Changes in breeding birds in the Monte Fenera Natural Park shaped by 30 years of forest encroachment

Changes in composition and abundance of breeding birds have been studied in the Monte Fenera Natural Park (north-west Italy, Piedmont), a foothill area at the margins of the Alps that has seen landscape upheaval over the last 40 years, from traditional mountain management to a substantial abandonment. This area symbolizes the impact of forest encroachment on the fringes of the Alps, as the current land use is predominantly characterized by young dense forests that have replaced hay meadows and crops. In this area, breeding birds have been investigated exhaustively since the 1990s. This study aims to show the changes related to breeding bird species over the last 30 years, comparing surveys from 1997, 2007, and 2023. The results show a significant turnover, with 24 species lost. The decrease in species diversity concerns above all shrublands and open habitat species. On the other hand, 9 species of forest birds are increasing between 20% to 267%. Of particular interest are two emblematic species: Columba oenas, which has been confirmed as a breeding species after 45 years of absence, and Dryocopus martius, which has increased from one to at least six pairs in the area. In conclusion, breeding birds in the Monte Fenera Natural Park are showing strong spatial and temporal dynamics because of changes in land use. Finally, a checklist of the 121 species of birds ever observed in the area is provided, with an updated status for the protected area for the year 2023.