Oral Presentation- Symposium 12th International Mammalogical Congress

Can apex predators retain their ecosystem function when the world changes? (#355)

Marianne Pasanen-Mortensen 1 , Bodil Elmhagen 1 , Harto Lindén 2 , Roger Bergström 3 , Märtha Wallgren 3 , Ype van der Velde 4 , Sara A. O. Cousins 1
  1. Stockholm University, Stockholm, Sweden
  2. Natural Resources Institute Finland, Helsinki, Finland
  3. Skogforsk, Uppsala, Sweden
  4. VU University Amsterdam, Amsterdam, Netherlands

Apex predators play an important role in structuring ecosystems. Can they retain this function when the world changes? We applied a space for time approach to explore a recolonising apex predator´s ability to limit mesopredator abundance when land use and climate have changed. First, we estimated to what extent Eurasian lynx (Lynx lynx, apex predator), cropland and winter temperatures drive red fox (Vulpes vulpes, mesopredator) abundance at a spatial scale. Second, we estimated lynx abundance, proportion of cropland and winter temperatures over time. Third, we used the estimates from the initial steps to project fox abundance in 1830, 1920, 2010 and 2050. Projected fox abundance was lowest in 1830 when lynx abundance was high, the proportion of cropland was low and winters were harsh. Persecution of lynx during the 19th century caused a mesopredator release that was boosted by agricultural expansion and global warming; the highest fox abundance was therefore reached in 1920 when lynx were extinct. In 2010, lynx recolonisation had suppressed fox abundance but not to the same level as in 1830, because of a smaller lynx population and an enriched environment with more crop fields and milder climate compared to 1830. Assuming that winter temperatures will increase yet another 1.5°C, lynx abundance is required to increase by 79% compared to 2010 to buffer the impact of global warming on foxes, and prevent increased mesopredator abundance. We suggest that environmental enrichment can give mesopredators and herbivores an opportunity to thrive unless apex predators can respond numerically or behaviourally.