Date:
2018/06/14

Time:
13:45

Room:
A2 Wivi


Drivers of forest β-diversity in different organisms and its relevance for conservation

(Oral)

Martin. M. Gossner
,
Peter Schall
,
Eric Allan

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Land-use intensity has been shown to not only affect local alpha-diversity, but also beta-diversity, i.e. the turnover of species among sites, resulting in a homogenization of communities at landscape scale [1]. Thus, for the conservation of forest biodiversity at larger spatial scales beta-diversity needs to be considered. However, the drivers of forest beta-diversity and its underlying processes in different taxonomic and functional groups are yet not well understood. We studied the drivers of beta-diversity in 15 organism groups from bacteria to vertebrates across 150 forest sites (unmanaged and managed beech, managed conifer) in three region of Germany, including environmental drivers (climate, soil, deadwood, forest stand structural properties), management intensity and geographic distance. In particular we addressed the following questions: (1) What is the relative importance of different drivers for beta-diversity and its components (spatial turnover, nestedness) in different organisms / trophic groups?, and (2) What are the underlying processes and does the importance of processes change with management intensity?

Our predictors explained up to 70% of the variation in beta-diversity, but the percentage of deviance explained highly varied among organism groups. While a change in soil variables was the major driver of beta-diversity in soil bacteria and ectomycorrhizal, forest structure was the main driver of beta-diversity in birds and vascular plants and spatial distance, climate and management intensity in beetles.

Overall our predictors explained more of the turnover than of the nestedness component of beta-diversity. However, in some groups, such as in vertebrates and spiders, richness differences were better explained by single drivers than spatial turnover. In other groups, such as plants, bryophytes and lichens, turnover and nestedness were caused by different drivers.

Our results demonstrate that different drivers are important for beta-diversity in different taxonomic and functional groups with varying underlying mechanisms (e.g. non-random species loss, environmental sorting). The high relative importance of interactions among drivers, e.g. with management intensity, suggests that processes underlying a change in beta-diversity are greatly shaped by management. In order to protect larger spatial scale forest biodiversity and related functions, the varying processes driving forest beta-diversity in different organisms need to be considered.

1. Gossner, M.M., et al., Land-use intensification causes multitrophic homogenization of grassland communities. Nature, 2016. 540(7632): p. 266-269.


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