Large-scale patterns of northern freshwater biota and water quality

The number of biogeographical studies from freshwater ecosystems has increased from the early 2000s onwards, and the investigations conducted at large-scales have become firmly established in freshwater ecology. Understanding the large-scale gradients in northern freshwaters is highly important due to changing environmental conditions, which alter the biotic and abiotic features of freshwaters. However, there is a clear bias in the studied freshwater biological groups at large-scales, as most of the studies have focused on fish and macroinvertebrates. Investigations on the less well-known groups, such as aquatic plants, can yield contradicting results, influencing on the generality of the studied phenomenon.

Aquatic plants are an important component in freshwater ecosystems, because they contribute to the primary productivity of these systems and affect various other organisms both directly and indirectly. Most studies on the ecology of aquatic plants have thus far been based on small-scale examinations within lakes and rivers, whereas large-scale patterns in their distribution, abundance, diversity and community structure have been examined less frequently. Our aim is to examine plant species and communities from a biogeographical perspective, i.e., study large-scale patterns and underlying factors across water bodies at the drainage basin, ecoregion, bioregion and continental spatial extents. We use both plant survey data from various regions of Europe and North America and plant atlas data from North America to study questions ranging from determinants of species distributions to diversity gradients.

Concerns about water systems, their condition and water quality have increased during recent decades. For example, European Union Water Framework Directive aims to achieve good surface water status in member states. Water quality is the outcome of countless environmental factors and their relations in the catchment. Land use, soil deposits, bedrock, topography, geomorphological processes and climate participate in different catchment processes, and thus, affect water quality. GIS-based methods combined with statistical analysis and modelling enable investigation of the multi-scale relationship between environment and water quality and forecasting possible changes in the future. Environmental characteristics provide an essential baseline for cost-efficient estimation and prediction of water quality attributes of boreal water systems in space and time.

Main objectives

  • To analyze large-scale patterns of freshwater biota and water quality at various spatial scales
  • To test biogeographical and macroecological theories using freshwater assemblages such as aquatic plants as a model group
  • To explore spatial patterns in freshwater bioassessment

Staff

  • Professor Jan Hjort
  • Dr. Janne Alahuhta
  • Researcher Sanna Varanka

Main collaborators

  • Dr. Jani Heino, Natural Environment Centre, Finnish Environment Institute & Department of Biology, University of Oulu, Finland
  • Dr. Jukka Aroviita, Freshwater Centre, Finnish Environment Institute, Finland
  • Dr. Seppo Hellsten, Freshwater Centre, Finnish Environment Institute, Finland

Projects

  • Macroecological approaches to understanding macrophyte diversity > Read more
  • Modelling current and future distributions of aquatic plants at a continental scale: trait group and species-level approaches

Main publications

  • Alahuhta, J. (In press). Georgaphic patterns of lake macrophyte communities and species richness at regional scale. Journal of Vegetation Science
  • Alahuhta, J., Rääpysjärvi, J., Hellsten, S., Kuoppala, M. & Aroviita J. 2015. Species sorting drives variation of boreal lake and river macrophyte communities. Community Ecology 16: 76-85.
  • Heino, J. & Alahuhta, J. (2015). Elements og regional beetle faunas: faunal variation and compositional breakpoints along climate, land cover and georgaphical gradients. Journal of Animal Ecology 84: 427441.
  • Alahuhta, J., Johnson, L.B., Olker, J. & Heino, J. (2014). Species sorting determines variation in the community composition of common and rare macrophytes at various spatial extens. Ecologial Complexity 20: 61–68.
  • Heino, J., Soininen, J., Alahuhta, J., Lappalainen, J. & Virtanen, E. (In press). A comparative analysis of metacommunity types in the freshwater realm. Ecology and Evolution.
  • Varanka, S. & Hjort, J. (In press). Geomorphological factors predict water quality in boreal rivers. Earth Surfaces Processess and Landforms.
  • Alahuhta, J., Kanninen, A., Hellsten, S., Vuori, K. M., Kuoppala, M. & H. Hämäläinen, H. (In press). Variable response of functional macrophyte groups to lake characteristics, land use, and space: implications for bioassessment. Hydrobiologia 737: 201-214.
  • Alahuhta, J. & J. Heino (2013). Spatial extent, regional specificity and metacommunity structuring in lake macrophytes. Journal of Biogeography 40, 1572–1582.
  • Alahuhta, J., A. Kanninen, S. Hellsten, K.-M. Vuori, M. Kuoppala & H. Hämäläinen (2013). Environmental and spatial correlates of community composition, richness and status of boreal lake macrophytes. Ecological Indicators 32, 172–181.
  • Alahuhta, J., I. Joensuu, J. Matero, K.-M. Vuori & O. Saastamoinen (2013). Freshwater ecosystem services in Finland. 35 p. Reports of the Finnish Environment Institute 16.
  • Kuusisto-Hjort, P. & J. Hjort (2013). Land use impacts on trace metal concentrations of suburban stream sediments in the Helsinki region, Finland. Science of the Total Environment 456–457: 222–230.
  • Alahuhta, J., A. Kanninen & K.-M. Vuori (2012). Response of macrophyte communities and status metrics to natural gradients and land use in boreal lakes. Aquatic Botany 103, 106-114.
  • Varanka, S. & M. Luoto (2012). Environmental determinants of water quality in boreal rivers based on partitioning methods. River Research and Applications 28, 1034–1046.
  • Alahuhta, J., K.-M. Vuori & M. Luoto (2011). Land use, geomorphology and climate as environmental determinants of emergent aquatic macrophytes in boreal catchments. Boreal Environment Research 16, 185–202.
  • Alahuhta, J., J. Heino & M. Luoto (2011). Climate change and the future distributions of aquatic macrophytes across boreal catchments. Journal of Biogeography 38, 383–393.

 

Last updated: 25.3.2015