Landscape level effects of modern forestry on bird communities in North Swedish boreal forests
- 206 Downloads
We address effects of large-scale forestry on landscape structure and the structure and composition of boreal bird communities in North Sweden. Specifically, we ask: after controlling for the effect of patch size, forest age and tree species composition, is there any residual effect attributable to the reduction in area of old forest? Pairs of landscape blocks (25 by 25 km) were selected to maximize area difference in human-induced disturbance, clear-cut as opposed to semi-natural old forest.
Median distance to natural edge (wetlands, open water) from randomly selected points in forest was 250 and 200 m in high and low impact landscapes, respectively, indicating a high degree of ‘natural’ fragmentation of the pristine boreal landscape in the area. By contrast, median distance to clear-cut in uncut forest was 750 and 100 m, respectively. Clear-cuts in high impact landscapes were disproportionally more common in areas with contiguous forest land than in areas with spatially disjunct forest, implicating that forestry increases natural fragmentation of the landscape by subdividing larger forest tracts.
Point counts along forestry roads showed that species richness and relative abundance of forest birds were higher in landscapes with low forestry impact. These differences can partly be explained by differences in age composition of forest and composition of tree species. After controlling for patch size, forest age and tree species composition, a significant effect of forestry impact remained for Sibirian species and the Tree pipitAnthus trivialis. Our results thus imply that this group of species and the Tree pipit may be sensitive to forest fragmentation.
In contrast to previous Finnish studies, we found relatively small negative effects on relative abundance of species hypothesized to be negatively affected by large-scale clear-cutting forestry. However, our picture of the present does not contradict results from Finnish long-term population studies. Five factors may account for this: 1) clear-cut areas are not permanently transformed into other land use types, 2) planted forests are not completely inhabitable for species preferring older forest, 3) the majority of species in the regional pool are habitat generalists, 4) the region studied is still extensively covered with semi-natural forest, and 5) our study area is relatively close to contiguous boreal forest in Russia, a potential source area for taiga species.
Keywordsboreal forest North Sweden bird community landscape clear cutting tree species composition
Unable to display preview. Download preview PDF.
- Ahti, T., Hämet-Ahti, L., and Jalas, J. 1968. Vegetation zones and their sections in northwestern Europe. Ann Bot Fennici 5: 169–211.Google Scholar
- Andrén, H. 1994. Effects of habitat fragmentation on birds and mammals in landscapes with different proportions of suitable habitat: a review. Oikos 71: 355–366.Google Scholar
- Anonymous 1994. Statistical yearbook of forestry. Official statistics of Sweden. National Forestry Board, Jönköping.Google Scholar
- Esseen, P.-A., Ehnström, B., Ericson, L. and Sjöberg, K. 1992. Boreal forests — the focal habitats of Fennoscandia.In Ecological Principles of Nature Conservation, pp. 252–325. Edited by L. Hansson. Elsevier, London.Google Scholar
- Hägglund, B. and Lundmark, J.-E. 1977. Site index estimation by means of site productivity. Stud For Suec 138.Google Scholar
- Haila, Y. and Järvinen, O. 1990. Northern conifer forest and their bird species assemblages.In Biogeography and Ecology of Forest Bird Communities, pp. 61–85. Edited by A. Keast. SPB Academic Publishing bv, The Hague.Google Scholar
- Haila, Y., Hanski, I.K., and Raivio, S. 1987a. Breeding bird distribution in fragmented coniferous taiga in southern Finland. Ornis Fennica 64: 90–106.Google Scholar
