Published Research

Does trophy hunting matter to long‐term population trends in African herbivores of different dietary guilds?; other Commentaries on this paper: Hunting tourism and animal conservation and the Response from the authors: The assessment of the role of trophy hunting in wildlife conservation.

Studies on the effects of off-road driving on soils were conducted in the Makuleke Contractual Park of the Kruger National Park. The studies were conducted on three different soils with different textures and soil compactibilities. Traffic pressure was applied with a game drive vehicle loaded with 10 sand bags, each weighing 70 kg, plus the driver. This gave a total vehicle mass of 3795 kg, simulating a vehicle fully laden with tourists. The results of the study reported here included comparing of the effects of four different tyre pressures on the root area distribution below each tyre pressure. At all sites, root density fractions under the tracks were reduced significantly at all tyre pressures, compared with the control values. Results indicated that root penetration percentage and root area distribution were reduced drastically as tyre pressure increased. Our work reaffirms previous research showing that higher tyre pressures cause higher sub-soil compaction than lower tyre pressures. Thus, driving with lower tyre pressures when driving off-road should be considered when developing management strategies for off-road driving in wildlife protected areas.

This study investigated the relationship between environmental impact and eco-tourists’ perceptions of it, in the Makuleke Contractual Park(MCP), Kruger National Park. The emphasis was on environmental damage caused by game drive vehicles driving off-road. The study wasbased on 112 completed visitor questionnaires, with an equal number of foreign and local tourists who completed the questionnaire. Tourists had significantly variable demographic characteristics. Tourists’ environmental perceptions varied, but a significant majority of tourists agreed that off-road driving has a negative impact on the environment. Contradictions exist between what they know or perceive as being damaging and what they prefer to act on. Results indicate a need for improved visitor education on the possible negative impacts of demands for off-road driving.Visitors were required to complete the first section regarding their demographics, followed by indicating their perceptions in sections two to five of the questionnaire on Likert-type scales. The questions were structured in such a way that it would be possible to draw correlations between the tourists’ environmental values and their perceptions on off-road driving.

Studies on the effects of off-road driving on soils were conducted in the Makuleke Contractual Park of the Kruger National Park. The studies were conducted on three different soils with different textures and soil compactibilities. Traffic pressure was applied with a game drive vehicle loaded with 11 sand bags, each weighing 70 kg. This gave a total vehicle mass of 3,795 kg, simulating a vehicle fully laden with tourists. The study included: (i) comparing of the effects of four different tyre pressures; (ii) comparing the effects of 1–3 vehicle passes over the same tyre tracks; (iii) comparison of traffic effects under dry and wet soil moisture conditions, on soil compaction, respectively. After each pass penetration resistances were measured (a) on the tyre tracks, (b) between the tyre tracks and (c) at different distances outside the tyre tracks. As expected, vehicular traffic caused soil compaction below the wheel tracks. Lower tyre pressures caused less compaction than higher tyre pressures. Fewer vehicle passes also caused less compaction than more passes on the same tracks, but most compaction occurred during the first pass. Thus, driving on the same tracks more than once is less damaging than driving once on different tracks. Controlled traffic should be considered when developing management strategies for off-road driving in wildlife protected areas.

Findings during reconnaissance studies in a private concession area in the north-eastern part of the Serengeti National Park, illustrated also in photographic evidence, indicate that eco-tourism and Maasai livestock do not co-exist well together. For the Maasai tribe in Kenya and Tanzania livestock (cattle, sheep and goats) play, and have for thousands of years played, a very important role, as they depend on it for food and livelihoods. However, for the Maasai, their livestock are more than just food and a livelihood, it is everything: including culture, ritual, wealth and pride. The pastoralist Maasai are brilliant cattle-herders. A person's entire life revolves around his cattle. However, when mixed with eco-tourism there exists the possibility of conflict. Eco-tourism depends on wildlife and tourists. Evidence also indicates that cattle and wildlife (especially wildlife grazers), migrate and feed differently, with consequences to the sustainability of soil and vegetation. The photographic evidence shows that the soil is damaged irreversibly in some cases, and this will have negative consequences for the grass cover and food for the grazers (wildlife and cattle).

The accuracy of predictive models (also known as mechanistic or causal models) of animal responses to climate change depends on properly incorporating the principles of heat transfer and thermoregulation into those models. Regrettably, proper incorporation of these principles is not always evident. We have revisited the relevant principles of thermal physiology and analysed how they have been applied in predictive models of large mammals, which are particularly vulnerable, to climate change. We considered dry heat exchange, evaporative heat transfer, the thermoneutral zone and homeothermy, and we examined the roles of size and shape in the thermal physiology of large mammals.

