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Southern Africa is expected to experience increased frequency and intensity of droughts through climate change, which will adversely affect mammalian herbivores. Using bio-loggers, we tested the expectation that wildebeest (Connochaetes taurinus), a grazer with high water-dependence, would be more sensitive to drought conditions than the arid-adapted gemsbok (Oryx gazella gazella). The study, conducted in the Kalahari, encompassed two hot-dry seasons with similar ambient temperatures but differing rainfall patterns during the preceding wet season. In the drier year both ungulates selected similar cooler microclimates, but wildebeest travelled larger distances than gemsbok, presumably in search of water. Body temperatures in both species reached lower daily minimums and higher daily maximums in the drier season but daily fluctuations were wider in wildebeest than in gemsbok. Lower daily minimum body temperatures displayed by wildebeest suggest that wildebeest were under greater nutritional stress than gemsbok. Moving large distances when water is scarce may have compromised the energy balance of the water dependent wildebeest, a trade-off likely to be exacerbated with future climate change.

While studies often focus on density-dependent responses of ungulate populations to resource limitations at large spatial scales, the dynamics at smaller scales remain relatively unexplored. To address this gap, we investigated the temporal dynamics of ungulate abundance in a small dystrophic grassland ecosystem over 20years, with minimal management interventions. We used annual counts and herd composition data to explore density-dependent responses at the population level and attempt to link such responses to demographic mechanisms. Counts were corrected using a state-space modeling approach. Populations of most species increased from low densities to approximate equilibrium densities. Our findings reveal evidence of density-dependent responses in population growth that shaped the population abundance dynamics. Additionally, juvenile-to-adult ratios exhibited patterns of density-dependent reductions in recruitment. This study suggests grassland ecosystems with moderate annual rainfall are regulated primarily by bottom-up processes.

The Critically Endangered African wild ass Equus africanus is one of the most threatened equids, with fewer than 400 individuals persisting in the Danakil Desert (Eritrea), and fewer than 600 globally. To effectively conserve the species, it is essential to determine the extent of available suitable habitats and understand the environmental factors that most influence its current distribution. During 2016–2019 we observed African wild asses, recorded their locations during both the wet and dry seasons and analysed the bioclimatic data and topography using the maximum entropy species distribution model. Distance from water sources and precipitation of the driest month were the top predictors of suitable habitat for the dry season, whereas seasonal temperature variability and precipitation during the warmest quarter were the top predictors for the wet season. Model performances were high, with area under the curve values of 0.97 and 0.98 for the dry and wet seasons, respectively. In the Danakil Desert of Eritrea, the extent of optimal habitat for African wild asses is estimated to be 130 km2 in the dry season and 739 km2 in the wet season, with a potential range of 11,000 km2 for both seasons. Our model results also indicate that in the dry season 89 km2 of the Messir Plateau is optimal habitat, and the entire plateau area of 124 km2 provides optimal habitat during the wet season. These findings provide wildlife management authorities with substantive information and rationale for the establishment of a protected area on the Messir Plateau for African wild asses in Eritrea.

The presence of humans and African elephants (Loxodonta africana) in the Great Limpopo Transfrontier Park can create situations of potential human–elephant conflict. Such conflict will likely be exacerbated as elephant and human populations increase, unless mitigation measures are put in place. In this study we analysed the movement patterns of 13 collared adult African elephants from the northern Kruger National Park over a period of eight years (2006–2014). We compared the occurrence and displacement rates of elephant bulls and cows around villages in the Limpopo National Park and northern border of the Kruger National Park across seasons and at different times of the day. Elephants occurred close to villages more often in the dry season than in the wet season, with bulls occurring more frequently around villages than cows. Both the bulls and the cows preferred to use areas close to villages from early evening to midnight, with the bulls moving closer to villages than the cows. These results suggest that elephants, especially the bulls, are moving through the studied villages in Mozambique and Zimbabwe at night and that these movements are most common during the drier months when resources are known to be scarce. Conservation implications: Elephants from the Kruger National Park are moving in close proximity to villages within the Great Limpopo Transfrontier Park. Resettlement of villages within and around the park should therefore be planned away from elephant seasonal routes to minimise conflict between humans and elephants.

