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Volume 44, Issue 2, 2014
Replacing grasslands with pine plantations on the Karkloof Plateau : the edge effects on downslope forest understorey birdsAuthor Gerard MalanSource: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 99 –114 (2014)More Less
The aim of this study was to examine if and how the exposure of indigenous forest edges to flanking exotic pine plantations transform the avian community and forest ecosystem found in the forest periphery. I compared bird diversity indices between forest bordering grassland and forest bordering pine plantation at 10 study locations. At each location, understorey birds were sampled with mist nets at the edge (0m) and progressively deeper into each forest interior in spring and autumn. Crown cover was measured at these sites in autumn. Crown cover decreased from the edge into the forest, more so in forest bordering plantation, and at 60 m was, on average, 18% lower than forest bordering grassland. Furthermore, in forest bordering grassland, bird species richness and total abundance (of individuals) increased with edge distance in both seasons, but in forest bordering plantation, these trends were absent. In addition, in forest bordering plantation, different dominant species were recorded in spring and species only found in this habitat only fed in the forest mid-stratum. I therefore recommend that plantations be planted 15 m from forest edges to prevent perforation and edge-effect loss that will allow the edge and understorey avifauna to function as a natural part of the indigenous Afrotemperate forest patch in South Africa.
The relative importance of trophy harvest and retaliatory killing of large carnivores : South African leopards as a case studySource: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 115 –134 (2014)More Less
There are considerable challenges in the conservation of large carnivores, caused by large area requirements, low reproduction rates and low population densities coupled with their tendency to cause conflict with humans. Trophy hunting is one strategy to increase support for large carnivore conservation. Leopards, Panthera pardus, rank among the most soughtafter trophies in South Africa. However, trophy hunting has been suggested as partly responsible for leopard population declines, and leopards are also killed in retaliatory actions. In this study we used a stochastic population model to evaluate the relative influences of retaliatory killing and trophy harvest on leopard population persistence, and to assess the sustainability of the current leopard trophy harvest in South Africa. There was a stronger effect of variation in retaliatory killing than of harvest on population persistence. Although we found low extinction risks for South African leopards within 25 years, high risks of population declines across a wide range of simulation scenarios call for concern regarding the viability of the South African leopard population. We suggest that conflict mitigation may be more effective in promoting leopard persistence than restricting trophy harvest, and that accurate estimates of retaliatory killing are necessary for assessments of harvest sustainability.
Habitat selection by transient African wild dogs (Lycaon pictus) in northern KwaZulu-Natal, South Africa : implications for range expansionSource: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 135 –147 (2014)More Less
Reintroductions of African wild dogs (Lycaon pictus) in the KwaZulu-Natal Province, through the managed metapopulation approach, promoted a population expansion from one pack in Hluhluwe-iMfolozi Park in 1997 to nine packs in three reserves by 2009. Consequently, the likelihood of dispersing wild dogs leaving their natal ranges from within fenced reserves also increased. Land outside these reserves could potentially be utilized to expand wild dog distribution and provide connectivity between the geographically isolated subpopulations. We used Maximum Entropy Modelling (Maxent) to characterize habitat niche selection of transient wild dogs outside of resident reserves, and to identify potential dispersal linkages between subpopulations. A habitat suitability model indicated four variables (elevation, land cover, road density and human density) best predicted probability of presence for transient wild dogs. Elevation (AUC > 0.80) and land cover (AUC > 0.75) were the two most influential variables when considered independently. Transient wild dogs preferred lower lying locations (130-330ma.s.l.) covered by woodland or bushland; habitat indicative of the preferred prey of wild dogs. Considerable habitat exists for subpopulation linkages; however, the majority of wild dog movements between subpopulations required mitigation of potential or real game or livestock losses. Development of formal linkages and wild dog management between subpopulations will require a sustained approach to improving tolerance towards wild dogs, clarity on financial obligations and management responses to pack and prey population dynamics.
