Predicted effects of climate change on indicator species of structural and biological diversity in mountain forests

Mountain forest (Photo: K. Bollmann)

Eurasian Pygmy owl (Photo: R. Arlettaz)

Background and goals of the study

Climate change is expected to affect species directly and indirectly. This particularly applies to habitat specialists of cold-adapted habitats, e.g. mountain forests. There, higher temperatures can directly cause contractions of the species’ ecophysiological niche, while drier vegetation periods and frequent wind storms will modify forest composition and structure. Thus, habitat specialists of mountain forests will be exposed to increasing ambient temperatures and changes in structural habitat quality, food availability and interspecific interactions.

The aim of the study is to assess how climatic variation may influence key structural and vegetational habitat components of mountain forests along the climatic gradient Black forest–Jura–Alps. We will focus on an appropriate set of bird species indicative of stand diversity and habitat quality in boreal and/or mountain forests. Based on this information we shall develop concrete guidelines for future adaptive forest management capable of ensuring the persistence of integral subalpine biocenoses under various climate change scenarios. Our set of model species includes: hazel grouse (Bonasa bonasia), capercaillie (Tetrao urogallus), three-toed woodpecker (Picoides tridactylus), and pygmy owl (Glaucidium passerinum).

Research questions

• Which factors define the ecoclimatic niches of the study species at the landscape scale; where and how do the niches overlap?
• How does species’ presence relate to forest composition and structure variables at the local scale; what are optimal habitat profiles and thresholds thereof?
• What amount of variability in forest structure is explained by climate variables?
• How will the distribution and habitat suitability of the studied species change under different IPCC-scenarios of climate change?

Project duration

July 2010 – June 2012

Project team

• Dr. Kurt Bollmann (WSL, Birmensdorf), Projekt leader
• Dr. Veronika Braunisch (FVA Baden-Württemberg and University Bern)
• Prof. Raphael Arlettaz (University Bern)
• MSc und BSc Studierende (WSL, Universities Bern, Zürich, Bonn, Bochum)