The use of riparian forests as ecological corridor by passerine birds in the south of Portugal

摘要

Despite riparian forests have long been considered ecological corridors still few empirical evidence exists. This thesis analyses the use of riparian forests as ecological corridors by birds in a Mediterranean type climate, focusing primarily on passerines. The aim was to investigate: 1) if riparian habitats supported significantly richer and more abundant assemblages regardless of the riparian quality and matrix; 2) if birds selected these habitats differently; 3) if habitat use changed after pressures upon riparian forests; 4) how these changes affected bird assemblages and condition; 5) which characteristics of the riparian area can be used to enhance their use as corridors and 6) which restoration practices could be developed to achieve broader conservation strategies. Point count and mist netting protocols were used in two distinct river basin of the South of Portugal (Tagus and Odelouca).;Riparian forests supported more diverse and abundant communities independently of matrix and riparian habitat quality and common European woodland bird species were using them as surrogate/refuge in depleted situations. After riparian clear-cut: richness and abundance significantly decreased in all habitats; the number of days migrants remained in the area was significantly lower and fat scores and mean weight were significant lower. To updated knowledge these findings have never been reported and suggest that poor quality riparian habitats might act as ecological traps and this should be considered when designing mitigation measures, restoring riparian corridors and developing ecological networks. Our results support the idea that riparian forests in xeric context act as corridors for resident and migratory birds; A utilizacao das galerias ribeirinhas como corredores ecologicos pelas aves Passeriformes no Sul de Portuga.