Samual T. Williams
University of Venda
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Featured researches published by Samual T. Williams.
PeerJ | 2016
Samual T. Williams; Kathryn S. Williams; Christoffel J. Joubert; Russell A. Hill
Large carnivores are decreasing in number due to growing pressure from an expanding human population. It is increasingly recognised that state-protected conservation areas are unlikely to be sufficient to protect viable populations of large carnivores, and that private land will be central to conservation efforts. In 2000, a fast-track land reform programme (FTLRP) was initiated in Zimbabwe, ostensibly to redress the racial imbalance in land ownership, but which also had the potential to break up large areas of carnivore habitat on private land. To date, research has focused on the impact of the FTLRP process on the different human communities, while impacts on wildlife have been overlooked. Here we provide the first systematic assessment of the impact of the FTLRP on the status of large carnivores. Spoor counts were conducted across private, resettled and communal land use types in order to estimate the abundance of large carnivores, and to determine how this had been affected by land reform. The density of carnivore spoor differed significantly between land use types, and was lower on resettlement land than on private land, suggesting that the resettlement process has resulted in a substantial decline in carnivore abundance. Habitat loss and high levels of poaching in and around resettlement areas are the most likely causes. The FTLRP resulted in the large-scale conversion of land that was used sustainably and productively for wildlife into unsustainable, unproductive agricultural land uses. We recommended that models of land reform should consider the type of land available, that existing expertise in land management should be retained where possible, and that resettlement programmes should be carefully planned in order to minimise the impacts on wildlife and on people.
Royal Society Open Science | 2017
Samual T. Williams; Kathryn S. Williams; Bradley P. Lewis; Russell A. Hill
Data on the population dynamics and threats to large carnivores are vital to conservation efforts, but these are hampered by a paucity of studies. For some species, such as the leopard (Panthera pardus), there is such uncertainty in population trends that leopard trophy hunting has been banned in South Africa since 2016 while further data on leopard abundance are collected. We present one of the first assessments of leopard population dynamics, and identify the key threats to a population of leopards outside of protected areas in South Africa. We conducted a long-term trap survey between 2012 and 2016 in the Soutpansberg Mountains, and drew on a previous estimate of leopard population density for the region from 2008. In 24 sampling periods, we estimated the population density and assessed population structure. We fitted eight leopards with GPS collars to assess threats to the population. Leopard population density declined by 66%, from 10.73 to 3.65 leopards per 100 km2 in 2008 and 2016, respectively. Collared leopards had a high mortality rate, which appeared to be due to illegal human activity. While improving the management of trophy hunting is important, we suggest that mitigating human–wildlife conflict could have a bigger impact on carnivore conservation.
Journal of Applied Ecology | 2017
Ross T. Pitman; Julien Fattebert; Samual T. Williams; Kathryn S. Williams; Russell A. Hill; Luke T. B. Hunter; Hugh S. Robinson; John Power; Lourens H. Swanepoel; Rob Slotow; Guy Balme
Understanding resource selection and quantifying habitat connectivity are fundamental to conservation planning for both land-use and species management plans. However, datasets available to management authorities for resource selection and connectivity analyses are often highly limited and fragmentary. As a result, measuring connectivity is challenging, and often poorly integrated within conservation planning and wildlife management. To exacerbate the challenge, scale-dependent resource use makes inference across scales problematic, resource use is often modelled in areas where the species is not present, and connectivity is typically measured using a source-to-sink approach, erroneously assuming animals possess predefined destinations. Here, we used a large carnivore, the leopard Panthera pardus, to characterise resource use and landscape connectivity across a vast, biodiverse region of southern Africa. Using a range of datasets to counter data deficiencies inherent in carnivore management, we overcame methodological limitations by employing occupancy modelling and resource selection functions across three orders of selection, and estimated landscape-scale habitat connectivity – independent of a priori source and sink locations – using circuit theory. We evaluated whether occupancy modelling on its own was capable of accurately informing habitat connectivity, and identified conservation priorities necessary for applied management. We detected markedly different scale-dependent relationships across all selection orders. Our multi-data, multi-scale approach accurately predicted resource use across multiple scales and demonstrates how management authorities can more suitably utilise fragmentary datasets. We further developed an unbiased landscape-scale depiction of habitat connectivity, and identified key linkages in need of targeted management. We did not find support for the use of occupancy modelling as a proxy for landscape-scale habitat connectivity and further caution its use within a management context. Synthesis and applications. Maintaining habitat connectivity remains a fundamental component of wildlife management and conservation, yet data to inform these biological and ecological processes are often scarce. We present a robust approach that incorporates multi-scale fragmentary datasets (e.g. mortality data, permit data, sightings data), routinely collected by management authorities, to inform wildlife management and land-use planning. We recommend that management authorities employ a multi-data, multi-scale connectivity approach—as we present here—to identify management units at risk of low connectivity.
