African Journal of Ecology最新文献

Understanding the spatial dynamics of landscape use by free-ranging herbivores is essential for species management and conservation in its natural environment. We used Ivelv’s selection index, binary logistic regression analyses and stepwise regression to understand how environmental factors shape habitat selection by the Grevy’s zebra (Equus greyvi). We measured biotic, abiotic and human factors that may influence presence or absence of Grevy’s zebra in Samburu-Laikipia landscape and showed: (1) during wet periods, percentage perennial grasses, livestock density and grass quality had the greatest effect on Grevy’s zebra presence; but (2) during dry weather periods a different suite of factors determined their landscape distribution, namely, the percentage of tree and bush density, distance to water and overall grass abundance. In addition, different Grevy’s zebra demographic and reproductive classes varied in their response to environmental selective forces, thus demonstrating flexibility in their patterns of habitat selection. While we recommend more detailed studies on how abiotic and biotic interact to shape habitat selection patterns, our findings underscored the need of maintaining both dry and wet season habitats to ensure essential grazing area refugia. Our findings show that ‘soft’ development with controlled livestock stocking rates within the landscape will enhance Grevy’s zebra conservation.

Large carnivore distribution in Ethiopia is not well documented; we did 108 interviews and 12 focus group discussions in six districts of the Somali Region to gather basic information. The Region is not listed as resident range for big cats, but our results indicate widespread presence of cheetah, and possible remnants of lion and leopard occurrence. Spotted and striped hyaena, plus many smaller species, are frequently encountered. In contrast to positive attitudes towards wild grazers, all carnivores are persecuted in response to frequent conflict leading to injuries and deaths among people and livestock. Lion and cheetah cubs were regularly captured and trafficked, and this may have contributed to lion declines especially. Cheetah cubs are still regularly caught and we mapped how they are smuggled to Somalia/Somaliland from where they enter the pet trade.

Understanding dispersal patterns and demographic processes is crucial for the development of evidence-based conservation practices. Obtaining such information relies on the ability to identify and track individuals across spatial and temporal scales relevant to the life-history events under investigation. This knowledge can be achieved by combining photographic and sighting data collected by various sources with a high accuracy automated individual identification platform. Here, we present the African Carnivore Wildbook (ACW), an AI-based graphical user interface tool capable of identifying individuals of several African carnivore species and specifically developed to accommodate the above outlined needs. We showcase the ACW functionality using the endangered African wild dog as an example. Pictures collected over an area >56,000 km² and submitted to ACW allowed inferences on movement patterns and dispersal at regional and international scales; for instance, transboundary dispersal events >200 km were documented. ACW furthermore enabled monitoring some individuals for >4 years; such information is invaluable for reliable survival analyses. We discuss how the ACW can contribute to data collection at appropriate spatial and temporal scales to support population monitoring, scientific research and management of African wild dogs and other apex carnivores and to the conservation of these charismatic species.

To inform the conservation of the Regionally Critically Endangered West African lion, we studied lion population size and social structure in Niokolo Koba National Park (NKNP), Senegal. Calling station and camera trap surveys were conducted and opportunistic lion observations were documented from 2015 to 2020. The average lion density was calculated as 0.50 lion/100 km² and the population size was estimated as 28–56 individuals. Average lion group size was 2.1 ± 1.45 lions (range 1–8 lions). There were no significant differences between observations of single individuals (43%), groups of two (22%), three (19%), four (4%) and more than four (5%) individual lions (X² = 30.021, p-value = 0.06452). Sex ratio showed a ratio of male:female of 1:1.1 to 1:2.8. About 13.59% of the lion population was composed of cubs while, respectively, 81.22% and 5.17% were adults and subadults. Based on the analysis of activity patterns, lions in NKNP are mainly nocturno-crepuscular (18:00–01:00) and matutinal (06:00–08:00). Lion population size and density are still low in NKNP compared to earlier estimates from the same area, in the late 1990s. We therefore conclude that the conservation of lions in NKNP must be further improved to safeguard this population in the long term.

Native multi-purpose tree species in West Africa, Cola nitida and Garcinia kola have the potential to advance agroforestry practices in the sub-region. There is limited information on the ecology of both species which are currently characterised by low yield (fruit). This study investigated the influences of vegetation type on the population structure and floral association of both species in Nigeria. Data were collected using a purposive sampling design. Dendrometric variables of all the subject trees were measured, and all plant species associated with the subject tree species were enumerated across their places of natural occurrence. A 3-parameter Weibull Distribution Function was used to describe both species' diameter and height structures. Data were analysed using descriptive and inferential statistics. A total of 84 and 71 plant species were found accompanying G. kola and C. nitida, respectively, in both zones. The height and stem diameter distribution of the two species showed a bell-shape population structure, suggesting an unstable demographic pattern. The diameter distribution is skewed to the right, indicating the predominance of adult individuals. The height–diameter relationships show a monotonic increment. Both species coexist freely with other species and can be used in agroforestry practices.

