African Zoology

Population status, distribution and seasonal range of Grevy’s zebra (Equus grevyi) in a protected savannah area

Tolera Abirham — 2023-12-15

The genus Equus comprises six species and 22 subspecies. Ethiopia is the only country in the world that has all three surviving species of zebra. The population status, structure, and seasonal range of Grevy’s zebra (Equus grevyi) were studied in the Hallaydeghe Asebot Protected Area (HAPA), southeast Ethiopia, using line transects and silent detection methods. Data were collected from 2021 to 2022 covering both the wet and dry seasons. The seasonal range of Grevy’s zebra was studied using the minimum convex polygon method. We counted 89 and 61 Grevy’s zebra during the wet and dry seasons, respectively. The total population size was estimated to be 75 individuals with a 95% confidence nterval of 60–90 individuals. The adult to sub-adult ratio was 3.1:1.0 during the wet season and 4:1 during the dry season. The sex ratio of adult female to adult male was 5:1 during the wet season and 4:1 during the dry season The seasonal range of the species in the HAPA was 477 km²(n = 89) during the wet season and 711 km² (n = 61) during the dry season. During the dry season Grevy’s zebra move out of the protected area to the Blen hot spring and its associated wetlands for green grazing and water. Hence, further study is needed on the possibility of incorporating the Blen hot spring and its associated wetlands into the protected area to promote the sustainable conservation of the species in the HAPA.

Lepidoptera as a tool for the assessment of human disturbance impacting ecological and taxonomic diversity in the Choke Mountains, Ethiopia

Tesfu F Tujuba — 2023-12-15

In tropical countries, frequent anthropogenic disturbances are primary drivers of the reduction in community diversity and local extinction of many insect taxa, including Lepidoptera. We assessed the impact of anthropogenic disturbances on lepidopteran assemblages across five different land use types (Fragmented Forest, Crop Fields, Pasture Land, Rural Settlements and undisturbed Natural Forest) in the Choke Mountains, Ethiopia. Lepidoptera were sampled using 20 W UV LED lights in 19 sites for 12 consecutive months. A total of 4 559 specimens representing 14 families and 339 species were sampled. The highest diversity was obtained from the Natural Forest, followed by the Fragmented Forest, Rural Settlements, Pasture Land and Crop Fields. The monthly trends of the diversity estimates showed strong differences among the five land use types, with months when the highest Hill–Shannon and Hill–Simpson values were observed not in the Natural Forest, but in the Rural Settlements and Fragmented Forest. The highest dominance values were observed in the Crop Fields and Pasture Land, with dominant species percentages of about 10%. The multivariate results clearly highlight the separation of the Natural Forest sites from all other sites and, in general, great consistency within each land use. A high positive linear relationship between the number of vascular plants and sampled Lepidoptera species was observed. The results of this study will be useful for guiding conservation management priorities to prevent irreversible biodiversity loss and maintain ecosystem provisioning services that are essential for the sustainable development of rural communities.

Species delimitation and molecular phylogeny of the grasshopper subfamily Gomphocerinae (Orthoptera: Acrididae) from Algeria based on mitochondrial and nuclear DNA markers

Rachida Hafayed — 2023-12-15

Gomphocerinae grasshoppers (Orthoptera: Acrididae) are generally characterised by their polymorphism and cryptic diversity, which can be confusing when relying on morphological identification alone. DNA taxonomy serves as a powerful molecular tool for species identification and biodiversity assessment. In the context of zoogeography and the biodiversity conservation of animal resources in ecosystems, DNA barcoding data for Algerian Gomphocerinae fauna remains limited in global databases, despite their agroeconomic and environmental importance. Therefore, in this study, we collected various species of this subfamily from the Biskra region in Algeria and conducted DNA barcoding analysis, employing different molecular species delimitation methods (the automatic barcode gap discovery, assemble species by automatic partitioning, single-threshold general mixed Yule coalescent model, Bayesian Poisson tree process and multi-rate Poisson tree process methods), as well as phylogenetic analyses (maximum-likelihood and Bayesian inference) based on two molecular markers (COI and ITS). The results of the 163 newly generated sequences demonstrated that DNA barcoding technology is highly efficient and valuable for species identification in the subfamily Gomphocerinae, showing strong congruence with morphological evidence for 12 species, including eight species that were sequenced for the first time. This study also reported a new record of the genus Stenohippus Uvarov, 1926 in Algeria, comprising two species. Additionally, taxonomic revision allowed the species Dociostaurus biskrensis Moussi & Petit, 2014, to be transferred to the genus Stenohippus. Molecular tree analyses revealed the phylogenetic positions of the newly sequenced species within the subfamily Gomphocerinae and provided insights into their evolutionary relationships. These new data serve as a starting point for future research in other geographical areas, enabling a better understanding of the biodiversity of this insect group in Algeria.

