Red-listed forest bird species in an urban environment -: assessment of green space corridors

The aim of this work was to investigate if the forest remnants of the city and the system of green space corridors could support target species for conservation, in the form of red-listed forest bird species, to show through the presence of the target species what habitat qualities are still possible near cities, and to reveal those features and properties of the landscape structure that were important in this sense. The findings could be used for developing guidelines for design of urban green space corridors. A spatial analysis was performed, covering the landscape in the study area and 67 sample sites with natural vegetation, within and outside of the green space corridors. Breeding forest birds were recorded and breeding of target species in the sample sites as functions of landscape descriptors was tested using logistic regression. Seven red-listed forest bird species were found breeding in the sample sites. Considering them as indicators of habitat qualities, the results would imply that the qualities of the urban and suburban forests were due to a vast range of deciduous forest, especially broad-leaved, and possibly also to a lower intensity of forestry than in rural areas, resulting in a sufficient number of mature and decaying trees. The logistic regression models showed that important properties of remnants of natural vegetation were large areas of forest on rich soils, together with connectivity in the form of amounts of this habitat in the landscape. These properties were associated with the green space corridors. Implications for the design of urban green space corridors would be to treat mature and decaying trees and patches of moist deciduous forest as a resource for vulnerable species, and to conserve large areas of natural vegetation together with a network of important habitats in the whole landscape, in this case forest on rich soils, also in built-up areas. (C) 2000 Elsevier Science B.V. All rights reserved.