359 research outputs found
Elephants in the Impenetrable (Bwindi) Forest, Uganda
Because of its probable role as a Pleistocene refuge, and its range in altitude, the 321 km2 Impenetrable Forest has one of the richest floras and faunas in Africa. Results of an ecological survey conducted between January 1983 and September 1984 show that elephants in this forest number fewer than 30, poaching being a primary cause for this low number. Elephants use only about 19% of the Forest area and then mostly within areas of low human activity. Assessments of the status of elephants in other forests in Uganda, and research on the role of elephants in these forests, are urgently needed so that appropriate management programs can be undertaken
Twenty years conservation and monitoring of re-introduced mountain gazelle in the Ibex Reserve, Saudi Arabia
Historically, the mountain gazelle (Gazella gazella) occurred across most of the Arabian Peninsula into northern Syria and Turkey. Early explorers and scientists reported that the mountain gazelle is closely associated with Acacia spp. trees. The current range includes southern Turkey, Jordan, Israel, Iran (Farur Island), Oman, United Arab Emirates, Yemen and Saudi Arabia. The IUCN Red List currently ranks this species as ‘Vulnerable’ (A2ad). Mountain gazelle numbers have decreased dramatically throughout their range, particularly in Saudi Arabia. The only protected areas in Saudi Arabia with natural populations of mountain gazelle are Al Khunfah, Harrat al Harrah, and Farasan Islands. A few scattered populations occur outside of protected areas in the western Asir Mountains, Hejaz Mountains, and possibly on the Tihama coastal plain. There are only two reports of mountain gazelle occurring historically in the central mountains of Saudi Arabia. Both reports are for mountain gazelle in the Jebel Tuwaiq, which is where the Ibex Reserve is situated. In an effort to re-establish the locally extinct population in the Tuwaiq Mountains (Ibex Reserve), the Saudi Wildlife Authority (SWA) initiated a mountain gazelle re-introduction program in 1990 (Dunham et al., 1993). The released gazelles came from the King Khalid Wildlife Research Centre (KKWRC), Saudi Arabia
Can morphotaxa be assessed with photographs? Estimating the accuracy of two-dimensional cranial geometric morphometrics for the study of threatened populations of African monkeys
The classification of most mammalian orders and families is under debate and the number of species is likely greater than currently recognized. Improving taxonomic knowledge is crucial, as biodiversity is in rapid decline. Morphology is a source of taxonomic knowledge, and geometric morphometrics applied to two dimensional (2D) photographs of anatomical structures is commonly employed for quantifying differences within and among lineages. Photographs are informative, easy to obtain, and low cost. 2D analyses, however, introduce a large source of measurement error when applied to crania and other highly three dimensional (3D) structures. To explore the potential of 2D analyses for assessing taxonomic diversity, we use patas monkeys (Erythrocebus), a genus of large, semi-terrestrial, African guenons, as a case study. By applying a range of tests to compare ventral views of adult crania measured both in 2D and 3D, we show that, despite inaccuracies accounting for up to one-fourth of individual shape differences, results in 2D almost perfectly mirror those in 3D. This apparent paradox might be explained by the small strength of covariation in the component of shape variance related to measurement error. A rigorous standardization of photographic settings and the choice of almost coplanar landmarks are likely to further improve the correspondence of 2D to 3D shapes. 2D geometric morphometrics is, thus, appropriate for taxonomic comparisons of patas ventral crania. Although it is too early to generalize, our results corroborate similar findings from previous research in mammals, and suggest that 2D shape analyses are an effective heuristic tool for morphological investigation of small differences
Neumann’s enigmatic gazelle (Gazella erlangeri) Threatened taxon or domesticated gazelle?