The status of COI and 12S rRNA DNA barcode reference libraries for freshwater fish in South Africa: Implications for future eDNA projects

Mahlatse F Mashaphu — 2023-12-15

Environmental DNA metabarcoding (eDNA) is a rapidly emerging field in which high-throughput sequencing is used to catalogue the biodiversity of ecosystems through the amplification of DNA extracted from environmental samples (water, air, faeces and soil). Although eDNA has strong links to DNA barcoding, the molecular marker most often used to detect vertebrates in eDNA studies is a portion of the mitochondrial 12S ribosomal RNA (12S rRNA) and not the standard cytochrome oxidase I (COI) marker used in traditional DNA barcoding. eDNA methods rely on a comprehensive reference library to link sequence data to species, which are often lacking in hyper-diverse countries such as South Africa. In this study, we review the present state of DNA barcode reference databases for both 12S rRNA and COI for freshwater fish (native and introduced) found in South African aquatic systems. Analysis of DNA records available on GenBank and the Barcode of Life Database (BOLD) revealed incomplete records of the examined taxa for both markers. Our findings showed that 34 species, 6 genera and 0 families of native South African freshwater fish lack COI barcode records, while 86 species, 22 genera and 8 families lack 12S rRNA records. Unlike the native freshwater fish, the non-native fish all had barcode records available for both COI and 12S rRNA. Producing comprehensive reference libraries for both markers is an important first step in developing an eDNA protocol for the non- invasive monitoring of native and non-native freshwater fish in South Africa.

Fine-scale drivers of extinction risk: tadpole occupancy dynamics of the Table Mountain Ghost Frog (Heleophryne rosei)

Joshua Weeber — 2023-12-15

Over the last four decades much progress has been made towards recognising causes of global amphibian declines, but knowledge of fine scale drivers, particularly for specialised species, remains poor, inhibiting conservation effectiveness. The case of the Table Mountain Ghost frog (Heleophryne rosei) provides an example of this, listed as Critically Endangered for the last 15 years with limited conservation actions identified due to a lack of information about threat mechanisms and magnitude of declines. To address this, we investigated H. rosei tadpole occupancy dynamics over three years in stream pools on Table Mountain in Cape Town, South Africa, the only locality where this species occurs. Tadpole spatiotemporal distribution was examined as a function of abiotic and biotic factors to quantify habitat requirements, rank threats, and identify conservation actions. Heleophryne rosei tadpole occupancy was negatively correlated with levels of fine sediments (silt and sand), which embed larger substrates and decrease the diversity of benthic microhabitat. Increased abundance of these fine sediments was also associated with higher extinction probabilities. Localised habitat degradation from hiking paths, alien vegetation, and flow manipulation were identified as the primary threats to this species, increasing the sources of fine sediments and inhibiting the fluvial systems ability to effectively flush these sediments out. Our results demonstrate the importance of pore space refugia for mountain headwater stream-adapted amphibians and provides the required data to inform management decisions for this Critically Endangered species.

A new record of a chick falling from a nest in Limpopo province, South Africa, adds to the known causes of Hooded Vulture Necrosyrtes monachus mortality

Lindy J Thompson — 2023-12-15

For all species, causes of mortality, both anthropogenic and natural, should be recorded. In Critically Endangered species these records are even more important, owing to their potential impacts on small and/or declining populations. Here we present a case of natural mortality that occurred when a 20-day old Hooded Vulture nestling fell from its nest in Limpopo province, South Africa, which is a new cause of mortality for the Critically Endangered Hooded Vulture Necrosyrtes monachus throughout its range. We also compile all known causes of mortality for Hooded Vultures from the scientific and grey literature. The carcass of this nestling was found on the ground below the nest some 25 days later. This cause of mortality is previously undocumented for this vulture species, and it was recorded on a series of photographs taken by a camera trap in the nest tree. We believe this cause of mortality to be uncommon when compared to other threats faced by this species.