Risks and Causes of Mortalities in Wild Ungulates of Tanzania
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RISKS AND CAUSES OF MORTALITIES IN WILD UNGULATES OF TANZANIA 1Mbassa GK, 2Pereka AE, 3Matovelo JA, 4Mgasa MN, 5Kaita M, 1Mwangalimi MO Departments of Veterinary 1Anatomy, 2Physiology, Biochemistry, Pharmacology, Toxicology, 3Pathology, 4Surgery and Theriogenology, Sokoine University of Agriculture, P. O. Box 3016 Morogoro, 5Department of Wildlife, Ministry of Natural Resources and Tourism, P. O Box 636 Morogoro Tanzania ABSTRACT Habitat and forensic studies in Mkomazi, Saadani and Selous game reserves and Longido, Gonabis and Doma-Mkata protected areas of Tanzania indicate fires, poachers, hunters, predators, lack of feed and water due to habitat deterioration, agriculture and livestock to pose high risk to survival of plains zebra, buffalo, blue wildebeest, eland, hartebeest, impala, Thomson’s and Grant’s gazelles. Wildebeests and buffaloes suffer high mortality rates followed by hartebeests, elands, zebras and giraffes, the causes being trauma due to wire snares, bullets and predators. Animals acquire intelligence and develop survival strategies including knowledge of being a target species, man and predator preferences, home range for safety, borders of reserve areas, protectors, tools held by man and maintain minimum distances from strangers, perform sudden, fast irregular movements and vertical jumps to avoid being targeted, females separate from males while running and animals migration from high risk areas to safe places. Measurement of risks and causes of deaths is prerequisite to prediction of population trends and developing effective wildlife conservation strategies and as shown by this study ethology, habitant examination, forensic diagnosis on dead animal remains and migrations are useful information sources. INTRODUCTION Wild ungulates are of great economic importance in East Africa and their utilisation for food and export is increasing. Their natural habitats are also shrinking because of rising human population who expand pastoralism. Most animals deemed safe now will probably be extinct in 15-20 years. Diseases have been reported in ungulates including anthrax, brucellosis, tuberculosis, lumpy skin disease, foot and mouth disease, rinderpest, trypanosomosis (Pastoret et al., 1988; Kariuki et al., 1989), theileriosis and other tick-transmitted diseases (Grootenhuis et al., 1980). Over the years wildlife protection has been achieved by force, enhanced by their existence in large numbers, availability of other sources of food and cash for man through domestic animals, which minimized wildlife utilization and because of small human population ecosystems were stable, favouring wildlife survival. Also few people knew about wildlife and wildlife product markets, keeping wildlife utilization low. The fast growing human population and diminishing resources to protect wildlife have exposed wildlife to risks of being consumed and their land being occupied by man. Consequently wildlife mortalities are rising causing population declining. This investigation was to determine the risks and causes of mortalities of wild ungulates, in order to develop effective conservation, disaster intervention and repopulation strategies. MATERIALS AND METHODS The study was conducted in 1996-1998 in Mkomazi and Saadani game reserves and open wildlife conservation areas of Gonabis-Kisaki and North Selous sector, Doma-Mkata area buffering Mikumi National Park, Morogoro and Longido, Arusha. Risk factors threatening survival of Grant’s (Bohm’s) and Selous (antiquorum) plains zebra (Equus burchelli bohemi, E. burchelli antiquorum) or Hipotigris (Quagga) quagga, African buffalo (Syncerus caffer), blue wildebeest (Connochaeta taurinus), eland (Taurotragus/Tragelaphus oryx), hartebeest (Alcelaphus buselaphus), impala (Aepyceros melampus), Thomson’s gazelle (Gazella thomsonii) and Grant’s gazelle (Gazella granti) were determined by assessing habitats as safe providing food, water and breeding sites, post Proceedings of the 9th International Symposium on Veterinary Epidemiology and Economics, 2000 Available at www.sciquest.org.nz 1 mortem studies of animals found dead, forensic diagnosis of remaining carcasses, bones, horns, heads and skins to identify species and causes of deaths. Carcases were examined for body condition, wounds, discharges, diarrhoea, hair coat, bites, scratches, bruises, bullets, snares and distokias. Animal strategies for survival and responses to risks were assessed by animal activities, preferred places, site selection and timing of grazing, drinking, evening collecting places, sensitivity and direction of run when pursued, reaction to moving objects and approachable distance. The giraffe (Giraffa camelopadalis), waterbuck (Kobus defassa), warthog (Phacochoerus