Using Mounds to Create Microtopography Alters Plant Community Development Early in Restoration

摘要

One potential means of promoting diversity in restoration is to use microtopographic features to increase habitat heterogeneity and concentrate resources. In this study, small mounds of sand or topsoil mix were constructed. We hypothesized that these features would improve the establishment and survival of seeded prairie plants. After the first growing season both seeded and total (seeded plus unseeded) plant density/m2 were greater on the mound features than other areas, although, in subsequent years, these differences were erased or reversed. Grass (seeded plus unseeded) density/m2, however, was always larger on the mounded features. Position within the mound also affected plant community development; the base, followed by the top, improved both seeded and total plant density. Mound aspect also interacted with year; the lee and windward sides had similar seeded species richness in the first and third field seasons, but during the second year the lee side had higher seeded species richness and seeded plant density. Grasses (seeded plus unseeded) were also denser on the lee side of the mound in the second year. Finally, the material of the mound created differences in the community response. Sand mounds supported a greater proportion of seeded to total plant density compared with the topsoil mounds. There was also a larger proportion of grasses to total plant density on the sand mounds. This topographic heterogeneity plays an important role in improving the development of both temporal and spatial vegetation variability in grassland restoration.