Effects of forest management on density and survival in three forest rodent species

Several studies have shown that small mammal communities are influenced by silvicultural activities, possibly because these affect the quality of wildlife habitats. Previous research mainly focused on community parameters and abundance of target species, however the most robust way to study the impacts of forestry on wildlife is to follow a demographic-response approach. Investigating multiple demographic measurements is essential to understand how populations respond to forest management, nevertheless studies focusing on multiple demographic parameters are lacking. Our analyses targeted individual survival and population density, to understand the demographic mechanisms by which forest management exerts its effects on small mammals. We focused on the populations of Apodemus flavicollis, A. sylvaticus and Myodes glareolus, constituting the guild of forest- and ground-dwelling rodents in central Italy. Populations were monitored for three years in a continuous forest subject to different management practices (mainly coppicing activities and conifer afforestation). We identified four forest management types (three coppice stands logged in different years and a conifer plantation) where we selected 12 sampling areas. We sampled a total of 31,752 trap-nights capturing more than 1350 individuals. We also gathered quantitative data on the amount of trophic and cover resources in each area to better interpret the response of populations to silvicultural activities. For all the three species, coppicing activities had strong positive effects on population density, which were, in some cases, matched by similar effects on individual survival whereas afforestation of conifer plantations negatively affected populations of A. flavicollis and M. glareolus. We found that different types of forest management, such as the recently coppiced stands, did not create high-density sinks but, rather, enhanced the carrying capacity of the habitats by increasing the availability of cover and food resources. On the contrary, the high forest resulted to be less preferred habitat for A. sylvaticus and M. glareolus, possibility due to its lack of food and cover resources. Our analyses encompassing multiple population parameters allowed us to highlight the mechanisms by which forest management affects small mammal populations.