For six decades the African Journal of Range & Forage Science and its precursors have contributed to understanding drivers of rangeland degradation and development of approaches for restoration of damage by grazing, mining and other forms of land use. Of the 857 articles selected by the keyword search, only around 150 focused on reversing loss of natural capital, including soil, water and biodiversity and or resilience, and were cited in this review. Restoration approaches ranged from grazing management such as resting, rotational grazing and grazing intensification, to interventions such as burning, browsing and clearing of encroaching woody or non-native plants, resource capture, reseeding and replanting. Global change brings novel challenges for restoration research. Major knowledge gaps include assessment of restoration progress, development of policy and incentives to promote and fund restoration, and identification of unintended risks posed by restoration interventions.

AimHigh temperatures during forest fires can cause significant damage to tropical dry forest areas and alter their ecological stability, particularly by affecting seed viability and seedling emergence. This study evaluates the seedling emergence response of 18 dry forest species to fire-simulated temperatures, aiming to assess their potential for restoration in fire-prone Colombian ecosystems.LocationThe seeds used in this study were obtained from three tropical dry forests in Colombia.MethodsA total of 9832 seeds from 18 dry forest species were collected directly from the soil seed bank in three tropical dry forests in Colombia. These seeds were then exposed to simulated forest fire temperatures (100 degrees C, 150 degrees C, and 200 degrees C) for 10 min. Seed viability was analyzed using the 2,3,5-triphenyl tetrazolium chloride reagent (tetrazolium test) and assessed using a generalized linear model. Seedling emergence and mean emergence time were evaluated using one-way analysis of variance (ANOVA) with temperature treatments as factors.ResultsThe study revealed that seedling emergence significantly decreased with higher heat shock temperatures. Notably, Hura crepitans and Parkinsonia aculeata tolerated temperatures up to 100 degrees C, while Caesalpinia pulcherrima and Enterolobium cyclocarpum showed increased emergence at that temperature. Based on their emergence responses, species were classified as stimulated, tolerant, sensitive, or vulnerable. Seed viability declined with rising temperatures, and the mean emergence time increased in species like Cordia alba, Crescentia cujete, and Lonchocarpus violaceus.ConclusionsThis study shows that heat shocks at 150 degrees C and 200 degrees C significantly reduced seed bank viability for most Colombian dry forest species. However, Caesalpinia pulcherrima and Enterolobium cyclocarpum were stimulated by 100 degrees C heat shocks, while Hura crepitans and Parkinsonia aculeata showed no adverse effects. Vulnerable species like Coccoloba acuminata and Pithecellobium dulce exhibited no viable seeds at higher temperatures, suggesting potential local extinctions. These results emphasize the need to focus on heat-tolerant species for restoration efforts in fire-prone ecosystems.

This study assessed whether a natural regeneration or active tree-planting reforestation strategy better restored the C and N-cycle processes and associated microbiota within soils after 18 years in a Premontane Wet Life zone site in Monteverde, Costa Rica, compared to adjacent old secondary forest and pasture soils (both >60 years). Our findings apply to small-scale restoration sites (<0.5 ha plots) commonly used in Monteverde. Both restoration strategies showed recovering soil C and N-cycle processes with similar levels of TN, NH4+, NO3-, Biomass-C, and efficiency of organic C use. Both strategies appeared to positively influence the recovery of the levels and community compositional stability of the Actinobacterial, Acidobacterial, N-fixing (N-Fixer) bacterial, ammonium-oxidizing bacterial, and complex organic C-degrading fungal communities. The main differences between the two strategies were that the tree-planted and pasture soils had similar compositions of the Actinobacterial, N-Fixer, and Fungal complex organic C degrader, while the natural regeneration and pasture soils had similar compositions of these groups and the Acidobacteria. However, the community compositions of all five microbial groups were different between restored forest and the old secondary forest soils. These results suggest that while the soil ecosystems from both reforestation strategies are recovering, after 18 years, there is still more recovery to occur. Lastly, possible indicators of post-restoration soil ecosystem enhancement included increasing constancy of critical microbial group composition, efficiency of organic C conversion to biomass, Biomass-C,NH4+, NO3-, and levels of Acidothermus, Acidobacteria subgroups 2, 3, and 5, Archaeorhizomyces, Anaeromyxobacter, Bradyrhizobium, Nitrosomonas, Flavobacterium, and Nitrospira.

In the coastal mountain range of the Maule region, 23 ravine rain forests dominated by canelo (Drimys winteri) and various native myrtaceae species were described in phytosociological terms in a study published in 1988. In this study, 20 of these forests were located again thirty years later to document their current situation in a context of successive anthropogenic impacts and climate change. The objectives of this study are to characterize changes in plant composition using the modified Braun-Blanquet phytosociological method, evaluate changes in soil occupation through comparative analysis of Landsat images from 1987, 2003 and 2017, and examine the natural regeneration of woody species inside and outside ravine forests. The results showed that between 1987 and 2017, the area occupied by native forest in the study area was reduced by 72 %. The importance and presence of representative species, such as Drimys winteri and Blechnum chilense reported in the original inventories, decreased, and sclerophyllous species, like Lithrea causticaand Cryptocarya alba, entered, along with introduced species, like Pinus radiata and Teline monspessulana.The regeneration of native trees and native creeping and climbing species was higher inside the ravine forests, while the germination of native shrubs was higher at their edges. The modification of the surrounding matrix of forests due to increased anthropic pressure and an advance of stressful conditions explains the observed changes.