Genetic marker studies can assist restoration practice through selection of seed sources that conserve historical levels of gene diversity and population genetic differentiation. We examined genetic variation and structure within and among mainland and island populations of Elymus glaucus, a perennial bunchgrass species native to western North American grasslands that is targeted for grassland restoration. Island populations of E. glaucus represent sensitive sites and potentially distinctive seed sources for reintroduction, and little is known of their genetic composition. Genetic diversity and structure were estimated using amplified fragment length polymorphism markers for 21 populations and 416 individuals distributed across two coastal California mainland locations and three California Channel Islands. Eight primer combinations resulted in 166 markers, of which 165 (99.4 %) were polymorphic. The number of polymorphic bands was significantly greater among mainland populations relative to island sites, and locally common alleles were present for each sampled island and mainland location. Population structure was high (62.9 %), with most variation (55.8 %) distributed among populations, 7.1 % between mainland and island locations, and the remainder (37.1 %) within populations. Isolation by distance was only apparent among islands. Using marker data to recommend appropriate seed sources for restoration, E. glaucus seeds are best derived within islands with collections representing a large number of individuals from matching environments. Given the limited gene flow and prior evidence of adaptive divergence among populations of this species, regional collections are recommended in all cases to maintain diversity and to avoid long-distance introductions of highly differentiated plant material.

When historical vegetation patterns are unknown and local environments are highly degraded, the relationship between plant species distributions and environmental properties may provide a means to determine which species are suitable for individual restoration sites. We investigated the role of edaphic variation in explaining the distributions of three native bunchgrass species (Bromus carinatus, Elymus glaucus and Nassella pulchra) among central California mainland and island grasslands. The relative contribution of soil properties and spatial variation to native grass species abundance was estimated using canonical redundancy analysis, with subsequent testing of individual variables identified in ordination. Soil variables predicted a significant proportion (22-27%) of the variation in species distributions. Abiotic soil properties that drive species distributions included serpentine substrates and soil texture. Biotic properties that correlated with species distributions were ammonium and nitrogen mineralization rates. Spatial autocorrelation also contributed to species presence or absence at each site, and the significant negative autocorrelation suggested that species interactions and niche differentiation may play a role in species distributions in central California mainland and island grasslands. We explored the application of plant-environment relationships to ecological restoration for species selection at locations where degradation levels are high and historical communities are unclear. © 2014 Hufford et al.