Conservation biology of an apex predator in the Anthropocene : poaching, pastoralism and lions in multi-use landscapes, South-Eastern Africa

Many of the world’s apex predators are experiencing catastrophic declines as a result of competition with humans. Understanding the mechanisms and ecosystem impacts of apex predator declines is a fundamental ecological question crucial to conserving the Earth’s biodiversity and functioning ecosystems. In this thesis I used the African lion Panthera leo, as a model species to investigate the impacts of anthropogenic pressures on the conservation and ecology of an apex predator. Specifically, I investigated the relative and cumulative influences of pastoralism and poaching on lion occurrence, population connectivity, ecological role, space use, prey selection and viability across a 73 000 km2 multi-use landscape in southern Africa. Using landscape occupancy spoor surveys, I tested the hypotheses that lions were most limited by either interference or by exploitative competition with humans and identified thresholds of lion tolerance to human activities. My results showed that lions occupied only a fraction of the landscape and were limited by a combination of interference and exploitative competition with humans. Interference competition with pastoralism however was the biggest driver limiting lion occupancy, creating a clear disturbance threshold for lions cumulating in their near complete loss from the landscape. I employed call-up surveys, pride monitoring and mortality analysis to investigate the numerical impacts of anthropogenic pressures on the viability of a lion sub-population. I found that persecution by pastoralists was the greatest source of lion mortalities across the landscape. However, the targeted poaching of lions for body parts had emerged as the greatest threat to lions in a nominally protected National Park where I documented a steep population decline and collapse of lion prides. I used GPS tracking and diet analysis of lions at the human-wildlands interface to test if lions foraged optimally or were constrained by competition with humans. I fount that individual lions appeared to select for prey and habitat optimally, while also showing some level of risk avoidance towards anthropogenic pressures. I then considered landscape resistances to test if sink habitats may provide connectivity between sources or act as ecological traps. I found that potential connectivity for lions between the region’s two source populations was limited by a loss of habitat and prey. Furthermore, the impacts of by-catch in snares risked transforming the few remaining potential conservation corridors into ecological traps. Finally, I examined interactions between lions and syntopic mesopredators across gradients of anthropogenic pressures to test if the functional role of lions was affected by human pressures. I found that lions showed limited suppression of mesopredators, however, anthropogenic pressures increased lion’s interactions with syntopic predators. As an apex predator, lions have evolved limited capacity to mitigate top-down competitive pressures, however, like many of the world’s apex predators, they are becoming increasingly limited by anthropogenic pressures. This study provides a predictive understanding of an apex predator’s ecological responses to top-down anthropogenic pressures which can be applied globally to the question of conservation in the Anthropocene

Trophic scaling and occupancy analysis reveals a lion population limited by top-down anthropogenic pressure in the Limpopo National Park, Mozambique

The African lion (Panthera Leo) has suffered drastic population and range declines over the last few decades and is listed by the IUCN as vulnerable to extinction. Conservation management requires reliable population estimates, however these data are lacking for many of the continent’s remaining populations. It is possible to estimate lion abundance using a trophic scaling approach. However, such inferences assume that a predator population is subject only to bottom-up regulation, and are thus likely to produce biased estimates in systems experiencing top-down anthropogenic pressures. Here we provide baseline data on the status of lions in a developing National Park in Mozambique that is impacted by humans and livestock. We compare a direct density estimate with an estimate derived from trophic scaling. We then use replicated detection/nondetection surveys to estimate the proportion of area occupied by lions, and hierarchical ranking of covariates to provide inferences on the relative contribution of prey resources and anthropogenic factors influencing lion occurrence. The direct density estimate was less than 1/3 of the estimate derived from prey resources (0.99 lions/100 km2 vs. 3.05 lions/100 km2). The proportion of area occupied by lions was Y= 0.439 (SE = 0.121), or approximately 44% of a 2 400 km2 sample of potential habitat. Although lions were strongly predicted by a greater probability of encountering prey resources, the greatest contributing factor to lion occurrence was a strong negative association with settlements. Finally, our empirical abundance estimate is approximately 1/3 of a published abundance estimate derived from opinion surveys. Altogether, our results describe a lion population held below resource-based carrying capacity by anthropogenic factors and highlight the limitations of trophic scaling and opinion surveys for estimating predator populations exposed to anthropogenic pressures. Our study provides the first empirical quantification of a population that future change can be measured against.KTE and LA were supported by the May and Stanley Smith Trust, The Wipplinger KL Bursary Found, Wilderness Wildlife Trust and Canada National Student Grants.http://www.plosone.orgam201

