Impact of recreation on forest bird communities: non-detrimental effects of trails and picnic areas (In English)

摘要

We analyzed changes in distribution and abundance of forest birds due to different types of recreational activity in the Madrid province (Guadarrama Range, Central Spain). Census plots were distributed in forest interiors (undisturbed sites), along forest trails (transiently disturbed hiking tracks), and in recreational areas (long-lasting disturbed picnic sites). Parameters describing the overall bird community (i.e. total bird abundance, species richness and diversity), groups of species (i.e. abundance of corvids and nesting or foraging guilds) and individual species abundances were compared. Forest sites with any type of human presence (trails and picnic sites pooled) had higher overall abundances and species richness per sampling plot than undisturbed forest interiors. Furthermore, fourteen species were significantly more abundant in disturbed sites than in forest interiors, while the converse was true only for five species. Anthropogenic sites did not affect forest specialists. Canopy-nesters, trunk and ground-foragers, and corvids were more abundant at recreational sites than in undisturbed forests, while the converse pattern was observed for ground-nesters. These patterns were more distinct in deciduous than in coniferous forest tracts. The positive effects of recreational sites were mostly associated with picnic sites, since forest trails were mostly indistinguishable from undisturbed forest interiors in terms of bird community patterns. Several habitat characteristics of disturbed sites can explain some of these differences: increased maturity of the tree layer, less dense subcanopy vegetation, higher abundance of holes and crevices, and greater predictability and availability of human food waste in picnic areas. So, contrary to expectations, we conclude that these types of nonconsumptive recreation do not decrease habitat suitability for most birds, although it might decrease suitability for ground-nesting birds [ Acta Zoologica Sinica 53(1): 54–63, 2006].