Intraspecific phenotypic differences in fish affect ecosystem processes as much as bottom–up factors

Abstract

Evolution of life history traits can occur rapidly and has the potential to infl uence ecological processes, which can also be shaped by abiotic and biotic factors. Few studies have shown that life history phenotype can aff ect ecological processes as much as commonly studied biotic ecological variables, but currently we do not know how the ecological eff ects of life history phenotype compare in size to the eff ects of abiotic factors, or whether the ecological eff ects of phenotypes are sensitive to variability in abiotic conditions. Using a factorial mesocosm experiment we compared the ecosystem eff ects of guppy Poecilia reticulata life history phenotypes in two light treatments representing a four-fold diff erence in light levels, which was comparable to upstream-downstream diff erences in light availability in Trinidadian streams. Light and phenotype had signifi cant eff ects on similar aspects of ecosystem function. Whereas light had a stronger eff ect on ecosystem structure (algal and invertebrate stocks) than phenotype, phenotype and light had nearly equal eff ects on many ecosystem processes (nutrient recycling, nutrient fl uxes, ecosystem metabolism and leaf litter decomposition). Light had a stronger eff ect on most guppy life history traits and guppy fi tness than diff erences between phenotypes. Th e eff ect of light on these traits was consistent with higher availability of food resources in the high light treatments. Interactions between light and phenotype were weak for the majority of response variables suggesting that abiotic variability did not alter the mechanisms by which phenotypes aff ect ecosystem function. We conclude that subtle phenotypic diff erences in consumers can aff ect ecosystem processes as much as meaningful variability in abiotic factors which until recently were thought to be the primary drivers of ecosystem function in nature. However, despite its eff ects on traits and the ecosystem, light did not alter the eff ect of guppy phenotype on ecosystem function.

Ecological mechanisms and phylogeny shape invertebrate stoichiometry: A test using detritus‐based communities across Central and South America

“…Conversely, the low proportion of the variation in a taxon partitioned among higher taxonomic levels shown for P content indicates that this element is randomly distributed with respect to invertebrate taxonomy, suggesting that evolutionary relatedness does not always reflect variation in stoichiometry traits (Narwani et al, ; Yamamichi, Meunier, Peace, Prater, & Rua, ). For C:P and N:P, the highest proportion of the variance was partitioned at lower taxonomic levels including large within‐ and among‐species trait variation, similar to those reported for other taxa (El‐Sabaawi et al, ; González et al, ).…”

The evolution of coexistence: Reciprocal adaptation promotes the assembly of a simple community

“…; El‐Sabaawi et al. ). Both guppies and killifish have evolved rapidly in response to some of these changes (Reznick et al.…”

Predictable adaptive trajectories of sexual coloration in the wild: Evidence from replicate experimental guppy populations*

“…In addition, reciprocal feedbacks between guppies and their newly colonized environments (e.g., El‐Sabaawi et al. ) will modify the nature of selection over time. We know for example that experimental populations experienced rapid intrinsic rates of increase, which in‐turn substantially altered the composition of resident algal communities (Bassar et al.…”