Use of site occupancy models for targeted monitoring of the cheetah

The cheetah Acinonyx jubatus has suffered dramatic range contractions and population declines as a result of habitat degradation, prey depletion and conflict with humans. Of further concern is that many of Africa’s remaining cheetah populations persist in human-dominated and highly fragmented landscapes, where their ecology is poorly understood and population data are lacking. Presence–absence surveys may be a practical means to collect these data; however, failing to account for detection error can lead to biased estimates and misleading inferences; potentially having deleterious consequences for species conservation. The goal of this study was to identify how an occupancy modelling technique that explicitly accounts for detectability could be used for quantifying cheetah status in humanimpacted landscapes. Replicated camera-trap and track surveys of 100-km2 sample units were used to estimate the proportion of area occupied by cheetahs and to determine the survey effort required to inform conservation planning. Based on our results, 16 km [±standard error (SE) = 12–22] of walking or 193 camera-trap nights (±SE = 141–292) are required to confirm cheetah absence at a given 100-km2 grid cell (with 95% certainty). Accounting for detection resulted in an overall cheetah occurrence estimate of 0.40 (SE = 0.13), which is 16% higher than the traditional presence–absence estimate that ignores detection error. We test a priori hypotheses to investigate factors limiting cheetahs using an occurrence probability model of their preferred prey. The results show that both cheetahs and their prey were strongly negatively influenced by human settlements. Our study provides an unbiased estimate of occurrence that can be used to compare status across different sites and as a basis for long-term monitoring. Based on our results, we suggest that track and/or camera-trap surveys coupled with site occupancy models may be useful for targeted monitoring of cheetahs across their distribution.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-7998hb201

Evidence for a resident population of cheetah in the Parque Nacional do Limpopo, Mozambique

Transboundary protected areas may be important for the conservation of large African carnivores because these species require large tracts of habitat to maintain viable population numbers and gene flow. Cheetah (Acinonyx jubatus Schreber, 1775), is a species that may benefit from transboundary conservation agreements. It occurs at naturally low population densities, makes use of large home ranges, and disperses over long distances, thus requiring large tracts of suitable habitat to maintain viable population numbers. Here we present the first scientific evidence of a breeding population of cheetah in Parque Nacional do Limpopo (PNL), Mozambique. We obtained data from camera-traps deployed during occupancy surveys conducted from 9 September 2011 to 31 August 2012 over a 3400 km2 study area located within the central third of PNL. These results highlight the importance of the Greater Limpopo Transfrontier Park (GLTFP) to the overall conservation of cheetah in Africa, and the potential value of transboundary protected areas for the conservation of wide-roaming terrestrial mammals.University of Pretoria, the Wilderness Trust and CIB

Evidence for a resident population of cheetah in the Parque Nacional do Limpopo, Mozambique

Transboundary protected areas may be important for the conservation of large African carnivores because these species require large tracts of habitat to maintain viable population numbers and gene flow. Cheetah (Acinonyx jubatus Schreber, 1775), is a species that may benefit from transboundary conservation agreements. It occurs at naturally low population densities,makes use of largehomeranges, and disperses over long distances, thus requiring large tracts of suitable habitat to maintain viable population numbers. Here we present the first scientific evidence of a breeding population of cheetah in Parque Nacional do Limpopo (PNL), Mozambique. We obtained data from camera-traps deployed during occupancy surveys conducted from 9 September 2011 to 31 August 2012 over a 3400 km2 study area located within the central third of PNL. These results highlight the importance of the Greater Limpopo Transfrontier Park (GLTFP) to the overall conservation of cheetah in Africa, and the potential value of transboundary protected areas for the conservation of wide-roaming terrestrial mammals.The University of Pretoria and the Wilderness Trusthttp://www.sawma.co.za/am201

