The role of spatio-temporal patch connectivity at the landscape level: an example in a bird distribution

The recent development of landscape ecology emphasizes the importance of connectivity for population viability. Landscape connectivity is the degree to which the landscape facilitates or impedes movement among resource patches. Most of the empirical data identifying landscape spatial patterns (connectedness) that interfere with individual movements, concern walking animals with low powers of dispersal. For flying animals, the distance between patches is measured in almost all cases using euclidean distance. This does not account for the behavioural characteristics of species that depend on landscape patterns for their movements. We hypothesized that the presence of Short-toed Tree Creeper (Certhia brachydactyla) depends on landscape spatial structure, so we tested it in two contrasting rural landscapes. These adjacent landscapes differ in grain size, the quality of linear landscape elements delimiting fields, and their history. in the recently reclaimed polder, Tree Creepers are only present in linear rows of trees with a high degree of connection, long enough to support the home range of this bird (supplementation process). Colonisation of this recent landscape from the 'bocage', acting as a source of dispersers, required connectedness between hedgerows and planted dykes (source-sink process). (C) 1997 Elsevier Science B.V.