Co-variation of lichens, bryophytes, saproxylic beetles and dead wood in Swedish boreal forests

Abstract

In order to effectively identify and protect the most valuable forest areas for conservation, it is essential to understand species diversity patterns and the co-variation of different taxonomic groups. In this study we analysed the extent to which lichens, bryophytes and saproxylic beetles co-vary, their ability to represent each other in a reserve network (surrogate capacity), and their patterns of beta-diversity. We also tested the surrogate capacity of dead wood. A species and dead wood inventory was conducted in forest sites in a boreal forest region in central Sweden. Overall, the correlations in species richness between taxa were weak, but some were statistically significant, i.e. those between red-listed lichens and red-listed bryophytes. Beetles were weakly positively correlated with bryophytes, but never with lichens. None of the tested taxa provided a reliable surrogate for representing the other taxa. However, dead wood diversity did represent saproxylic beetles and bryophytes better than random selection and might therefore function as a conservation surrogate for those taxa. Beta-diversity differed significantly between the taxa; lichens had the lowest, while beetles had the highest. Altogether beetles showed low association with the other taxa but high beta-diversity, which implies that they may require specific conservation planning.

Key words:

• beta-diversity
• bryophytes
• dead wood
• lichens
• red-listed species
• reserve selection
• saproxylic beetles
• species richness
• surrogate capacity

Acknowledgements

We thank Ulf Olsson, Olof Widenfalk, Alexandro Caruso and Johanna Boberg for valuable comments and help during the preparation of the manuscript. The species survey was ably conducted by Jan ten Hoopen, Fredrik Jonsson, Ulrika Nordin, Henrik Wiebull and Olof Widenfalk. This study was part of the research programme ‘Biodiversity and Economy’, financed by FORMAS, Skogforsk and the Swedish University of Agricultural Sciences.