Wildlife Densities Research Articles

Disease outbreak thresholds emerge from interactions between movement behavior, landscape structure, and epidemiology

Disease models have provided conflicting evidence as to whether spatial heterogeneity promotes or impedes pathogen persistence. Moreover, there has been limited theoretical investigation into how animal movement behavior interacts with the spatial organization of resources (e.g., clustered, random, uniform) across a landscape to affect infectious disease dynamics. Importantly, spatial heterogeneity of resources can sometimes lead to nonlinear or counterintuitive outcomes depending on the host and pathogen system. There is a clear need to develop a general theoretical framework that could be used to create testable predictions for specific host-pathogen systems. Here, we develop an individual-based model integrated with movement ecology approaches to investigate how host movement behaviors interact with landscape heterogeneity (in the form of various levels of resource abundance and clustering) to affect pathogen dynamics. For most of the parameter space, our results support the counterintuitive idea that fragmentation promotes pathogen persistence, but this finding was largely dependent on perceptual range of the host, conspecific density, and recovery rate. For simulations with high conspecific density, slower recovery rates, and larger perceptual ranges, more complex disease dynamics emerged, and the most fragmented landscapes were not necessarily the most conducive to outbreaks or pathogen persistence. These results point to the importance of interactions between landscape structure, individual movement behavior, and pathogen transmission for predicting and understanding disease dynamics.

Quantifying the ecological success of a community-based wildlife conservation area in Tanzania.

In Tanzania, community-based natural resource management of wildlife occurs through the creation of Wildlife Management Areas (WMAs). WMAs consist of multiple villages designating land for wildlife conservation, and sharing a portion of subsequent tourism revenues. Nineteen WMAs are currently operating, encompassing 7% of Tanzania’s land area, with 19 more WMAs planned. The ecological success or failure of WMAs for wildlife conservation has yet to be quantified. We defined ecological success in this case as significantly greater densities of wildlife and significantly lower densities of livestock in the WMA relative to the control site, after the WMA was established. We used 4 years of distance sampling surveys conducted 6 times per year for wild and domestic ungulates to quantify wildlife and livestock densities before and after the establishment and implementation of management efforts at Randilen WMA, relative to a control site on adjacent land of similar vegetation and habitat types. We documented similarity between the sites before WMA establishment, when both sites were managed by the same authority. After WMA establishment, we documented significantly higher densities of resident wildlife (giraffes and dik-diks) and lower densities of cattle in the WMA, relative to the control site, indicating short-term ecological success. Continued monitoring is necessary to determine longer-term effects, and to evaluate management decisions.

Spatial mark-resight models to estimate feral pig population density

Population size is a highly important parameter for wildlife management and conservation. However, its estimation can be challenging when a portion of the population is undetectable. Spatially explicit capture-recapture models are a precise approach to estimate wildlife population density while accounting for imperfect detection, but all animals must be individually identifiable. Spatial mark-resight models (SMR) allow the estimation of population sizes when only some individuals can be identified. This is the case in feral pigs ( Sus scrofa ), where some individuals are recognizable by natural marks. We compared two SMR approaches to estimate feral pig population density: SMR for an unknown number of marked individuals (SMR-UM) and SMR for a known number of marked individuals (SMR-KM). Both approaches are applicable in species with some individuals recognisable by natural marks, such as feral pigs. The SMR-KM is similar to a process of capture-mark-recapture of fewer individuals, which can be used in species with non-recognisable in dividuals (e.g., wild boar, S. scrofa ). First, we fitted a SMR-UM using the complete capture history (individuals/traps/days) for all recognisable individuals (n=33) and the latent capture history (traps-days) for unmarked individuals throughout the entire sampling occasion (66 days). Secondly, we fitted SMR-KM dividing the sampling occasions into two periods: the sighting period (25 days) to identify individuals (n=13), and the resighting period (41 days) in which we used the complete capture and latent capture histories of the marked and unmarked individuals, respectively. We estimated very similar densities with the two approaches for feral pigs in our study area: 13.27 (SD=3.07) (8.12-20.02 95% BCI) and 12.87 (SD=2.21) (8.96–17.59 95% BCI) pigs/km 2 , for SMR-UM and SMR-KM, respectively. Our results indicate that SMR models are an effective tool to monitor feral pig populations, as well as similar non-individually identifiable species, by tagging a small sample of the population.

