Survey of the Lynx distribution in the French Alps: 2000–2004 population status analysis

Abstract

Within the SCALP framework, the status of the pan-alpine population of Eurasian Lynx is assessed every 5 years, based on the compilation of national reports and standardized classification of lynx presence signs according to data confidence levels (C1, C2, C3). From2000 to 2004, the French national network of lynx experts collected N= 393 data, out of which 224 (compared to only 69 in 1995–1999) were considered as robust enough to evidence the presence of lynx (C1 = 1%; C2 = 42%; C3 = 57%) and were used for further analysis. A majority of the signs concerned the northern part of the Alps, however, in mostly two regions (Chartreuse/Epine: 34% of the signs; Maurienne: 21%). Other data were more scattered over space, from the Cha- blais region close to Switzerland down to the Haut-Verdon close to the Mercantour mountains. A negative trend was noticed from north to south in proportions of best quality signs(C1+C2), and a positive one in low quality ones – C3 – (c² = 3.56, 1 df, p = 0.06), which could point at some methodological artefacts. Discarding C3 may however be too conservative a strategy to assess the species range and status. Using spatial recurrence and trend over time of all signs available (C1+C2+C3) could, therefore, provide the right balance between being too much versus not enough conservative. – When doing so, the area with lynx signs regularly detected sharply increased between 1996–1998 (100 km²), 1999–2001(250 km²), and 2002–2004 (1195 km²). The latter area is still quite small regarding what is required for a viable large carnivore population.A simple demographic model suggested that even a quite moderate proportion of immigrants (e.g. dispersal inflow from neighbouring coreareas – French Jura or Swiss Alps) could considerably decrease the theoretical demographic extinction risk of such a small population, but stilldepending upon adult survival rates, which also strongly influenced the extinction risk. The factors that may influence this sensitivity analysis(such as habitat connectivity and management of wooded corridors) should be evaluated within the Scalp framework.