University of Western Ontario - SILKE NEBEL's research

Dr SILKE NEBEL

Silke Nebel's research interests:

1) The evolution of sexual size dimorphism is usually attributed to sexual selection. However, sex-biased resource partitioning (a form of natural selection) offers an intriguing, yet neglected, alternative explanation. Shorebirds (or waders) exhibit a very large degree of sexual size dimorphism. Using comparative phylogenetic methods, I am testing whether sexual size in Australian shorebirds arose through sex-biased resource partitioning or sexual selection.

2) Dwindling resources of fresh water are one of the most pressing environmental issues of our time. This is a particularly serious problem in Australia, where wetland habitats crucial for overwintering shorebirds are disappearing. In a collaborative effort, I was able to link the drastic decline of shorebirds occurring Australia (83% decline over 24 years) to a loss of wetlands due to river regulation and water extraction for use in irrigated agriculture. Our work was chosen as one of the top 100 science stories of 2008 by Discover Magazine.

3) Birds feeding on flying insects are undergoing acute population declines across North America. The declines became apparent in the mid-1980s and have since become so severe that three of these species have been listed as threatened in Ontario. These trends are likely indicative of underlying ecosystem changes and are cause for serious concern for scientists and policy makers alike. Our most recent analyses show that population trends of aerial insectivores vary geographically. Species breeding in the eastern part of North America are more heavily in decline than further west, and declines grow more pronounced from south to north. While several hypotheses have been suggested to explain these patterns, we are still trying to understand the underlying factors.

4) My current project looks at the trade-off between immune function and flight performance in migratory birds. Migratory birds are often blamed for the spread of avian influenza, however, evidence that birds infected with highly-pathogenic avian influenza can migrate long-distances unhampered is still lacking. Both migration and mounting an immune response are energetically very demanding, and according to life-history theory, birds cannot optimize both simultaneously. To study this trade-off, we are carrying out experiments in a wind tunnel at the Advanced Facility for Avian Research at UWO.

Last revised: 8 June 2011

western sandpiper