Revisiting the “nature of nurture”: how insights from developmental ecology can inform desert fish conservation

Authors: Sean C. Lema

Year: 2012 (xliv)

Abstract

Aquatic habitats in the desert have distinctive environmental characteristics relative to their counterparts in wetter climates. Whether a large desert river or a small, isolated spring or marsh, the physical conditions of these aquatic habitats have shaped the evolutionary adaptations and genetic variation of the fishes that live there. Conservation efforts for desert fishes have accordingly focused on preserving a species’ unique phenotypic adaptations and the genetic variation underlying those adaptations, and, in many cases, have also sought to maintain the distinguishing environmental conditions of the aquatic habitat. In scenarios where conservation efforts have relied on artificial refuges or aimed to restore degraded habitats to support self-sustaining populations, it is clear that the likelihood of phenotypic shifts in these built environments can be high. Such phenotypic changes have often been attributed to shifts in genetic composition (e.g., founder effects, genetic drift), but it is also necessary to consider the developmental influences that built environments can have on phenotypic expression. Over the past decade, accumulating evidence has revealed that heritable change in ecologically relevant phenotypic traits can occur even with little genetic variation. These changes may arise through environmentally induced developmental plasticity or through mechanisms that have been traditionally categorized as ‘non-genetic,’ such as epigenetic variation, behavioral inheritance, and maternal effects. Here, I will explore how recent insights into the ‘nature of nurture’ provide a fuller understanding of how organism-environment interaction shapes phenotypic variation. I will draw on specific findings of neural, behavioral and morphological plasticity in desert pupfishes and salmonids to illustrate how investigations that borrow approaches from developmental ecology and ecological genetics can uncover overlooked mechanisms of interaction that developmentally link the phenotypic characteristics of fish to their habitats. Such mechanisms provide a window into the interconnectedness of fish and their environments, and inform our understanding of the origins of phenotypic variation in wild populations. Moreover, they can complement genetic approaches to improve conservation efforts aimed at managing the phenotypic responses of desert fishes in built environments including artificial refuges, hatcheries, and restored habitats.