Per Gustav Thingstad

Management Strategies in Forest Landscapes in Norway

The main purpose of this work is to present some views on the management of landscape change in forest landscapes from the perspectives of ecological integrity and management regimes, using a transdisciplinary approach. This gives us an opportunity to describe the practice of various management regimes and discuss future management strategies. the presentation is based on the project The Battlefield of Regimes, financially supported by the Research Council of Norway (Skjeggedal 2001; Skjeggedal et al. 2001). This project is mainly concerned with the management of landscape change in forested areas in an ecological perspective.

Human-induced alteration of two boreal forest landscapes in central Norway, and some possible consequences for avian fauna

Abstract Exploitation over the last 50 years has altered the Fennoscandian boreal forest landscapes quite considerably. The situation in our two study areas in Lierne (Berglia and Raudberga) in central Norway in three periods, the 1950s, the 1970s and 1999, exemplifies this development. The ecological consequences of the landscape alterations identified during this period are illustrated by tracing the trend of the bird guild associated with old-growth forest. We have used existing and estimated density data for this guild, theories on landscape ecology and Geographical Information System (GIS) analyses. At Berglia, the area covered with old-growth forest was reduced by a further 19% in 1999 compared with the “pristine” situation where 65% of the landscape was forested. At Raudberga there has been a further 36% reduction from the original 72% coverage, leaving just 36% of this area covered by old growth. Given our assumptions (e.g. a 100-metre edge effect), the old-growth bird guild has been declining at ratios of 1.23–1.49 at Raudberga and 1.60–1.93 at Berglia relative to the reduction in the proportion of areas covered by old-growth forest stands, a significantly higher rate of decline than the one-to-one relationship expected if the loss of habitat areas had been the only effect. The difference in the spatial habitat configuration between these two areas can explain some of the variation as Raudberga shows a more coarse-grained fragmentation pattern. If the current trends, according to our best-fit models, are allowed to continue until 2050, only 30–44% of the population sizes at the “pristine” state will survive at Berglia and 22–32% at Raudberga. For some of the species involved, this certainly implies that the critical threshold value for maintaining viable population sizes will be exceeded, not least because the long-established practice of clear-felling will lead to a lack of important habitat features such as dead wood and large trees in the landscape. The boreal forest is, however, a natural, dynamic system whose resilience should be quite good and, as shown by our best possible scenario, a significantly improved situation can be achieved by 2050. However, this presupposes that the current alarming trends are taken seriously by the management authorities, and that the multi-professional knowledge available is applied in future planning processes for our rural areas.

Predicting autumn population sizes of tetraonid game birds from reproduction data of pied flycatcher Ficedula hypoleuca

Abstract Data on the breeding success of the pied flycatcher, which reflects the combined effects of various biotic and abiotic factors affecting the quality of the breeding habitat each year, could explain more than three quarters of the variation in the autumn population levels of woodland tetraonids (capercaillie Tetrao urogallus and black grouse T. tetrix) in a subalpine forest area in Lierne, central Norway, during the period 1986–1995. The applicability of a simple regression model is evaluated on the basis of the data from 1996. Much less time is required to collect these breeding parameters on the flycatcher from nest boxes than to obtain reasonably good population estimates for the tetraonid species themselves directly. Data on the production of pied flycatcher, collected well in advance of the shooting season, could be used to set bag limits for woodland tetraonids the following autumn. This might be used as a tool for sustainable harvest to avoid future over-exploitation of these species in years with predicted low production.