HISTORICAL CHANGES OF LANDSCAPE AFFECT POPULATION SIZE AND CONNECTIVITY OF ITALIAN ROCK PARTRIDGE

After the Second World War, agro - pastoral practices in Italian mountain areas were progressively abandoned due to the development of industry and intensive crop. Human depopulation of rural mountain areas and the consequent abandonment of traditional land management are among the greatest driving forces behind changes in this ecosystem in whole Western Europe. This change involves a specific ecological succession, in which grassland gradually turns into scrubland and, ultimately, into forest, increasing in agro - pastoral landscape fragmentation, reducing patches size and increasing in mutual distance. The animal associated with agro - pastoral habitat may suffer from decreased connectivity as a consequence. The Rock Partridge ( Alectoris graeca ) is a mountain species endemic to Europe here used as a model for investigating the impact of habitat loss, fragmentation, hunting and climate change. We compared the habitat suitability of the Apennine Rock Partridge prior to abandonment of traditional agro - pastoral activities with the current landscape, in order to investigate the effect of secondary succession on the distribution and v iability of the species. We aimed to understand the type and extent of habitat loss that the Apennine population has experienced. We assessed the past landscape throughout historical aerophotography an d species distribution (c. 1900 - 1950) by quantifying anecdotal evidence from interviews. Current landscape and distribution were assessed from GIS resource and survey data respectively. We applied ecological niche factor analysis and connectivity approaches to obtain historical and current Rock Partridge hab itat suitability. Results indicated that in just five decades our study area has experienced profound changes in landscape structure and function. We observed a drastic decrease in connectivity as a result of a reduction in numbers and size of high suitabi lity patches. We suggest to maintain a viable populatio n it requires an ensemble of ecological conditions along corridors connecting the actual residual populations. In the Rock Partridge, we also showed that, during this time period, species experienced a shift of niche and an increase of marginality. However, if the increased population’ s fragmentation recorded since the 1900s persists, the extinction of some of the subpopulations appears inevitable