The common impala (Aepyceros melampus melampus), a medium-sized herbivore in Eastern and Southern African savannahs, faces challenges from climate change. Using a species distribution model, we found temperature of the driest quarter (30.32%) and wettest month precipitation (20.36%) as the most influential factors. Surprisingly, land cover change had less impact (0.25%). Projections suggest a significant habitat reduction for impalas by 2050, with estimated losses of 18.12% (SSP-126) and 25.62% (SSP-585). These findings highlight climate change and land cover alterations as potential threats to impala survival, impacting crucial resources like forage and water. This research guides conservation efforts for common impala.

Human–wildlife conflicts (HWC) predominate in areas proximal to wildlife rich protected zones. Whereas herbivore driven HWC is easy to detect, the stealth, nocturnal and predacious nature of carnivores leads to human injury and fatality, livestock depredation and loss of livelihoods in communities proximal to Sengwa Wildlife Research Area (SWRA) in northwest Zimbabwe. This study aimed to: (1) determine the nature of human–hyaena conflicts (HHCs), (2) explore the drivers of HHCs and (3) investigate the spatial and temporal movement patterns of hyaenas in HHC hotspots in areas proximal to SWRA. The results indicated that prevalent HHC types include livestock depredation, property damage, harassment, nuisance and disruption of human movements around SWRA. Locals indicated removal of park fences, human settlement on wildlife migration corridors, increases in hyaena populations, easy stray livestock targets, increased poaching and removal of natural wildlife death carcasses by illegal hunters as key drivers of HHC. Hyaenas have a predetermined non-seasonal movement pattern following traditional wildlife migration corridors through SWRA into proximal communities. Human–hyaena conflict abatement strategies should be underpinned by indigenous local knowledge of hyaena movement and hunting patterns. Integrating citizen science data and remote sensing techniques aids to track and understand movement and hunting patterns of hyaenas inside and outside of protected areas.

Large transboundary protected areas such as the Kavango-Zambezi Transfrontier Conservation Area (KAZA-TFCA), improve mammal conservation by addressing biodiversity threats on regional and international levels, but an adequate understanding of mammal space use and richness within protected areas is critical for effective management planning. This information has however been missing from the Angolan component of the KAZA-TFCA, such as areas of Luengue-Luiana National Park (LLNP), especially compared with neighbouring countries. We used camera trap data from 2021 to 2023 to investigate species richness of medium- and large-sized mammals in two hotspot areas of LLNP, as well as assess the space use patterns of 9 carnivore and 16 herbivore species. A total of 48 species were recorded over 10,781 camera trapping nights, with African elephant (Loxodonta africana) and small antelope (e.g. common duiker Sylvicapra grimmia and steenbok Raphicerus campestris) being the most common. Species composition differed significantly between sites, with 21 species more relatively abundant at Ndunjuru, including cheetah (Acinonyx jubatus) and African wild dog (Lycaon pictus), and eight species more relatively abundant at Bico, including lion (Panthera leo) and hippopotamus (Hippopotamus amphibius). The detection probability of 22 species were affected by one or more ecological (e.g. proximity to rivers) or anthropogenic (e.g. human settlement) covariate. These results are intended to act as a baseline to monitor conservation effort and aid habitat management in LLNP, as well as similar protected areas within the KAZA-TFCA and elsewhere.

Restoring valuable timber trees is a necessary part of regaining many ecosystem services and products provided by degraded tropical forests. However, knowledge of seed production, a regeneration prerequisite, is limited for many tropical timber tree species. We studied the fruit production of African mahogany (Khaya anthotheca) in a semi-deciduous rainforest in East Africa, to provide information for ecological restoration programs. First, we quantified population variability and synchrony in fruit production. Then, we assessed how reproductive status and output were influenced by tree size, neighbourhood crowding, exchangeable cations, liana presence, and crown exposure. We found fruit production at the population level was weakly synchronised, with high interannual variability at the population and individual levels. Tree size determined reproductive status. Individual quantity of fruit produced increased with tree size but decreased with neighbourhood crowding. Our results indicate that K. anthotheca does not meet the criteria for mast fruiting. Our findings suggest that reproductive output in mahogany is regulated by tree size and competition. In addition to active protection, thinning to reduce competition around seed trees may boost fruit production at the individual tree level to provide seed for forest enrichment.

The ground pangolin (Smutsia temminckii Smuts 1832) is vulnerable to extinction due to poaching and trafficking. Recovery of pangolins from the trade and subsequent rehabilitation and release form a core component of pangolin conservation. Post-release monitoring of rehabilitated pangolins through the attachment of very high frequency (VHF) transmitters and satellite devices is carried out to determine the efficacy of release protocols. We report on 14 confirmed and 19 potential incidents of device removal by predators during non-fatal attacks, which occurred over a 6 year period. During this time, 78 devices were deployed 109 times attached to 36 rehabilitated pangolins. These incidents should be considered during the design of future post-release monitoring protocols.