Document: RIC-3-10-3

Genetic and evolutionary issues in large scale restoration efforts.

RICE, K.J.*

University of California, Davis, CA 95616 USA ¹

Abstract:
At the landscape level, the evolutionary "topography" of a restoration site is often a complex, nested mosaic of selection gradients. The efficacy of these gradients in forming locally adapted ecotypes can be strongly influenced by landscape elements that act as either barriers or conduits for gene flow. Ecological genetic studies in plants, including some of our work on native grasses, indicates that local adaptation is fairly common, especially at larger regional scales. We have found that patterns of local adaptation often reflect the action of regional selective gradients (e.g., climatic gradients) as well as highly localized selective agents (e.g.,disease). However, whether this local adaptation represents the action of strong natural selection cannot be determined without independently estimating the rate of gene flow across the putative selective gradient. Although new molecular markers are available for estimating gene flow, the theory underlying these estimates is still in development and many assumptions of the theory may reduce the usefulness of these techniques. Given the impracticality of measuring the fine scale selective mosaic that may exist at every restoration site, I suggest that an appropriate strategy might be that of "coarse adaptive tuning" where the population restored to a site represents a mixture of genotypes local to the region but representing significant within-population genetic diversity. This approach protects against the introduction of completely inappropriate genotypes while providing sufficient genetic variation for in situ adaptive "fine tuning".

Keywords: Ecological genetics, restoration, natural selection, gene flow

This abstract is being presented at: 3:00 PM in session:
Symposium # 5: Incorporating Landscape Processes in Ecological Restoration.