The abandonment of man-made pastures below the tree line is favouring natural reforestation in the European Alps. As a consequence, although the development of ski areas has severely disturbed the environment in the Alps, the creation of forest ski-pistes might, paradoxically, be beneficial to butterflies, which are predominantly open-habitat species. This study is the first to focus on the effects of forest ski-pistes on butterfly assemblages (Lepidoptera, Rhopalocera). We sampled both butterflies and flowers on ski-pistes, in three ski resort sites (i.e. Torgnon, Antagnod and Colle di Joux) located in the Tournanche and the Ayas valleys of the north-western Italian Alps, in the Aosta Valley region. We surveyed ski-pistes (1,600-2,300 m a.s.l., 15-70 m width), adjacent coniferous forests and nearby pastures. Twenty transects for each habitat type were established. Transect counts showed that butterflies were more abundant on ski-pistes (and forests) than in pastures. However, species richness and diversity were lower on ski-pistes than on nearby pastures. Flower abundance was higher, but flower richness and diversity were lower on ski-pistes than in pastures. Multivariate Regression Trees indicated that butterfly abundance was positively associated with flower abundance, and butterfly diversity was positively associated with flower diversity. We conclude that: i) butterfly abundance on ski-pistes was higher because in mid-summer these grassland strips were more abundant in flowers than nearby pastures and ii) butterfly diversity was lower, both because of the lower flower diversity and because of the higher isolation and/or smaller area of ski-pistes by comparison with pastures. In the Alps, several grassland butterfly species are of conservation concern. Ski-pistes are probably sub-optimal habitats for butterflies. Nevertheless, within a natural reforestation framework, they may be useful to butterfly conservation, on condition that they are completely re-vegetated and that grass cover of ski-pistes is encouraged and maintained to facilitate their colonization.
Do forest ski-pistes represent a habitat gain for butterflies?
NEGRO, MATTEO;ROLANDO, Antonio;PASSERIN D'ENTREVES, Pietro;BALLETTO, Emilio;PALESTRINI, Claudia
2012-01-01
Abstract
The abandonment of man-made pastures below the tree line is favouring natural reforestation in the European Alps. As a consequence, although the development of ski areas has severely disturbed the environment in the Alps, the creation of forest ski-pistes might, paradoxically, be beneficial to butterflies, which are predominantly open-habitat species. This study is the first to focus on the effects of forest ski-pistes on butterfly assemblages (Lepidoptera, Rhopalocera). We sampled both butterflies and flowers on ski-pistes, in three ski resort sites (i.e. Torgnon, Antagnod and Colle di Joux) located in the Tournanche and the Ayas valleys of the north-western Italian Alps, in the Aosta Valley region. We surveyed ski-pistes (1,600-2,300 m a.s.l., 15-70 m width), adjacent coniferous forests and nearby pastures. Twenty transects for each habitat type were established. Transect counts showed that butterflies were more abundant on ski-pistes (and forests) than in pastures. However, species richness and diversity were lower on ski-pistes than on nearby pastures. Flower abundance was higher, but flower richness and diversity were lower on ski-pistes than in pastures. Multivariate Regression Trees indicated that butterfly abundance was positively associated with flower abundance, and butterfly diversity was positively associated with flower diversity. We conclude that: i) butterfly abundance on ski-pistes was higher because in mid-summer these grassland strips were more abundant in flowers than nearby pastures and ii) butterfly diversity was lower, both because of the lower flower diversity and because of the higher isolation and/or smaller area of ski-pistes by comparison with pastures. In the Alps, several grassland butterfly species are of conservation concern. Ski-pistes are probably sub-optimal habitats for butterflies. Nevertheless, within a natural reforestation framework, they may be useful to butterfly conservation, on condition that they are completely re-vegetated and that grass cover of ski-pistes is encouraged and maintained to facilitate their colonization.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