Improving inference for aerial surveys of bears: The importance of assumptions and the cost of unnecessary complexity.

Obtaining useful estimates of wildlife abundance or density requires thoughtful attention to potential sources of bias and precision, and it is widely understood that addressing incomplete detection is critical to appropriate inference. When the underlying assumptions of sampling approaches are violated, both increased bias and reduced precision of the population estimator may result. Bear (Ursus spp.) populations can be difficult to sample and are often monitored using mark‐recapture distance sampling (MRDS) methods, although obtaining adequate sample sizes can be cost prohibitive. With the goal of improving inference, we examined the underlying methodological assumptions and estimator efficiency of three datasets collected under an MRDS protocol designed specifically for bears. We analyzed these data using MRDS, conventional distance sampling (CDS), and open‐distance sampling approaches to evaluate the apparent bias‐precision tradeoff relative to the assumptions inherent under each approach. We also evaluated the incorporation of informative priors on detection parameters within a Bayesian context. We found that the CDS estimator had low apparent bias and was more efficient than the more complex MRDS estimator. When combined with informative priors on the detection process, precision was increased by >50% compared to the MRDS approach with little apparent bias. In addition, open‐distance sampling models revealed a serious violation of the assumption that all bears were available to be sampled. Inference is directly related to the underlying assumptions of the survey design and the analytical tools employed. We show that for aerial surveys of bears, avoidance of unnecessary model complexity, use of prior information, and the application of open population models can be used to greatly improve estimator performance and simplify field protocols. Although we focused on distance sampling‐based aerial surveys for bears, the general concepts we addressed apply to a variety of wildlife survey contexts.

Pathogen Exposure in Cattle at the Livestock-Wildlife Interface.

Land use is an important driver of variation in human infectious disease risk, but less is known about how land use affects disease risk in livestock. To understand how land use is associated with disease risk in livestock, we examined patterns of pathogen exposure in cattle across two livestock ranching systems in rural Kenya: private ranches with low- to medium-intensity cattle production and high wildlife densities, and group ranches with high-intensity cattle production and low wildlife densities. We surveyed cattle from six ranches for three pathogens: Brucella spp., bovine viral diarrhea virus (BVDV) and Leptospira serovar Hardjo. We found that exposure risk for Leptospira was higher on private ranches than on group ranches, but there was no difference in exposure by ranch type for Brucella or BVDV. We hypothesize that variation in livestock and wildlife contact patterns between ranch types may be driving the pattern observed for Leptospira exposure and that the different relationships we found between exposure risk and ranch type by pathogen may be explained by differences in transmission mode. Overall, our results suggest that wildlife-livestock contact patterns may play a key role in shaping pathogen transmission to livestock and that the magnitude of such effects likely depend on characteristics of the pathogen in question.

Epidemiology of La Crosse Virus Emergence, Appalachia Region, United States.

La Crosse encephalitis is a viral disease that has emerged in new locations across the Appalachian region of the United States. Conventional wisdom suggests that ongoing emergence of La Crosse virus (LACV) could stem from the invasive Asian tiger (Aedes albopictus) mosquito. Efforts to prove this, however, are complicated by the numerous transmission routes and species interactions involved in LACV dynamics. To analyze LACV transmission by Asian tiger mosquitoes, we constructed epidemiologic models. These models accurately predict empirical infection rates. They do not, however, support the hypothesis that Asian tiger mosquitoes are responsible for the recent emergence of LACV at new foci. Consequently, we conclude that other factors, including different invasive mosquitoes, changes in climate variables, or changes in wildlife densities, should be considered as alternative explanations for recent increases in La Crosse encephalitis.

