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Information on genetic variation within and among populations is relevant for a broad range of topics in biology. We use a combination of mitochondrial and nuclear microsatellite markers to evaluate genetic variation within and between two populations of bat-eared foxes (Otocyon megalotis Desmarest, 1822) in South Africa. The bat-eared fox is a small canid occurring in southern and eastern Africa. The species is currently not threatened with extinction, but a lack of information on genetic diversity has been identified as a deficit for its future conservation. We observed low to moderate genetic differentiation between the two geographically separated populations, but neither mitochondrial nor nuclear microsatellite markers suggested that there have been dispersal barriers between them. Similar genetic diversity within both populations was contrasted by interpopulational differences in relatedness variation among males and females. A high genetic relatedness within both populations, indicated by mitochondrial data, is likely caused by a common historical origin or a combination of species-specific social organization and environmental dispersal constraints. We call for further research on the genetic divergence of bat-eared fox populations as well as on the genetic consequences of interactions between environmental characteristics and social organization in this species.
Richard D Lyamuya, Kwaslema M Hariohay, Emmanuel H Masenga, John K Bukombe, Grayson G Mwakalebe, Maulid L Mdaki, Ally K Nkwabi, Robert D Fyumagwa, Eivin Røskaft
Globally, traffic associated with roads that pass through protected areas are the cause of many negative impacts on wildlife, such as wildlife roadkill, which has occurred within the Serengeti ecosystem. A 200 km stretch of gravel road networks that passes through the Serengeti ecosystem was surveyed in 2015 for five consecutive days during each study period during the wet and dry seasons, between March and August 2015, to document the magnitude, patterns and composition of wildlife roadkill. We found a total of 51 wildlife roadkills that consisted of 26 species of wild animals and included 18 bird and 8 mammal species. Bird species (60.8%) were more frequently killed than mammal species (39.2%). Moreover, a higher incidence of wildlife roadkill was recorded in the morning (56.9%) than in the afternoon (43.1%) and more mammals (51.7%) than birds (48.3%) were recorded in the morning. Greater numbers of wildlife roadkill were recorded along road segments with good road conditions (69.4%) that were wider (>8 m) and with higher traffic volumes than along roads with poor conditions (30.6%). Overall, the Cape hare (Lepus capensis) was the most frequently killed species (17.6%) among the mammals, whereas the helmeted guineafowl (Numida meleagris) (13.7%) was most frequently killed among the avifauna. To reduce the number of roadkill incidents, we recommend changing driver speeding behaviours by installing wildlife-warning signage that consists of picture-based signs, because they have been proved to be more effective than word-based signs to reduce speeds and hence, reduce collisions. Additionally, the responsible management authorities should provide education to drivers on safe driving and enforcement of laws and regulations. Further, policy briefings that focus on wildlife roadkill should be made available to assist decision-makers and engineers to improve road design in protected areas.
Most migratory aquatic birds are regarded as reservoir hosts for many parasitic diseases, including digenetic trematodes that cause significant losses to farmed fish. However, in Tanzania, studies of birds focus more on their species diversity and patterns of speciation than their parasites. The current study attempted to use molecular methods, mitochondrial DNA (mtDNA), cytochrome c oxidase subunit I (COX-1) in particular, and ribosomal DNA (rDNA) i.e. 28S rRNA and internal transcribed spacer (ITS1-5.8S-ITS2) regions, to investigate the occurrence of intestinal echinostomatoid species recovered from fish-eating birds, i.e. Grey Herons (Ardea cinerea) and Great Cormorants (Phalacrocorax carbo), from Mwanza Gulf in Lake Victoria. Both morphology and molecular markers revealed the presence of three echinostomatoid species: Stephanoprora amurensis and Petasiger phalacrocoracis in P. carbo, and the Patagifer vioscai in A. cinerea. The present species are reported for the first time in African bird species.
Anthropogenic activities have propelled the exploitation of natural environments, which along with climate change have resulted in salinity intrusion to freshwater ecosystems worldwide. To determine the extent the hypersalinity stressor has on freshwater ecosystems, physiological cardiac responses in the freshwater gastropod Melanoides tuberculata were analysed during an acute exposure to varying salinity concentrations. A non-invasive method was used to monitor the cardiac activity of the organisms. The mean heart rate (bpm) of M. tuberculata declined significantly between 20 ppt and 30 ppt. Melanoides tuberculata exhibited a hypersalinity threshold of 25 ppt and tolerated salinity concentrations up to 50 ppt. Data collected provide background data for the use of M. tuberculata as a bioindicator organism to assess the effects of hypersalinity on cardiac response of organisms in a freshwater ecosystem.
