| Disappointing restoration efforts have led ecologists to consider incorporating different theories of community ecology into restoration projects. Community assembly theory examines how dispersal constraints, biotic interactions, and environmental constraints limit a species membership in a community. Incorporating community assembly theory into restoration projects may result in more successful restoration efforts.; The first study examined the effect of dispersal constraints on community composition in a prairie restoration. Dispersal limitation was controlled by seeding 30 forb species in a 4 year-old former agricultural field in northeastern Kansas. Sowing led to increased species richness, diversity, floristic quality, and seeded species establishment, but did not effect evenness, vegetative cover, bare ground, or native, exotic, perennial, annual, forb, grass, woody, or legume species cover. Results suggest that the impact of dispersal limitation on community attributes depends on the stage of community development and the attributes in question. Results also suggest that species additions can accelerate changes during succession.; The second study examined the effect of timing of species introduction on establishment of 30 forbs along a natural nitrogen gradient, in the same field as above, using two planting strategies. Planting strategies were based on Egler's models of succession. Results supported the inhibition, tolerance, and competition-colonization models of succession, but did not support the facilitation model of succession. Nine species exhibited greater establishment when seeded with the initial floristics planting strategy. Overall, total soil nitrogen did not interact with planting strategy to effect establishment success. Results suggest that difference in timing of introduction may affect establishment success for target species in restoration projects.; The third study examined inter- and intra-specific differences in salt tolerance for Pascopyrum smithii and Distichlis spicata collected from Kansas and Nebraska. Growth rates of these species were evaluated under five salinity levels in a greenhouse experiment. Results indicate that P. smithii grew faster than D. spicata at all comparable salinity levels. Only D. spicata exhibited differences in growth rate between populations. Results suggest that P. smithii should be considered for the restoration of salt-affected areas and that differences between source populations should be considered when evaluating plant material used in restoration. |
