Climate change and interspecific interactions

One of the most compelling effects of climate change is on breeding phenology in birds. Many species have advanced their breeding phenology during the last decades, and within species the strongest advances were observed in regions within Europe with the highest temperature changes. Whether these changes are sufficient to match the changes in timing of important food sources is still an open question. In some cases they are, in others they seem to lag behind, and may even result in population declines.

What is often not considered is whether one bird species by changing its phenology, also affects the optimal response of another species that shares the same resource. Interspecific competition may either increase of decrease if one species changes its timing more than the other species. To understand this better, responses of co-occurring populations of competing species should be compared, and their niche overlap measured in circumstances with more and less overlap in breeding time.

We are at the start of taking this approach, by studying interactions between different nest box breeding passerines (mostly tits and flycatchers).

PhD student:

• Jelmer Samplonius