Examining disease prevalence for species of conservation concern using non‐invasive spatial capture–recapture techniques

Summary Non‐invasive techniques have long been used to estimate wildlife population abundance and density. However, recent technological breakthroughs have facilitated non‐invasive estimation of the proportion of animal populations with certain diseases. Giraffes Giraffa camelopardalis are increasingly becoming recognized as a species of conservation concern with decreasing population trajectories across their range in Africa. Diseases may be an important component impacting giraffe population declines, and the emerging ‘giraffe skin disease’ (GSD), characterized by the appearance of wrinkled skin and alopecic lesions on the limbs, neck and chest of infected giraffe, may hinder movement causing increased susceptibility to predation. We examined the prevalence of GSD in Tanzania's Ruaha National Park over a 4‐month period in 2015, using photographic capture–recapture surveys via road‐based transects. We divided the study area into five circuitous survey units, each approximately 100 km in length ( = 99·22 km, SD = 3·72), and surveyed for giraffes for 4 months. From these surveys, we developed a data base of spatially explicit giraffe photographs. We processed these photographs for individual identification and fitted spatial capture–recapture models to predict the spatial configuration of giraffe abundance and GSD prevalence within the study area. Our results indicated that >86% of the giraffe population showed signs of GSD and that the disease was more prevalent in the northern and north‐eastern portion of Ruaha National Park. Synthesis and applications. Our research shows that data from non‐invasive surveys can be used in spatial capture–recapture (SCR) models to estimate the proportion of a population affected by a visible disease. Researchers and conservationists can use SCR models to better examine the variation in parameters associated with these populations such as sex, age class, movement, and encounter rate, which may be linked to the prevalence of the disease, while incorporating broad spatial and temporal dimensions of the population in such areas. We discuss the implications of this research for conservation of threatened species with an emphasis on disease ecology and vulnerability to predations, and more broadly, for wildlife conservation.

Wildlife species richness and densities in wildlife corridors of Northern Tanzania

Wildlife corridors are crucial for effective conservation in fragmented landscapes, yet these corridors are vanishing across Africa. In order to assess the relative conservation effectiveness of two distinct management areas linking Tarangire and Lake Manyara National Parks in Northern Tanzania, we assessed seasonal densities of wild and domestic species as well as species richness of large mammals over a 3-plus-year time period. Line distance sampling showed that livestock densities were considerably higher in a human-dominated area with little enforcement of natural resource utilization (Mto wa Mbu Game Controlled Area; CA) than in a Maasai pastoral area with stricter limitations and enforcement of natural resource utilization (Manyara Ranch; MR). Conversely, densities of most corridor-dwelling (giraffe, Kirk’s dik dik, and ostrich) and migratory (Grant’s gazelles, zebra, and wildebeest) wildlife species were mostly higher in MR compared to the CA. Large mammal species richness was about two times higher in MR than in the CA. Despite strong anthropogenic pressures on communal lands and natural resources, our long-term wildlife monitoring provides evidence of continued connectivity in the Tarangire-Manyara ecosystem. At the same time, we caution that continued land-use changes and illegal exploitation of wildlife resources severely threaten the functional connectivity of this ecosystem. Our comparative analysis highlights the conservation value of pastoral lands in East African savannahs, provided that additional stressors such as land-use changes and uncontrolled hunting of wildlife are restricted.

Ecological legacies of civil war: 35‐year increase in savanna tree cover following wholesale large‐mammal declines

Summary Large mammalian herbivores (LMH) exert strong effects on plants in tropical savannas, and many wild LMH populations are declining. However, predicting the impacts of these declines on vegetation structure remains challenging. Experiments suggest that tree cover can increase rapidly following LMH exclusion. Yet it is unclear whether these results scale up to predict ecosystem‐level impacts of LMH declines, which often alter fire regimes, trigger compensatory responses of other herbivores and accompany anthropogenic land‐use changes. Moreover, theory predicts that grazers and browsers should have opposing effects on tree cover, further complicating efforts to forecast the outcomes of community‐wide declines. We used the near‐extirpation of grazing and browsing LMH from Gorongosa National Park during the Mozambican Civil War (1977–1992) as a natural experiment to test whether megafaunal collapse increased tree cover. We classified herbaceous and tree cover in satellite images taken (a) at the onset of war in 1977 and (b) in 2012, two decades after hostilities ceased. Throughout the 3620‐km2 park, proportional tree cover increased by 34% (from 0.29 to 0.39) – an addition of 362 km2. Four of the park's five major habitat zones (including miombo woodland, Acacia–Combretum–palm savanna, and floodplain grassland) showed even greater increases in tree cover (51–134%), with an average increase of 94% in ecologically critical Rift Valley habitats. Only in the eastern Cheringoma Plateau, which had historically low wildlife densities, did tree cover decrease (by 5%). The most parsimonious explanation for these results is that reduced browsing pressure enhanced tree growth, survival and/or recruitment; we found no directional trends in rainfall or fire that could explain increased tree cover. Synthesis. Catastrophic large‐herbivore die‐offs in Mozambique's flagship national park were followed by 35 years of woodland expansion, most severely in areas where pre‐war wildlife biomass was greatest. These findings suggest that browsing release supersedes grazer–grass–fire feedbacks in governing ecosystem‐level tree cover, consistent with smaller‐scale experimental results, although the potentially complementary effect of CO2 fertilization cannot be definitively ruled out. Future work in Gorongosa will reveal whether recovering LMH populations reverse this trend, or alternatively whether woody encroachment hinders ongoing restoration efforts.