It is unclear whether the methodology was geared to test a specific hypothesis or to find a model that best fit the selected variables. The author's framing of the commentary suggests that it was meant to test the hypothesis that a number of pre-selected variables may influence a student's choice when considering studies in the biological sciences. However, as written, the analytical approach appears to use model selection, rather than test an a priori hypothesis. The author describes variables that appear to be sequentially added to the model before a best-fit model is selected. Instead of using the best-fit models, where 'black South African' is no longer a significant variable, the author makes inferences about each model. Further, the variable that makes the largest contribution to explaining variability in the Regression 2 is 'Agrees 'I support wildlife conservation but have no interest in having a career in it\". At this point, the variable 'black South African' is far from significant and no interaction effect is shown to support that these are linked to the dependent variable.

The geographic distribution of a species is governed by climatic conditions, topography, resources and habitat structure determining the fundamental niche, while the local distribution expressed via home range occupation may be compressed by biotic interactions with competitors and predators, restricting the realised niche. Biotic influences could be especially important for relatively rare species. We investigated how rainfall, geology, land type and abundance of other ungulate species serving as competitors or prey for predators contributed to the patchy distribution of sable antelope herds within Kruger National Park. Data were provided by annual aerial surveys of ungulate populations conducted between 1978 and 1988. Sable herds were more commonly present on granitic and sandstone substrates than on more fertile basalt. They occurred both in the moist south-west and dry north of the park. They were most abundant in sour bushveld and mopane savanna woodland, and mostly absent from knob thorn-marula parkland. The presence of sable was negatively associated with high concentrations of impala and wildebeest, less consistently related to the abundance of zebra, and positively associated with the occurrence of buffalo herds. Best supported models included the separate effects of the most abundant grazers along with land type. Interspecific relationships seemed more consistent with vulnerability to predation as the underlying mechanism restricting the distribution of sable herds than with competitive displacement. Sable favoured land types distinct from those where wildebeest, the most preferred prey of lions, and impala, numerically the most important resident prey species, were most abundant. Hence the risk of predation, associated with habitat conditions where abundant prey species are most concentrated, can exert an overriding influence on the distribution of rarer species in terms of their home range occupation.

Similar to declines in antelope species across African conservation areas, sable ( Hippotragus niger ) at Kgaswane Mountain Reserve, South Africa, has exhibited a negative trend in abundance since 2000. To investigate the cause of decline, we assessed three hypotheses: seasonal forage abundance, habitat conditions and interspecific competition. We considered the evidence for each hypothesis by analysing reserve survey data, rainfall records and historical burn data with hierarchical models that incorporated potential density-dependent effects and environmental covariates. After accounting for the effects of sable abundance, we found that sable population growth was most strongly related to the interspecific competition covariates and to waterbuck ( Kobus ellipsiprymnus ) count in particular. Also, the strength of the relationship was shaped by the trend in sable numbers and whether the population was before or after peak abundance: the strongest indication of interspecific competition occurred after sable had reached peak abundance. The interaction between abundance of sable and that of potentially competing species emphasizes the importance of accounting for density-dependent processes, and in particular longer-term phases in abundance, when judging the roles of other factors that affect species abundance.

