Distribution of biodiversity in managed landscapes – can remotely sensed data be used to find biodiversity hot-spots?

Abstract

Management of boreal forests for timber production has caused changes in forest structures and disturbance regimes, which have influenced distribution patterns and abundance for a wide range of organisms. The aim of this study was to evaluate how bird and beetle species composition is influenced by stand age and management history in a heavily managed boreal forest landscape and whether it is possible to find biodiversity hot spots in these landscapes using remotely sensed data. Taxa included was flying and epigaeic beetles, and birds. We first compared the assemblages among stands of three ages: 1) young (8-25 years) and 2) middle-aged (40-58 years) stands regrown after clear-cutting, and 3) mature stands (80-130 years) that had been selectively cut historically but never clear felled. We sampled beetles in 42 stands and birds in 47 stands during one summer. Both bird and beetle assemblages in young stands differed from those in middle-aged and mature stands. Young stands generally harbored fewer species and lower abundances compared with middle aged and mature stands. Lack of differences in assemblage composition, species richness and abundance of beetles between middle aged and mature stands suggests that beetle assemblages recolonize following clear-felling. However, our collections included large numbers of unique and usually rare beetle species in mature stands, including several species associated with old growth characteristics, indicating that old forest is important for conservation. The lower abundance of beetles in young stands indicates that an increasing proportion of young stands on managed landscapes will reduce the overall abundances of species, with potentially negative impacts on recolonization [1]. When testing the potential of airborne laser scanning (ALS) and forest estimates derived from satellite images for predicting the stand-scale abundance and species richness of birds and beetles in the same landscape we found that the abundance and species richness of both birds and beetles was best described by the maximum vegetation height within 50 m (and thus correlated to stand age). For birds the vegetation cover between 0.5 and 3 m was important, highlighting the importance of layered stands for birds. These results show that forest estimates derived from satellite images and ALS data provide complementary information for explaining forest biodiversity patterns and may provide an efficient tool for conservation planning in managed boreal landscapes [2].

1. Johansson, T., Hjältén, J., Olsson, J., Dynesius, M., Roberge, J.-M. 2016. Long-term effects of clear-cutting on epigaeic beetle assemblages in boreal forests. Forest Ecology and Management 359: 65-73.

2. Lindberg, E., Roberge, J.-M., Johansson, T., Hjältén, J. 2015. Can airborne laser scanning (ALS) and forest estimates derived from satellite images be used to predict abundance and species richness of birds and beetles in boreal forest? Remote Sensing 7: 4233-4252.