Rhino poaching may cause atypical trophic cascades

Current anthropogenic pressures drive the widespread loss of apex consumers where the effects of their removal from a system may cascade through lower trophic levels, with unanticipated impacts (Estes et al. 2011; Ripple et al. 2014). Similarly, the observed global decline in large herbivores has complex outcomes for ecosystem functioning (Ripple et al. 2015). Key to predicting and understanding the consequences of declines in both these guilds has been the concept of ecological cascades. Thus, hypothesizing ecological pathways and species’ interactions is an important first step in forecasting ecological responses to changes in the abundance and distribution of both apex predators and large herbivores. We raise the question of whether the recent surge in poaching of white rhinoceros (Ceratotherium simum) and, to a lesser extent, the less abundant black rhinoceros (Diceros bicornis) in the Kruger National Park, South Africa, is providing the ingredients for an atypical cascade – one in which the mechanisms include an artificial enhancement rather than reduction of apex predators. We further hypothesize that this atypical trophic cascade could act synergistically with another anthropogenic pressure, the related poaching of lions (Panthera leo) for body parts coveted by rhino poachers, and subsistence poaching of wild meat in the adjoining Limpopo National Park, Mozambique, leading to the creation of an “ecological trap” (where species mistakenly respond to environmental cues that no longer match habitat quality) for an endangered species.This is the publisher’s final pdf. The article is copyrighted by the Ecological Society of America and published by John Wiley & Sons, Inc. It can be found at: http://esajournals.onlinelibrary.wiley.com/hub/journal/10.1002/%28ISSN%291540-9309

Saving the world’s terrestrial megafauna

From the late Pleistocene to the Holocene, and now the so called Anthropocene, humans have been driving an ongoing series of species declines and extinctions (Dirzo et al. 2014). Large-bodied mammals are typically at a higher risk of extinction than smaller ones (Cardillo et al. 2005). However, in some circumstances terrestrial megafauna populations have been able to recover some of their lost numbers due to strong conservation and political commitment, and human cultural changes (Chapron et al. 2014). Indeed many would be in considerably worse predicaments in the absence of conservation action (Hoffmann et al. 2015). Nevertheless, most mammalian megafauna face dramatic range contractions and population declines. In fact, 59% of the world’s largest carnivores (≥ 15 kg, n = 27) and 60% of the world’s largest herbivores (≥ 100 kg, n = 74) are classified as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List (supplemental table S1 and S2). This situation is particularly dire in sub-Saharan Africa and Southeast Asia, home to the greatest diversity of extant megafauna (figure 1). Species at risk of extinction include some of the world’s most iconic animals—such as gorillas, rhinos, and big cats (figure 2 top row)—and, unfortunately, they are vanishing just as science is discovering their essential ecological roles (Estes et al. 2011). Here, our objectives are to raise awareness of how these megafauna are imperiled (species in supplemental table S1 and S2) and to stimulate broad interest in developing specific recommendations and concerted action to conserve them

β- coefficient estimates for covariates influencing buffalo site use () in order of their summed model weights (∑w).

<p>^* Indicates covariate has robust impact (<i>â</i>±1.96 x SE not overlappling 0).</p

Survey effort in the Limpopo National Park (LNP), Mozambique.

<p>LNP is bounded to the west by the Kruger National Park in South Africa, characterized by formal protection and high wildlife densities, and to the east by the Limpopo River, characterized by agro-pastoralist settlements. Surveyed grid cells (100 km²) and call-up stations shown overlaid across a gradient of landscape types and human impact. Inset map: Location of LNP (dark grey) in relation to the Greater Limpopo Trans-frontier Park (light grey), including the region to the south of LNP which has been recently seperated by a wildlife barrier fence, and to Zimbabwe and South Africa.</p