African Journals Online
South African Journal of Wildlife Research

Volume 32, Issue 2, October 2002
ABSTRACTS

Forage intake rates and foraging efficiency of free-ranging zebra and impala

Okello, M.M.; Wishitemi, R.E.L.; Muhoro, F.

Abstract: Intake rates and foraging efficiency depend on the anatomic features of the foraging animal and its foraging behaviour. Foraging parameters of Burchell's zebra (Equus burchelli) and Impala (Aepyceros melampus) were collected to determine the intake rate, cropping rate and bite size through observation and bite count methods. Intake rates were 48.76 ± 0.49 g/min and 27.28 ± 0.22 g/min for the zebra and impala, respectively. Bite size and cropping rate for zebra were 1.93 ± 0.04 and 25.92 ± 0.30, respectively. For impala, they were 0.78 ± 0.01 and 35.20 ± 0.16, respectively. The maximum theoretical intake rate for zebra was 100.96 g/min and 77.32 g/min for impala. The foraging efficiency index was higher for impala (1.03) than zebra (0.61). For zebra to achieve a 63% intake satiation, forage biomass with a bite size of 1.65 g/bite was necessary, while for impala, biomass with a bite size of 0.97 g/bite was necessary. Zebra's large intake rates, bite sizes and low foraging efficiency are possibly due to its bulk and unselective foraging. Impala's high foraging efficiency, cropping rate and relatively low intake rate are associated with its relatively selective foraging strategy.

Small mammal diversity in the Maguga Dam inundation area, Swaziland

Avenant, N.L.; Kuyler, P.

Abstract: Owing to the limited knowledge of small mammals of Swaziland, the present study conducted a small mammal survey in the Maguga Dam inundation and surrounding areas in Swaziland. In addition it assessed small mammal diversity, species richness (variety), and abundance ratio (evenness) in specific vegetation (or habitat) types. Mean diversity values of 0.9 at 66.6% of transects indicated that pockets of fairly pristine habitat still exist. Large differences in mammal composition, trap success and diversity were found between habitats. In the most disturbed areas, fewer species were found and Mastomys sp. dominated. Lack of dominance of Mastomys species, species richness and diversity are small mammal community characteristics that indicate ecosystem integrity. Thus direct monitoring of small mammals can be a time- and cost-efficient method of assessing ecological disturbance. The six Grammomys dolichurus specimens found during this study are to date the only records of this species in Swaziland.

Primate sanctuaries - a delicate conservation approach

Schoene, C.U.R.; Brend, S.A.

Abstract: Sanctuaries - centres that care for rescued, orphaned or confiscated animals - hold an uneasy position in the conservation community. Commonly, the problem of captive primates is seen as an unfortunate distraction from the real issue of habitat loss and over-hunting, and sanctuaries are categorized as serving welfare purposes only. Frequently, they struggle for funding and are unable to secure the large grants that are directed towards other conservation initiatives. Sanctuaries also have to face welfare problems created when capacities are exceeded and they lack safe, viable habitat for the species they try to protect. The solutions, discussed in this paper, are integrating care for rescued animals with habitat protection and education. Reintroduction efforts, which would otherwise be of conservation benefit, are constrained by the unresolved issues including disease transfer, competition with wild populations, and the interface with ecotourism activities.

Time bias and correction factors for helicopter-based total counts of large ungulates in bushveld

Reilly, B.K.; Van Hensbergen, H.J.

Abstract: Annual helicopter total counts took place over the period 1987 to 1994 in various bushveld areas of the Limpopo Province, Mpumalanga and North West Province, South Africa. Subjective examination suggested that the number of observations during the course of each of these counts consistently declined over time. In this study, all 13 295 observations of animals and animal groups from counts of four hours or longer were logged in 30-minute intervals up to four hours with a view to quantifying the decline in observations and proposing correction factors. A significant decline in observations over time is shown for sourish mixed bushveld and northwest arid bushveld, but this is not the case for mopane veld.

Accuracy, bias and precision of helicopter-based counts of black rhinoceros in Pilanesberg National Park, South Africa

Brockett, B.H.

Abstract: Accuracy, bias and precision of helicopter-based counts for black rhinoceros in Pilanesberg National Park were established using accurate population estimates derived from intensive monitoring. Over the 19-year period studied there were changes in sampling methods, and techniques employed. Accuracy and precision increased similarly as the number of observers increased. Total area counts were more accurate than sampled counts. The most accurate and precise estimates were produced using total area parallel transect counts with three observers. Confidence limits using one observer were wide, and widest for sampled counts with one observer. Sampled counts were more repeatable than total area block counts. Total area counts using blocks produced positively biased estimates for two successive years. This was attributed to management functions, the counting operation, lack of standardization of methods, observer error and environmental factors. The use of multiple teams of observers, multiple scribes/navigators, and inexperienced observers over the period of a count are not recommended. To achieve repeatable counts the technique should be applied in a consistent manner. A logistic regression model predicted the proportion of population counted as a function of the number of observers and seasonal rainfall.