Disturbance and habitat factors in a small reserve : space use by establishing black rhinoceros (Diceros bicornis)Source: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 148 –160 (2014)More Less
Continued persistence of black rhinoceros (Diceros bicornis) will likely depend on the cooperation of many reserves and the application of metapopulation models to manage across reserves. The suitability of any reserve, however, depends on factors that promote and constrain occupancy. Constraining factors, particularly human disturbance, are of concern in small reserves because constraints have potentially greater effects, relative to reserve size, than in large reserves. We investigated landscape use by black rhinos at Zululand Rhino Reserve. South Africa, as a function of elevation, slope, patch type, areas burnt and factors associated with disturbance (distances to nearest water point, human settlement, boundary fence, and roads). Estimated home ranges consistently demonstrated avoidance of human settlements, fragmentation of home ranges and sometimes multi-modal core areas. Resource selection functions confirmed that use of areas increased with greater distance from human settlements (log-odds = 1.3831 ± 0.4623 [95% CI]) and from perennial water points (2.2859 ± 0.8261). Space use was greater for thicket (1.0072 ± 0.5775) and closed savanna (0.8656 ± 0.6153) than for other patch types. Managers who plan reintroductions of black rhinos should consider availability of forage and cover, disturbances that might restrict access to resources, and effects of reserve size on those disturbances.
Source: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 161 –166 (2014)More Less
Wildlife-proof fencing is increasing in extent as a result of the growing wildlife industry on private lands in southern Africa. In environments where such fences hinder the movements of free-ranging wildlife, the provision of artificial passageways can restore connectivity for some species. We tested the use of 49 discarded car tyres as wildlife passageways along the border of a Namibian wildlife farm. Tyres were installed into a wildlife-proof fence to reduce regular warthog (Phacochoerus africanus) damage to the fence and to provide connectivity and dispersal opportunities for selected indigenous wildlife species between adjacent farmland properties. The total cost for all 49 tyre installations was USD 252, which is significantly cheaper than daily fence patrols and maintenance. In addition, one tyre was monitored specifically for large carnivore activity with a motion-triggered camera trap (n = 96 trap days between August and December 2010). Eleven mammalian species used the tyre as a passageway and both cheetahs (Acinonyx jubatus) and leopards (Panthera pardus) made regular and repeated use of the tyre. Nine independent recordings of cheetahs, representing seven individuals, were made. One leopard was photographed four times. The suitability of discarded tyres as cost-effective artificial wildlife passageways for a range of mammalian species is stressed.
A review of the anthropogenic threats faced by Temminck's ground pangolin, Smutsia temminckii, in southern AfricaSource: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 167 –178 (2014)More Less
Throughout its range, Temminck's ground pangolin, Smutsia temminckii, is becoming increasingly threatened, predominantly as a result of anthropogenic pressures. This species is currently listed as Vulnerable in South Africa and Least Concern globally, although many assessment criteria are data deficient and thus hamper an accurate assessment of its actual status. Current knowledge of the threats faced by Temminck's ground pangolin largely stem from a handful of ecological studies and ad hoc observations. Here we synthesize data on the known threats faced by this species in southern Africa and highlight a number of new threats not previously recognized. The main threats faced by this species include electrocution on electrified fences, the traditional medicine (muthi) trade, habitat loss, road mortalities, capture in gin traps, and potentially poisoning. Electrocutions arguably pose the greatest threat and mortality rates may be as high as one individual per 11 km of electrified fence per year. However, the magnitude of the threat posed by the muthi trade has not yet been quantified. Most southern African countries have adequate legislation protecting this species, although implementation is often lacking and in some instances the imposed penalties are unlikely to be a deterrent. We propose mitigating actions for many of the identified threats, although further research into the efficacy of these actions, and the development of additional mitigating procedures, is required.
