The ecological consequences of environmentally induced phenotypic changes

Abstract

Population dynamics and species persistence are often mediated by species traits. Yet many important traits, like body size, can be set by resource availability and predation risk. Environmentally induced changes in resource levels or predation risk may thus have downstream ecological consequences. Here, we assess whether quantity and type of resources affect the phenotype, the population dynamics, and the susceptibility to predation of a mixotrophic protist through experiments and a model. We show that cell shape, but not size, changes with resource levels and type, and is linked to carrying capacity, thus affecting population dynamics. Also, these changes lead to differential susceptibility to predation, with direct consequences for predator-prey dynamics. We describe important links between environmental changes, traits, population dynamics and ecological interactions, that underscore the need to further understand how trait-mediated interactions may respond to environmental shifts in resource levels in an increasingly changing world.

Eco‐evolutionary processes underlying early warning signals of population declines

“…Such a phenotypic trait, for example, could be body size. Body size is a quantitative trait fundamental to life‐history theory and population dynamics (Gibert, Allen, Hruska, & DeLong, ; Pigeon, Ezard, Festa‐Bianchet, Coltman, & Pelletier, ), which has been shown to decline in response to decreases in resource availability (Clements & Ozgul, ), increases in temperature (Forster, Hirst, & Atkinson, , ; Gardner, Peters, Kearney, Joseph, & Heinsohn, ; Tseng et al, ) and increases in harvest rate (Clements et al, ). In our model, the optimum environmental change will affect the dynamics of the phenotype.…”

“…Such a phenotypic trait, for example, couldbe body size. Body size is a quantitative trait fundamental to lifehistory theory and population dynamics(Gibert, Allen, Hruska, & DeLong, 2017;Pigeon, Ezard, Festa-Bianchet, Coltman, & Pelletier, 2017)…”

Simple traits predict complex temperature responses across scales

“…This shows how multiple traits can have important but distinct effects on higher-level processes. Why cell shape would influence demographic parameters is poorly understood, but has been observed at least once before 42 . Because body shape determines the surface area to volume ratio in unicellular organisms, it mediates the rate of passage of material across the cell membrane 41 .…”

Body size and shape responses to warming and resource competition

“…Body shape is also an important functional trait that directly influences motility (Beveridge et al, 2010;Gibert et al, 2017), encounter rates, and, thus species interactions (Berger, 1980). Body shape responses to changing resource level and environmental temperature have been observed in phytoplankton (Naselli-Flores & Barone, 2011), cyanobacteria (Jezberová & Komárková, 2007) and protists (DeLong et al, 2017;Gibert et al, 2017;Hammill et al, 2010). For instance, high resource levels have been found to increase protist body length (relative to other body axes), resulting in individuals being more Accepted Article elongate in shape (Gibert et al, 2017).…”