Abundance Of Large Mammals Research Articles

Large African herbivore diversity is essential in transformed landscapes for conserving dung beetle diversity

Abstract Mammals are globally in decline, with habitat loss a primary driver. There are also human–wildlife conflicts, such as elephants destroying crops, which results in the ranges of many large mammal species being fenced off. Yet, how this activity affects functional associations of insects with large mammals has received little attention. Previous work suggests a generalised association with large mammals, as well as a strong response to landscape transformation. Here we assess how well dung beetle diversity tracks large African mammal herbivore diversity across a forestry plantation land use gradient by assessing how dung beetle taxonomic, phylogenetic and functional richness compares to large mammal diversity. We also determine how land use intensity affects dung beetle‐to‐mammal interaction networks. Dung beetles responded more intensively to an array of large mammals than to differences in land use intensity. Beetles also showed a strong preference for specific mammalian dung, with elephant dung being the most important factor for maintaining local dung beetle diversity. Large mammal abundance, functional diversity, dung beetle phylogenetic richness and number of realised mammal‐to‐dung beetle interactions were highest in the protected area. Land use intensity categories had distinct mammal and dung beetle assemblages. Transformed areas also have conservation value but provided that there is functional connectivity between remnant vegetation within the modified landscapes. Synthesis and applications. The loss of any native large mammal, especially African elephants, from transformed landscapes is likely to lead to a decline in biodiversity. This suggests that protected areas are essential for the conservation of native biodiversity and its interactions, while well‐designed and managed transformed areas can have additional conservation value. African conservation managers and landowners should be encouraged to maintain a diversity of large mammals on their properties to maintain functional diversity and ultimately ecological resilience.

Human footprint differentially impacts genetic connectivity of four wide‐ranging mammals in a fragmented landscape

AbstractAimMaintaining connectivity is critical for long‐term persistence of wild carnivores in landscapes fragmented due to anthropogenic activity. We examined spatial genetic structure and the impact of landscape features on genetic structure in four widespread species—jungle cat (Felis chaus), leopard (Panthera pardus), sloth bear (Melursus ursinus) and tiger (Panthera tigris).LocationOur study was carried out in the central Indian landscape, a stronghold in terms of distribution and abundance of large mammals. The landscape comprises fragmented forests embedded in a heterogeneous matrix of multiple land use types.MethodsMicrosatellite data from non‐invasively sampled individuals (90 jungle cats, 82 leopards, 104 sloth bears and 117 tigers) were used to investigate genetic differentiation. Impact of landscape features on genetic structure was inferred using a multimodel landscape resistance optimization approach.ResultsAll four study species revealed significant isolation by distance (IBD). The correlation between genetic and geographic distance was significant only over a short distance for jungle cat, followed by longer distances for sloth bear, leopard and tiger. Overall, human footprint had a high negative impact on gene flow in tigers, followed by leopards, sloth bears and the least on jungle cats. Individual landscape variables—land use, human population density, density of linear features and roads—impacted the study species differently. Although land use was found to be an important variable explaining genetic structure for all four species, the amount of variation explained, and the optimum spatial resolution and the resistance values of different land use classes varied.Main conclusionsAs expected from theory, but rarely demonstrated using empirical data, the pattern of spatial autocorrelation of genetic variation scaled with dispersal ability and density of the study species. Landscape genetic analyses revealed species‐specific impact of landscape features and provided insights into interactions between species biology and landscape structure. Our results emphasize the need for incorporating functional connectivity data from multiple species for landscape‐level conservation planning.

Nocturnal activity in wild chimpanzees (Pan troglodytes): Evidence for flexible sleeping patterns and insights into human evolution.

We investigated occurrences and patterns of terrestrial nocturnal activity in wild chimpanzees (Pan troglodytes) and modelled the influence of various ecological predictors on nocturnal activity. Data were extracted from terrestrial camera-trap footage and ecological surveys from 22 chimpanzee study sites participating in the Pan African Programme: The Cultured Chimpanzee. We described videos demonstrating nocturnal activity, and we tested the effects of the percentage of forest, abundance of predators (lions, leopards and hyenas), abundance of large mammals (buffalos and elephants), average daily temperature, rainfall, human activity, and percent illumination on the probability of nocturnal activity. We found terrestrial nocturnal activity to occur at 18 of the 22 study sites, at an overall average proportion of 1.80% of total chimpanzee activity, and to occur during all hours of the night, but more frequently during twilight hours. We found a higher probability of nocturnal activity with lower levels of human activity, higher average daily temperature, and at sites with a larger percentage of forest. We found no effect of the abundance of predators and large mammals, rainfall, or moon illumination. Chimpanzee terrestrial nocturnal activity appears widespread yet infrequent, which suggests a consolidated sleeping pattern. Nocturnal activity may be driven by the stress of high daily temperatures and may be enabled at low levels of human activity. Human activity may exert a relatively greater influence on chimpanzee nocturnal behavior than predator presence. We suggest that chimpanzee nocturnal activity is flexible, enabling them to respond to changing environmental factors.

