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Louis Trichardt, South Africa

Van Langevelde F.,Wageningen University | De Groot C.,Wageningen University | Groen T.A.,University of Twente | Heitkonig I.M.A.,Wageningen University | Gaigher I.,Lajuma Research Center
International Journal of Wildland Fire | Year: 2014

In tropical grasslands and savannas, fire is used to reduce woody vegetation expansion. Woody vegetation in these biomes is often patchily distributed, and micro-climatic conditions can largely vary locally with unknown consequences for fire effects. We hypothesised that (1) fire has higher temperature and maintains high temperatures for a longer period at the windward side than at the leeward side of wooded patches, (2) this difference increases with patch size, (3) fire has a larger effect on woody vegetation at the windward side than at the leeward side of wooded patches and (4) this effect increases with patch size. We planted tree seedlings around wooded patches in a grassland and burnt these plots. We found that fire had a lower temperature and had an elevated temperature for a shorter time period at the leeward side of wooded patches than at the windward side. Also, we found smaller effect of fire on the seedlings at the leeward side. We conclude that patches of woody vegetation can have a large effect on the role of fire in tropical grasslands and savannas. This effect suggests a 'safe zone' for seedlings at the leeward side, which consequently promotes woody vegetation expansion. This paper contributes to understanding of the effect of patchiness of woody vegetation on the role of fire in tropical grasslands and savannas in reducing woody vegetation expansion. © IAWF 2014. Source

Constant N.L.,Durham University | Constant N.L.,Lajuma Research Center | Constant N.L.,University of the West of England | Bell S.,Durham University | And 2 more authors.
Biodiversity and Conservation | Year: 2015

Human–carnivore conflict represents a global problem, negatively impacting carnivore populations and local livelihoods worldwide. Game farming in South Africa has increased introducing a new form of conflict due to predation on game, but is poorly understood. We contribute to this deficit by adopting an interdisciplinary research approach bringing together quantitative and qualitative data with longitudinal engagement with farmers. We assess the impacts, characteristics and management of human–leopard conflict on game and livestock in the Blouberg Mountain Range. Leopards represented 89 % of reported game attacks with the highest number of attacks on impala and 60 % of reported livestock attacks. The economic costs of leopard predation were highest for nyala compared to other game species and the financial cattle and donkey losses represented large economic costs for communal farmers compared to commercial farmers. Both farming communities experienced a reduced sense of wellbeing and for communal farmers, negative spiritual and cultural impacts. The spatial predation risk of game attacks were most affected by increasing distance to water and the risk of predation on livestock attacks increased further away from villages. Livestock attacks were associated with seasonal grazing patterns and the erosion of traditional management livestock strategies due to the economic costs of their implementation and the migrant labour system altering management roles in the community. The timing of game attacks by leopards was related to the birthing seasons for game and seasonal changes in water supply. Similarly, temporal patterns on livestock were related to the calving season and land degradation in communal areas. © 2015, The Author(s). Source

Howlett C.,Durham University | Howlett C.,Lajuma Research Center | Setchell J.M.,Durham University | Hill R.A.,Durham University | And 2 more authors.
Behavioral Ecology and Sociobiology | Year: 2014

Prenatal androgens are responsible for sex differences in behaviour and morphology in many species, causing changes in neural structure and function that persist throughout life. Some variation in the expression of behaviour between individuals of the same sex can also be attributed to differences in exposure to prenatal sex hormones. The ratio of the second and fourth digits (2D:4D ratio) is a proposed biomarker for prenatal androgen effects (PAE). Through assessment of 2D:4D ratios, this study aimed to investigate the relationship between inferred PAE and social behaviours in female chacma baboons (Papio ursinus). We validated a new method to measure 2D:4D indirectly using digital photographs and computer-assisted image analysis software. There was a strong correlation between 2D:4D ratio and dominance rank amongst female baboons. Low 2D:4D ratios were associated with high rank, lower submission rates and higher rates of non-contact and contact aggression. This is consistent with the hypothesis that prenatal androgens are linked to the expression of these behaviours in female baboons, although it was not possible to separate the effects of PAE and dominance rank on some rank-related behaviours. The 2D:4D ratio did not correlate with interest in infants or with the rate of affiliative behaviours, possibly because these behaviours are more affected by ovarian hormones in adult life than by PAE. Finally, mean 2D:4D ratios were positively correlated in six mother/infant pairs, consistent with a heritable basis for the 2D:4D ratio in primates. We suggest that PAE contribute significantly to the patterning of social relationships in female primates. © 2014, Springer-Verlag Berlin Heidelberg. Source

Coleman B.T.,Durham University | Coleman B.T.,Lajuma Research Center | Hill R.A.,Durham University | Hill R.A.,Lajuma Research Center
Animal Behaviour | Year: 2014

Spatial variation in predation risk generates a 'landscape of fear', with prey animals modifying their distribution and behaviour in response to this variable predation risk. In systems comprising multiple predators and prey species, a key challenge is distinguishing the independent effects of different predator guilds on prey responses. We exploited the acoustically distinct alarm calls of samango monkeys, Cercopithecus mitis erythrarchus, to create a predator-specific landscape of fear from eagles to assess its impact on space use within mixed regressive-spatial regressive models incorporating data on resource distribution and structural characteristics of the environment. The landscape of fear from eagles was the most significant determinant of samango range use, with no effect of resource availability. The monkeys also selected areas of their range with higher canopies and higher understory visibility, behaviour consistent with further minimizing risk of predation. These results contrast with those of vervet monkeys, Chlorocebus aethiops pygerythrus, at the same site for which the landscapes of fear from leopards and baboons were the most significant determinants of space use. While highlighting that predation risk is a key driver of primate behaviour in this population, the landscapes of fear experienced by samango monkeys and vervet monkeys appear to differ despite exposure to identical predator guilds. This emphasizes the importance of distinguishing between the risk effects of different predators in understanding prey ecology, but also that closely related prey species may respond to these predator-specific risks in different ways. © 2013 The Association for the Study of Animal Behaviour. Source

Grey J.N.C.,Durham University | Grey J.N.C.,Lajuma Research Center | Kent V.T.,Durham University | Hill R.A.,Durham University | Hill R.A.,Lajuma Research Center
PLoS ONE | Year: 2013

Populations of large carnivores can persist in mountainous environments following extensive land use change and the conversion of suitable habitat for agriculture and human habitation in lower lying areas of their range. The significance of these populations is poorly understood, however, and little attention has focussed on why certain mountainous areas can hold high densities of large carnivores and what the conservation implications of such populations might be. Here we use the leopard (Panthera pardus) population in the western Soutpansberg Mountains, South Africa, as a model system and show that montane habitats can support high numbers of leopards. Spatially explicit capture-recapture (SECR) analysis recorded the highest density of leopards reported outside of state-protected areas in sub-Saharan Africa. This density represents a temporally high local abundance of leopards and we explore the explanations for this alongside some of the potential conservation implications. Copyright: © 2013 Chase Grey et al. Source

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