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27 result(s) for "Kobus ellipsiprymnus"
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Ecological and behavioral mechanisms of density-dependent habitat expansion in a recovering African ungulate population
Major disturbances can temporarily remove factors that otherwise constrain population abundance and distribution. During such windows of relaxed top-down and/or bottom-up control, ungulate populations can grow rapidly, eventually leading to resource depletion and density-dependent expansion into less-preferred habitats. Although many studies have explored the demographic outcomes and ecological impacts of these processes, fewer have examined the individual-level mechanisms by which they occur. We investigated these mechanisms in Gorongosa National Park, where the Mozambican Civil War devastated largemammal populations between 1977 and 1992. Gorongosa's recovery has been marked by proliferation of waterbuck (Kobus ellipsiprymnus), an historically marginal 200-kg antelope species, which is now roughly 20-fold more abundant than before the war. We show that after years of unrestricted population growth, waterbuck have depleted food availability in their historically preferred floodplain habitat and have increasingly expanded into historically avoided savanna habitat. This expansion was demographically skewed: mixed-sex groups of prime-age individuals remained more common in the floodplain, while bachelors, loners, and subadults populated the savanna. By coupling DNA metabarcoding and forage analysis, we show that waterbuck in these two habitats ate radically different diets, which were more digestible and protein-rich in the floodplain than in savanna; thus, although individuals in both habitats achieved positive net energy balance, energetic performance was higher in the floodplain. Analysis of daily activity patterns from high-resolution GPS-telemetry, accelerometry, and animal-borne video revealed that savanna waterbuck spent less time eating, perhaps to accommodate their tougher, lower-quality diets. Waterbuck in savanna also had more ectoparasites than those in the floodplain. Thus, plasticity in foraging behavior and diet selection enabled savanna waterbuck to tolerate the costs of density-dependent spillover, at least in the short term; however, the already poorer energetic performance of these individuals implies that savanna occupancy may become prohibitively costly as heterospecific competitors and predators continue to recover in Gorongosa. Our results suggest that behavior can provide a leading indicator of the onset of density-dependent limitation and the likelihood of subsequent population decline, but that reliable inference hinges on understanding the mechanistic basis of observed behavioral shifts.
Anthropogenically driven spatial niche partitioning in a large herbivore assemblage
Understanding how human activity can influence species distributions and spatial niche partitioning between sympatric species is a key area of contemporary ecology. Extirpations of large mammalian populations, the result of a 15-year civil war, within the Gorongosa National Park in Mozambique, have been followed by an extended period of restoration. The species-specific recovery of these populations has provided an ideal system to identify how niche partitioning between coexisting species is altered as a consequence of extreme disturbance events. Here, we aimed to understand how distribution patterns of grazing herbivores, as well as spatial niche overlap between them, changed between the pre- and post-war scenarios. We focused on the following four grazer species: buffalo (Syncerus caffer); sable (Hippotragus niger); waterbuck (Kobus ellipsiprymnus); and zebra (Equus quagga). Using long-term aerial survey data, we quantified range size for each species, as well as spatial niche overlap between each species pair, for pre- and post-war periods. Range size of buffalo and zebra decreased drastically from the pre-war period; with both species inhabiting subsets of their historical distribution in the park. Sable and waterbuck have both colonised historically avoided habitat, with waterbuck doubling their pre-war range size. Spatial overlap between all four grazers pre-war was significantly high, indicating niche similarity; however, this decreased in the post-war period, with some species pairs displaying spatial niche dissimilarity. Our findings highlight how population responses to anthropogenic disturbance can result in significant alterations to species’ distributions, with consequences for patterns of niche similarity.
