The effect of plant source location on restoration success: A reciprocal transplant experiment with winterfat (Krascheninnikovia lanata)

Ecological restoration is becoming more frequent due to the increased pace of land disturbance, more comprehensive government regulations, and the recognition of the valuable ecosystem services that natural areas provide (Rice and Emery, 2003 Dodds et al., 2008). One part of restoration is revegetation, or the introduction of off-site plant materials to the restoration site. As the applications of revegetation have become more diverse, so too have the objectives of these projects. More specifically, it is increasingly important that plant propagules used in revegetation projects are from a location that is geographically or ecologically similar to the planting site.Local adaptation and population genetic differentiation studies have provided evidence supporting the use of local plant materials for revegetation with several native plant species, primarily grasses. However, along with grass species, shrub species are also frequently used in revegetation seed mixes. To better understand the consequences of using non-local plant materials, I chose to study the population biology of the widespread shrub winterfat (Krascheninnikovia lanata, Chenopodiaceae) among five populations in New Mexico, USA.The investigation of winterfat population biology included a comparison of winterfat plant morphology in situ, quantification of the ecological distance between the five sites, and measurement of the rate of emergence and floral onset in a greenhouse common garden. I also carried out a reciprocal transplant experiment in which individuals from different locations were planted in replicate common gardens. Transplant survival, size, and reproduction were quantified for two years. To complement the morphological studies, the genetic structure of winterfat was quantified using nine isozyme loci. Genetic variation, population differentiation, and correlations among genetic, geographic, and ecological distance were assessed.The following questions were addressed: (1) Do winterfat populations differ in the vegetative or inflorescence size of individuals in the field? (2) Do winterfat populations differ in emergence phenology in the greenhouse? (3) Do winterfat populations differ in floral phenology in the greenhouse? (4) How do study sites differ in soil characteristics, climate, and plant community composition? (5) Do winterfat plants perform better than plants from other locations at their site of origin? (6) Was the weather at the planting locations during the experiment different from the historical climate at those locations? (7) How much neutral genetic variation do these populations of winterfat possess? (8) How is this neutral genetic variation partitioned among populations? (9) Is genetic distance correlated with geographic or ecological distance? The data from these experiments will assist restoration practitioners in determining appropriate plant material sources for revegetation projects.