Phenotype management: a new approach to habitat restoration

The goal of habitat restoration is to provide environmental conditions that promote the maintenance and growth of target populations. But rarely is it considered how the allocation of resources influences the diversity of phenotypes in these populations. Here we present a framework for considering how habitat restoration can shape the development and expression of phenotypes.' We call this approach phenotype management as it entails restoring the resources in a habitat to manage phenotypic diversity. Phenotype management is achieved by manipulating the spatial and temporal distribution of resources to alter the degree of competition among individuals. Differences in competition, in turn, lead to changes in phenotypic and life history expression that affect population. parameters including demography and effective population size (N-e). To illustrate how phenotype management can be applied, we explore how resource distributions shape variation in phenotypes in two imperiled fishes, Pacific salmon and desert pupfish. In both examples, modulating male reproductive phenotypes changes the allocation of reproductive success among population members to subsequently affect N-e. These examples further demonstrate that whether to increase or decrease phenotypic diversity depends on the primary conservation pressures faced by the species. (C) 2002 Elsevier Science Ltd. All rights reserved.