, S. |
| Citation Contributing Office: | Forest and Rangeland Ecosystem Science Center |
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| Citation End Page: | 1464 |
| Citation Issue: | 6 |
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| Citation Language: | English |
| Citation Larger Work Title: | Ecology |
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| Citation Month: | JUN |
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| Citation Number Of Pages: | 7 |
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| Citation Phsyical Description: | p. 1458-1464 |
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| Citation Search Results Text: | GIS-based niche modeling for mapping species‘ habitats; 2006; Article; Journal; Ecology; Rotenberry, J. T.; Preston, K. L.; Knick, S. |
| Citation Start Page: | 1458 |
| Citation Volume: | 87 |
| Citation Year: | 2006 |
| Type: | citation/reference |
| Text: | GIS-based niche modeling for mapping species‘ habitats; 2006; Article; Journal; Ecology; Rotenberry, J. T.; Preston, K. L.; Knick, S. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sun, 1 Jan 2006 00:00 -0600 |
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