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| Location: |
Africa - Southern Africa - Zimbabwe |
| Subject: |
Ecology - Census Methods |
| Species: |
Black Rhino |
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Estimating numbers from surveys - Zimbabwe. No detailed survey of the population numbers of hook-lipped rhinoceros in Rhodesia has ever been carried out. The difficulties inherent in estimating their numbers in large areas of densely wooded and often broken terrain are considerable. Between May 1967 and September 1969, while making aerial surveys of the Zambezi Valley and escarpment from Lake Kariba to the Mozambique border, mainly in order to obtain elephant and buffalo distribution patterns and population estimates, we investigated the efficacy of estimating hook-lipped rhinoceros populations from the air. In ten surveys, which covered about a quarter of the 4,000-square-mile area, the maximum number of rhinoceros counted on any one of them was only 34. Goddard (1967), in a similar test in Tanzania, where eighty-five per cent of his study area consisted of open plains country studded with trees and shrubs, found that, even under the most favourable conditions only 50 per cent of the known population was detected, and obviously, in the densely wooded and broken country in which the great majority of rhinoceros live in Rhodesia, the value of aerial survey is even more limited. It was therefore necessary to base our estimates primarily on ground sightings, tracks and other signs, supplemented by aerial sightings in the case of the Zambezi Valley area; in addition reports from departmental staff living in areas we did not cover have been invaluable. Thus, although obtained by imprecise method, the estimates might provide a minimum figure for the overall population.
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Black rhinoceros in Rhodesia
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