Estimación poblacional y conservación de felinos (Carnivora: Felidae) en el norte de Quintana Roo, México

Wildlife density estimates provide an idea of the current state of populations, and in some cases, reflect the conservation status of ecosystems, essential aspects for effective management actions. In Mexico, several regions have been identified as high priority areas for the conservation of species that have some level of risk, like the Yucatan Peninsula (YP), where the country has the largest population of jaguars. However, little is known about the current status of threatened and endangered felids, which coexist in the Northeastern portion of the Peninsula. Our objective was to estimate the wild cats' density population over time at El Eden Ecological Reserve (EEER) and its surrounding areas. Camera trap surveys over four years (2008, 2010, 2011 and 2012) were conducted, and data were obtained with the use of capture-recapture models for closed populations (CAPTURE + MMDM or 1/2 MMDM), and the spatially explicit capture-recapture model (SPACECAP). The species studied were jaguar (Panthera onca), puma (Puma concolor), ocelot (Leopardus pardalis), jaguarundi (Puma yaguaroundi) and margay (Leopardus wiedii). Capture frequency was obtained for all five species and the density for three (individuals/100km2). The density estimated with The Mean Maximum Distance Moved (MMDM), CAPTURE, ranged from 1.2 to 2.6 for jaguars, from 1.7 to 4.3 for pumas and from 1.4 to 13.8 for ocelots. The density estimates in SPACECAP ranged from 0.7 to 3.6 for jaguars, from 1.8 to 5.2 for pumas and 2.1 to 5.1 for ocelots. Spatially explicit capture recapture (SECR) methods in SPACECAP were less likely to overestimate densities, making it a useful tool in the planning and decision making process for the conservation of these species. The Northeastern portion of the Yucatan Peninsula maintains high populations of cats, the EEER and its surrounding areas are valuable sites for the conservation of this group of predators. Rev. Biol.

Anaplasma phagocytophilum prevalence in ticks and rodents in an urban and natural habitat in South-Western Slovakia.

