ConFoBiNM · A multidimensional analysis on the joint-effect of retention forestry and landscape structure on large mammals communities

A multidimensional analysis on the joint-effect of retention forestry and landscape structure on large mammals communities

The integration of conservation into production forest management is crucial to achieve desired biodiversity goals at the EU level. Retention forestry – the retaining of deadwood and a portion of the original stand at the moment of harvesting - was introduced as a conservation tool to mitigate the negative impact of transformation and homogenization of forests. As it is now common practice in Central European forests, the design of efficient retention strategies hinges on ecological knowledge, yet research-based evidence for its effectiveness is lacking especially for the terrestrial mammals in temperate forests. Here, I addressed this knowledge gap by using a combination of advanced techniques and statistical methods to investigate how the large mammal community occupancy (a measure of abundance) changed in response to varying levels of retention forestry in the Black Forest in Southwestern Germany, my model system for multiple-use forests in Central Europe. I expected retention forestry to enhance mammals species richness and occupancy. I carried out camera-trapping in 135 plots embedded in patches of mixed-montane forests which differed along 2 gradients of retention and landscape fragmentation. I used multispecies hierarchical modelling in a Bayesian framework to quantify the effects of retention forestry on mammal species at different spatial grains. A total of 17 species was recorded, and while species richness did not differ with different amount of standing deadwood (a proxy for retention amount), species composition changed with both standing deadwood and forest cover surrounding the plots. Specifically, the majority of the species benefited from a higher amount of standing dead trees, possibly because of more abundant hiding cover, and forage availability. In contrast, several species such as the marten and the squirrel were more abundant in areas with lower retention. Moreover, while most species responded positively to the amount of forest in the landscape, the proportion of broadleaf forest in the landscape had mixed effect on the occupancy of mammal species, with half of the species negatively affected and the other half positively affected. In sum, there is no one-size-fits-all when it comes to manage forest to enhance mammal species. A thorough understanding of how individual mammal species respond to retention forestry and landscape configuration is therefore important to develop accurate guidelines for sustainable forest management that will often require a trade-off between favouring the majority of the species, or some species in particular. Such Knowledge is also relevant as the Black Forest is located in the middle of other large forest massifs in Central Europe and therefore acts as a stepping stone for forest species of conservation concern such as the Eurasian lynx that require large tracts of forest. This study was part of a larger interdisciplinary research project that combines multi-scale, ecological studies of forest biodiversity combined with social and economic studies of biodiversity conservation. This integrated approach is designed to establish a lively exchange of knowledge and expertise between scientific disciplines as well as forestry and conservation practitioners. Such research is especially important to bridge the gap between science and policy, and improve the management of natural resources.

Data: CORDIS, © European Union