African Journal of Wildlife Research - latest Issue
Volume 47, Issue 1, Apr 2017
Importance of Lake Ashenge, a small Important Bird Area in northern Ethiopia, to Palaearctic and other migratory birdsSource: African Journal of Wildlife Research 47, pp 1 –9 (Apr 2017) http://dx.doi.org/10.3957/056.047.0001More Less
Tropical inland lakes harbour a variety of waterbirds and provide a wintering habitat for Palaearctic and other migratory birds. However, the importance of the lakes as a temporary site for migrant bird populations has not been adequately studied. The point count method was used to study waterbird species diversity and abundance in Lake Ashenge, in the semi-arid region of northern Ethiopia, with the main aim to underscore the lake’s importance as a stop-over site for Palaearctic and other migratory birds. A total of 36 species belonging to 14 waterbird families were encountered. Fifteen of the species were resident birds, including the endemic Wattled Ibis (Bostrychia carunculata), and 14 of the species were Palaearctic migrants, including the globally Near-Threatened Ferruginous Duck (Ayithya nyroca) and Maccoa Duck (Oxyura maccoa). Significant temporal variation in diversity and abundance was observed during the study period; diversity was highest (Shannon-Wiener H’ = 1.98) in the dry season (December/January) and lowest (H’ = 1.11) in the rainy season (August/September), whereas mean abundance was highest (c. 4219 individuals) in the post-rainy season (October/November) and lowest (c. 2631 individuals) in the dry season. Increased abundance of Palaearctic species towards the dry season increased species diversity,but may have caused displacement of resident birds resulting in lower overall abundance in this season. This study provides a new distributional record for Maccoa Duck, highlights the significance of the lake for several waterbird species and calls for its protection.
Source: African Journal of Wildlife Research 47, pp 10 –23 (Apr 2017) http://dx.doi.org/10.3957/056.047.0010More Less
African lions (Panthera leo) are threatened across their natural range. However, the Kgalagadi Transfrontier Park (KTP) is a stronghold for the species.A population assessment in 2010 observed a skew in the sex structure with a greater proportion of males (56%) which raised concerns about the long-term sustainability of the greater KTP lion population. A key indicator of how a population responds to changes in population structure is population size. We conducted an intensive lion census between 2013 and 2015 in the southwestern KTP (14 250 km2) driving 49 784 km over 317 sampling days, which resulted in 1162 lion sightings. Registering the population through individual identification (n = 261) provided a benchmark against which other techniques could be measured and for a non-invasive marking technique. Open-population mark-recapture provided the most precise estimate of population size (n = 246; 95% CI: 237–256). Track indices (n = 242; 95% CI: 176–307) provided a similar best estimate, but were imprecise. Minimum-known-alive calculations (n = 145) provided a gross underestimate. All the methods used in this study indicate a larger lion population size than previous estimates.
Source: African Journal of Wildlife Research 47, pp 24 –31 (Apr 2017) http://dx.doi.org/10.3957/056.047.0024More Less
Body mass and organ size dynamics during flight-feather moult vary among waterfowl species. To better understand adaptations of the African waterfowl, we measured how body masses of Spur-winged Goose (Plectropterus gambensis),South African Shelduck (Tadorna cana), Yellow-billed Duck (Anas undulata), Red-billed Teal (Anas erythrorhyncha) and Southern Pochard (Netta erythrophthalma) change during flight-feather moult. We further assessed how pectoral muscle size of Spur-winged Goose and South African Shelduck varied during the same period of flight-feather moult. Our results indicate that Spur-winged Goose and South African Shelduck underwent atrophy and subsequent regeneration of the pectoral muscles, while their body mass decreased at the onset of moult and later stabilized from the time when flight feathers were two-thirds grown until moult was completed. Body mass of Yellow-billed Duck and Red-billed Teal decreased from the onset of moult until the mid-point but thereafter increased rapidly, returning to pre-moult levels by the time moult was completed. Southern Pochard gradually lost mass from the start of moult almost until moult completion, at which time mass increased slightly. We conclude that African waterfowl exhibit different fluctuations in body mass and pectoral muscle size during flight-feather moult. Taken together, these findings suggest that no single hypothesis can fully explain the interspecific differences in the moult strategies of African waterfowl as reflected in changes in body and pectoral muscle conditions.
