Dave J. Druce

The megaherbivore concept suggests that mammals >1000 kg are insensitive to predation as adults. Consequently, their space use should be largely driven by resources. This does not account for the fact that megaherbivores have been hunted by humans for >100,000 years and likely evolved innate responses against human predation. Recent studies indeed show that megaherbivores, such as elephants and rhino, strongly respond to human voices. Few, however, have examined the relative influence of resource versus human risk drivers on the landscape use of megaherbivores. Using a long-term dataset from aerial rhino surveys and poaching events in Hluhluwe-iMfolozi Park, South Africa, we investigated how resource and human risk factors shape the landscape distribution of white rhinoceros ( Ceratotherium simum ). We used rainfall, fire, catena position, and terrain ruggedness as resource drivers and poaching intensity, and distance to human sound-generating infrastructure as human risk drivers. Both resource and human risk drivers affected rhino landscape distribution. Rhino preferred valley bottoms over midlands and uplands, and the use of the latter two habitats increased during the dry season. During drier wet seasons, rhinos increased their upland habitat use. Rhino avoided the park’s fenceline and other infrastructure (roads and camps). Poaching intensity did not influence rhino landscape use. Avoidance of human infrastructures may reduce the effective size of protected areas for rhino. Future work should assess how rhino respond to resources and risk over shorter timescales. Our findings encourage a re-evaluation of the megaherbivore concept to include humans as drivers of their ecology.

Before 2014, spotted hyaenas were not present on Welgevonden Game Reserve, Limpopo. However, from 2014 sporadic sightings have occurred, becoming more frequent with observed denning, indicating residency. Here we attempt to document this natural recolonization using 10 years of existing camera trapping data from the South African Leopard Monitoring Project managed by Panthera. Individual spotted hyeanas were identified by applying machine learning and computer vision in the African Carnivore Wildbook platform. We documented 10 years of spotted hyaena recolonization and noted an increasing frequency of captured spotted hyaenas using camera traps as follows: 2014, 6 photogaphs; 2015, 50; 2016, 33; 2017, 110; 2018, 164; 2019, 131; 2020, 267; 2021, 174; 2022, 250; and 2023, 417. The natural recolonization of spotted hyaenas is poorly understood and managing them in fenced reserves through reintroductions is poorly described. This will add to our limited knowledge of reintroduction biology for the species and aid in supporting managed metapopulations in the future.

Because of its global status as well as its conservation dependence, the African elephant requires national attention. Within South Africa, the Norms and Standards for the Management of Elephants, provide a ‘how to’ tool, but these do not define a national common vision for elephant conservation, nor provide a broader understanding of the role of elephants in society. South Africa thus urgently needed an overarching strategy. Following a whole of society co-development consultation process, the wide range of values and expectations held by a diverse set of stakeholders was realized. While the National Elephant Heritage Strategy includes key elements required by typical conservation planning, the strategy focuses on achieving South African societal aspirations for elephants, including promoting a sustainable intergenerational legacy for all. The strategy provides a framework for planning and decision-making around living landscapes with elephants, which maximizes all values that elephants contribute to South Africans while mitigating risks to people and the environment, through a common vision, goals and key actions. The strategy broadens beyond conserving populations of the species, to a contextualization of the role of elephants in society. We describe the approach and process followed in the co-development of the strategy and key outcomes. This process and approach can inform other national conservation strategies to better align with the different value systems and whole of society principles encapsulated within the Global Biodiversity Framework.