- Haila, Y., Järvinen, O. and Raivio, S. 1987b. Quantitative versus qualitative distribution patterns of birds in the western Palearctic taiga. Ann Zool Fennici 24: 179–194.Google Scholar
- Helle, P. and Järvinen, O. 1986. Population trends of North Finnish land birds in relation to their habitat selection and changes in forest structure. Oikos 46: 107–115.Google Scholar
- Helle, P. and Mönkkönen, M. 1990. Forest succession and bird communities: theoretical aspects and practical implications.In Biogeography and Ecology of Forest Bird Communities, pp. 299–318. Edited by A. Keast. SPB Academic Publishing bv The Hague.Google Scholar
- Hunter, M. 1990. Wildlife, Forests, and Forestry, Prentice Hall, Englewood Cliffs, New Jersey.Google Scholar
- Järvinen, O., Kuusela, K. and Väisänen, R.A. 1977. Effects of modern forestry on the numbers of breeding birds in Finland in 1945–1975. (In Finnish with English summary). Silva Fennica 11: 284–294.Google Scholar
- Järvinen, O. and Väisänen, R.A. 1976. Species diversity of Finnish birds, II: Biotopes at the transition between taiga and tundra. Acta Zool Fennici 145: 1–35.Google Scholar
- Järvinen, O. and Väisänen, R.A. 1977. Long-term changes of the North European land bird fauna. Oikos 29: 225–228.Google Scholar
- Kempe, G., Toet, H., Magnusson, P.-H. and Bergstedt, J. 1992. The Swedish national forest inventory 1983–87. Swedish University of Agricultural Sciences, Department of Forest Survey, Umeå, Report 51.Google Scholar
- Linder, P. and Östlund, L. 1992. Changes in the boreal forests of Sweden (In Swedish with English summary). Sven Bot Tidskr 86: 199–216.Google Scholar
- Mikkonen, A.V. 1983. Breeding site tenacity of the ChaffinchFringilla coelebs and the BramblingF. montifringilla in northern Finland. Ornis Scand 14: 36–47.Google Scholar
- Mönkkönen, M. and Welsh, D.A. 1994. A biogeographical hypothesis on the effects of human caused landscape changes on the forest bird communities of Europe and North America. Ann Zool Fennici 31: 61–70.Google Scholar
- Pastor, J., Mladenoff, D., Haila, Y., Bryant, J. and Payette, S. Biodiversity and ecosystem processes in boreal regions.In Functional Roles of Biodiversity: A Global Perspective. Edited by H.A. Mooney, J.H. Cushman, E. Medina, O.E. Sala and E.-D. Schulze. Wiley Press, New York. In press.Google Scholar
- Simberloff, D.S. 1978. Use of rarefaction and related methods in ecology.In Biological Data in Water Pollution Assessment, pp. 150–165. Edited by K.L. Dickson, J. Cairns Jr. and R.J. Livingstone. American Society for Testing and Materials, STP 652.Google Scholar
- Solonen, T. 1994. Structure and dynamics of the Finnish avifauna. Memoranda Soc Fauna Flora Fennica 70: 1–22.Google Scholar
- Svensson, S. 1995. Svenska häckfågeltaxeringen 1994. Fågelåret 1995: 11–19. SOF, Stockholm. (In Swedish).Google Scholar
- Syrjänen, K., Kalliola, R., Puolasmaa, A. and Mattson, J. 1994. Landscape structure and forest dynamics in subcontinental Russian European taiga. Ann Zool Fennici 31: 19–34.Google Scholar
- Tirén, L. 1937. Skogshistoriska studier i trakten av Degerfors i Västerbotten. (In Swedish). Meddel Skogsfoers Anst 30: 67–322.Google Scholar
- Virkkala, R. 1987. Effects of forest management on birds breeding in northern Finland. Ann Zool Fennici 24: 281–294.Google Scholar
- Väisänen, R.A., Järvinen, O. and Rauhala, P. 1986. How are extensive, human-caused habitat alterations expressed on the scale of local bird populations in boreal forests? Ornis Scand 17: 282–292.Google Scholar
- Voous, K.H. 1960. Atlas of European Birds. Nelson, London.Google Scholar
- Wiens, J.A. 1989. The Ecology of Bird Communities. Cambridge University Press, Cambridge.Google Scholar
- Zackrisson, O. 1977. Influence of forest fires on the North Swedish boreal forest. Oikos 29: 22–32.Google Scholar