Drivers of spatio-temporal population dynamics of game species in a mountain landscape.

Since the end of the nineteenth century, socio-economic changes have greatly altered the Central European landscape and the structural and functional quality of habitats. Urban sprawl areas have appeared, a reduction of multiple forest uses has resulted in the densification of forests and agricultural land use has changed fundamentally through specialisation and intensification. Many of these changes affect biodiversity. To determine the important drivers of spatio-temporal dynamics of the population of 28 game species, we first considered a total of 130 potential explanatory variables. Second, we aggregated the main drivers of single-species models for habitat guilds. Third, we evaluated the results to aid in the development and implementation of mitigation measures for different ecoregions. We used harvest data as a surrogate for population density from 1875 to 2014 in South Tyrol, Italy. In generalised linear models, we used environmental characteristics such as climate, landscape diversity and structures, land cover, hunting, wildlife diseases, competition and predation, land-use type, and intensity (including pesticide use) as explanatory variables to predict the spatio-temporal dynamics of game species. The important drivers are land use and management changes (intensification in the agriculturally favourable areas, extensification or abandonment in the unfavourable areas) as well as associated changes in the landscape features, diversity and structure, and hunting management. Climatic variables, interspecific competition and diseases only play a subordinate role. The dynamics of the habitat guilds and their drivers provide concrete indications for measures to maintain or improve the habitat quality for the investigated species. Particularly important are transfer payments to ensure extensive agricultural use, increasingly through the takeover of personnel costs, but also for the installation of an independent body that monitors and evaluates the effectiveness of the measures.

Long-term game species dynamic as indicator for changing landscape quality.

Urban sprawl, increased traffic and modern forestry, as well as the globalisation of agriculture, have increasingly been affecting the landscape and its quality as habitat for species especially since the middle of the last century. Still, there are hardly any methods nor indicators which can measure the quality of the landscape for species over a long period. In this study, we investigated the influence of landscape structure and landscape quality on harvest data of 28 game species in South Tyrol, Italy, over the last 150 years. The harvest data were used to assess the population dynamics of individual species and habitat guilds since 1870. As a first result, we could show, on the examples of six species, that count population data were highly correlated with harvest data and are therefore well suited to estimate their population size. Second, the populations of ungulates consistently increased during the study period. The numbers of mesocarnivores as well as smaller forest and alpine game species increased strongly until the 1970s/80s of the last century, followed by a decline. The populations of farmland species and some synanthropic species have decreased substantially, and some species have even disappeared completely. Based on these results, we were able to show, in a third step, that the landscape quality for game species in South Tyrol has developed differently: In particular, the agriculturally used habitats have lost quality, whereas forests and alpine regions have initially gained quality due to the extensification of use; during the last five decades, the quality decreases again, at least for small game species. Our results thus provide concrete implications for the active improvement of the landscape quality for farmland and forest species, as well as indications for future priorities in funding support of alpine pasture management.