The role of the metapopulation concept in conservation of European woodland grouse
Storch, I. 1997: The role of the metapopulation concept in conservation of European woodland grouse. - Wildl. Biol. 3: 272.
The possible role of metapopulation theory in conservation of central European woodland grouse is discussed. Grouse habitats in central Europe are fragmented at hierarchial levels of scale. At the continental scale, grouse are restricted to isolated, mostly montane, distribution ranges; nearest neighbour distances average 37, 54, and 100 km for hazel grouse Bonasa bonasia, black grouse Tetrao tetrix, and capercaillie T. urogallus, respectively. Based on a review of published reports, median juvenile dispersal distances and adult movements range within 1-3 km; maximum reported dispersal distances were 7 km in hazel grouse, 34 km in black grouse, and 75 km in capercaillie. These distances indicate that exhange between most distribution ranges is unlikely. At the regional scale, i.e. within distribution ranges, grouse habitats are interspersed with farmland and other unsuitable habitat types. Nearest neighbour distances between patches of grouse habitats in an area of the Alps averaged 2.0 km for capercaillie and possibly hazel grouse, and 4.6 km for black grouse and, thus, were within the range of juvenile dispersal distances. Therefore, metapopulation dynamics are likely within but not among central European grouse ranges. The metapopulation hypothesis has important implications for conservation of central European woodland grouse. Many populations are <100 birds, which is most probably too small for long-term viability. Thus, dispersal between local populations may be of major importance. Attempts to stabilize a population below minimum viable population size will fail unless dispersal from neighbouring populations occurs. Therefore, conservationists concerned with remnant grouse populations also have to consider potential donor populations. Conservation policy might be wrong in concentrating efforts exclusively on populations close to extinction. As a conceptional framework, the greatest value of the metapopulation theory is in communicating the importance of spatial aspects for population persistence in fragmented habitats.
Key words: central Europe, conservation, metapopulation theory, woodland grouse
Ilse Storch, Munich Wildlife Society, Linderhof 2, 82488 Ettal, Germany