Missing in action: Species competition is a neglected predictor variable in species distribution modelling
The central role of species competition in shaping community structure in ecosystems is well appreciated amongst ecologists. However species competition is a consistently missing variable in Species Distribution Modelling (SDM). This study presents results of our attempt to incorporate species competition in SDMs. We used a suit of predictor variables including Soil Adjusted Vegetation Index (SAVI), as well as distance from roads, settlements and water, fire frequency and distance from the nearest herbivore sighting (of selected herbivores) to model individual habitat preferences of five grazer species (buffalo, warthog, waterbuck, wildebeest and zebra) with the Ensemble SDM algorithm for Gonarezhou National Park, Zimbabwe. Our results showed that distance from the nearest animal sighting (a proxy for competition among grazers) was the best predictor of the potential distribution of buffalo, wildebeest and zebra but the second best predictor for warthog and waterbuck. Our findings provide evidence to that competition is an important predictor of grazer species' potential distribution. These findings suggest that species distribution modelling that neglects species competition may be inadequate in explaining the potential distribution of species. Therefore our findings encourage the inclusion of competition in SDM as well as potentially igniting discussions that may lead to improving the predictive power of future SDM efforts.
Protecting cows in small holder farms in East Africa from tsetse flies by mimicking the odor profile of a non-host bovid
For the first time, differential attraction of pathogen vectors to vertebrate animals is investigated for novel repellents which when applied to preferred host animals turn them into non-hosts thereby providing a new paradigm for innovative vector control. For effectively controlling tsetse flies (Glossina spp.), vectors of African trypanosomosis, causing nagana, repellents more powerful than plant derived, from a non-host animal the waterbuck, Kobus ellipsiprymnus defassa, have recently been identified. Here we investigate these repellents in the field to protect cattle from nagana by making cattle as unattractive as the buck. To dispense the waterbuck repellents comprising guaiacol, geranylacetone, pentanoic acid and δ-octalactone, (patent application) we developed an innovative collar-mounted release system for individual cattle. We tested protecting cattle, under natural tsetse challenge, from tsetse transmitted nagana in a large field trial comprising 1,100 cattle with repellent collars in Kenya for 24 months. The collars provided substantial protection to livestock from trypanosome infection by reducing disease levels >80%. Protected cattle were healthier, showed significantly reduced disease levels, higher packed cell volume and significantly increased weight. Collars >60% reduced trypanocide use, 72.7% increase in ownership of oxen per household and enhanced traction power (protected animals ploughed 66% more land than unprotected). Land under cultivation increased by 73.4%. Increase in traction power of protected animals reduced by 69.1% acres tilled by hand per household per ploughing season. Improved food security and household income from very high acceptance of collars (99%) motivated the farmers to form a registered community based organization promoting collars for integrated tsetse control and their commercialization. Clear demonstration that repellents from un-preferred hosts prevent contact between host and vector, thereby preventing disease transmission: a new paradigm for vector control. Evidence that deploying water buck repellents converts cattle into non-hosts for tsetse flies-'cows in waterbuck clothing'.
Mio-Pliocene Faunal Exchanges and African Biogeography: The Record of Fossil Bovids
The development of the Ethiopian biogeographic realm since the late Miocene is here explored with the presentation and review of fossil evidence from eastern Africa. Prostrepsiceros cf. vinayaki and an unknown species of possible caprin affinity are described from the hominid-bearing Asa Koma and Kuseralee Members (∼5.7 and ∼5.2 Ma) of the Middle Awash, Ethiopia. The Middle Awash Prostrepsiceros cf. vinayaki constitutes the first record of this taxon from Africa, previously known from the Siwaliks and Arabia. The possible caprin joins a number of isolated records of caprin or caprin-like taxa recorded, but poorly understood, from the late Neogene of Africa. The identification of these two taxa from the Middle Awash prompts an overdue review of fossil bovids from the sub-Saharan African record that demonstrate Eurasian affinities, including the reduncin Kobus porrecticornis, and species of Tragoportax. The fossil bovid record provides evidence for greater biological continuity between Africa and Eurasia in the late Miocene and earliest Pliocene than is found later in time. In contrast, the early Pliocene (after 5 Ma) saw the loss of any significant proportions of Eurasian-related taxa, and the continental dominance of African-endemic taxa and lineages, a pattern that continues today.
