Spatial insurance against a heatwave differs between trophic levels in experimental aquatic communities

Abstract

Climate change-related heatwaves are major threats to biodiversity and ecosystem functioning. However, our current understanding of the mechanisms governing community resistance to and recovery from extreme temperature events is still rudimentary. The spatial insurance hypothesis postulates that diverse regional species pools can buffer ecosystem functioning against local disturbances through the immigration of better-adapted taxa. Yet, experimental evidence for such predictions from multitrophic communities and pulse-type disturbances, like heatwaves, is largely missing.We performed an experimental mesocosm study to test whether species dispersal from natural lakes prior to a simulated heatwave could increase the resistance and recovery of plankton communities. As the buffering effect of dispersal may differ among trophic groups, we independently manipulated the dispersal of organisms from lower (phytoplankton) and higher (zooplankton) trophic levels. The experimental heatwave suppressed total community biomass by having a strong negative effect on zooplankton biomass, probably due to a heat-induced increase in metabolic costs, | 3055 VAD et al.

Heatwave-induced functional shifts in zooplankton communities result in weaker top-down control on phytoplankton

“…A moderate increase in temperature increases both the phytoplankton growth rate and the metabolic demands of consumers, shifting to higher feeding rates and, consequently, higher consumer-to-producer biomass (Kratina et al, 2012;O'Connor et al, 2009). Heatwaves, at the same time, may disrupt the predator-prey relationships, thus increasing algal growth (Ross et al, 2022;Vad et al, 2023). Our results highlight the importance of copepods and microzooplankton in trophic cascades.…”

“…Though the one-month duration of our study limits long-term forecasts, it delivers relevant information on the short-term effects of intermittent heatwaves on community dynamics. The relatively short experimental duration may also be the reason for the absence of strong effects in treatment W, which can be considered a press disturbance, typically resulting in permanent restructuring of communities on longer time scales, while the pulse disturbance in treatment H can cause sudden changes followed by a certain extent of recovery (Glasby & Underwood, 1996;Vad et al, 2023).…”

Proximity to freshwater and seagrass availability mediate the impacts of climate change on the distribution of the West Indian manatee

“…Other studies show that different trophic levels can have different sensitivities, resistance, and recovery from climate change. How the reshuffling of ecological communities under climate change will transcend different trophic levels is still unclear (Vad et al, 2023;Voigt et al, 2003). We propose a potential workflow for including projected climate change layers for ecological niche modelling of species within the context of their resources and consumers using the methodology described for seagrass (Fig.…”

Ensemble learning model identifies adaptation classification and turning points of river microbial communities in response to heatwaves

“…According to the World Health Organization (WHO), a heatwave is identified as heat and hot weather that can last for several days and have a significant impact on society. By quickly surpassing the thermal limits of organisms, heatwaves may alter ecological communities and functions more strongly than a gradual increase in average temperature (Bennett et al., 2021; Stillman, 2019; Vad et al., 2023). While the crucial influence of extreme weather events in driving ecosystem changes has been acknowledged for a long time (Jentsch et al., 2007), previous climate change studies have largely concentrated on the impacts of increasing average temperatures (Thompson et al., 2013; Woodward et al., 2016).…”