It has been reported that the restoration of semi-arid thicket with woody species is not ecologically feasible in South Africa. Transformed and degraded semi-arid thicket exhibits exceedingly poor resilience with normal succession precipitating low species diversity dominated by grasses and ephemerals. The transformed and degraded mesic-thicket types have only slightly improved resilience but also limited species richness with many guilds missing – despite many decades without the drivers of degradation being present. The restoration of thicket has largely been focused on the en masse planting of one species (Portulacaria afra) with the assumption that, once established, it will facilitate the natural return of the other species, specifically the missing woody plant guild. A lack of understanding regarding the ecophysiology of key woody species, as well as the nuances of the microclimate needed for succession has limited restoration success in the thicket. This research seeks to take a systems approach to understanding the multi-scale dynamics for the restoration of mesic-thickets, then apply the wisdom gained from this process to tackling the major challenge of effective restoration of degraded thicket areas with woody species. The results from fifteen common woody species found in mesic thickets indicates that drought-sensitivity, germination success, seedling growth rate, herbivory, nurse-planting, tree-shelters, ponding, and other treatments have significant species-specific effects. The intimate understanding of these relationships correlated spatially and temporally with the major thresholds that limit the germination, establishment, survival, growth rate, and canopy recruitment – will enable the successful restoration of thicket with woody species.
Audio/Video, Conference Presentation, SER2019
Pre-approved for CECs under SER's CERP program
Society for Ecological Restoration