Characterization of a composite with enhanced attraction to savannah tsetse flies from constituents or analogues of tsetse refractory waterbuck (Kobus defassa) body odor
Savannah tsetse flies avoid flying toward tsetse fly-refractory waterbuck ( Kobus defassa ) mediated by a repellent blend of volatile compounds in their body odor comprised of δ-octalactone, geranyl acetone, phenols (guaiacol and carvacrol), and homologues of carboxylic acids (C 5 -C 10 ) and 2-alkanones (C 8 -C 13 ). However, although the blends of carboxylic acids and that of 2-alkanones contributed incrementally to the repellency of the waterbuck odor to savannah tsetse flies, some waterbuck constituents (particularly, nonanoic acid and 2-nonanone) showed significant attractive properties. In another study, increasing the ring size of δ-octalactone from six to seven membered ring changed the activity of the resulting molecule (ε-nonalactone) on the savannah tsetse flies from repellency to attraction. In the present study, we first compared the effect of blending ε-nonalactone, nonanoic acid and 2-nonanone in 1:1 binary and 1:1:1 ternary combination on responses of Glossina pallidipes and Glossina morsitans morsitans tsetse flies in a two-choice wind tunnel. The compounds showed clear synergistic effects in the blends, with the ternary blend demonstrating higher attraction than the binary blends and individual compounds. Our follow up laboratory comparisons of tsetse fly responses to ternary combinations with different relative proportions of the three components showed that the blend in 1:3:2 proportion was most attractive relative to fermented cow urine (FCU) to both tsetse species. In our field experiments at Shimba Hills game reserve in Kenya, where G . pallidipes are dominant, the pattern of tsetse catches we obtained with different proportions of the three compounds were similar to those we observed in the laboratory. Interestingly, the three-component blend in 1:3:2 proportion when released at optimized rate of 13.71mg/h was 235% more attractive to G . pallidipes than a combination of POCA (3- n -Propylphenol, 1-Octen-3-ol, 4-Cresol, and Acetone) and fermented cattle urine (FCU). This constitutes a novel finding with potential for downstream deployment in bait technologies for more effective control of G . pallidipes , G . m . morsitans , and perhaps other savannah tsetse fly species, in ‘pull’ and ‘pull-push’ tactics.
Viral threats: the role of TikTok in facilitating trade in CITES-listed species in Lomé, Togo
Wild meat trade poses significant threats to biodiversity and human health. Despite these threats, trade and consumption are increasing, driven largely by growing demand in urban centers. Easy access to the internet and social media platforms further facilitates wildlife trade and consumption by connecting traders and consumers. This study examines 80 TikTok videos from public (open) accounts of two wild meat traders in Lomé, Togo, showcasing wild meat sales between November 2022 and April 2024. The videos featured various smoked wild animals, representing approximately 3,526 individuals across 27 inferred species, predominantly birds (40.9%) and mammals (39.6%), but also included reptiles (19.5%). Prices for whole smoked animals varied significantly (from a minimum of 3.4 USD to a maximum of 340 USD), depending on the species and the size of the individual animal. Among the 27 recorded species were the Endangered white-bellied pangolin ( Phataginus tricuspis ), classified as a CITES Appendix I species with a declining population trend; the Vulnerable Buffon’s kob (Kobus kob ssp. kob); the Near Threatened Defassa waterbuck (Kobus ellipsiprymnus ssp. defassa); and three CITES II-listed species. The 80 videos had each been viewed between 660 and 216,000 times, and all 80 videos had been viewed 1,795,079 times in total. This high level of visibility may fuel demand and unintentionally promote further trade by exposing a broad audience to such content. The findings highlight how social media can have significant negative conservation implications for the long-term survival and sustainable management of these species. Although enforcement mechanisms have been implemented to curb illegal wildlife trade on social media, these platforms still serve as vast, often unregulated marketplaces where traders and customers can easily connect, offering a level of convenience that traditional markets lack. We recommend that social media platforms strengthen their enforcement measures while conservationists leverage these platforms to raise awareness, promote wildlife protection laws, and mobilize public support for conservation efforts. The demand for wild meat in Lomé is driven by the growing population, cultural and economic benefits, as well as a lack of awareness. The study highlights the urgent need for targeted education, stronger enforcement of wildlife protection laws, and better communication about the legal status and conservation importance of the species.
