Henrik Smith
Professor
Is the large-scale decline of the starling related to local changes in demography?
Author
Summary, in English
The decline of one farmland bird, the migratory European starling, has been attributed to both agricultural intensification and farmland abandonment and to factors operating both during the winter and during the breeding season. We analysed population data from thirty-three Swedish nestbox colonies over more than two decades to determine if the national decline was caused by a common factor affecting all colonies or by local changes in the breeding grounds affecting starling colonies. We found that numbers of breeding starling had declined significantly, but at different rates in different colonies. The local population sizes were affected by previous years productivity at both national and local scales, suggesting that changes in habitat quality at both scales could affect local population trends. There were no long-term trends in reproductive output, but fledgling production was lowest at intermediate years. The local population changes were positively related to local changes in reproductive output, but only when including complete nest-failures. A relationship between population declines and low mean local productivity was the result of the association between population sizes and reproductive success over time, since decline rates of starlings were not related to the average success during the first part of the study, but to the average success during the later part of the study. The relationship between population change and changes in reproductive output was evident, but fledgling production showed negative density-dependence. In conclusion this study suggests that the decline of the starling population in Sweden has been affected by processes at small spatial scales during the breeding season affecting reproductive success, but does not exclude an additional role for processes at large spatial scales or outside the breeding season.
Department/s
- Centre for Environmental and Climate Science (CEC)
- Biodiversity
- BECC: Biodiversity and Ecosystem services in a Changing Climate
- Biodiversity and Conservation Science
Publishing year
2012
Language
English
Pages
741-748
Publication/Series
Ecography
Volume
35
Issue
8
Links
Document type
Journal article
Publisher
Wiley-Blackwell
Topic
- Earth and Related Environmental Sciences
- Ecology
Status
Published
Research group
- Biodiversity and Conservation Science
ISBN/ISSN/Other
- ISSN: 1600-0587