Thursday, June 13, 2024

KAZA survey raises concerns over elephant carcass ratio in Botswana

An elephant aerial survey report titled “An aerial survey of elephants and other large herbivores in the Kavango Zambezi Transfrontier Conservation Area” reveals that Botswana has a high all-carcass ratio. Botswana is part of the KAZA which was established in 2011 and is situated in a region of Southern Africa where the international borders of five countries converge namely Botswana, Angola, Namibia, Zambia and Zimbabwe.

According to the report, the terrestrial conservation area has an all-carcass ratio of 10.47%, computed from the estimated 26641 (±1645) elephant carcasses estimated. While the report notes that the Sebungwe Region in North Western Zimbabwe has the highest all-carcass ratio in KAZA, it made mention of the fact that Botswana has the third highest all-carcass ratio in region.

Despite the fact that the Sebungwe area in North Western Zimbabwe has the highest all-carcass ratio in KAZA, the report mentions that Botswana has the third-highest all-carcass ratio in the region.

“Notably among the various zones, Sebungwe (17.46%), Angola (16.27%) and Botswana (12.80%) had the highest all-carcass ratios, while other zones had all-carcass ratios that were below 8%,” states the report, adding that “the value calculated from this survey serves as a useful baseline value and potentially as a cautionary signal of a possible negative population trend. This will however require further assessment to confirm.”

According to the report, carcass ratios exceeding 8% may indicate excessive mortality and should be closely monitored.

“Comparing the current carcass ratios with those from spatially localised previous surveys, the CR14 for the identified zones has decreased for all zones, except for Botswana,” states the report. Furthermore, it adds that “The underlying reasons for high mortality rates could be diverse and are likely to be a combination of several factors such as of poaching, habitat loss (i.e., elephant population compression) and associated human-elephant conflict, disease, and other natural causes. For the conservation of elephants, a priority is to carry out further investigations to identify the drivers of the high mortality rates and to ensure that appropriate interventions are implemented”.

The all-carcass ratio, abbreviated CR14, is represented as a percentage of the number of dead elephants (of all carcass categories) divided by the number of dead elephants (of all carcass categories) plus live elephants.

According to the report, the fresh and recent carcass ratio (CR12) is a useful indicator of recent mortality since it includes elephant carcasses that have died a year prior to the survey.

“The highest CR12 ratios were observed in Botswana (0.72%), Angola (0.57%), and the Kavango Zambezi zone (0.49%),” states the report, adding that “Of concern is the observation that in Botswana the CR12 increased from 0.1% in 2014 to 0.70% in 2018 and remains at a similar level at 0.72% in 2022.”

Among other things, the report notes that “there were an estimated 1165 (±290) fresh and recent elephant carcasses in the KAZA TFCA survey area.”


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