BackgroundIxodes ricinus is the principal vector of Anaplasma phagocytophilum, the ethiological agent of granulocytic anaplasmosis in Europe. Anaplasmosis is an emerging zoonotic disease with a natural enzootic cycle. The reservoir competence of rodents is unclear. Monitoring of A. phagocytophilum prevalence in I. ricinus and rodents in various habitat types of Slovakia may contribute to the knowledge about the epidemiology of anaplasmosis in Central Europe.MethodsOver 4400 questing ixodid ticks, 1000 rodent-attached ticks and tissue samples of 606 rodents were screened for A. phagocytophilum DNA by real-time PCR targeting the msp2 gene. Ticks and rodents were captured along six transects in an urban/suburban and natural habitat in south-western Slovakia during 2011–2014. Estimates of wildlife (roe deer, red deer, fallow deer, mouflon, wild boar) densities in the study area were taken from hunter’s yearly reports. Spatial and temporal differences in A. phagocytophilum prevalence in questing I. ricinus and relationships with relative abundance of ticks and wildlife were analysed.ResultsOverall prevalence of A. phagocytophilum in questing I. ricinus was significantly higher in the urban/suburban habitat (7.2 %; 95 % CI: 6.1–8.3 %) compared to the natural habitat (3.1 %; 95 % CI: 2.5–3.9 %) (χ2 = 37.451; P < 0.001). Significant local differences in prevalence of infected questing ticks were found among transects within each habitat as well as among years and between seasons. The trapped rodents belonged to six species. Apodemus flavicollis and Myodes glareolus prevailed in both habitats, Microtus arvalis was present only in the natural habitat. I. ricinus comprised 96.3 % of the rodent-attached ticks, the rest were Haemaphysalis concinna, Ixodes trianguliceps and Dermacentor reticulatus. Only 0.5 % of rodent skin and 0.6 % of rodent-attached ticks (only I. ricinus) were infected with A. phagocytophilum. Prevalence of A. phagocytophilum in questing I. ricinus did not correlate significantly with relative abundance of ticks or with abundance of wildlife in the area.ConclusionThe study confirms that urban I. ricinus populations are infected with A. phagocytophilum at a higher rate than in a natural habitat of south-western Slovakia and suggests that rodents are not the main reservoirs of the bacterium in the investigated area.

Foodborne parasites from wildlife: how wild are they?

The majority of wild foods consumed by humans are sourced from intensively managed or semi-farmed populations. Management practices inevitably affect wildlife density and habitat characteristics, which are key elements in the transmission of parasites. We consider the risk of transmission of foodborne parasites to humans from wildlife maintained under natural or semi-natural conditions. A deeper understanding will be useful in counteracting foodborne parasites arising from the growing industry of novel and exotic foods.

Modeling elephant-mediated cascading effects of water point closure.

Wildlife management to reduce the impact of wildlife on their habitat can be done in several ways, among which removing animals (by either culling or translocation) is most often used. There are, however, alternative ways to control wildlife densities, such as opening or closing water points. The effects of these alternatives are poorly studied. In this paper, we focus on manipulating large herbivores through the closure of water points (WPs). Removal of artificial WPs has been suggested in order to change the distribution of African elephants, which occur in high densities in national parks in Southern Africa and are thought to have a destructive effect on the vegetation. Here, we modeled the long-term effects of different scenarios of WP closure on the spatial distribution of elephants, and consequential effects on the vegetation and other herbivores in Kruger National Park, South Africa. Using a dynamic ecosystem model, SAVANNA, scenarios were evaluated that varied in availability of artificial WPs; levels of natural water; and elephant densities. Our modeling results showed that elephants can indirectly negatively affect the distributions of meso-mixed feeders, meso-browsers, and some meso-grazers under wet conditions. The closure of artificial WPs hardly had any effect during these natural wet conditions. Under dry conditions, the spatial distribution of both elephant bulls and cows changed when the availability of artificial water was severely reduced in the model. These changes in spatial distribution triggered changes in the spatial availability of woody biomass over the simulation period of 80 years, and this led to changes in the rest of the herbivore community, resulting in increased densities of all herbivores, except for giraffe and steenbok, in areas close to rivers. The spatial distributions of elephant bulls and cows showed to be less affected by the closure of WPs than most of the other herbivore species. Our study contributes to ecologically informed decisions in wildlife management. The results from this modeling exercise imply that long-term effects of this intervention strategy should always be investigated at an ecosystem scale.

Can diverse herbivore communities increase landscape heterogeneity? Comparing wild and domestic herbivore assemblages in a South African savanna

The structure and composition of woody and grassy vegetation in savannas is strongly influenced by herbivores. In recent decades, the proportion of browsers has declined across African savannas in favour of more grazers, triggered by large-scale human-induced cattle grazing. This has led to overgrazing and an imbalance of woody and grassy vegetation. Our study investigated mono-specific and multi-species herbivore assemblages of varying density and assessed similarities in vegetation patterns under wildlife and livestock herbivory in and around Kruger National Park, South Africa. Under mono-specific herbivory, overall tree cover was more than twice as high compared to multi-species herbivory while the branching height of small and tall trees was lowest. Small tree and bush densities were strongly elevated at mono-specific compared to multi-species herbivore sites. Tall trees were dominated by Acacia nigrescens under multi-species herbivory at low wildlife density but not at high density sites. Grass leaf nitrogen contents were almost twice as high at multi compared to mono herbivory sites, particularly beneath tree canopies. Livestock and wildlife herbivore sites showed similar patterns in their woody plant structure and grass nutrients. We conclude that a characteristic herbaceous and woody vegetation structure as well as species composition can be matched with mammalian herbivore communities, which has implications for landscape heterogeneity and grazing management in savanna systems.

