Long-Term Human Impact and Vegetation Changes in a Boreal Forest Reserve: Implications for the Use of Protected Areas as Ecological References

Abstract

Northern boreal forest reserves that display no signs of modern forest exploitation are often regarded as pristine and are frequently used as ecological reference areas for conservation and restoration. However, the long-term effects of human utilization of such forests are rarely investigated. Therefore, using both paleoecological and archaeological methods, we analyzed temporal and spatial gradients of long-term human impact in a large old-growth forest reserve in the far north of Sweden, comparing vegetational changes during the last millennium at three sites with different land use histories. Large parts of the forest displayed no visible signs of past human land use, and in an area with no recognized history of human land use the vegetation composition appears to have been relatively stable throughout the studied period. However, at two locations effects of previous land use could be distinguished extending at least four centuries back in time. Long-term, but low-intensity, human land use, including cultivation, reindeer herding and tree cutting, has clearly generated an open forest structure with altered species composition in the field layer at settlement sites and in the surrounding forest. Our analysis shows that past human land use created a persistent legacy that is still visible in the present forest ecosystem. This study highlights the necessity for ecologists to incorporate a historical approach to discern underlying factors that have caused vegetational changes, including past human activity. It also indicates that the intensity and spatial distribution of human land use within the landscape matrices of any forests should be assessed before using them as ecological references. The nomenclature of vascular plants follows Krok and Almquist (Svensk flora. Fanerogamer och ormbunksvaxter, 2001).