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Many savannas are experiencing increased cover of trees and shrubs, resulting in reduced herbaceous productivity, shifts in savanna functional structure and potential reductions in ecotourism. Clearing woody plants has been suggested as an effective management strategy to mitigate these effects and restore these systems to an open state with higher rates of grass production and herbivory. This study investigated the effectiveness of repeated shrub clearing as a tool to mitigate bush encroachment in a semi‐arid savanna in southern Africa.We present data from a 7‐year experiment in the Mthimkhulu Game Reserve bordering Kruger National Park, South Africa. Colophospermum mopane stems and resprouting shoots were basally cut 2–3 times per year (2015–2022) in three pairs of treatment and control plots of 60 × 60 m. We monitored changes in soil moisture, grass biomass and herbivore activity via dung counts. We assessed C. mopane physiological responses to repeated cutting using non‐structural carbohydrates and stable water isotopes to infer changes to energy storage and functional rooting depth, respectively.The cleared treatment had higher soil moisture and grass biomass than the control treatment. Dung counts showed impala and buffalo visited the cleared treatment more frequently than the control treatment.Repeated cutting had limited effects on C. mopane survival in the first 2–3 years after initial clearing, but 80% of individuals were dead after 7 years. Repeatedly cut C. mopane had lower belowground starch concentrations and used water from shallower soil depths than C. mopane in control plots.Synthesis and applications. Repeated cutting increased soil moisture availability and grass biomass, and attracted charismatic grazing herbivores. While more costly than once‐off clearing methods, this practice created more employment opportunities for a neighbouring rural community. Transforming portions of the ecosystem to a grass‐dominated state may increase ecotourism potential through improved game viewing in open systems. [ABSTRACT FROM AUTHOR]

Grasslands are one of the most threatened terrestrial ecosystem types, and montane grasslands of particular conservation concern. Despite high rates of transformation in recent decades, croplands and plantations are being abandoned in parts of many countries, creating an opportunity for conservation of montane grasslands through restoration. We report on the changes in the cover of major vegetation types (indigenous forest, grassland, and plantations) between 1935 and 2022, in an area that was intensively afforested from 1930 to 1960 and abandoned in 2000. Montane grassland at the site declined from over 50% of all landcover to below 15%, but subsequently recovered to 30% within 20 years. Many former plantations developed into secondary grassland with estimated gamma plant species richness of 231 for herbaceous species and 45 for savanna species. These are high values considering the size of the study area (4000 ha), and comparable to estimates from primary grassland sites in the broader region. However, at the scale of 1 m² sampling quadrats, richness in the secondary grasslands was below that recorded in the last remaining patches of primary grassland at the site (means of 2.6 versus 4.7 for graminoid species, and 1.9 versus 2.9 for forbs). Some of the former Eucalyptus plantations had transformed into novel savannas dominated by firetolerant, resprouting trees, and may require more active restoration. Secondary grasslands such as those reported on here could potentially make a significant contribution to the conservation of montane biodiversity over the coming decades, warranting further research (both socio-economic and ecological) on the factors that lead to abandonment and promote the emerge of secondary grasslands of high diversity. [ABSTRACT FROM AUTHOR]

Over the past century, increases in indigenous woody plant species, also known as woody encroachment (WE), has occurred in grasslands and savannas across the globe. While the impact on grassland and savanna composition and productivity has been well studied, little is known of the impacts on the hydrological cycle. WE may increase evapotranspiration (ET) losses, leading to reduced infiltration and ultimately reduced freshwater availability, which is of particular concern in arid and semi-arid areas. The aim of this study was to determine the effect of Colophospermum mopane (mopane) encroachment on ET in a semi-arid savanna located in South Africa. Mopane is widely distributed across southern Africa, and is one of the main encroaching species of the region. Following an assessment of the validity of two surface renewal approaches, SR1 and SRDT, against short eddy covariance campaigns for sensible heat flux estimation, the SR1 approach was used to estimate ET at an experimental woody plant clearing trial from November 2019 to July 2022. For the two drier years of the study, the removal of mopane trees had little effect on ET. However, for the wettest year of the study, the removal of mopane trees decreased ET by 12%, supporting the hypothesis that the conversion from grass dominance to woody dominance can increase ET. Annual ET exceeded annual rainfall in all 3 years, indicating that the vegetation supplements its water use with soil water that has accumulated during previous wet seasons, or that tree roots facilitate hydraulic lift of deep soil water, or groundwater, to depths within the rooting depth of both trees and grasses. Further research is needed to confirm the exact mechanism involved, and the consequences of this for groundwater and streamflow at landscape scales. [ABSTRACT FROM AUTHOR]