One of the most challenging questions in regard to Arabian gazelles is the status of G. erlangeri Neumann, 1906 (Fig. 1). Gazelles currently kept in captivity at King Khalid Wildlife Research Centre in Saudi Arabia and Al Wabra Wildlife Preservation in Qatar (Fig. 2) show the described combination of diagnostic features, and thus, were considered to represent G. erlangeri, even though the exact provenance of these gazelles remains obscure. However, captive ‘G. erlangeri’ may have also originated from eastern Oman and could be therefore assigned to G. muscatensis (Fig. 3). Both taxa are considered ‘extinct in the wild’ by the IUCN Red List. Past conservation efforts have been plagued by confusion about the phylogenetic relationship among various—phenotypically discernable—populations (e.g., G. erlangeri, G. muscatensis), and even the question of species boundaries was far from being certain. This lack of knowledge had a direct impact on conservation measures, especially ex situ breeding programmes, hampering the assignment of captive stocks to potential conservation units
Vocal Repertoire and Intraspecific Variation within Two Loud Calls of the Small-Eared Greater Galago (Otolemur garnettii) in Tanzania and Kenya
© 2019 S. Karger AG, Basel. All rights reserved. Vocal repertoires and call structure can provide insights into the behaviour and evolution of species, as well as aid in taxonomic classification. Nocturnal primates have large vocal repertoires. This suggests that acoustic communication plays an important role in their life histories. Little is known about the behavioural context or the intraspecific variation of their vocalisations. We used autonomous recording units and manual recorders to investigate the vocal behaviour and structure of loud calls of the small-eared greater galago (Otolemur garnettii)in Kenya and Tanzania. We describe the vocal repertoire, temporal calling patterns and structure of 2 loud calls of 2 subspecies: O. g. panganiensis and O. g. kikuyuensis. We found considerable intraspecific structural differences in both loud calls. These are congruent with the current subspecies classification. Differences in vocalisations among populations are not consistent with the "acoustic adaptation hypothesis," rather they are likely a result of geographic variation due to isolation caused by vegetational barriers in southern Kenya
Population dynamics of the Manyara monkey (Cercopithecus mitis manyaraensis) and vervet monkey (Chlorocebus pygerythrus) in Lake Manyara National Park, Tanzania
Estimating population densities and their trends over time is essential for understanding primate ecology and for guiding conservation efforts. From 2011 through to 2019, we counted two guenon species during seasonal road transect surveys in Lake Manyara National Park: the Tanzania-endemic Manyara monkey Cercopithecus mitis manyaraensis (International Union for Conservation of Nature and Natural Resources, IUCN, Red List category of “endangered”) and the vervet monkey Chlorocebus pygerythrus (Red List category of “least concern”). To account for imperfect detectability, we analysed the data in a line distance sampling framework, fitted species-specific detection functions, and subsequently estimated seasonal densities. To test for seasonal differences and yearly trends in the species-specific density estimates, we fitted generalized additive models. Seasonal point density estimates fluctuated considerably during the 9 years (2011–2019) of our study, ranging from 3 to 29 individuals km−2 for Manyara monkeys and from 19 to 83 individuals km−2 for vervet monkeys. Densities of both taxa did not differ seasonally, and we did not detect marked directional population trends. Our study illustrates the utility and limitations of line distance sampling for long-term primate monitoring. Beyond informing primate ecology and management, our results highlight the conservation importance of Lake Manyara National Park for primate conservation.</p
Dark grey gazelles Gazella (Cetartiodactyla: Bovidae) in Arabia: Threatened species or domestic pet?
True gazelles (genus Gazella) are a prime example of a mammalian group with considerable taxonomic confusion. This includes the descriptions of several dark grey taxa of questionable validity. Here, we examined captive dark grey putative Neumann’s gazelle Gazella erlangeri. Our concerted efforts to retrieve mitochondrial sequence information from old museum specimens of two dark grey gazelles, putative G. erlangeri and putative Muscat gazelle G. muscatensis, were unsuccessful. We did, however, find the mtDNA haplotypes of extant putative G. erlangeri to be nested within the haplotype variation of the Arabian gazelle G. arabica. The observed population genetic divergence between G. arabica and putative G. erlangeri (based on 11 nuclear microsatellites) was driven by genetic impoverishment of putative G. erlangeri. These results, along with morphological signatures of domestication (e.g., reduced brain case size), suggest genetic bottle necks and domestication effects as a consequence of prolonged captive breeding. Three hypotheses are discussed: (a) G. erlangeri and/or G. muscatensis are valid species but are now extinct; (b) one or both taxa represent phenotypic variation within G. arabica and, therefore, are synonyms of G. arabica; and (c) captive stocks, exhibiting the effects of domestication and inbreeding, are the sources for the descriptions of G. erlangeri and G. muscatensis. As concerns the conservation of gazelles, based on current knowledge, we strongly advise against using putative G. erlangeri for any introduction initiative but recommend the continued captive management of putative G. erlangeri
Sleep patterns, daytime predation, and the evolution of diurnal sleep site selection in lorisiforms.
