Functional shifts in lake zooplankton communities with hypereutrophication

Abstract

Functional variation among consumer communities can alter ecosystem nutrient cycling. These impacts on ecosystem function can be specifically driven by interspecific variation in stoichiometric traits; thus, functional trait‐based approaches can be used to explain the processes controlling ecosystem stoichiometry. However, eutrophication may reduce the functional importance of consumers in ecosystems by eliminating heterogeneity in nutrient recycling among taxa. To test whether zooplankton functional diversity, i.e. aspects of the stoichiometric trait space occupied by zooplankton communities, varies over gradients in trophic state and nutrient stoichiometry, we examined functional and taxonomic variation in the zooplankton communities of 130 lakes in the agriculturally dominated state of Iowa (U.S.A.) over 7 years. Stoichiometric functional dispersion decreased with trophic state index, supporting the trait abundance shift hypothesis that hypereutrophic lakes are characterised by different combinations of functional traits than their less eutrophic counterparts. Zooplankton communities became increasingly N‐rich relative to P as TSI increased. Specifically, P‐poor Bosmina, Chydorus, and cyclopoid copepods increased in abundance with eutrophication. Stoichiometric trait distributions of zooplankton shift with eutrophication, which implies that the unique functioning of hypereutrophic lakes could be due in part to the consumers inhabiting them. As zooplankton N:P increased with trophic state while lake total nitrogen to total phosphorus ratio decreased with trophic state, P‐poor zooplankton taxa may exacerbate excess P availability in these hypereutrophic systems by differentially recycling P at higher rates.

Is the Cyanobacterial Bloom Composition Shifting Due to Climate Forcing or Nutrient Changes? Example of a Shallow Eutrophic Reservoir

“…Total abundances of meso-zooplankton appeared high, but remained in agreement with other shallow eutrophic lakes [ 32 , 33 , 34 ]. Small zooplanktonic taxa seemed to dominate at the detriment of larger cladoceans, e.g., Daphnia sp., as known from eutrophic temperate lakes of both Europe [ 34 ] and the USA [ 35 ]. As sampling size was low in this study, more research focusing on zooplankton dynamics in that reservoir would be beneficial.…”

A unifying framework for analyzing temporal changes in functional and taxonomic diversity along disturbance gradients

“…Functional and taxonomic loss and turnover responses have been seen in response to natural and experimental extreme droughts in stream insect communities (Boersma et al 2016, Aspin et al 2018) and functional loss responses were observed in marine intertidal communities along a wave-stress gradient (Valdivia et al 2017). However, a recent study found support for the differential impact hypothesis along a gradient of nutrient pollution in lake zooplankton communities (Moody and Wilkinson 2019). We encourage future work explicitly testing our predictions across different ecosystem types, especially identifying when thresholds of disturbance intensity and different combinations of traits result in markedly different functional and taxonomic responses.…”

Functional responses of zooplankton communities to depth, trophic status, and ion content in mine pit lakes

“…Zooplankton functional traits allow for the identification of the mechanisms that are responsible for various environmental gradients in aquatic ecosystems, including trophic levels, primary productivity (Barnett & Beisner, 2007;Obertegger & Manca, 2011;Oh et al, 2017;Moody & Wilkinson, 2019), temperature (Lokko et al, 2017;Obertegger & Flaim, 2018), depth (Gauthier et al, 2014;Obertegger & Flaim, 2018), hydrological regime (Galir Balkić et al, 2018), salinity (Lokko et al, 2017;Gutierrez et al, 2018) and anthropogenic activity (Simões et al, 2020). The functional traits of zooplankton related to their feeding strategies have been used both to interpret functioning mechanisms in food webs (Kim et al, 2000) and to evaluate the impact of environmental pollution (acidification, turbidity) on ecosystem health and resilience (Hogsten et al, 2009;Petchey et al, 2009;Moreira et al, 2016;Goździejewska et al, 2019a).…”

“…The functional traits of zooplankton related to their feeding strategies have been used both to interpret functioning mechanisms in food webs (Kim et al, 2000) and to evaluate the impact of environmental pollution (acidification, turbidity) on ecosystem health and resilience (Hogsten et al, 2009;Petchey et al, 2009;Moreira et al, 2016;Goździejewska et al, 2019a). Many studies have shown that zooplankton functional traits can be homogenized due to extreme environmental gradients including high trophic and primary productivity (Moody & Wilkinson, 2019), high salinity (Gutierrez et al, 2018), small or large suspended particles (Goździejewska et al, 2019a), high anthropogenic impact (Simões et al, 2020). In turn, an intermediate range of factors or spatial variation in conditions (e.g.…”