Macrosystem community change in lake phytoplankton and its implications for diversity and function

Benjamin Weigel, Niina Kotamäki, Olli Malve, Kristiina Vuorio, Otso Ovaskainen

Research output: Contribution to journalArticleScientificpeer-review



We use lake phytoplankton community data to quantify the spatio-temporal and scale-dependent impacts of eutrophication, land-use and climate change on species niches and community assembly processes while accounting for species traits and phylogenetic constraints.



Time period


Major taxa



We use hierarchical modelling of species communities (HMSC) to model metacommunity trajectories at 853 lakes over four decades of environmental change, including a hierarchical spatial structure to account for scale-dependent processes. Using a “region of common profile” approach, we evaluate compositional changes of species communities and trait profiles and investigate their temporal development.


We demonstrate the emergence of novel and widespread community composition clusters in previously more compositionally homogeneous communities, with cluster-specific community trait profiles, indicating functional differences. A strong phylogenetic signal of species responses to the environment implies similar responses among closely related taxa. Community cluster-specific species prevalence indicates lower taxonomic dispersion within the current dominant clusters compared with the historically dominant cluster and an overall higher prevalence of smaller species sizes within communities. Our findings denote profound spatio-temporal structuring of species co-occurrence patterns and highlight functional differences of lake phytoplankton communities.

Main conclusions

Diverging community trajectories have led to a nationwide reshuffling of lake phytoplankton communities. At regional and national scales, lakes are not single entities but metacommunity hubs in an interconnected waterscape. The assembly mechanisms of phytoplankton communities are strongly structured by spatio-temporal dynamics, which have led to novel community types, but only a minor part of this reshuffling could be linked to temporal environmental change.
Original languageEnglish
JournalGlobal Ecology and Biogeography
Issue number2
Pages (from-to)295-309
Number of pages15
Publication statusPublished - Feb 2023
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1181 Ecology, evolutionary biology
  • Hmsc
  • Biodiversity
  • Community assembly
  • Freshwater
  • Lake
  • Niche conservatism
  • Species distribution modelling
  • Traits

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