The effect of temperature and predation on performance in monoculture and in competition in three Daphniidae differing in body size

Abstract

Zooplankton body size shows a strong association with temperature, competition, and predation. Global warming affects all three drivers of body size and is thus expected to lead to substantial changes in zooplankton community composition and body size distributions. To disentangle the isolated and joint effect of temperature, competition, and fish predation on species biomass and community composition in zooplankton, we monitored population biomasses of three Daphniidae species that differ in body size (Daphnia magna, Daphnia pulex, and Ceriodaphnia reticulata) for 20 days, manipulating competition (monoculture, pairwise trials, and three-species communities), temperature (20 C, 24 C, and 28 C) and presence or absence of fish predation. In the absence of predation, D. magna dominated in all competition experiments, even at high temperatures. D. magna went extinct, however, in the predation treatments at 24 C and 28 C. D. pulex outcompeted C. reticulata and was negatively affected by predation and high temperature. C. reticulata did not reduce biomass at high temperatures and was negatively affected by all competition trials, but was positively affected by predation. Our results indicate that the two larger-bodied species are more negatively affected by the combination of temperature and predation than the smallest species. While higher temperatures reduced the biomass of the larger-bodied species, it did not fundamentally change their ability to dominate over the smallest species in competition. The combined effect of warming and predation changed community composition more fundamentally, resulting in the dominance of small-bodied species. This can have important ecosystem-wide impacts, such as the transition to turbid, algae-dominated systems.

Cascading, interactive, and indirect effects of climate change on aquatic communities, habitats, and ecosystems

“…Interestingly, variance among sampling sites increased over time, indicating differences in recovery capacity and stressing the need for long-term observations. The results of Lange et al (2023) emphasizing species-specific differences in responses parallel the findings of several other studies documenting speciesspecific physiology and behavior in zooplankton, including Bomfim et al (2023), Carrier-Belleau et al (2023, Ramondenc et al (2023), andFields et al (2023), documenting zooplankton species specific physiology and ecology. Similarly, Meyer-Gutbrod et al (2023) showed that right whale pod identity is critically important, and Su et al (2023) concluded that location and species were critical to the differential results in their aquaculture lake study.…”

“…It is a strength of this special issue to be representative of diverse habitats and scales, including alpine streams (Leathers et al 2023), wetlands of the North American Great Plains (Hu et al 2023), lakes (Hébert et al 2023;Katkov and Fussmann 2023;Su et al 2023), estuaries (Douglas et al 2023;Franzè et al 2023), tropical reefs (Lange et al 2023), and the arctic ocean (Ramondenc et al 2023), as well as diverse organisms, from single celled algal primary producers (Vrana et al 2023) to top consumers such as right whales (Meyer-Gutbrod et al 2023). Moreover, contributions cover ecologically and climate-relevant ranges of scales, including laboratory experimentation lasting days (Bomfim et al 2023;Carrier-Bellau et al 2023, Fields et al 2023, mesocosm experiments of 1-month duration (Katkov & Fussmann 2023;Wang et al 2023), as well as the paleorecord (Hu et al 2023). Despite this diversity of habitats and scales, the contributions to the special issue reflect only a subset of breadth, approaches, and geographic coverage; several gaps in contributions of climate-oriented aquatic research are apparent.…”

“…The results allowed Carrier-Belleau et al (2023) to recommend management strategies that avoid osmotic stress for Daphnia due to saltwater intrusions as a particularly impactful stressor. Focusing on the same genus, but very different questions, Bomfim et al (2023) disentangled a matrix of factors including species-specific differences, predation, competition and temperature. Their study emphasized the need to go beyond mono-specific investigations.…”

Temperature and hypoxia‐driven shifts in Daphnia interspecific competition

“…It is important to note that these correlations do not necessarily exclude the possibility that other extrinsic factors, in addition to elevated temperature, may provide a better explanation for the observed patterns (Gillooly and Dodson 2000). Interestingly, experimental studies conducted on cladoceran species have not found consistent evidence for a positive effect of temperature on the relative competitive ability of smaller species, contradicting the findings of correlational studies (Achenbach and Lampert 1997;Sikora and Dawidowicz 2014;Bomfim et al 2023). Consequently, the influence of elevated temperature on size-related interspecific competition remains an open question.…”

“…As the ANOVA assumptions were not met for the analysis of Daphnia population dynamics parameters, Box-Cox transformations were applied to the data. The analyses carried out used a statistical approach similar to that previously used in studies such as Bomfim et al (2023) and Schür et al (2023). Subsequent data analyses used linear models (ANOVA or ANCOVA; type III sum of squares (SS)) with Tukey's honestly significant difference for each factor interaction.…”