At the brink of extinction: Three decades of decline of Corncrake (Crex crex) in North-eastern Italy with a conceptual framework of threats and suggested conservation measures

Abstract

We present data on the population density and distribution of Corncrake breeding sites across a broad region of North-eastern Italy, collected over a 30-year period. Additionally, based on an extensive literature review, we conducted a literature review about driving forces, anthropogenic threats, related mechanisms, and impacts affecting this species of conservation concern in breeding sites. In the North-eastern Alps, Corncrake populations have experienced a significant decline in local density from 1993 to 2024, with a particularly dramatic decrease between 2012 and 2013. Grouping data for decades, in the 11 sites we recorded 47.2 ± 12.21 males in 1993–2002; 30.5 ± 6.96 in 2003–2012 and 7 ± 3.33 in 2013–2024. The population decline in the Friuli region was accompanied by significant range contraction—by the end of the study period, the species was present at only 40 % of the surveyed sites. Similar trends of decline have been reported in other Alpine regions, though with varying timeframes depending on local contexts. The declining trend is strongly linked to socio-economic driving forces, particularly those related to European agricultural policies. These policies have been identified as the primary drivers behind changes in mowing regimes. However, local variations between sites highlight how both threats and corresponding conservation measures are highly dependent on the geographical context. The framework of this situation suggests that anthropogenic threats can be divided into three main categories of driving forces: (i) local changes in disturbance regimes, primarily related to meadow mowing; (ii) regional changes in land use; and (iii) large-scale climate change. Since the driving forces and threats may differ in terms of spatial and temporal scales, as well as in local conditions, further analyses should incorporate quantitative approaches, such as expert-based evaluations, to rank and prioritize threats.