Understanding how human activity can influence species distributions and spatial niche partitioning between sympatric species is a key area of contemporary ecology. Extirpations of large mammalian populations, the result of a 15-year civil war, within the Gorongosa National Park in Mozambique, have been followed by an extended period of restoration. The species-specific recovery of these populations has provided an ideal system to identify how niche partitioning between coexisting species is altered as a consequence of extreme disturbance events. Here, we aimed to understand how distribution patterns of grazing herbivores, as well as spatial niche overlap between them, changed between the pre- and post-war scenarios. We focused on the following four grazer species: buffalo (Syncerus caffer); sable (Hippotragus niger); waterbuck (Kobus ellipsiprymnus); and zebra (Equus quagga). Using long-term aerial survey data, we quantified range size for each species, as well as spatial niche overlap between each species pair, for pre- and post-war periods. Range size of buffalo and zebra decreased drastically from the pre-war period; with both species inhabiting subsets of their historical distribution in the park. Sable and waterbuck have both colonised historically avoided habitat, with waterbuck doubling their pre-war range size. Spatial overlap between all four grazers pre-war was significantly high, indicating niche similarity; however, this decreased in the post-war period, with some species pairs displaying spatial niche dissimilarity. Our findings highlight how population responses to anthropogenic disturbance can result in significant alterations to species’ distributions, with consequences for patterns of niche similarity.

Extreme weather events perturb ecosystems and increasingly threaten biodiversity 1 . Ecologists emphasize the need to forecast and mitigate the impacts of these events, which requires knowledge of how risk is distributed among species and environments. However, the scale and unpredictability of extreme events complicate risk assessment 1 – 4 —especially for large animals (megafauna), which are ecologically important and disproportionately threatened but are wide-ranging and difficult to monitor 5 . Traits such as body size, dispersal ability and habitat affiliation are hypothesized to determine the vulnerability of animals to natural hazards 1 , 6 , 7 . Yet it has rarely been possible to test these hypotheses or, more generally, to link the short-term and long-term ecological effects of weather-related disturbance 8 , 9 . Here we show how large herbivores and carnivores in Mozambique responded to Intense Tropical Cyclone Idai, the deadliest storm on record in Africa, across scales ranging from individual decisions in the hours after landfall to changes in community composition nearly 2 years later. Animals responded behaviourally to rising floodwaters by moving upslope and shifting their diets. Body size and habitat association independently predicted population-level impacts: five of the smallest and most lowland-affiliated herbivore species declined by an average of 28% in the 20 months after landfall, while four of the largest and most upland-affiliated species increased by an average of 26%. We attribute the sensitivity of small-bodied species to their limited mobility and physiological constraints, which restricted their ability to avoid the flood and endure subsequent reductions in the quantity and quality of food. Our results identify general traits that govern animal responses to severe weather, which may help to inform wildlife conservation in a volatile climate. A study that tracked mammal populations before, during and after a severe storm in Mozambique’s Gorongosa National Park finds that behavioural responses and survival are linked to body size, with increased mortality of small species owing to limited mobility and changes in food availability.

Questions: Termite mounds are known to host a suite of unique plants compared with the surrounding savanna matrix. However, most studies testing the significance of mounds for ecosystem heterogeneity have been conducted at single sites. Mound effects on savanna heterogeneity across varying landscapes are less well understood, and how effects might vary across geological types and mounds of different sizes is as yet unknown. Location: Gonarezhou National Park, Zimbabwe. Methods: We studied effects of termite mounds on vegetation spatial heterogeneity across two geologies (granite and basalt), including effects of mound size and the spatial extent of termite influence. Herbaceous vegetation was sampled on mounds and savanna matrix plots, and along distance transects away from mounds. Soil nutrients on mounds and in the matrix were also compared between geologies. Results: Soil nutrients were more concentrated in large mounds compared with the matrix on granite, but not on basalt, with mounds therefore acting as nutrient hotspots only on nutrient-poor granite. Large- and medium-sized mounds hosted compositionally different grass species to the matrix on granite, but not on basalt. Large mounds on granite also had significantly lower grass and forb species richness compared with the matrix. However, small mounds on granite, and all mound size categories on basalt, did not have an effect on grass and forb species richness or assemblage composition, an observation attributed to a lack of difference in soil nutrients between the mounds and matrix. Conclusion: Our study shows that the significance of termite mounds to ecosystem spatial heterogeneity is strongly influenced by geology and mound size, with mound effects on herbaceous plant species heterogeneity more pronounced in dystrophic geologies and around large mounds. Future studies should take greater cognisance of landscape context and mound size when seeking to understand the contribution of termite mounds to ecosystem structure and function.