Epsilon Open Archive

Abstract

In northern Europe, a long history of anthropogenic land use has led to profound changes within forest ecosystems. One of the proposed approaches for conservation and restoration of forest biodiversity is the use of umbrella species, whose conservation would confer protection to large numbers of naturally co-occurring species. This thesis aims to evaluate some of the prerequisites to the umbrella species concept, focusing on resident birds in hemiboreal and boreal forests. The study was performed in four areas belonging to the southern Baltic Sea region: central and southern Sweden, south-central Lithuania and northeastern Poland. A review of empirical evaluations of the umbrella species concept performed in various systems suggested that multispecies approaches addressing the requirements of both the umbrellas and the beneficiary species have better potential than approaches based coarsely on the area needs of single species. An analysis of co-occurrence patterns among resident forest birds in landscape units of 100 ha showed that some species reliably indicated high species richness through their presence. For birds of deciduous forests, there was high cross-regional consistency in the identity of the best indicators. Specialised woodpeckers (Picidae) were prominent among the species that performed well as indicators. Their presence in the landscape units was generally linked positively to the degree of naturalness of the forest and to the amounts of resources that have become scarce in intensively managed forests, such as dead wood and large trees. In Sweden, occurrence of the white-backed woodpecker (Dendrocopos leucotos) in bird atlas squares was positively related to species richness among forest birds of conservation concern, as well as to the area of deciduous and mixed forests of high value for conservation. Moreover, the number of red-listed cryptogam species linked to deciduous trees and dead wood was higher where the woodpecker bred. Those results for birds of northern forests suggest that the umbrella species concept may constitute a useful component of conservation planning, especially in the work towards the derivation of quantitative targets. However, umbrella species are not a panacea and should therefore be seen as part of a complementary suite of approaches.