Wildlife Conservation on the Rangelands of Eastern and Southern Africa: Past, Present, and Future

Our objective was to assess the status of the large native rangeland mammals in the eastern and southern African countries focusing on conservation strategies that will benefit the animals, their rangeland habitats, and the people who live in this region. Eastern and southern African rangelands are renowned for supporting a globally unique diversity and abundance of large mammals. This wildlife legacy is threatened by changing demographics, increased poaching, habitat fragmentation, and global warming, but there are reasons for optimism. After sharp declines from 1970 to 1990 across Africa, wildlife populations in some countries have subsequently increased due to incentives involving sport hunting and ecotourism. National parks and protected areas, which have been critically important in maintaining African wildlife populations, are being increased and better protected. Over the past 50 years, the number of parks has been doubled and the areas of several parks have been expanded. The major problem is that no more than 20% of the national parks and reserves set aside for wildlife are adequately protected from poaching. The southern African countries where wildlife has recently thrived have robust hunting and ecotourism programs, which economically benefit private landowners. Considerable research shows rural communities dependent on rangelands can be incentivized to participate in large mammal conservation programs if they can economically benefit from wildlife tourism, sport hunting, and the legal sale of animal by-products. Community-based wildlife conservation programs can be economically and ecologically effective in sustaining and enhancing African wildlife biodiversity, including rhinos, elephants, and lions. Low-input ranching wild ungulates for meat and hunting may be an economically viable alternative to traditional range livestock production systems in some areas. However, in many situations, common-use grazing of livestock and wildlife will give the most efficient use of rangeland forages and landscapes while diversifying income and lowering risk.

Ground Night Nesting in Chimpanzees: New Insights from Central Chimpanzees (Pan troglodytes troglodytes) in South-East Cameroon

Some chimpanzee populations exhibit ground night nesting, which occurs in different habitat types, is driven by a variety of interconnected factors, and may reflect cultural or social differences. This has important implications for ape conservation management, given that accurate nest builder identification is required to estimate density, crucial in monitoring, and allows inferences about environmental and social factors that may have contributed to the transition from tree to ground sleeping in early hominins. We conducted a 24-month marked nest count survey in La Belgique, Cameroon, and recorded the occurrence of chimpanzee tree and ground night nests, temperature and rainfall, predator and large mammal abundance, human activities, nesting tree species, and Uapaca spp. consumption. Ground night nesting occurred at a rate of 3.47% (n = 1,008), with more in swamps, in the dry season and with increasing human activities. We found no influence of leopard/elephant presence, but a possible influence of lack of nesting trees. We suggest chimpanzees visit swamps in the dry season (low water levels) for relief from hunting pressure and to consume Uapaca spp. fruits. Ground nesting may be enabled due to high abundance of terrestrial herbaceous vegetation, and may be favoured for inconspicuousness and safety from gun hunters.

Species richness and abundance of large mammals in Zaraninge forest, Coast region, Tanzania

A study on the large mammals of Zaraninge Forest was conducted using the line transect method between 1995 and 2001. They comprised 16 species from 7 families, including Bovidae (5), Canidae (1), Cercopithecidae (4), Felidae (1), Galagonidae (2), Orycteropodidae (1) and Suidae (2). Only nine species of primates and antelopes were encountered frequently enough for densities to be estimated. A total of 404 sightings from 40 counts were recorded, the majority being for blue monkey (34.9%) and Angolan colobus (26.0%). For galagos, 210 sightings from 58 counts were recorded, the majority being for Rondo galago (62.2%). Absolute density (individuals km-2) (±SE) for blue monkey (12528.8) was highest, followed by the Angolan colobus (74.03.9) and yellow baboon (33.68.1). Antelopes had much lower densities with that of suni (23.48.7) being the highest, followed by Harvey's red duiker (13.6±9.5), blue duiker (9.5±6.4) and bushbuck (2.3±0.5). Densities for the Rondo galago and Zanzibar galago were 23.4±9.1 and 12.9±10.5, respectively. Only one bushbuck pellet pile was encountered while for the two duikers and suni a total of 106 fresh pellet piles were counted. Relative pellet pile density (piles km-2) for suni was 280.1±73.7, while for red duiker and blue duiker densities were 170.9±50.6 and 119.9±52.9, respectively. Endemic large mammals were not observed in the forest though six were forest specialists, one near endemic, six threatened and seven in the CITES list. Tanzania Journal of Science Vol. 32 (2) 2006: pp. 105-116

