Andrew B. Stein

Atlantic Sturgeon Marine Distribution and Habitat Use along the Northeastern Coast of the United States

Abstract Though the distribution of Atlantic sturgeon Acipenser oxyrinchus is relatively well known in freshwater and estuarine habitats in the northern portion of their range, their distribution in marine habitats is poorly understood. Sturgeon migrate into marine waters to forage between spawning events and probably maintain gene flow between river populations by entering nonnatal river systems to spawn. While at sea, they are captured in commercial fishing gears. We investigated data collected by onboard fishery observers to determine the occurrence and habitat preference of Atlantic sturgeon off the northeastern coast of the United States. Sturgeon distributions were based on monitored fishing trips over the period 1989–2000 and referenced to local bathymetry and sediment data. The results show that peak sturgeon captures along the coast were approximately bracketed by isobaths ranging from 10 to 50 m. Sturgeon were present more frequently on gravel and sand sediment types and were associated with spe...

Leopard (Panthera pardus) status, distribution, and the research efforts across its range

The leopard’s (Panthera pardus) broad geographic range, remarkable adaptability, and secretive nature have contributed to a misconception that this species might not be severely threatened across its range. We find that not only are several subspecies and regional populations critically endangered but also the overall range loss is greater than the average for terrestrial large carnivores. To assess the leopard’s status, we compile 6,000 records at 2,500 locations from over 1,300 sources on its historic (post 1750) and current distribution. We map the species across Africa and Asia, delineating areas where the species is confirmed present, is possibly present, is possibly extinct or is almost certainly extinct. The leopard now occupies 25–37% of its historic range, but this obscures important differences between subspecies. Of the nine recognized subspecies, three (P. p. pardus, fusca, and saxicolor) account for 97% of the leopard’s extant range while another three (P. p. orientalis, nimr, and japonensis) have each lost as much as 98% of their historic range. Isolation, small patch sizes, and few remaining patches further threaten the six subspecies that each have less than 100,000 km2 of extant range. Approximately 17% of extant leopard range is protected, although some endangered subspecies have far less. We found that while leopard research was increasing, research effort was primarily on the subspecies with the most remaining range whereas subspecies that are most in need of urgent attention were neglected.

Panthera pardus (Carnivora: Felidae)

Abstract: Panthera pardus (leopard; Linnaeus, 1758) is the smallest of the 4 large felids in the genus Panthera. A solitary and adaptable species, P. pardus is the widest ranging of all wild felids, inhabiting rain forests, mountains, semiarid environments, and suburban areas throughout sub-Saharan Africa, the Middle East, and South Asia to the Russian Far East. Despite this distribution, P. pardus is listed as “Near Threatened” by the International Union for Conservation of Nature and Natural Resources and several Asian subspecies are listed as endangered. P. pardus primarily feeds on small to medium-sized ungulates, but has a varied diet including fish, reptiles, birds, and small mammals.

Opportunistic use of camera traps to assess habitat-specific mammal and bird diversity in northcentral Namibia

In northcentral Namibia, Waterberg Plateau Park (WPP) is a protected area that acts as a refuge for rare and endangered species, while the farmlands surrounding the Park are managed for livestock production, but support populations of wildlife for game farming, trophy hunting, and conservation. During June–October 2006, camera-traps were set within and surrounding WPP to assess leopard (Panthera pardus) density (n = 19 camera stations and 946 camera-trap-nights). Fortuitously, photographic results (2,265 photos of identifiable mammal (n = 37) and bird (n = 25) species) allowed us to assess aspects of species diversity and differences among the Park, the farmland areas along the Waterberg Plateau escarpment, and the flatlands surrounding the escarpment. Species composition among the three areas was markedly different, and made sense with respect to differences in habitat and management features. Camera-trapping efforts, although intended for a narrow purpose, may also provide a rather robust record of differences in mammal and bird diversity in adjacent habitats and can be incorporated into long-term monitoring programs.

Avoiding Intraguild Competition: Leopard Feeding Ecology and Prey Caching in Northern Botswana

Leopards (Panthera pardus) are the most widely distributed wild felid in the world, living sympatrically with numerous competitively dominant species in various large carnivore guilds. Leopards generally feed on small to medium-sized ungulates and risk kleptoparasitism from intraguild competitors. One unique, adaptive response to intraguild competition is arboreal caching (‘hoisting’) by leopards. Hoisting behaviour is thought to vary in frequency among individuals, populations, and between sexes. In our study, leopards fed primarily (85% of observed kills) on impala (Aepyceros melampus), which is the most locally abundant potential prey species. Although we did not detect statistical differences in hoisting rates among individuals within each sex, our results confirmed moderate hoisting rates of 35% in an area with medium densities of lions (Panthera leo), spotted hyaenas (Crocuta crocuta) and African wild dogs (Lycaon pictus). Sex differences in prey hoisting were related to size, and males as the larger sex, hoisted kills (47.7%, n = 44) more often than overlapping females (27%, n = 62). Female leopards hoisted 25–33% of detected kills irrespective of prey size, season, habitat type, presence of dependent cubs, or location in relation to high competitor density areas (‘competitor hotspots’). Consistent with this, males hoisted kills more often where visibility and, therefore, probability of detection was highest. We conclude that hoisting is likely correlated with energetic costs, seasonally increased detection by competitors, and direct competitor interactions rather than the potential risk of conflicts within generalized areas of high competitor use (‘hotspots’).