Behavioral correlates of supplementary feeding of wildlife: Can general conclusions be drawn?

Supplementary feeding is a common, but controversial, tool in wildlife management, because it can benefit both humans and wildlife (e.g., increased wildlife densities), but has certain downsides (e.g., increased disease transmission). For species that are often involved in human-wildlife conflicts, two opposing paradigms with respect to supplementary feeding exist, i.e., (i) that supplementary feeding is efficient to lure animals away from undesired places (i.e., diversionary feeding; hypothesis 1), and (ii) that supplementary feeding stimulates ‘nuisance’ behavior (i.e., increased tolerance for humans and selection for human facilities; hypothesis 2). We formulated an alternative hypothesis (hypothesis 3); i.e., that behavioral variation among individuals dilutes population-wide, general patterns with respect to supplementary feeding. Based on GPS relocation data and resource selection functions, we show that neither of the two opposing management paradigms (hypothesis 1 and 2) hold in a particularly ‘conflict rich’ species, the brown bear (Ursus arctos), because individual variation in selection behavior with respect to supplementary feeding diluted population-wide patterns (hypothesis 3), even under very different environmental contexts (Sweden vs. Slovenia; i.e., different human and bear population density, history and intensity of supplementary feeding, topography, etc.). Our results emphasize that individual variation is an important component of behavioral ecology and should be considered in wildlife management and conservation.

Acoustic capture-recapture methods for animal density estimation

Capture-recapture methods are one of the two most widely-used methods of estimating wildlife density and abundance. They can be used with passive acoustic detectors—in which case acoustic detection on a detector constitutes “capture” and detection on other detectors and/or at other times constitute “recaptures.” Unbiased estimation of animal density from any capture-recapture survey requires that the effective area of the detectors be estimated, and information on detected animals' locations are essential for this. While locations are not observed, acoustic data contain information on location in a variety of guises, including time-difference-of arrival, signal strength, and sometimes directional information. This talk gives an overview of the use of such data with spatially explicit capture-recapture (SECR) methods, including consideration of some of the particular challenges that acoustic data present for SECR methods, ways of dealing with these, and an outline of some unresolved issues.

Effective spatial scales for evaluating environmental determinants of population density in Yakushima macaques

Population densities of wildlife species tend to be correlated with resource productivity of habitats. However, wildlife density has been greatly modified by increasing human influences. For effective conservation, we must first identify the significant factors that affect wildlife density, and then determine the extent of the areas in which the factors should be managed. Here, we propose a protocol that accomplishes these two tasks. The main threats to wildlife are thought to be habitat alteration and hunting, with increases in alien carnivores being a concern that has arisen recently. Here, we examined the effect of these anthropogenic disturbances, as well as natural factors, on the local density of Yakushima macaques (Macaca fuscata yakui). We surveyed macaque densities at 30 sites across their habitat using data from 403 automatic cameras. We quantified the effect of natural vegetation (broad-leaved forest, mixed coniferous/broad-leaved forest, etc.), altered vegetation (forestry area and agricultural land), hunting pressure, and density of feral domestic dogs (Canis familiaris). The effect of each vegetation type was analyzed at numerous spatial scales (between 150 and 3,600-m radii from the camera locations) to determine the best scale for explaining macaque density (effective spatial scale). A model-selection procedure (generalized linear mixed model) was used to detect significant factors affecting macaque density. We detected that the most effective spatial scale was 400 m in radius, a scale that corresponded to group range size of the macaques. At this scale, the amount of broad-leaved forest was selected as a positive factor, whereas mixed forest and forestry area were selected as negative factors for macaque density. This study demonstrated the importance of the simultaneous evaluation of all possible factors of wildlife population density at the appropriate spatial scale.