aethiopicus) and reedbuck (Redunca arundinum) were studied for comparative risk responses. RESULTS AND DISCUSSION The order from largest to smallest herds of ungulates were, Longido; zebra, impala, Thomson’s gazelle, Grant’s gazelle, giraffes, impala and wildebeests, Mkomazi; Grant’s gazelle, hartebeest, zebra, buffalo, eland, lichtenstein’s hartebeest Alcelaphus lichtensteini, Waller’s gazelle or gerenuk Litocranius valleri, Clark’s gazelle or dibatag, Ammodorcas clarkei, greater kudu Tragelaphus imberbis, Saadani; blue wildebeests (Connochatae taurinus/connochatae), defassa water buck, Kobus elipsiprymmus, reed buck, warthog, giraffe, white giraffe, Coke’s hartebeest, giant eland, Buffalo, plains zebra, Gonabis; blue wildebeest, plains zebra, reed buck, buffalo, impala, Giant eland, giraffe, warthog, elephant Loxodonta africana, sable antelope Hippotragus niger, hippopotamus Hippopotamus amphibious, Doma-Mkata; blue wildebeest, Selous zebra, impala, giraffe, buffalo and hartebeest. Selous; zebra, reed buck, buffalo, impala, giant eland, giraffe, warthog, elephant, sable antelope and hippopotamus. Risk factors and animals found dead are indicated on tables 1 and 2. Table 1: Risk factors for ungulates in areas of study in 1996-1998. Game ReserveRisk factors Animals affected, in order from most threatened Longido Droughts, lack of feeds, lack of water, riskZebra, of impala, Thomson’s gazelle, being cropped, few scattered herds, frightenedGrant’s gazelle, wildebeests, giraffes animals Mkomazi Droughts, lack of feeds and water, few scatteredImpala, Grant’s gazelle, hartebeest, herds of frightened animals zebra, buffalo, eland, hartebeest, Waller’s gazelle, Clark’s gazelle, greater kudu, Saadani Traumatic injuries of various causes, poachersBuffalo most affected, followed by eland and blue wildebeest Gonabis Traumatic injuries of various causes, predators,Blue wildebeest, buffalo, eland, poachers hartebeest, zebra Doma-Mkata Traumatic injuries of various causes, predators,Blue wildebeest, zebra, impala, giraffe, poachers buffalo, hartebeest Selous Traumatic injuries of various causes, predators,Blue wildebeest, plains zebra, buffalo, poachers impala, giant eland, elephant Survival strategies included preference for areas with short grasses and few trees, grazing and drinking early morning or late evening, hiding in forests during the day (buffaloes). Wildebeests, zebras, elands grazed together, but gazelles, sable antelopes, hartebeests and impala preferred their own herds. Reed bucks were found everywhere in Saadani and Gonabis mixing with every other animal but were reluctant to follow the runs of others, hide in grass and bushes, aware of being not targets. Giraffes and water bucks preferred own herds, run in different direction not along zebras, Proceedings of the 9th International Symposium on Veterinary Epidemiology and Economics, 2000 Available2 at www.sciquest.org.nz Table 2: Animals found dead and decided cause of death in game reserves and protected areas Place Wildebeest Buffalo Zebra Hartebeest Impala Others Longido 0 0 1, lions 0 0 2 ostrich hyena Doma-Mkata 0 0 0 0 0 1 giraffe wire trap Mkomazi 0 2, unknown 0 0 0 Saadani 1, unknown 1, trauma 0 0 0 1 giraffe Gonabis 12 wire trap 3, trauma (2 3 trauma 4 trauma 0 0 bullets found) buffaloes and wildebeests. Elands were hypersensitive, not trusting approaching object, took off first leaving wildebeests and zebras behind. Except the buffalo, these ungulates collected at game park rangers camps during the night, indicating trust to game rangers. Most ungulates went to drink late evening after sun set especially in Saadani and Gonabis. Giraffes stood 200- 500 m from strangers, 500 – 600 m for waterbucks, 700-1500 m zebras, gazelles, impala, sable antelopes and wildebeest, 1500- 2000 m for elands. The animals acquire intelligence to be aware of predators, poachers and protectors, keen on tools carried by observers, knowing poacher and predator preferences, small herds avoid dangerous strays, knowledge of borders of protected areas, impalas and gazelles perform sudden vertical jumps to avoid being targeted. Wildebeests and zebras performed very fast irregular moves, in sideways, zigzag and quick turns to confuse enemies, female buffaloes, wildebeests, elands and zebras cushion their off springs and separate from males, elands do fast, high long jumps and non-stop trots. In East Africa diseases causing high mortalites are anthrax and rinderpest. The most risks to wildlife survival, however are traumas. Drought and water scarcity were in Mkomazi and Longido, and fires in all. Ungulates were under risk being prey of man and predators during the search for feeds and water, these actions risk life. Buffaloes, wildebeests, zebras and hartebeests found dead, revealed the cause of death to be traumatic (bullets or snares).