Changes in sooty shearwater (Puffinus griseus) abundance and harvesting on the Rakiura Titi Islands
| Autor: | P. Johnson, Brian Bell, Sam McKechnie, David Fletcher, Darren Scott, Henrik Moller, Jamie Newman, D Flack, Corey Bragg, Philip Lyver |
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| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | New Zealand Journal of Zoology. 36:325-341 |
| ISSN: | 1175-8821 0301-4223 |
| DOI: | 10.1080/03014220909510158 |
| Popis: | We estimated the change in abundance of sooty shearwater (titi, Puffinus griseus) at six Rakiura Titi Islands, New Zealand, by comparing historical and recent surveys of the density of entrances to breeding burrows. We found evidence that entrance density between 1994 and 2006 was lower than it was between 1961 and 1976. Our overall estimate of the annual rate of change in burrow entrance density is ‐1.0% (95% CI ‐2.3 to ‐ 0.1%). Declines have been slower on four islands where Rakiura Maori maintain a traditional harvest of sooty shearwater chicks ("muttonbirding") compared with three unharvested islands. Density‐dependent population processes may explain this difference: rates of decline have been faster in areas of relatively high initial entrance density, and historically the harvested islands have had lower initial density. There was a strong, apparently linear, relationship between entrance density and chick density on breeding colonies, so changes in entrance density probably do indicate a ... |
| Databáze: | OpenAIRE |
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