Underperformance of African protected area networks and the case for new conservation models: insights from Zambia.

Many African protected areas (PAs) are not functioning effectively. We reviewed the performance of Zambia’s PA network and provide insights into how their effectiveness might be improved. Zambia’s PAs are under-performing in ecological, economic and social terms. Reasons include: a) rapidly expanding human populations, poverty and open-access systems in Game Management Areas (GMAs) resulting in widespread bushmeat poaching and habitat encroachment; b) underfunding of the Zambia Wildlife Authority (ZAWA) resulting in inadequate law enforcement; c) reliance of ZAWA on extracting revenues from GMAs to cover operational costs which has prevented proper devolution of user-rights over wildlife to communities; d) on-going marginalization of communities from legal benefits from wildlife; e) under-development of the photo-tourism industry with the effect that earnings are limited to a fraction of the PA network; f) unfavourable terms and corruption which discourage good practice and adequate investment by hunting operators in GMAs; g) blurred responsibilities regarding anti-poaching in GMAs resulting in under-investment by all stakeholders. The combined effect of these challenges has been a major reduction in wildlife densities in most PAs and the loss of habitat in GMAs. Wildlife fares better in areas with investment from the private and/or NGO sector and where human settlement is absent. There is a need for: elevated government funding for ZAWA; greater international donor investment in protected area management; a shift in the role of ZAWA such that they focus primarily on national parks while facilitating the development of wildlife-based land uses by other stakeholders elsewhere; and new models for the functioning of GMAs based on joint-ventures between communities and the private and/or NGO sector. Such joint-ventures should provide defined communities with ownership of land, user-rights over wildlife and aim to attract long-term private/donor investment. These recommendations are relevant for many of the under-funded PAs occurring in other African countries.

Spatial distribution of snares in Ruma National Park, Kenya, with implications for management of the roan antelope Hippotragus equinuslangheldi and other wildlife

AbstractPoaching with snares has been identified as the main cause of decline of the endemic roan antelope Hippotragus equinuslangheldi in Ruma National Park, Kenya, from &gt; 200 in 1979 to 37 in 2009. However, the spatial snaring patterns in the Park are not clearly understood. The focus of our study was to map the spatial distribution of snares in the Park and to identify the factors influencing this distribution, to develop effective methods of wildlife protection. Using data collected from 56 sample plots during 2006–2008, coupled with geographical information system techniques, we investigated the association between the occurrence of snares and the distribution of geographical features (slope, elevation), infrastructure (roads, fences), essential resources for wildlife (water, salt licks, forage), roan locations and wildlife density. Ripley's L function for assessing complete spatial randomness indicated that snares occurred in clumps (hotspots) up to 4 km apart. Negative binomial regression indicated that these hotspots occurred (1) near water resources, salt licks and the Park boundary, (2) far from roan locations and Park roads, (3) in areas with low gradients and low wildlife density, and (4) in areas with burned vegetation. We recommend concentrating routine security patrol efforts and resources on snare hotspots to reduce snaring and to protect the roan antelope and other threatened wildlife.

Rapid assessment of wildlife abundance: estimating animal density with track counts using body mass–day range scaling rules

AbstractLimited resources in conservation dictate the need for efficient means of assessing wildlife abundance. Body mass–day range scaling rules and empirical track counts were applied to an established formula to estimate a wide range of wildlife densities. Using the southern Kalahari ecosystem of Botswana as an example, I provide the first comprehensive density estimates for the mammalian wildlife community (&gt;0.2 kg), including densities for several species previously unattainable by other methods. Among a subset of species, empirical day ranges from this area were consistently greater than those predicted using scaling rules modeled with species from diverse ecosystems. I applied a correction factor based on this discrepancy, which generated values congruent with independent density estimates from the area. Although accurate measures of day range are a practical constraint to estimating densities from track counts, the results suggest that modest efforts to obtain location‐specific day range estimates for a subset of species can improve density estimates for others derived from general allometric relationships. Given the strength of track surveys to accumulate unbiased observations quickly, in environments where animal tracks are readily visible, this approach shows potential for the rapid assessment of wildlife abundance.