Aquatic communities consist of trophic guilds embedded in food webs with multiple interacting trophic levels, for which multi-trophic indices of diversity should provide deeper insight than do those estimated for individual trophic levels. We sampled bacterioplankton, phytoplankton, and zooplankton in 560 lakes across Canada as part of the NSERC Lake Pulse Network to evaluate predictors of diversity both between phylogenetic kingdoms and across orders. Individual kingdoms showed varied responses to lake physico-chemistry and climate, while scaling up diversity indices to incorporate multi-trophic variation revealed a significant role for climate variables in structuring community diversity. Watershed land use did not have significant direct effects on multi-taxa species diversity, but it did have important indirect effects via changes to local water chemistry. Our findings highlight how multi-trophic approaches may be beneficial for identifying general drivers of diversity across Canadian lakes, especially within a context of climate change.

Primary Presenter: Beatrix Beisner, University of Quebec at Montreal (beisner.beatrix@uqam.ca)

Authors:

Vincent Fugère, University of Québec at Trois-Rivières  ()

Gillian Martin, University of Québec at Montréal  ()

Annick St-Pierre, University of Québec at Montréal  ()

Rebecca Garner, Concordia University  (rebecca.garner@mail.concordia.ca)

Marco Rodriguez, University of Québec at Trois-Rivières  ()

Katrine Turgeon, University of Québec in Outaouais  ()

Yannick Huot, University of Sherbrooke  ()

David Walsh, Concordia University  ()

Beatrix Beisner, University of Québec at Montréal  (beisner.beatrix@uqam.ca)