Changes in β‐diversity of saproxylic beetles along environmental gradients in temperate forests depend on species relative abundances

Abstract

Listen

Translate article

AbstractAimUnderstanding the processes that structure biological communities along environmental gradients remains one of the main aims of ecological research. A leading question is how differences in species composition between sites, that is, β‐diversity, change in habitats ordered along environmental gradients and how such changes vary with species relative abundances. The existing literature remains descriptive, mostly comparing communities from different parts of a gradient, but not tracking sequential changes of β‐diversity along the entire gradient.LocationTemperate deciduous forests in Central Europe.TaxaSaproxylic beetles.MethodsWe applied a generalized concept of Hill numbers to data on the distribution of saproxylic beetles to test (i) whether community dissimilarities correlate with dissimilarities in major environmental variables (canopy openness, tree diameter and tree genus) and (ii) which mechanisms explain sequential changes of β‐diversity along these environmental gradients. Furthermore, we illustrate changes in the mean (α‐diversity) and total (γ‐diversity) number of species along the gradients.ResultsDissimilarities in saproxylic beetle communities were positively correlated with dissimilarities in all studied environmental variables. Changes in β‐diversity along the gradients differed for different weighting of rare, common and dominant species, with rare and dominant species always showing opposite trends. β‐diversity increased simultaneously with increasing γ‐diversity when weight was given to dominant species. On the other hand, β‐diversity decreased when weight was given to rare species.Main conclusionsThe different response of rare and dominant species indicates a similar importance of stochastic and deterministic processes in determining β‐diversity. Although the changes in β‐diversity detected along the environmental gradients were relatively slight, major community dissimilarities were found when comparing communities in different locations of the environmental gradients.