, Volume 18, Issue 1, pp 57-71
First online:
30 September 2015
- Marietta L. Fischer
- , Martin J. P. Sullivan
- , Grit Greiser
- , José Guerrero-Casado
- , Mike Heddergott
- , Ulf Hohmann
- , Oliver Keuling
- , Johannes Lang
- , Ina Martin
- and 3 more
Abstract
As the second
largest cause of biodiversity loss worldwide, there is an urgent need to
study the dynamics of biological invasions and identify factors
limiting the distribution of invasive alien species. In the present
study we analyze national-scale hunting bag data from Germany to predict
the dispersal of raccoons in the largest non-native population of the
species. Our focus is (1) to document changes in the distribution and
abundance of raccoons, (2) to identify the species–environment
relationship and predict which areas will be suitable for future
colonization and (3) to apply a dispersal model to predict how fast the
raccoon will spread to these areas. The increase from about
9000 harvested raccoons in 2000/01 to about 71,000 in 2011/12 reflects
the extensive amount of suitable habitat for this omnivorous species in
Central Europe. The best model for explaining range expansion in Germany
identified coverage of agriculture and fragmentation and coverage of
forests as the most important explanatory variables. The range of
raccoons (area with harvest index >0.1 per 100 ha) increased from
26,515 km2 in 2001 to 111,630 km2 in 2011, and is predicted to expand to 252,940 km2
by 2061, 71 % of the area of Germany. This vast area encompasses
strategically important areas for conservation biology, such as wetlands
with endangered native terrapins. The combination of merging of
separated introduced populations and accelerating population growth
highlights the potential for future impacts of raccoons on native
communities, ecosystems and economic life in Germany and Central Europe.