Estimating occurrence and detectability of a carnivore community in eastern Botswana using baited camera trapsSource: African Journal of Wildlife Research 47, pp 32 –46 (Apr 2017) http://dx.doi.org/10.3957/056.047.0032More Less
Human–wildlife conflict and habitat loss are threatening carnivore populations in southern Africa, where the bulk of research focuses on large predators. However, scant research exists on medium and small carnivore (mesocarnivore) ecology.We employed hierarchical community modelling to estimate the effect of habitat on species occurrence and the effect of bait on detection probabilities for the carnivore community in the Mashatu Game Reserve, Botswana.We tested sites baited with either impala (Aepyceros melampus) meat (meat sites) or cheesecloth soaked in used cooking fat (fat rag sites) against unbaited sites (control sites). Within each bait classification, we divided our sampling effort between two habitat classifications, riverine and non-riverine sites. Thirteen of 16 carnivore species inhabiting the area (81%), including 10 of 12 species of mesocarnivore (83%), were recorded. Occupancy rates were higher in riverine habitat for several species, in particular African civet (Civettictis civetta), brown hyaena (Hyaena brunnea), and large-spotted genet (Genetta tigrina), demonstrating the importance of riverine habitat, which is declining in the study region. Our results suggest that the use of bait improves detectability. Several large carnivores, including spotted hyaena (Crocuta crocuta), brown hyaena, and leopard (Panthera pardus), were detected at highest rates at meat sites. Many mesocarnivores, including black-backed jackal (Canis mesomelas) and African civet responded equally to meat and fat rag sites, with detections greater than at control sites. Notably, large-spotted genet showed highest detection rates at fat rag sites, and brown hyaena showed higher rates at fat rag sites than control sites. Our detection results indicate that spent cooking fat may be used as an effective bait alternative to meat when studying mesocarnivore communities in southern Africa, whereas meat may still be the most effective for studying large carnivore communities. Identifying effective methods of increasing detection rates will benefit carnivore survey and monitoring initiatives, especially for cryptic species.
Source: African Journal of Wildlife Research 47, pp 47 –58 (Apr 2017) http://dx.doi.org/10.3957/056.047.0047More Less
Observer impacts on animal behaviour concern conservation managers and researchers of critically endangered species, like black rhino (Diceros bicornis). Repeated observations are sometimes necessary, but may distress and displace animals. Information from more remote observations using radio-triangulation is limited and includes larger measurement errors. We investigated the influence of observer visits on average daily displacement by 14 black rhinos in Hluhluwe-iMfolozi Park, South Africa, and the accuracy of triangulated locations with increasing observer distance and the time to complete bearing sets. Fortnightly observer visits for 34 months that often disturbed rhino (52% of visits) had an insignificant impact on daily movements.However, increasing observer distance from rhino, and the time taken to triangulate,were both significant explanations of rhino location error. We recommend that measures to quantify and minimize observer influence become standard monitoring protocol and that bearings for radio-triangulation of black rhino locations occur from <1 km (not >2 km), and be completed within 30 minutes. Reporting measures for spatial error and observer influence permit the development of objective thresholds for data inclusion to improve radio-telemetry data and inter-study comparisons of black rhino range studies.
Hiding in plain sight : evidence of hybridization between Cape mountain zebra (Equus zebra zebra) and plains zebra (Equus quagga burchelli)Source: African Journal of Wildlife Research 47, pp 59 –64 (Apr 2017) http://dx.doi.org/10.3957/056.047.0059More Less
Historically, Cape mountain zebras (Equus zebra zebra) were widely distributed along mountain ranges in the Eastern and Western Cape provinces of South Africa (Boshoff, Landman & Kerley, 2015). By the 1930s, excessive hunting and habitat loss resulted in a reduction in Cape mountain zebra numbers with populations being confined to only five localities. Two of these subpopulations subsequently became extinct. Three relic populations currently exist; the population in the Cradock district,was formally protected in 1937 by the proclamation of the Mountain Zebra National Park (MZNP; Lloyd 1984). The two other populations in the Kammanassie and Gamka Mountains, have been protected since 1923 and 1971, respectively. Cape mountain zebra numbers increased steadily from their critical status of fewer than 80 individuals in the 1950s, to an estimated minimum of 4791 individuals by 2015 (Hrabar & Kerley, 2015). Plains zebra (Equus quagga burchelli) were subsequently introduced, in sympatry with Cape mountain zebra into four formally protected areas, including the MZNP in 1999 and Karoo National Park in 1998. Until recently no cases of hybridization between plains zebra and Cape mountain zebra were known. Hybridization was not of great concern as a threat to Cape mountain zebra populations as fertile hybrids were thought to be unlikely, due to the relatively large difference in the number of chromosomal pairs between the two species (44 versus 32 in plains zebra and Cape mountain zebra, respectively; Ryder, Epel & Benirschke, 1978; Cordingley et al., 2009; Hrabar & Kerley, 2013). By 2013, the plains zebra population had increased substantially in the MZNP (estimated at 769 Cape mountain zebra and 124 plains zebra by aerial census (unpublished aerial census data, 2013) and were potentially competing with Cape mountain zebra for resources. A decision was thus taken to remove the plains zebra. This intervention resulted in a disruption in the social structure, and some of the small, fragmented groups or plains zebra individuals joined Cape mountain zebra herds. In addition, conservation officials observed ‘Cape mountain zebra’ with plains zebra characteristics. These included slight shadow striping, stripes extending all the way down to the ventral midline of the chest and abdomen, and, although they did have the reddish muzzle of mountain zebra, they did not have the characteristic mountain zebra gridiron pattern on their rumps (Fig. 1), but rather had absent or distorted patterns on the rump. They exhibited the distinct dewlap of the Cape mountain zebra and ear shapes were similar to plains zebra. This raised concerns of possible hybridization between the two species. Here, we report on a molecular evaluation using maternal, paternal and biparental markers to identify suspected hybrid Cape mountain and plains zebra in MZNP and Karoo National Park, South Africa.