Spatial constraints and seasonal conditions but not poaching pressure are linked with elevated faecal glucocorticoid metabolite concentrations in white rhino

DATA AVAILABILTY : The data that support the findings of this study are available from the Science Manager at South African National Parks Mrs Judith Botha ([email protected]), upon reasonable request.CONTEXT : Due to considerable declines in African wildlife populations, most large African mammals are managed inside protected areas. Protected areas come in various sizes, and have different environmental features, climates and management strategies (i.e. ‘hands-on’ or ‘hands-off’) that can influence an animals’ homeostasis. White rhinos (Ceratotherium simum simum) are found almost exclusively within protected areas where population sizes are driven by natural factors and poaching pressures. AIMS : Our aim was to understand the effect of natural and anthropogenic factors on the adrenocortical response of white rhinos within three protected areas. Specifically, we wanted to understand how poaching pressure, protected area size (<500 km2), season (wet and dry) and rainfall patterns were responsible for driving adrenocortical activity in white rhino. METHODS : To understand the relationship between rhino adrenocortical responses and different environmental and anthropogenic stressors, we quantified glucocorticoid metabolites in faecal samples (fGCM) collected from four populations within three protected areas (i.e. two small parks, one big park) during the wet and dry seasons. KEY RESULTS : We found differences in seasonal fGCM concentrations, with a 42% increase during the dry season, and no differences in fGCM concentrations between the high and low poaching areas. Additionally, we found fGCM concentrations in samples from the small parks were respectively 38% and 42% higher than in samples from the large park during both the dry and wet seasons compared. CONCLUSIONS : Our results suggest that white rhinos may experience physiological stress in smaller parks, especially during the dry season when resources are limited. IMPLICATIONS : By mitigating stress associated with reduced access to resources and spatial constraints, managers may better promote the viability of large mammals in small protected areasThe South African National Parks.https://www.publish.csiro.au/WRhj2023Mammal Research Institut

The white rhino can again be a conservation success

No abstract available.https://zslpublications.onlinelibrary.wiley.com/journal/14691795hj2023Mammal Research InstituteZoology and Entomolog

The reproductive success of black rhinoceroses in the Hluhluwe–iMfolozi Park, KwaZulu-Natal, South Africa

Black rhinoceroses (Diceros bicornis) are endangered and the southern-central sub-species (Diceros bicornis minor) is considered critically endangered. We assessed the reproductive lifehistories of black rhinoceroses in Hluhluwe–iMfolozi Park (HiP), KwaZulu-Natal, South Africa, to determine whether this historically important donor sub-population was meeting regional reproductive targets. Detailed life-history information for known individuals (n = 79–120) was used to investigate reproductive parameters between 1998 and 2013. Mean age at sexual maturity was 12 years, which exceeded a target period of 7 years and 5 months. The mean inter-calving interval was 3 years and 8 months – 8 months longer than the recommended 3 years. The poor population performance of the HiP black rhinoceroses could be a result of poor habitat quality, poor animal condition, females losing their first calves, predation of calves or a negative social effect of annual live-harvesting of the population. However, we believe that the estimated ecological carrying capacity of black rhinoceroses at HiP (a figure used to ascertain whether the population can be harvested at all) may be incorrect, leading to the poor reproductive performance. We recommend that the accuracy of the ecological carrying capacity estimate be assessed as a matter of urgency and that a moratorium be placed on the live-harvesting of individuals until the estimate has been refined. Conservation implications: Our results provide key data which can be used to refine black rhinoceros breeding targets in South Africa and the region more broadl

White rhinos and other herbivores decrease visitations and increase vigilance in response to human vocalizations

Harnessing the fear animals have of humans has the potential to aid in the conservation of wildlife. Most vertebrates perceive humans as “super predators.” While predator cues are an important nonlethal management tool, the use of human cues for management has rarely been implemented or experimentally tested. Extensive poaching is threatening the persistence of white rhinos (Ceratotherium simum simum), and there is a need to deter them from areas with elevated poaching risks. To investigate the feasibility of harnessing the fear white rhinos have of humans to aid in their conservation, we conducted playback experiments at rhino middens. We broadcasted repeated human (treatment) and bird (control) vocalizations, and measured changes in visitations and antipredator responses. We found that overall rhino visitations did not change in response to controls but decreased by 46% in response to human vocalizations. This pattern appears to be driven by the response of females, who decreased their visitations by 70% in response to human vocalizations, while visitations by males remained unchanged. This difference is likely related to males defending small exclusive territories. Providing evidence that changes in female visitation rates were a function of the perceived fear of white rhinos, we found that both sexes exhibited more vigilance in response to human vocalizations (males 69.5%, females 96%) compared to controls. We also saw a 63% reduction of other herbivores at treatment sites. Our findings provide evidence that the fear of humans can be used to alter the movements and behavior of female white rhinos, critical for population recovery, as well as other large herbivores.The University of Florida.https://academic.oup.com/jmammalhj2023Mammal Research InstituteZoology and Entomolog