Anthropogenic habitat alteration induces rapid morphological divergence in a native stream fish

Abstract

Anthropogenic habitat alteration creates novel environments that can alter selection pressures. Construction of reservoirs worldwide has disturbed riverine ecosystems by altering biotic and abiotic environments of impounded streams. Changes to fish communities in impoundments are well documented, but effects of those changes on native species persisting in reservoirs, which are presumably subjected to novel selective pressures, are largely unexplored. I assessed body shape variation of a native stream fish in reservoir habitats and streams from seven reservoir basins in the Central Plains of the USA. Body shape significantly and consistently diverged in reservoirs compared with stream habitats within reservoir basins; individuals from reservoir populations were deeper-bodied and had smaller heads compared with stream populations. Individuals from reservoir habitats also exhibited lower overall shape variation compared with stream individuals. I assessed the contribution of genotypic divergence and predator-induced phenotypic plasticity on body shape variation by rearing offspring from a reservoir and a stream population with or without a piscivorous fish. Significant population-level differences in body shape persisted in offspring, and both populations demonstrated similar predator-induced phenotypic plasticity. My results suggest that, although components of body shape are plastic, anthropogenic habitat modification may drive trait divergence in native fish populations in reservoir-altered habitats.

Shape variation in the least killifish: ecological associations of phenotypic variation and the effects of a common garden

“…Second, the pattern of population variation in our data matches patterns seen in other studies. For example in some taxa, longer more streamlined caudal peduncles offer benefits in flowing waters, whereas shorter and deeper ones improve maneuverability and foraging economy in lentic ones, especially in thicker vegetative cover where increased habitat complexity alters flow rate and can affect the locomotion ability of fish (Franssen 2011; Ruehl et al. 2011; Gaston and Lauer 2015).…”

“…2015). Fish populations occurring in high flow areas are often thinner and have more streamlined bodies when compared to conspecifics found in low flow areas (Franssen 2011; Fu et al. 2013; Gaston and Lauer 2015).…”

The Influence of Preservation on Fish Morphology in Museum Collections Based on Two Species of the Genus <I>Lepomis</I> (Actinopterygii: Perciformes: Centrarchidae)

“…Given the plethora of morphometric evaluations in population analysis (Meyer 1989, Reznick et al 1994, Langerhans et al 2003 AguilarMedrano et al 2011, Franssen 2011, it is necessary to identify whether shrinkage of preserved specimens confounds morphometric analysis. Thus, the objectives of this study were:…”

Shared and unique morphological responses of stream fishes to anthropogenic habitat alteration

“…obligate stream fishes are usually extirpated from reservoir habitats, increased abundances of piscivorous fishes; [11,12]). However, in spite of these pressures, some stream fishes can persist in these man-made habitats, and initial investigations suggest reservoirs may drive contemporary phenotypic divergence in native, resident populations [13,14]. Understanding how phenotypic traits of populations are affected by reservoir habitats will be a first step in identifying potential evolutionary consequences of anthropogenically altered habitats.…”

“…phenotypic plasticity; [29,30]). The relative contribution of phenotypic plasticity and 'genetic components' can be nearly equivalent in explaining phenotypic variation in stream fishes [14]. Nonetheless, environmentally contingent traits can become canalized, where the previous environmental stimulus is no longer required to produce the trait [31,32].…”