Competition alters species\u2019 plastic and genetic response to environmental change

Lynn Govaert,Florian Altermatt,Luis J Gilarranz

doi:10.1038/s41598-021-02841-8

Abstract

Species react to environmental change via plastic and evolutionary responses. While both of them determine species’ survival, most studies quantify these responses individually. As species occur in communities, competing species may further influence their respective response to environmental change. Yet, how environmental change and competing species combined shape plastic and genetic responses to environmental change remains unclear. Quantifying how competition alters plastic and genetic responses of species to environmental change requires a trait-based, community and evolutionary ecological approach. We exposed unicellular aquatic organisms to long-term selection of increasing salinity—representing a common and relevant environmental change. We assessed plastic and genetic contributions to phenotypic change in biomass, cell shape, and dispersal ability along increasing levels of salinity in the presence and absence of competition. Trait changes in response to salinity were mainly due to mean trait evolution, and differed whether species evolved in the presence or absence of competition. Our results show that species’ evolutionary and plastic responses to environmental change depended both on competition and the magnitude of environmental change, ultimately determining species persistence. Our results suggest that understanding plastic and genetic responses to environmental change within a community will improve predictions of species’ persistence to environmental change.

Highlights

The rate of anthropogenically-induced environmental change is nowadays faster than e ver[1], including changes in temperature and p recipitation[2], pollution by n utrients3, salts[4], and synthetic c hemicals[5]
It remains largely unknown whether species interactions, such as interspecific competition, can alter the plastic and genetic response to the abiotic change, whether the effect of interspecific competition depends on the magnitude of the abiotic change, and whether this effect varies among different member species of the community
Even though an increasing number of studies show the importance of competing species for evolutionary responses to environmental change[27,37,47,48,49], it remains largely unknown whether interspecific competition can alter the plastic and genetic response to abiotic environmental change, whether the effect of competition depends on the magnitude of the abiotic environmental change, and whether this effect varies among different member species of the community

Summary

Introduction

The rate of anthropogenically-induced environmental change is nowadays faster than e ver[1], including changes in temperature and p recipitation[2], pollution by n utrients3, salts[4], and synthetic c hemicals[5]. Previous studies have shown that species interactions (such as competition, predation, or parasitism) can influence species’ responses to environmental change[19,22,23,24] and that this effect can even depend on the abiotic environment[21]. These studies have shown that species respond differently to a novel environment depending whether they occur alone or in Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587 Berlin, Germany. We used three naturally co-occurring and competing freshwater ciliate species[28] (Paramecium aurelia, Spirostomum teres, and Tetrahymena thermophila) to experimentally quantify plastic and genetic responses to abiotic environmental change (here: salinity) within the absence and presence of competing species. It is expected that its devastating effects on freshwater systems will intensify with increasing climate change[35]

Methods

Results

Conclusion