Long‐term effects of prairie restoration on plant community structure and native population dynamics

Abstract

The key to restoring degraded grassland habitats is identifying feasible and effective techniques to reduce the negative impacts of exotic species and promote self‐sustaining native populations. It is often difficult to extend monitoring of restoration efforts to evaluate long‐term success, but doing so is essential to understanding how initial outcomes change over time. To assess how initial treatment effects persist, we revisited degraded patches of Pacific Northwest prairie habitat 6 years after experimental restoration efforts ceased. We evaluated plant community composition to determine the lasting effects of supplemental native seeding and disturbance treatments (burning, mowing, and herbicide to reduce exotic species). We tracked the persistence of seeded species and measured spread of their populations to evaluate suitability of species for restoration and the ability of the habitat to support native plant populations. We found that plots that received supplemental seeding continued to exhibit higher richness of native species than those left unseeded, and that both seeding and disturbance treatments could positively influence native species abundance over the long term. The initially observed effects of disturbance treatments on reducing exotic grass abundance had diminished, highlighting the importance of long‐term monitoring and ongoing control of exotic species. Nevertheless, these treatments significantly influenced the population trajectories of 4 out of 8 seeded native species. There was evidence of spatial advance of most seeded species. Results from extended monitoring confirm that dispersal limitation of native species and difficulties maintaining the reduction of exotic grasses continue to be major barriers to success in restoration of invaded grasslands.

Are two strategies better than one? Manipulation of seed density and soil community in an experimental prairie restoration

“…Previous work has shown variable results in the responsiveness of non‐native species (Reinhart et al ) to inoculation with native soil, but some research indicates that plant–soil‐feedback in native soil communities can be disadvantageous to invasive plant species (Bunn et al ; Kulmatiski ; Smith et al ). While non‐native species were the smallest portion of cover in the study, they represent a large portion of ongoing expense and effort in maintaining restorations (Rowe ; Trowbridge et al ).…”

Impacts of plant diversity on arthropod communities and plant–herbivore network architecture

“…, Trowbridge et al. ). While the biological mechanism for species loss is not known, potential causes include previous disruption of soil seed and bud banks, disrupted soil structure or chemical composition, or changes to the soil microbial community.…”

Urban meadows as an alternative to short mown grassland: effects of composition and height on biodiversity

“…The plant community will interact with soil microbial and invertebrate communities, and there is emerging evidence that soil microbial communities may facilitate, not simply follow, vegetation development (Harris 2009, van der Putten et al 2013. Establishing seminatural grasslands in the longer term is, however, also highly dependent on environmental conditions (Stuble et al 2017), and future management interventions will impact the community trajectory, particularly the frequency of mowing, the choice of whether vegetation clippings are removed (see next paragraph), and any management designed to enhance plant diversity or density, for example re-seeding or scarifying (Westbury et al 2006, Trowbridge et al 2017.…”