2 - Genetic considerations for plant population restoration and conservation  pp. 34-62

Genetic considerations for plant population restoration and conservation

By Charles B. Fenster and Michelle R. Dudash

Image View Previous Chapter Next Chapter



Introduction

Successful restoration policy involves three basic criteria. First, sufficient habitat must be protected for the continued persistence of a species (Gilpin & Soulé 1986). Second, demographic information must be collected to determine which life history stages are most critical to survival, reproduction, and longterm population vigor (Marcot & Holthausen 1987, Lande 1988). Third, once these fundamental criteria for population survival are met, genetic variation can be considered as an issue in restoration and conservation policy. Overall, we believe that genetic issues may be more pertinent to population restoration than to population conservation. In attempting to conserve taxa, one is initially interested in saving numbers of individuals regardless of their relatedness. Given that natural areas managers will have the opportunity to reintroduce populations that have been extirpated in nature, it seems reasonable that any genetic manipulations that may help restore a population's vigor in situ for the short or long term may be beneficial.

Rare and endangered taxa often exist as a few relatively small populations (Holsinger & Gottlieb 1989) subject to population bottlenecks. Thus, genetic drift and mating among relatives contributes to the loss of genetic variation and reduction in the population's overall vigor through inbreeding depression (Lacy 1987, Polans & Allard 1989). A short-term conservation goal should be to ensure that the vigor of a population is maintained or restored in the face of inbreeding by appropriate manipulation of the remaining genetic variation (Ledig 1986).