Population Ecology and Possible Threats to Defassa Waterbuck (Kobus Ellipsiprymnus Defassa) in the Nechsar National Park, Ethiopia
Because of potential conflicts with humans, we investigated the population structure of waterbuck (Kobus ellipsiprymnus defassa) in the Nechsar National Park, Ethiopia, from November 2019 to August 2020, using line transect methods. The estimated population was 118 and 104 in the wet and dry seasons, respectively, and averaged 111 (+8) or 0.23/km2. The proportion of each age group averaged 31% adult males, 45% adult females, 12% subadult males, 11% subadult females, and 2% juveniles; the large number of female individuals suggests a healthy and increasing waterbuck population. The distribution of waterbuck sightings among habitat types differed by season (χ2 = 15.97, df = 3, p<0.05). Different conservation measures should be taken to create a conducive environment for waterbuck and large park biodiversity.
Serological Evidence of Antibodies to Rift Valley Fever Virus in Wild and Domestic Animals in Bauchi State, Nigeria
Rift Valley fever (RVF) is an arthropod-borne zoonotic disease responsible for severe outbreaks in livestock and humans with concomitant economic losses in many countries in sub-Saharan Africa. The study, therefore, investigated the seroprevalence of the Rift Valley fever virus (RVFV) among wild and domestic animals. Blood samples were collected between 2013 and 2015 from 106 wild animals, 300 cattle (Bos indicus), and 200 horses (Equus caballus), respectively, in Yankari Game Reserve (YGR) and Sumu Wildlife Park (SWP) in Bauchi state, Nigeria. Harvested sera from blood were evaluated for the presence of anti-RVFV IgM/IgG antibodies. The overall seroprevalence in cattle was 11.3% (p = 0.677; 95% CI: 0.624–0.730) and in wildlife was 8.5% (p = 0.006; 95% CI: 0.00–0.60). The diversity of wildlife species sampled indicated seropositivity of 36.0% in waterbuck (Kobus ellipsiprymus), 25.0% in elephant (Loxodonta africana), 12.5% in eland (Taurotragus oryx), and 8.3% in wildebeest (Connochaetes taurinus). Whereas, samples from zebra (Equus quagga crawshayi), kudu (Tragelaphus strepsiceros), and hartebeest (Alcelaphus buselaphus caama) did not show detectable antibodies to RVFV, and seroprevalence in female (15.0%) wildlife species was higher than in males (4.5%) (p = 0.061). Classification of cattle into breed and sex showed no significant difference in seropositivity. Seropositivity of 12.0% was observed in White Fulani, 12.1% in Red Bororo, and 7.8% in Sokoto Gudali breeds of cattle (p = 0.677). Whereas, seropositivity of 13.6% was observed in females and 6.4% observed in males (p = 0.068). This study indicated the presence of antibodies to RVFV among some wild animals and cattle in the absence of a reported outbreak in the study area. The circulation of RVFV in the study area may pose a significant health risk to livestock, wildlife, and humans. Therefore, surveillance for RVFV should be intensified targeting mosquito vectors and humans in Bauchi state, Nigeria.
Feeding Preference and Habitat Association of Defassa Waterbuck (Kobus ellipsiprymnus defassa) in Nechisar National Park, Southern Ethiopia
This study investigated feeding preference and habitat association of waterbucks in Nechisar National Park from November 2016 to August 2017 by total count and direct observation methods. From this survey, 20 plant species were observed to be the food items consumed by waterbucks. Waterbucks were mostly grazers than browser. The plant species consumed by waterbucks was highly significant between seasons (χ2 = 121.34, df = 1, p<0.05). Out of 20 total plant species consumed, annual grass (11.5%), Leersia virginica (8.4%), and Cynodon dactylon (8.4%) were the most frequently consumed food items, but Tamarindus indica (2.9%), Balanites aegyptica (3.3%), and Acacia polycantha (2.36%) were the least consumed food items. There was significant difference between plant species consumed during both seasons (χ2 = 177.67, df = 19, p<0.05). The Shannon–Wiener diversity index result revealed that there were different varieties of food items for waterbucks in dry season (H’ = 2.9) than in wet season (H’ = 2.6). Young leaves comprised the largest proportion of plant parts consumed by waterbucks compared to others. There was a highly significant difference in feeding plant parts in both seasons (χ2 = 88.5, df = 7, p<0.05). Waterbucks spent more time on feeding in the morning and late afternoon during both seasons. The total number of waterbucks in each habitat varied due to food availability in different seasons. Different conservation measures should be taken against waterbuck reduction and create appropriate environment for waterbuck.