Population Survey

Elephants and other large herbivores, wild and domestic, in Gonarezhou National Park, Malapati Safari Area and Mahenye and Naivasha communal lands in south-eastern Zimbabwe were surveyed from the air during October 2018. The survey area lies within the Great Limpopo Transfrontier Conservation Area. A fixed-wing aircraft was used to conduct a sample survey, flying transects over the area. The area surveyed totalled 5633 km2 and was divided into 10 strata. By design, sampling intensity varied between strata and ranged from 13 to 23 %. Sampling intensity averaged 20 % in Gonarezhou NP and 19.6 % in the entire survey area. The principal objective of the survey was to provide relatively precise and accurate estimates of the number of elephants in the survey area as a whole, using a technique that could be executed within a reasonable time and at a reasonable cost. Secondary objectives included provision of population estimates for other large herbivores, determination of the spatial distributions of elephants and other large herbivores; and estimation of the number and spatial distribution of elephant carcasses. The methods used were suitable for meeting the survey objectives, repeatable and technically robust. Some large herbivores are not easily seen from the air and their numbers were undoubtedly underestimated. Nonetheless, population estimates are given for these species, because the estimates provide useful indices of abundance with measures of precision and can be used to determine spatial distribution, as well as temporal trends in population number. No corrections have been applied to any of the estimates to compensate for any undercounting or missed animals. The estimated population numbers of the principal large herbivores in Gonarezhou NP were: elephant 10764 (upper and lower 95% confidence limits ± 17 %); impala 3420 (± 39 %); buffalo 6805 (± 54 %), kudu 586 (± 31 %); zebra 1878 (± 28 %); wildebeest 401 (± 69 %); giraffe 635 (± 41 %); eland 232 (± 63 %); nyala 120 (± 63 %); waterbuck 324 (± 70 %); cattle 1435 (± 48 %); and sheep and goats 550 (± 82 %). Most domestic animals were in the Chitsa area in the north of the park, but others were seen in the very south of the park. There were estimated to be 637 elephant carcasses in the entire survey area and 583 in Gonarezhou NP. The all-carcass ‘ratio’ (i.e. the ‘ratio’ for elephant carcasses of all age categories) was 5.5 % in the survey area as a whole and 5.2 % in Gonarezhou NP. If it is assumed that all unidentified carcasses were elephant carcasses, the all-carcass ratio increases to 7.2 % for the entire survey area and 6.9 % for Gonarezhou NP. The 1+2 carcass ‘ratio’ [based on fresh (age category 1) and recent (age category 2) carcasses of elephants] was 0.20 % for the entire survey area and 0.21 % for Gonarezhou NP.