Rodent and insectivore species diversity of Seekoeivlei Provincial Nature Reserve, Free State province, South Africa

Wandrag, G.F.; Watson, J.P.; Collins, N.B.

Abstract: Seekoeivlei Provincial Nature Reserve in the Free State province, South Africa, consists mainly of a wetland which is a RAMSAR site. Five sample sites were identified and classified according to hydrological regime. Step point plant surveys were performed at each site and the species richness, abundance and species diversity of the small mammals at each site were determined using snap-traps. A total of 104 individuals of seven small mammal species were trapped during 2250 trap-nights in the reserve resulting in a 4.6% trap-success. Data collected were compared with research done in similar habitat types or mountainous grassland. A species diversity index of 1.44 was calculated for Seekoeivlei Provincial Nature Reserve, which is higher than reported for Qwa-Qwa National Park (1.29), Giants Castle (1.34) and Cathedral Peak Nature Reserves (1.39). It was found that Rhabdomys pumilio was present in all the habitat types sampled and that species such as Crocidura mariquensis, Myosorex varius and Otomys irroratus were closely associated with dense vegetation and close proximity to water/marshland.

Aerial survey of African white-backed vulture colonies around Kimberley, Northern Cape and Free State provinces, South Africa

Murn, Campbell; Anderson , Mark D.; Anthony, Angus

Abstract: Following preliminary ground surveys, microlight aircraft were used to conduct an aerial survey of African white-backed vulture (AWbV; Gyps africanus) breeding colonies in the Kimberley area, South Africa. Six colonies ranging from five to 135 km²in area (covering a total area of 506 km²) were surveyed during June and July 2001. Ground and aerial surveys revealed 119 and 227 active nests, respectively. Total breeding population across the colonies was found to be higher than previous estimates and concluded to be approximately 240 pairs, with a concurrent census population estimated to be approximately 650 birds. Nest densities within colonies ranged from 0.32 to 0.61 nests per km²(mean 0.46/km²), and were lower than previous estimates. Recorded population estimates and the aerial survey technique are discussed in relation to regional AWbV populations.

Population characteristics of Indo-Pacific humpback dolphins at Richards Bay, South Africa: implications for incidental capture in shark nets

Keith, M.; Peddemors, V.M.; Bester, M.N.; Ferguson, J.W.H.

Abstract: The population characteristics of Indo-Pacific humpback dolphins (Sousa chinensis) were investigated at Richards Bay, South Africa, from April to October 1998. This area has the highest incidental catches of humpback dolphins in shark nets on the KwaZulu- Natal coast. A minimum of 181 individuals were individually identified in a boat-based photo-identification study and this sampled population appeared to be open in nature. Long-term photo-identification suggested that some humpback dolphins display long distance movement patterns (up to 150 km), while other individuals display long-term residency within the KwaZulu-Natal area. Investigation into the associations between individual humpback dolphins yielded low and varying levels of affiliations. Unfamiliarity and naiveté of individual dolphins to netted areas seemed to be the main factors affecting captures in shark nets.

Seroprevalence of Toxoplasma gondii in free-ranging lion and leopard populations in southern Africa: short communications

Penzhorn, B.L.; Stylianides, E.; Van Vuuren, M.; Alexander, K.; Meltzer, D.G.A.; Mukarati, N.

Abstract: Antibodies to Toxoplasma gondii were detected in 92% of 53 sera from lions from Botswana, in 100% of 21 sera from Zimbabwe, in 100% of 12 sera from Kruger National Park and 100% of 30 sera from Hluhluwe-Umfolozi Park, South Africa. The single leopard serum from Botswana was positive, while 86% of 7 leopard sera from Kruger National Park were positive. Clinical implications of T. gondii infection in free-ranging non-domestic felids are unknown.

Notes on habitat use by helmeted guinea fowl in the Krugersdorp Game Reserve, South Africa: short communications

Van Niekerk, J.H.

Abstract: This study describes home range and movement of seven marked helmeted guineafowl ( Numida meleagris) flocks in the Krugersdorp Game Reserve. The home range of each flock was found to have three distinguishable portions, which corresponded with seasonal changes. The primary portion (breeding territory) was the smallest and was occupied during summer. The larger secondary portion was occupied during the transition phase from the breeding season to the non-breeding season (March to May), just before winter. The tertiary portion was occupied during winter and included the areas of the primary and secondary portions. The secondary and tertiary portions were defined as home ranges. The large home range during winter suggested that the birds covered longer distances in search of diminishing food sources. Like other galliforms, the home ranges of helmeted guineafowl flocks overlapped with each other.