Browsing by Subject "Macroinvertebrates"

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  • Kärnä, Olli-Matti; Heino, Jani; Laamanen, Tiina; Jyrkänkallio-Mikkola, Jenny; Pajunen, Virpi; Soininen, Janne; Tolonen, Kimmo T.; Tukiainen, Helena; Hjort, Jan (2019)
    Context One 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. Objectives The 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. Methods We 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. Results We 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. Conclusions In 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.
  • Vilmi, Annika; Zhao, Wenqian; Picazo, Félix; Li, Mingjia; Heino, Jani; Soininen, Janne; Wang, Jianjun (2020)
    Understanding the role of climatic variation on biodiversity is of chief importance due to the ongoing biodiversity loss and climate change. Freshwaters, one of the most threatened ecosystems in the world, offer a valuable context to study biodiversity patterns of distinct organism groups in relation to climatic variation. In the Tibetan Plateau biodiversity hotspot, we studied the effects of climate and local physico-chemical factors on stream microorganisms (i.e. bacteria) and macroorganisms (i.e. macroinvertebrates) in two parallel catchments with contrasting precipitation and temperature. Diversities and community structures were better explained by climatic and local environmental variables in the drier and colder catchment and at higher elevations, than in the warmer and wetter conditions and at lower elevations. This suggests that communities may be more strongly assembled by deterministic processes in the former, comparatively harsher conditions, compared to the latter, more benign conditions. Macroinvertebrates were more strongly affected by climatic and local environmental factors compared to bacteria, but the diversities and community structures of the two groups showed spatially similar responses to overall abiotic variation, being especially evident with their community structures’ responses to climate. Furthermore, bacterial and macroinvertebrate diversities were positively correlated in the drier and colder catchment, implying that these biologically and ecologically distinct organism groups are likely to be driven by similar processes in areas with such climatic conditions. We conclude that changes in climatic and local environmental conditions may affect the diversity of macroorganisms more strongly than that of microorganisms, at least in subtropical mountainous stream ecosystems studied here, but simultaneous responses of both groups to environmental changes can also be expected.