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Reproductive females of a cooperatively breeding rodent are in better body condition when living in large groups
Finn, K.T.; Janse van Vuuren, Andries Koch; Suess, Tobias; Hart, Daniel William; Bennett, Nigel Charles; Zottl, M. (Wiley, 2025-07)
Cooperation and group living have been suggested to facilitate survival in varying environments and under challenging conditions. However, group living may also be associated with costs, particularly in species where individuals within groups may compete for limited resources. The costs and benefits of cooperative group living on cooperatively breeding mammals in varying environments remain unclear. Here, we use data collected from wild, cooperatively breeding Natal mole-rats (Cryptomys hottentotus natalensis) inhabiting a seasonally varying environment to assess whether body condition changes between seasons and whether these changes are contingent upon group size. We demonstrate that the body condition of reproductive females improved with increasing helper number during both the benign summer and the harsher winter seasons. However, the body condition of other group members showed little dependency on group size or season. Only when including one extremely large group did the body condition of non-breeders weakly, albeit significantly, change depending on group size and seasonality. These results suggest that larger group sizes may yield some benefits for non-breeding group members during winter and may invoke some costs during summer. Group living in Natal mole-rats is likely promoted by a combination of collective foraging, thermoregulatory benefits, and potentially some indirect fitness benefits through improved body condition of the breeding female.
Fertility up in flames : reduced fertility indices as a consequence of a simulated heatwave on small African mammals
Jacobs, Paul Juan; Bennett, Nigel Charles; Du Plessis, L.; Hart, Daniel William (Wiley, 2025-03)
With the increasing frequency and intensity of heatwaves due to climate change, the survival and reproductive success of mammals could be under significant threat. However, the specific effects of these environmental stressors on mammalian reproductive fitness remain insufficiently explored. This study investigates the impact of a simulated heatwave on male fertility indices in two African rodent species: the mesic four-striped field mouse (Rhabdomys dilectus) and the Namaqua rock mouse (Micaelamys namaquensis) during the breeding season. We measured key indicators of male fertility, including testes mass, testes volume, seminiferous tubule diameter, the presence of sperm, and plasma testosterone levels. Our findings reveal that both species experienced significant effects on male fertility indices, with the smaller R. dilectus showing a decline in all fertility indices following a simulated heatwave. These results suggest that the projected increase in heatwave events may compromise the reproductive success of small mammals, potentially leading to population declines. Finally, this study highlights the need for focused studies on the effect of heatwaves on long-term reproductive success in both males and females.
Examining alterations in fGCM concentrations post-defaecation across three animal feeding classes (ruminants, hindgut fermenters and carnivores)
Osburn, Kayla Rae; Crossey, Bruce Gareth; Majelantle, Tshepiso Lesedi; Ganswindt, Andre (Wiley, 2025-05)
Quantification of faecal glucocorticoid metabolites (fGCMs) is a popular non-invasive technique for monitoring wildlife's response to stressors, demanding an understanding of the stability of fGCM concentrations post-defaecation to ensure comparability of determined fGCM values across samples. To provide species-specific recommendations for the duration within which sampling can take place, we measured the rate at which the fGCM concentrations of nine different species changed throughout a 7-day period post-defaecation. In this study, we explored the temporal dynamics of fGCM concentrations in nine species across three feeding classes (ruminants, hindgut fermenters and carnivores): impala (Aepyceros melampus), giraffe (Giraffa camelopardalis), blue wildebeest (Connochaetes taurinus), plains zebra (Equus quagga), African elephant (Loxodonta africana), white rhino (Ceratotherium simum), cheetah (Acinonyx jubatus), spotted hyena (Crocuta crocuta) and leopard (Panthera pardus). Utilizing enzyme immunoassays already established for each of the focal species, we identified broader feeding class-specific patterns. All herbivores exhibited a significant decrease in fGCM concentrations over time, starting from 6 h (impala) to 48 h (giraffe, blue wildebeest, white rhino and African elephant) post-defaecation. For carnivores, concentrations remained fairly comparable for 12–24 h, after which fGCM concentrations either decreased (spotted hyena), increased (leopard) or remained stable (cheetah), with notable variation in triplicate concentrations (cheetah and leopard). These findings offer insights into scheduling faecal sampling for endocrine monitoring, particularly from free-roaming wildlife, to ensure comparability of determined hormone metabolite concentrations. Furthermore, the species-specific variation in fGCM concentration post-defaecation demonstrated in this study underlines the necessity to investigate every new species to ensure accurate and comparable results. Future studies ought to investigate how the mass of collected material, sex and drying methodologies affect the measurement of fGCMs post-defaecation.
