INVESTIGADORES
POLICELLI nahuel
artículos
Título:
Increase in nonnative understorey vegetation cover after nonnative conifer removal and passive restoration
Autor/es:
SAMPLE MARTHA; ASLAN CLARE E. ; POLICELLI NAHUEL; SANFORD ROBERT L. ; NIELSEN ERIK ; NUÑEZ MARTIN A
Revista:
AUSTRAL ECOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2019
ISSN:
1442-9985
Resumen:
Nonnative conifers are widespread in the southern hemisphere, where their use as plantation species has led to adverse ecosystem impacts sometimes intensified by invasion. Mechanical removal is a common strategy used to reduce or eliminate the negative impacts of nonnative conifers, and encourage native regeneration. However, a variety of factors may preclude active ecological restoration following removal. As a result, passive restoration?unassisted natural vegetation regeneration?is common following conifer removal. We asked: what is the response of understorey cover to removal of nonnative conifer stands followed by passive restoration? We sampled understorey cover in three site types: clearcuts two to ten years old, native forest, and current plantations. We grouped understorey species by origin (native/nonnative) and growth form, and compared proportion and percent cover of these groups as well as of bare ground and litter between the three site types. For clearcuts, we also analyzed the effect of time since clearcut on the studied variables. We found that clearcuts had a significantly higher average proportion of nonnative understorey vegetation cover than native forest sites, where nonnative vegetation was nearly absent. The understorey of clearcut sites also averaged more overall vegetation cover and more nonnative vegetation cover (in particular, nonnative shrubs and herbaceous species) than either plantation or native forest sites. Notably, 99% of nonnative shrub cover in clearcuts was the invasive nonnative species Scotch broom (Cytisus scoparius). After ten years of passive recovery since clearcutting, the proportion of understorey vegetation cover that is native has not increased, and remains far below the proportion observed in native forest sites. Reduced natural regeneration capacity of the native ecosystem, presence of invasive species in the surrounding landscape, and land-use legacies from plantation forestry may inhibit native vegetation recovery and benefit opportunistic invasives, limiting the effectiveness of passive restoration in this context.