Saproxylic species are linked to the amount and isolation of dead wood across spatial scales in a beech forest

ContextDead wood is a key habitat for saproxylicspecies, which are often used as indicators of habitatquality in forests. Understanding how the amount andspatial distribution of dead wood in the landscapeaffects saproxylic communities is therefore importantfor maintaining high forest biodiversity.ObjectivesWe investigated effects of the amountand isolation of dead wood on the alpha and betadiversity of four saproxylic species groups, with afocus on how the spatial scale influences results.MethodsWe inventoried saproxylic beetles, wood-inhabiting fungi, and epixylic bryophytes and lichenson 62 plots in the Sihlwald forest reserve in Switzer-land. We used GLMs to relate plot-level speciesrichness to dead wood amount and isolation on spatialscales of 20–200 m radius. Further, we used GDMs todetermine how dead wood amount and isolationaffected beta diversity.ResultsA larger amount of dead wood increasedbeetle richness on all spatial scales, while isolation hadno effect. For fungi, bryophytes and lichens this wasonly true on small spatial scales. On larger scales ofour study, dead wood amount had no effect, whilegreater isolation decreased species richness. Further,we found no strong consistent patterns explaining betadiversity.