Indices for assessment and monitoring of large mammals within an adaptive management framework.

Many development projects intended to exploit natural resources are occurring in fragile ecosystems, and therefore the need for sound biodiversity assessment and monitoring programs is growing. Large mammals are important components of these fragile ecosystems, yet there are few strategies that attempt to assess and monitor entire large mammal communities in relation to development projects. We propose the use of two indices applied within a framework of adaptive management. An occurrence index assesses the composition and distribution of large mammals at a site, and an abundance index monitors the abundance of large mammals over time in relation to development. We discuss the design, applicability and effectiveness of these indices based on our experience with a natural gas development project in the Amazon forests of southeastern Peru.

Distribution of Population Declines in Large Mammals

Uncertainty in the temporal abundance of species may be attributed to sampling error, demographic or environmental stochasticity, changes in genetic structure, or catastrophes. These sources of variability influence the persistence time of small populations (Shaffer 1987; Lande 1988, 1993; Boyce 1992; Caughley 1994), although a consensus on their relative importance has not emerged. And it is not clear whether any such consensus will emerge given the disparate life histories and habitats of the species of interest. What is clear is that much empirical information is still needed regarding the significance and frequency of uncertain events in ecological dynamics. Based on Lande's (1993) result that the effects of environmental stochasticity and catastrophes on persistence time are similar in kind, Caughley (1994) argued that the artificial distinction between environmental stochasticity and catastrophes be abandoned. In essence, catastrophes simply represent a tail of the distribution of environmental stochasticity. Young (1994), however, presented an analysis of the across-species frequency of declines in abundance of large mammals and concluded that severe population crashes in populations of large mammals are apparently widespread and not uncommon in nature. His results show that the number of die-offs between 70% and 90% occurred with higher frequency than those between 25% and 70%. This contradicts the suggestion that catastrophes represent the tail of an environmental stochasticity distribution. Such discrepancy may result from inadequacies in Caughley's (1994) suggestion or Young's (1994) analysis. Our initial concerns with the nature of Young's (1994) data prompted us to suspect the latter. And although Young's synthesis does provide information on the occurrence of catastrophic declines, we were not convinced that the results provided a clear or useful picture. The following are five primary concerns with Young's (1994) approach. 1. Reported population declines will be biased toward those of larger proportion, a bias increased by Young's in-

Use of Vocalizations to Estimate Population Size of Roe Deer

Estimating population abundance of large mammals generally requires substantial time and effort, and low-investment alternatives are needed. We present a novel application of a capture-mark-recapture (CMR) method, using vocalization frequency to estimate the size of roe deer (Capreolus capreolus) populations. The technique involves walking along fixed transects to disturb all animals present on a study plot, potentially provoking a vocal response. Those animals heard to vocalize (whether observed or not) are then considered the total number of 'marked' individuals in the population. The proportion of 'marked' individuals in the population is estimated from the proportion of animals that vocalize in the subsample of individuals observed (the vocalization frequency). Population size is estimated by dividing the number of marked individuals by the vocalization frequency, correcting for bias, which is directly analogous to the Lincoln-Petersen (L-P) estimate for CMR. We used this method to estimate population size for roe deer inhabiting a 150-ha forest plot for 8 separate surveys, and we used the L-P estimator to compare our estimates to mark-resight estimates. We estimated deer density as 23.45±7.80 deer/100 ha by CMR and 19.87 ± 7.92 deer/100 ha by the vocalization frequency (VF) method (x¯ ± SE). If the assumptions are met, this method provides estimates of absolute population size at low cost and with little material investment, because physical capture and marking of animals is not necessary. Further research is required to validate the assumption that visually observed animals have the same probability of vocalizing as those disturbed but not seen.