Source: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 179 –188 (2014)More Less
The carcass yield and dress out percentage of the common warthog (Phacochoerus africanus) was investigated as influenced by season and sex. Season did not have a significant impact on carcass weight (P = 0.64) and dress out percentages (P = 0.28) of adult warthogs (n = 46). Males (n = 21) had heavier carcasses (35.24 kg ± 2.59) than females (n = 25) (27 kg ± 0.96) (P = 0.03) and had a higher dress out percentage (57.14% ± 0.91) than females (52.14% ± 0.91) (P < 0.01).Due to the imbalance in sampled populations age was not included as a variable in the final analyses. Warthogs have a favourable carcass yield and can be utilized for commercial game meat production.
Distribution and numbers of breeding cormorants (Phalacrocoracidae) and herons (Ardeidae) in Lesotho : short communicationAuthor Grzegorz KopijSource: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 189 –192 (2014)More Less
Owing to a scarcity of larger natural wetlands, waterbirds are, in general, uncommon in Lesotho (Osborne & Tigar 1990; Bonde 1992; Hockey et al. 2005). Besides Anseriformes, the most characteristic species in this group are represented by Ciconiiformes and Pelecaniformes. In Lesotho, Reed Cormorant (Phalacrocorax africanus), White-breasted Cormorant (Phalacrocorax lucidus), Cattle Egret (Bubulcus ibis), Black-headed Heron (Ardea melanocephala), Purple Heron (Ardea purpurea) and Black-crowned Night Heron (Nycticorax nycticorax) have been recorded breeding (Osborne & Tigar 1990; Bonde 1992). Other members of Ciconiifomes, such as the Hamerkop (Scopus umbretta), Black Stork (Ciconia nigra) and Southern Bald Ibis (Geronticus calvus) are not regarded as waterbirds, but do breed in Lesotho (Osborne & Tigar 1990; Bonde 1992).
From a conservation perspective, it is important and relatively easy to survey colonially breeding waterbirds, i.e. herons and cormorants. Since these colonies are occupied annually, their status can be monitored on a regular basis (Sutherland 1996, 2000). However, only the distribution and abundance of the Cattle Egret has been thoroughly investigated in Lesotho (Kopij 2008). The purpose of this study was to determine the status and distribution of all other herons and cormorants breeding in Lesotho.
A note on the population structure of leopards (Panthera pardus) in South Africa : short communicationSource: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 193 –197 (2014)More Less
The leopard (Panthera pardus) occurs throughout Africa and Asia, although their range in Africa has declined by 37% in the last century (Ray et al. 2005). The main factors contributing to the decline in leopard distribution seem to be a combination of habitat destruction, human persecution, and prey depletion (Henschel et al. 2011). These activities have increased habitat fragmentation and can affect leopard behaviour through home range shifts and limited dispersal (Ngoprasert et al. 2007).
Limited dispersal, and hindered gene flow, can decrease genetic variation and increase genetic differentiation in fragmented subpopulations due to inbreeding, genetic drift and selection (Haag et al. 2010). Lowered genetic diversity may in turn cause reduced survival and reproduction success because of increased accumulation of deleterious mutations and increased probabilities in allele loss (Whitlock 2000; Reed & Frankham 2003; Frankham et al. 2004).
Build a bridge and get over it : the effect of bridges over water on terrestrial animal presence : short communicationAuthor Ashley PearcySource: South African Journal of Wildlife Research - 24-month delayed open access 44, pp 198 –201 (2014)More Less
Human infrastructure has resulted in habitat disturbance both inside and outside protected areas (Makki et al. 2013). Infrastructure disturbs habitats through fragmentation, resulting in changes in species composition (Brittingham & Temple 1983; Yahner 1988; Winslow et al. 2000). Roads have been widely studied as causes of habitat fragmentation because they divide the landscape and decrease canopy cover (McLaren et al. 2011). Despite the similarity between bridges and roads as man-made infrastructure, bridges link habitats and can facilitate rather than hinder movement (e.g. Way 2009).
Mapping correlates of parasitism in wild South African vervet monkeys (Chlorocebus aethiops), South African Journal of Wildlife Research 44(1) April 2014 : pp. 56-70 : erratumSource: South African Journal of Wildlife Research - 24-month delayed open access 44 (2014)More Less