Does catchment geodiversity foster stream biodiversity?

Olli-Matti Kärnä,Jenny Jyrkänkallio-Mikkola,Virpi Pajunen,Jani Heino,Janne Soininen,Jan Hjort,Tiina Laamanen,Kimmo T Tolonen,Helena Tukiainen

doi:10.1007/s10980-019-00901-z

Olli-Matti Kärnä, Jenny Jyrkänkallio-Mikkola + Show 7 more

Open Access

https://doi.org/10.1007/s10980-019-00901-z

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Abstract

ContextOne approach to maintain the resilience of biotic communities is to protect the variability of abiotic characteristics of Earth’s surface, i.e. geodiversity. In terrestrial environments, the relationship between geodiversity and biodiversity is well recognized. In streams, the abiotic properties of upstream catchments influence stream communities, but the relationships between catchment geodiversity and aquatic biodiversity have not been previously tested.ObjectivesThe aim was to compare the effects of local environmental and catchment variables on stream biodiversity. We specifically explored the usefulness of catchment geodiversity in explaining the species richness on stream macroinvertebrate, diatom and bacterial communities.MethodsWe used 3 geodiversity variables, 2 land use variables and 4 local habitat variables to examine species richness variation across 88 stream sites in western Finland. We used boosted regression trees to explore the effects of geodiversity and other variables on biodiversity.ResultsWe detected a clear effect of catchment geodiversity on species richness, although the traditional local habitat and land use variables were the strongest predictors. Especially soil-type richness appeared as an important factor for species richness. While variables related to stream size were the most important for macroinvertebrate richness and partly for bacterial richness, the importance of water chemistry and land use for diatom richness was notable.ConclusionsIn addition to traditional environmental variables, geodiversity may affect species richness variation in streams, for example through changes in water chemistry. Geodiversity information could be used as a proxy for predicting stream species richness and offers a supplementary tool for conservation efforts.

Highlights

Global change can be seen as degradation of natural ecosystems, which in turn is the most important reason underlying biodiversity change (Fuller et al 2007)
We explored the usefulness of catchment geodiversity in explaining the species richness on stream macroinvertebrate, diatom and bacterial communities
We detected a clear effect of catchment geodiversity on species richness, the traditional local habitat and land use variables were the strongest predictors

Summary

Introduction

Global change can be seen as degradation of natural ecosystems, which in turn is the most important reason underlying biodiversity change (Fuller et al 2007). The undesirable trend of biodiversity loss is associated with key stressors, such as pollution, invasive species, dams, and modification of in-stream habitats (Vorosmarty et al 2010). The effects of these stressors are highly alarming because freshwater ecosystems cover only a small fraction of the Earth’s surface area (0.8%), but harbor a considerable (6%) proportion of all known species on Earth (Dudgeon et al 2006). It is generally understood that inclusive conservation of freshwater ecosystems requires a whole-catchment approach (Dudgeon et al 2006)

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