Quarante ans de suivi de l'avifaune forestière nicheuse d'un chablis

Abstract

Forty years of monitoring the breeding-bird community in a windfall area After a hurricane, a secondary forest succession was studied during forty years (1974–2013) in a windfall area in the Canton of Vaud on the Swiss Plateau, from the sapling stage to the young forest stage, where a mixed stand with 77% conifers (four species) and 23% deciduous trees (two species) has grown. The breeding birds were surveyed on a 9.2 ha study plot during 21 breeding seasons using the territory-mapping method. Overall, 41 breeding species were recorded. Species richness varied from 12 to 25 species and population density from 35.9 to 98.4 territories/10 ha, both parameters showing a bimodal curve: first peak with the installation of semiopen habitat species, second peak with the arrival of pure forest species. The bird community is dominated by a group of seven rather generalist species, which are frequent and abundant. Bird diversity during the succession was positively influenced by the following forestry practices: leaving stumps, a small number of snags and patches of old stands, planting tree species in groups and limiting forestry management in the first five years. On the Swiss Plateau, open-spaced deciduous or mixed forests (≤50% conifers) with a diverse age structure should be favoured.