Freeze events can be important disturbances in savanna ecosystems, yet the interactive effect of freezing with other environmental drivers on plant functioning is unknown. Here, we investigated physiological responses of South African tree seedlings to interactions of water availability and freezing temperatures. We grew widely distributed South African tree species (Colophospermum mopane, Combretum apiculatum, Acacia nigrescens, and Cassia abbreviata) under well-watered and water-limited conditions and exposed individuals to nighttime freeze events. Of the four species studied here, C. mopane was the most tolerant of lower water availability. However, all species were similarly tolerant to nighttime freezing and recovered within one week following the last freezing event. We also show that water limitation somewhat increased freezing tolerance in one of the species (C. mopane). Therefore, water limitation, but not freezing temperatures, may restrict the distribution of these species, although the interactions of these stressors may have species-specific impacts on plant physiology. Ultimately, we show that unique physiologies can exist among dominant species within communities and that combined stresses may play a currently unidentified role in driving the function of certain species within southern Africa. [ABSTRACT FROM AUTHOR]

Colophospermum mopane woodland covers large areas of dry lowland savanna in southeastern Africa. Dominant land usage is conservation (45%) with the remainder mostly modified by farming. Dung beetle responses to environment (dung type, habitat, weather) and land usage (conservation, farming, mining) were examined at Phalaborwa (23.9431° S 31.1411° E) in the Phalaborwa- Timbavati Mopaneveld, South Africa. Partitioning of gamma species richness and diversity showed lower alpha values in mine areas than in farm and conserved areas. However, between-land usage differences in species richness, alpha diversity, abundance and biomass, showed lower significance than those between dung type and different weather. At two sampling scales, three multivariate techniques variously separated assemblages according to land usage, dung type and weather. Analysis of 21 mean samples separated clusters according to dung type ( Canonical Correspondence Analysis, CCA) or mine assemblages, conserved plus farm assemblages on pig plus elephant, or cattle dung ( NMDS, Factor Analysis) with shared variance of >80% and unique variance of 16-18% per cluster. In analysis of 188 samples ( CCA), each overlapping dung type cluster was offset in ordinal space with congruent patterns of separation according to land usage and weather (drier days distant from moister days; conserved plus farm areas distant from early succession mine areas, which were distant from disturbed and later succession mine areas). Mining, dung types, and moist conditions were the strongest contributors to between-assemblage differences. Compared with conserved areas, dung beetle diversity is appreciably altered by mining but only slightly altered by intensive game farming or livestock ranching with subsistence agriculture. [ABSTRACT FROM AUTHOR]

Identifying key ecophysiological traits that differ among dominant plant species and can be linked to species-specific responses to drought would improve our ability to forecast community and ecosystem responses to global climate change. The mesic grasslands of the central plains of North America are dominated by two C4 grass species, Andropogon gerardii and Sorghastrum nutans, which purportedly differ in their tolerance of water stress. Individuals of these two species were grown in the field under rain-out shelters and subjected to wet (watered every 2–3 d) or dry (repeatedly subjected to wilting before watering) soil moisture regimes. A range of ecophysiological traits potentially important for tolerating water stress were concurrently measured. Although few traits differed between the species in the wet treatment, several traits were identified in the dry treatment that may enable A. gerardii to better tolerate drought. These were greater allocation to roots, reduced allocation to flowering, more rapid leaf turnover, and more rapid recovery of photosynthesis after wilting. The latter two traits may be particularly important for coping with increased variability in rainfall regimes in the future and are consistent with recently documented responses of A. gerardii to experimental increases in soil moisture variability. [ABSTRACT FROM AUTHOR]