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A test for a shift in the boundary of the geographical range of a species |
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| Authors: | Andrew Solow Andrew Beet Uri Roll Lewi Stone |
| Affiliation: | 1.Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA;2.School of Geography and the Environment, Oxford University, Oxford OX1 3QY, UK;3.Department of Zoology, Tel Aviv University, PO Box 39040, Tel Aviv 69978, Israel;4.School of Mathematical and Geospatial Sciences, RMIT University, Melbourne, Victoria 3001, Australia |
| Abstract: | One predicted impact of climate change is a poleward shift in the boundaries of species ranges. Existing methods for identifying such a boundary shift based on changes in the observed pattern of occupancy within a grid of cells are sensitive to changes in the overall rate of sightings and their latitudinal distribution that are unconnected to a boundary shift. A formal test for a boundary shift is described that allows for such changes. The test is applied to detect northward shifts in the northern boundary of the Essex skipper (Thymelicus lineola) butterfly and the European goldfinch (Carduelis carduelis) in Great Britain. A shift is detected in the latter case but not in the former. Results from a simulation study are presented showing that the test performs well. |
| Keywords: | climate change extreme value statistics occupancy species range |