Mapping black panthers: Macroecological modeling of melanism in leopards (Panthera pardus)

The geographic distribution and habitat association of most mammalian polymorphic phenotypes are still poorly known, hampering assessments of their adaptive significance. Even in the case of the black panther, an iconic melanistic variant of the leopard (Panthera pardus), no map exists describing its distribution. We constructed a large database of verified records sampled across the species’ range, and used it to map the geographic occurrence of melanism. We then estimated the potential distribution of melanistic and non-melanistic leopards using niche-modeling algorithms. The overall frequency of melanism was ca. 11%, with a significantly non-random spatial distribution. Distinct habitat types presented significantly different frequencies of melanism, which increased in Asian moist forests and approached zero across most open/dry biomes. Niche modeling indicated that the potential distributions of the two phenotypes were distinct, with significant differences in habitat suitability and rejection of niche equivalency between them. We conclude that melanism in leopards is strongly affected by natural selection, likely driven by efficacy of camouflage and/or thermoregulation in different habitats, along with an effect of moisture that goes beyond its influence on vegetation type. Our results support classical hypotheses of adaptive coloration in animals (e.g. Gloger’s rule), and open up new avenues for in-depth evolutionary analyses of melanism in mammals.

Brown hyaena feeding ecology on Namibian farmlands

We identified the diet of brown hyaenas (Hyaena brunnea) on the farmlands of north-central Namibia based on scat analysis, den site orts, and evidence of scavenging at leopard (Panthera pardus) kills. In the absence of larger carnivores, which have been credited with providing larger food items for brown hyaenas elsewhere, we compared interspecific dietary overlap and activity patterns with the remaining large carnivores, leopards and cheetahs (Acinonyx jubatus). Where hyaenas and leopards were sympatric, diets of both nocturnal species (n = 212 hyaena scats and 41 leopard scats) were quite similar (both >89% wild, with some domestic ungulates), and only somewhat different from cheetahs in a previous study. Additionally, evidence of brown hyaena scavenging was found at 76% of 29 leopard kills available to them. Brown hyaenas occurring on Namibian farmlands likely find medium-sized to large ungulate prey by scavenging from leopards and perhaps cheetahs.

Living on the edge: characteristics of human–wildlife conflict in a traditional livestock community in Botswana

Abstract Context. Conflicts between wildlife and humans have occurred for millennia, and are major drivers of wildlife decline. To promote coexistence, Botswana established buffer zones called wildlife-management areas (WMAs) adjacent to National Parks and Reserves where communities assume stewardship of wildlife and derive financial benefits from it. In contrast, communities outside WMAs are generally excluded from these benefits despite incurring ‘coexistence costs’, including crop damage and livestock depredation, although they may receive compensation for these losses. Aims. To investigate the perceptions and actions of a livestock farming community outside (but surrounded by) WMAs in northern Botswana, especially in relation to predator management. Methods. We conducted standard-format interviews with 62 heads of households (cattleposts), and evaluated responses using descriptive and multivariate statistics. Key results. Almost half (46%) of respondents expressed negative perceptions of predators, with 67% reporting losses to predation. After disease, predation was the most commonly reported source of livestock losses. Increased age of the head of household was the strongest predictor of reported predation. Few households employed husbandry beyond kraaling at night, but some (21%) reported conducting lethal control of predators. Reported use of lethal control was independent of the household experience with predation and whether they derived financial benefits from wildlife. Instead, households with larger herds were more likely to report using lethal control, despite the most educated farmers tending to have larger herds. Lethal control was almost twice as likely in households previously denied government compensation for losses (42%) than in those granted compensation (23%). Perhaps as a result of perceived failures of the government compensation scheme, most households (91%) supported the development of an independent insurance program, with 67% expressing willingness to pay a premium. Conclusions. Our results challenge the assumption that deriving financial benefit from wildlife increases tolerance. A measurable disconnect also exists between the willingness of a household to employ lethal control and their experience with predation, suggesting that lethal control was used pre-emptively rather than reactively. Implications. Efforts must be made to connect the financial costs incurred during farming alongside wildlife with the financial benefits derived from wildlife. Where compensation schemes exist, timely payments may reduce retaliatory killing.