Endemic plants and animals are susceptible to extinction in an imperilled alpine hotspot in southern Africa
Taylor, Peter J.; Bredenhand, Emile; Monadjem, Ara; Armstrong, Adrian J.; Rakotoarivelo, Andrinajoro R.; Mdluli, Veli Monday; Howard, Alexandra; Modise, Serero; Motitsoe, Samuel N.; Ntloko, Pindiwe; Kirkaldy, Abigail P.; Kleynhans, Dewald J.; Jankielsohn, Astrid; Mosikidi, Toka; Oosthuizen, Maria Kathleen; Payne, Stephanie; Munyai, Thinandavha C.; Carbutt, Clinton; Ramoejane, Mpho; Bereng, Mosiuoa; Stiller, Michael; Haddad, Charles R.; Steenhuisen, Sandy-Lynn; Mlambo, Musa C.; Moyo, Sibusisiwe; Nyembe, Nthatisi I.; Mofokeng, Lehlohonolo; Van As, Johann; Malekana, Lesego; Daniel, Gimo M.; Gwate, Onalenna; Van As, Michelle; Harrison, James Du Guesclin; Thabethe, Nokubonga F.; Kheswa, Nozipho; Moloi, Karabo; Sishange, Nkanyiso; Clark, V. Ralph (South African National Biodiversity Institute, 2025-11)
BACKGROUND : As global temperatures rise, alpine species at the upper limit of their distribution are at risk of decline and extinction due to shrinking habitats downslope. The alpine (> 2 800 m a.s.l.) biodiversity of the Maloti-Drakensberg is poorly known but may be threatened by climate change. OBJECTIVES : Using expert BioBlitzes, we documented species richness and elevational patterns of distribution in 14 plant and animal higher taxa from alpine and upper-montane zones in an unexplored corner of the Maloti-Drakensberg. METHODS : Using standardised methods such as Sherman traps, acoustic monitoring, bird timed counts, pitfall traps, sweep nets, aquatic SASS5 kick-nets, timed searches and herbarium collections, we assessed elevational zonation of flowering plant and selected invertebrate and vertebrate diversity in the Witsieshoek Community Conservation Area (WCCA). RESULTS : GBIF records complemented expert BioBlitz data, together enumerating 1 216 plant, vertebrate and invertebrate species along an elevation gradient from 1 760 m to 3 145 m at WCCA. Birds, insects and plants showed concordant beta diversity patterns from BioBlitz and GBIF data: high turnover compared to nestedness in more sedentary insects and plants, and the opposite in more mobile birds (GBIF data not available for bats). Although identifications are ongoing, 17% of species or morphospecies were exclusively recorded in the alpine zone, including 82 species of plants and 92 of animals. CONCLUSION : Alpine endemics are vulnerable to the ‘escalator to extinction’ process due to climate change. Surveys of under-explored alpine hotspots should be prioritised, drawing on mountain tourism-based citizen science. We advocate an ecotourism- and community-centred, restoration and rewilding approach for this strategic and biodiverse community conservation area.
A South African perspective on the 2023 IPBES Thematic Assessment Report on Invasive Alien Species and their control
Wilson, John R.U.; Faulkner, Katelyn T.; Winzer, L. Fernandez; Mcculloch-Jones, E.J.; Van Wilgen, B.W.; Blanchard, R.; Carbutt, C.; Dechoum, M.S.; Foxfroft, L.C.; Greve, Michelle; Hui, C.; Ivey, P.; Kgope, B.; Kumschick, S.; Le Roux, Peter Christiaan; Masehela, T.S.; Measey, J.; Miza, S.; Mogapi, T.; Mpikanisi, F.; Mulaudzi, L.; Nelukalo, K.; Nnzeru, L.; Nsikani, M.M.; Pattison, Z.; Rahlao, S.J.; Richardson, D.M.; Robinson, T.B.; Shackleton, R.T.; Tererai, F.; Tshidada, N.; Tshikhudo, P.P.; Tshivhandekano, I.; Wanjau, K.; Ziller, S.R.; Zengeya, Tsungai Alfred (South African National Biodiversity Institute, 2025-11-06)
BACKGROUND : Biological invasions are a major threat to biodiversity and sustainable development. A global assessment of biological invasions released in 2023 by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), concluded that while invasions ‘…cause dramatic and, in some cases, irreversible changes…’ they can be ‘…overcome through a context-specific integrated governance approach’. AIM : Here we evaluate insights from the IPBES assessment in the context of South Africa and explore how these insights could inform the development of a national policy and strategy to address biological invasions. RESULTS : Trends and status of biological invasions in South Africa are similar to those seen globally, but there are some distinct local nuances. South Africa has: 1) a long history of invasions with negative impacts caused especially by invasive trees and freshwater fishes, whilst invasive marine invertebrates have transformed large parts of the coastline; 2) a long history of control (biological control was first implemented in 1913) with large-scale, state-run invasive species management programmes currently in place; 3) a comprehensive regulatory system (e.g., there is provision for beneficial invasive species to be used under permits); 4) relatively high levels of awareness and engagement (at least among some stakeholder groups); and 5) a well-connected community of practice. DISCUSSION : Efforts to limit introductions (intentional or unintentional) are difficult given South Africa’s extensive and porous borders and the pressing need to increase trade and travel. Regulatory and implementation efforts aimed at prevention are improving, with the newly established Border Management Authority aiming to integrate biosecurity interventions at ports of entry. Such integrated governance is, we argue, needed more broadly if affected sectors, society groups and stakeholders are to be effectively included in decision-making and management. A more systematic flow of information from observation to action is essential, as is better feedback between research, policy and implementation at all scales. Biological invasions will continue to pose threats, but many of these can be effectively mitigated through focussed interventions. Co-ordinating such interventions in the context of other cross-cutting global change challenges and initiatives is a cost-effective way of protecting and improving livelihoods, human health, quality of life and biodiversity.