Wild animals can modulate ecosystem-climate feedbacks, e.g. through impacts on vegetation and associated carbon dynamics. However, vegetation cover and composition also affect land surface albedo, which is an important component of the global energy budget. We currently know very little about the influence of wild animals on land surface albedo and the resulting climate forcing of these albedo changes. Leveraging a unique, ecosystem-scale, semi-experimental approach, we study how the local removals of the world’s largest, terrestrial grazer, white rhinoceros (Ceratotherium simum), affected the coupling between fire dynamics, woody encroachment and surface albedo in Hluhluwe–iMfolozi Park (HiP), South Africa. Our path analysis revealed that areas in the park where more rhinos had been removed showed a stronger increase in burnt area and woody encroachment compared to areas with fewer rhinos removed, which were both related to a decrease in surface albedo. Increasing burnt area was further associated with higher rates of woody encroachment, indirectly reinforcing the negative effect of rhino loss on albedo. Our study demonstrates that removals of megagrazers in HiP were related to complex ecosystem-wide cascades with measurable impacts on land cover and surface albedo and consequences on climate forcing. This highlights the importance of restoring functional ecosystems by reinstating trophic processes.

Summary: Positive biodiversity–ecosystem function relationships (BEFRs) have been widely documented, but it is unclear if BEFRs should be expected in disturbance‐driven systems. Disturbance may limit competition and niche differentiation, which are frequently posited to underlie BEFRs. We provide the first exploration of the relationship between tree species diversity and biomass, one measure of ecosystem function, across southern African woodlands and savannas, an ecological system rife with disturbance from fire, herbivores and humans. We used > 1000 vegetation plots distributed across 10 southern African countries and structural equation modelling to determine the relationship between tree species diversity and above‐ground woody biomass, accounting for interacting effects of resource availability, disturbance by fire, tree stem density and vegetation type. We found positive effects of tree species diversity on above‐ground biomass, operating via increased structural diversity. The observed BEFR was highly dependent on organismal density, with a minimum threshold of c. 180 mature stems ha⁻¹. We found that water availability mainly affects biomass indirectly, via increasing species diversity. The study underlines the close association between tree diversity, ecosystem structure, environment and function in highly disturbed savannas and woodlands. We suggest that tree diversity is an under‐appreciated determinant of wooded ecosystem structure and function.

Competitively dominant carnivore species can limit the population sizes and alter the behavior of inferior competitors. Established mechanisms that enable carnivore coexistence include spatial and temporal avoidance of dominant predator species by subordinates, and dietary niche separation. However, spatial heterogeneity across landscapes could provide inferior competitors with refuges in the form of areas with lower competitor density and/or locations that provide concealment from competitors. Here, we combine temporally overlapping telemetry data from dominant lions (Panthera leo) and subordinate African wild dogs (Lycaon pictus) with high‐resolution remote sensing in an integrated step selection analysis to investigate how fine‐scaled landscape heterogeneity might facilitate carnivore coexistence in South Africa’s Hluhluwe‐iMfolozi Park, where both predators occur at exceptionally high densities. We ask whether the primary lion‐avoidance strategy of wild dogs is spatial avoidance of lions or areas frequented by lions, or if wild dogs selectively use landscape features to avoid detection by lions. Within this framework, we also test whether wild dogs rely on proactive or reactive responses to lion risk. In contrast to previous studies finding strong spatial avoidance of lions by wild dogs, we found that the primary wild dog lion‐avoidance strategy was to select landscape features that aid in avoidance of lion detection. This habitat selection was routinely used by wild dogs, and especially when in areas and during times of high lion‐encounter risk, suggesting a proactive response to lion risk. Our findings suggest that spatial landscape heterogeneity could represent an alternative mechanism for carnivore coexistence, especially as ever‐shrinking carnivore ranges force inferior competitors into increased contact with dominant species.

Global warming compels larger endothermic animals to adapt either physiologically or behaviourally to avoid thermal stress, especially in tropical ecosystems. Their adaptive responses may however be compromised by other constraints, such as predation risk or starvation. Using an exceptional camera-trap dataset spanning 32 protected areas across southern Africa, we find that intermediate-sized herbivores (100–550 kg) switch activity to hotter times of the day when exposed to predation by lions. These herbivores face a tight window for foraging activity being exposed to nocturnal predation and to heat during the day, suggesting a trade-off between predation risk and thermoregulation mediated by body size. These findings stress the importance of incorporating trophic interactions into climate change predictions.