Woody encroachment can lead to a complete switch from open habitats to dense thickets, and has the potential to greatly alter the biodiversity and ecological functioning of grassy ecosystems across the globe. Plant litter decomposition is a critical ecosystem process fundamental to nutrient cycling and global carbon dynamics, yet little is known about how woody encroachment might alter this process. We com-pared grass decay rates of heavily encroached areas with adjacent non encroached open areas in a semi-arid South African savanna using litterbags that allowed or excluded invertebrates. We also assessed the effect of woody encroachment on the activity of termites— dominant decomposer organisms in savanna systems. We found a significant reduction in decomposition rates within encroached areas, with litter taking twice as long to decay compared with open savanna areas. Moreover,invertebrates were more influential on grass decomposition in open areas and termite activity was substantially lower in encroached areas, particularly during the dry season when activity levels were reduced to almost zero. Our results suggest that woody encroachment created an unfavourable environment for invertebrates, and termites in particular, leading to decreased decomposition rates in these areas. We provide the first quantification of woody encroachment altering the functioning of African savanna ecosystems through the slowing of above ground plant decomposition. Woody encroachment is intensifying across the globe, and our results suggest that substantial changes to the carbon balance and biodiversity of grassy biomes could occur.

As a non-invasive monitoring method camera traps are noted as being an effective, accurate and rapid means of compiling species richness estimates of medium to large terrestrial mammals. However, crucial elements of camera trap survey design are rarely empirically addressed, which has raised the need for both a standardised and optimised camera trapping protocol. Our study confirms that an appropriate camera placement buffer and targeting areas of animal activity, contributes to more complete species richness estimates as well as significantly reducing the rate of false trigger events. However, attaining the required survey effort in terms of camera days was the most important factor in providing accurate species richness estimates. Our results suggest that reliable estimates of species richness can be achieved in open scrubland when cameras are spaced 1 × 1 km apart and left in the targeted area until a survey effort of a 1000 camera days is realised.

Context Conservation planning for biodiversity within anthropogenic landscapes is crucial given the rate of habitat conversion and human population growth. Investigating anthropogenic impacts on the persistence of biodiversity is key to management decision-making. Objectives We investigated the influence of protected areas (PAs), agriculture and urbanisation on the occupancy of mammal communities in an anthropogenic matrix containing indigenous forest fragments of the Coastal Belt of southern KwaZulu-Natal, South Africa. Methods We integrated camera-trap mammal data, land-use and human population density within occupancy models, and compared occupancy of individual species across the land-use mosaic. Results We modelled occupancy of seven mammal species with sufficient naïve occupancy (> 0.20, range 0.25–0.87). The occupancy of Philantomba monticola was positively influenced by human population size and was higher within urban areas compared with PAs. Although human population size positively affected Hystrix africaeaustralis occupancy, it along with Atilax paludinosus had a lower occupancy within urban areas. Tragelaphus scriptus and Potamochoerus larvatus overall had higher and Sylvicapra grimmia had lower occupancies within PAs. Main conclusions Species were variable in their response to the anthropogenic changes in the landscape. For example, occupancy of P. monticola was low within PAs but high in areas where change in land ownership and loss of habitat are threats. For other species, it appeared that the density of infrastructure of the urban landscape, rather than human population density, affected them negatively. However, seasonal differences within different management regimes also provided context-specific influences on occupancy and detectability. We emphasize the importance of natural vegetation patches within anthropogenic landscapes for maintaining native fauna, whilst stressing the value of temporally replicated, multi-species, regional-scale studies when making conservation decisions.

The modification of natural habitats requires behavioural plasticity, which may be challenging for ‘specialist’ species. Quantifying habitat requirements and behavioural responses of specialists to landscape transformation is thus a priority for baseline data to inform conservation practices. Using camera-trap surveys of the forest-dependent Lemon Dove Aplopelia larvata in conjunction with detailed microhabitat-scale covariates, we assessed habitat use during two periods in the year: autumn–winter and spring–summer (which largely encompassed peak breeding). We used occupancy modelling of forest-structural covariates to produce models of the probability of occupancy and detection of Lemon Doves in patches of the Indian Ocean Coastal Belt Forest of South Africa. The average occupancy and detection probability as indicated by the top-performing models was 0.39 ± 0.08 and 0.26 ± 0.05, respectively, during autumn–winter, and 0.37 ± 0.08 and 0.25 ± 0.04, respectively, during spring–summer. Although occupancy and probability of detection remained relatively constant between seasons, there was seasonal variation in the influence of individual covariates for both measures. The overall trend of positive influences on Lemon Dove occupancy was that of complex and diverse habitat structures and high plant species richness. The specific covariates that influenced occupancy positively during spring–summer may reflect the ecological requirements for nestling provisioning for both dietary needs and an avoidance of potential disturbance. Thus, while Lemon Doves may be less habitat-specific during autumn–winter, conservation management plans for safeguarding the breeding success of the species are advised to ensure adequate protection of large forest patches with complex and diverse interior structures and minimal disturbance