bioRxiv | 2018
Daan Loock; Samual T. Williams; Kevin W. Emslie; Wayne S. Matthews; Lourens H. Swanepoel
As the environment becomes increasingly altered by human development, the importance of understanding the ways in which wildlife interact with modified landscapes is becoming clear. Areas such as industrial sites are sometimes presumed to have little conservation value, but many of these sites have areas of less disturbed habitats around their core infrastructure, which could provide ideal conditions to support some species, such as mesocarnivores. We conducted the first assessments of the density of serval (Leptailurus serval) at the Secunda Synfuels Operations plant, South Africa. We ran three camera trap surveys to estimate serval density using a spatially explicit capture recapture framework. Servals occurred at densities of 76.20-101.21 animals per 100 km2, which are the highest recorded densities for this species, presumably due to high abundance of prey and the absence of persecution and/or competitor species. Our findings highlight the significant conservation potential of industrialised sites, and we suggest that such sites could help contribute towards meeting conservation goals.
Ticks and Tick-borne Diseases | 2018
Anna H. Baauw; Heloise Heyne; Kathryn S. Williams; Russell A. Hill; Ignas M. A. Heitkönig; Samual T. Williams
Ixodid ticks (Acari: Ixodidae) are important disease vectors for large carnivores, but the composition of the tick communities that parasitize carnivores is poorly understood. We collected ticks from leopards (Panthera pardus) and brown hyenas (Hyaena brunnea) in the Soutpansberg Mountains, South Africa, to determine which species feed on these carnivores. We identified a total of eight tick species belonging to six genera, and recorded Ixodes neitzi and Hyalomma rufipes on P. pardus for the first time.
Science | 2018
Jamshid Parchizadeh; Samual T. Williams
Millions of migratory birds arrive each autumn at Fereydunkenar International Wetland (FIW) in Iran due to its rich ecosystem ([ 1 ][1]). FIW comprises 5427 ha located in the southern Caspian Sea and includes Fereydunkenar, Sorkhrud, and Azbaran lagoons, which are designated as Wetlands of
Current Biology | 2018
Jamshid Parchizadeh; Fraser Shilling; Maria Gatta; Roberta Bencini; Ali Turk Qashqaei; Mohammad Ali Adibi; Samual T. Williams
Wildlife-vehicle collisions are an important cause of mortality for many animal species. They also prove extremely detrimental to the critically endangered Asiatic cheetah (Acinonyx jubatus venaticus) [1,2]. One to two Asiatic cheetahs are killed by vehicles on Irans roads annually [3,4]. As such, the Asiatic cheetah could be the next charismatic felid subspecies to go extinct in the near future [5]. We identified one statistically-significant cluster of cheetah-vehicle collisions on the Shahroud-Sabzevar Highway (SSH), in Semnan Province. Because of the extremely small population of cheetahs and the corresponding difficulty of finding statistically-significant clusters, we propose that every single cheetah-vehicle collision should be considered important. We further recommend that wildlife underpasses and associated fencing be constructed in areas of previous cheetah-vehicle collisions.
bioRxiv | 2017
Jamshid Parchizadeh; Maria Gatta; Roberta Bencini; Ali Turk Qashqaei; Mohammad Ali Adibi; Samual T. Williams
Wildlife-vehicle collisions are an important cause of mortality for many species, and the number of collisions is expected to grow rapidly as the global road network quickly expands over the next few decades. Wildlife-vehicle collisions also have the potential to be extremely detrimental to small wildlife populations, such as the critically endangered Asiatic cheetah (Acinonyx jubatus venaticus), with only 43 individuals remaining in the wild. We assessed the spatial distribution of road mortalities between 2004 and 2016 to identify roadkill hotspots involving Asiatic cheetahs in Iran using network kernel density estimation. A total of sixteen cheetah fatalities due to wildlife-vehicle collisions were recorded, and we identified six road fragments as roadkill hotspots. Efforts to reduce wildlife-cheetah collisions should be targeted in the densest hotspots. We review the options available to achieve this, and we recommend a strategic shift away from the ineffective warning signage currently used, and instead suggest adopting an evidence-based approach focusing on installing wildlife crossing structures in conjunction with fencing in roadkill hotspots. These measures will help to enhance the conservation status of the Asiatic cheetah, as the current high level of mortality of Asiatic cheetahs on Iran’s roads could have potentially dramatic impacts on this critically endangered subspecies.
Conservation Letters | 2017
Ross T. Pitman; Julien Fattebert; Samual T. Williams; Kathryn S. Williams; Russell A. Hill; Luke T. B. Hunter; Rob Slotow; Guy Balme
Archive | 2011
Samual T. Williams