Synthesize information on sleep patterns, sleep site use, and daytime predation at sleep sites in lorisiforms of Asia and Africa (10 genera, 36 species), and infer patterns of evolution of sleep site selection. We conducted fieldwork in 12 African and six Asian countries, collecting data on sleep sites, timing of sleep and predation during daytime. We obtained additional information from literature and through correspondence. Using a phylogenetic approach, we established ancestral states of sleep site selection in lorisiforms and traced their evolution. The ancestral lorisiform was a fur-clinger and used dense tangles and branches/forks as sleep sites. Use of tree holes and nests as sleep sites emerged ∼22 Mya (range 17-26 Mya) in Africa, and use of bamboo emerged ∼11 (7-14) Mya in Asia and later in Africa. Fur clinging and some sleep sites (e.g., tree holes, nests, but not bamboo or dense tangles) show strong phylogenetic signal. Nests are used by Galagoides, Paragalago, Galago and Otolemur; tree holes by Galago, Paragalago, Sciurocheirus and Perodicticus; tangles by Nycticebus, Loris, Galagoides, Galago, Euoticus, Otolemur, Perodicticus and Arctocebus; all but Sciurocheirus and Otolemur additionally sleep on branches/forks. Daytime predation may affect sleep site selection and sleep patterns in some species of Nycticebus, Galago, Galagoides, Otolemur and Perodicticus. Most lorisiforms enter their sleep sites around sunrise and leave around sunset; several are active during twilight or, briefly, during daytime. Variations in sleep behavior, sleep patterns and vulnerability to daytime predation provide a window into the variation that was present in sleep in early primates. Overall, lorisiforms use the daytime for sleeping and no species can be classified as cathemeral or polycyclic
Low geographic and subspecific variation in the loud call of the widespread and phenotypically cryptic northern lesser galago (Galago senegalensis) suggests taxonomic uniformity
Like other nocturnal primates, many species of galago (Galagidae) are phenotypically cryptic, making their taxonomic status difficult to resolve. Recent taxonomic work has disentangled some of the confusion. This has resulted in an increase in the number of recognised galago species. The most widespread galago species, and indeed the most widespread nocturnal primate, is the northern lesser galago (Galago senegalensis) whose geographic range stretches >7,000 km across Africa. Based on morphology, 4 subspecies are currently recognised: G. s. senegalensis, G. s. braccatus, G. s. sotikae and G. s. dunni. We explore geographic and subspecific acoustic variation in G. senegalensis, testing three hypotheses: isolation by distance, genetic basis, and isolation by barrier. There is statistical support for isolation by distance for 2 of 4 call parameters (fundamental frequency and unit length). Geographic distance explains a moderate amount of the acoustic variation. Discriminant function analysis provides some degree of separation of geographic regions and subspecies, but the percentage of misdesignation is high. Despite having (putative) parapatric geographic ranges, the most pronounced acoustic differences are between G. s. senegalensis and G. s. dunni. The findings suggest that the Eastern Rift Valley and Niger River are significant barriers for G. senegalensis. The acoustic structures of the loud calls of 121 individuals from 28 widespread sites are not significantly different. Although this makes it unlikely that additional unrecognised species occur within G. senegalensis at the sites sampled, vast areas of the geographic range remain unsampled. We show that wide-ranging species do not necessarily exhibit large amounts of variation in their vocal repertoire. This pattern may also be present in nocturnal primates with smaller geographic ranges
Prey preferences of the chimpanzee (Pan troglodytes)
The common chimpanzee Pan troglodytes is the closest extant relative of modern
humans and is often used as a model organism to help understand prehistoric human
behavior and ecology. Originally presumed herbivorous, chimpanzees have been observed
hunting 24 species of birds, ungulates, rodents, and other primates, using an
array of techniques from tools to group cooperation. Using the literature on chimpanzee
hunting behavior and diet from 13 studies, we aimed to determine the prey
preferences of chimpanzees. We extracted data on prey-specific
variables such as
targeted species, their body weight, and their abundance within the prey community,
and hunter-specific
variables such as hunting method, and chimpanzee group size and
sex ratio. We used these data in a generalized linear model to determine what factors
drive chimpanzee prey preference. We calculated a Jacobs’ index value for each
prey species killed at two sites in Uganda and two sites in Tanzania. Chimpanzees
prefer prey with a body weight of 7.6 ± 0.4 kg or less, which corresponds to animals
such as juvenile bushbuck (Tragelaphus scriptus) and adult ashy red colobus monkeys
(Piliocolobus tephrosceles). Sex ratio in chimpanzee groups is a main driver in developing
these preferences, where chimpanzees increasingly prefer prey when in proportionally
male-dominated
groups. Prey preference information from chimpanzee
research can assist conservation management programs by identifying key prey species
to manage, as well as contribute to a better understanding of the evolution of
human hunting behavior.The University of Newcastle.http://www.ecolevol.orgam2022Mammal Research Institut
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