Measures of activity patterns in relation to environmental conditions provide insights into ecologically driven requirements and climate preferences of species, particularly for ectotherms, due to the strong relationship between body temperature (Tb) and environmental temperatures. Lygodactylus incognitus (cryptic dwarf gecko) and Lygodactylus soutpansbergensis (Soutpansberg dwarf gecko) are range-restricted endemics to the Soutpansberg Mountains, South Africa, and have recently been shown to be potentially vulnerable to the effects of climate change. This prompted us to study the relationship between the thermoregulatory characteristics and environmental temperatures for these syntopic species. Active geckos (i.e. those outside of a refuge) and environmental variables were recorded during scan surveys across two seasons. Binomial logistic regressions were used to predict and explain activity based on presence/absence measures and environmental variables for each species. Of the variables measured, air temperature (Ta) was the main predictor of activity for both species. Cryptic dwarf geckos were active in cooler Ta than warmer temperatures in comparison to Soutpansberg dwarf geckos. Cryptic dwarf geckos are thus well adapted to temperate conditions. Soutpansberg dwarf geckos appear well adapted for warmer conditions, as they were more likely to be active at higher Ta. Our findings suggest that both species will alter their daily activity times in response to changing climate, but that the cryptic dwarf gecko is likely to be more negatively impacted than the Soutpansberg dwarf gecko, due to their affinity for cooler temperatures and avoidance of the hottest temperatures exhibited during the study period. Therefore, although these broadly sympatric, syntopic, range-restricted species are closely related and have similar life histories, they occupy different thermal niches and are likely to respond to climate change idiosyncratically. Our findings caution against the overuse of proxy species in predicting species geographic distribution changes in response to climate change.
The skink Mochlus sundevallii is widespread throughout the African continent, but no detailed research on its ecology, reproduction and sexual dimorphism patterns has been performed yet. Here we address phenotypic and ecological data of M. sundevallii from the southernmost part of its distribution, using multiple populations from Southern Africa (mostly from South Africa) collected throughout different seasons. We aimed to assess the degree of intersexual and seasonal differences in morphological and reproductive aspects, as well as their experienced predation pressure. Morphological analyses confirmed that the species exhibits sexual dimorphism, evidenced by a larger body size for females and larger heads and longer limbs for males. However, tail autotomy (used as an estimation of predation rate) was found to be similar for both sexes and seasonally stable. Overall, the reproductive cycles of males and females were synchronised across the seasons, for an optimal breeding period during spring and summer, but males showed certain spermatogenic activity throughout the whole year.
Despite the commonly held belief that reptiles are immune to extreme temperatures, global warming is predicted to result in the loss of 40% of all reptile species by 2080. In order to understand the effects of elevated temperature on African reptile physiology and health, additional research is required. We studied the physiological stress response of sungazer lizards (Smaug giganteus) facing elevated temperatures within captivity. Control animals (1M, 2F) were kept at 30 °C throughout the 13-week study period. Test animals (1M, 2F) were exposed to 30 °C for four weeks (stage 1), 39 °C for six weeks (stage 2) and 30 °C for three weeks (stage 3). Faecal samples were collected from both control and test animals to monitor faecal glucocorticoid metabolite (fGCM) concentrations as a proxy of physiological stress. Although the fGCM levels of control females remained constant, test females showed an acute fGCM increase following the increase and subsequent decrease of temperatures. The test male had significantly higher fGCM levels during stage 3, compared with stage 1 and 2. The control male, although displaying constant fGCM levels throughout the study, had higher fGCM levels than the test male. The results indicate that a considerable temporal increase in environmental temperature did not lead to chronically elevated adrenocortical activity in sungazer lizards. It is likely that inherent traits within the species allow the species to adapt to such changes. Furthermore, the endangered status of the species and limited availability of study animals restricted the sample size in this study to a few, captive-based lizards. Therefore, although our results are an important addition to reptile conservation, they should be extrapolated to free-ranging populations with caution. Future research should consider the effects of chronically elevated temperature in relation to water and food shortages, as well as interindividual variation in physiological responses.
To date, there have been few published reports of Caracal spp. (or other non-domestic carnivores) preying upon nocturnal strepsirrhine primates anywhere in continental Africa. However, in South Africa, most studies of caracal diet have been conducted outside of the known geographic range of South Africa's nocturnal primates. Here we report Otolemur crassicaudatus (the greater or thick-tailed bushbaby/galago) remains recovered from the stomach of a caracal, collected in Limpopo province, South Africa, in 2018, which included portions of the limbs, tail, skull and dentition, allowing confident taxonomic assignment. Sixty-seven carnivores (equal in size or larger than O. crassicaudatus), including one other caracal, also had stomach contents examined between 2012 and 2019 in northern South Africa. None included O. crassicaudatus remains, making this the first documented example of this non-human primate species being preyed upon by an endemic carnivore; kills of O. crassicaudatus by domestic dogs, though not being consumed, have previously been documented. These data expand the knowledge of the diet of caracal in southern Africa and may signal an expanding caracal dietary regime and possible behavioural changes in O. crassicaudatus, such as increased terrestrial movement, with increasing human actions and reduction of endemic forests and habitats.
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