NEWS have prevented the elephant population in Seronga from dispersing under unfavourable conditions ;
2 . The overlap between natural and unnatural factors – the elephants were likely more susceptible to natural diseases / toxins due to anthropogenic restrictions and , potentially , stress due to human-wildlife conflict ;
3 . Land-sharing between people and elephants becomes superficial when the elephants ’ access to resources is restricted , and they are prevented from dispersing naturally .
Their recommendation to mitigate future mass die-offs is to remove or realign certain fences around the Seronga district of Botswana .
The background
As would be expected , the deaths of such large numbers of elephants fuelled considerable concern and significant media speculation , though investigating authorities ruled out poisoning , poaching , and anthrax .
Samples were sent for testing in Zimbabwe , the United States and South Africa ’ s Faculty of Veterinary Science at the University of Pretoria , though COV- ID-19 restrictions delayed the process significantly . In September , Botswanan officials announced that the deaths had resulted from poisoning by cyanobacterial toxins caused by a bloom of cyanobacteria in the available waterholes . These bacteria are naturally occurring , and ‘ blooms ’ happen when conditions are suitable .
The recently published ( 11 January 2021 ) report was written in October 2020 , just after the Botswana government ’ s announcement regarding the cause of death . However , the authors note that other carcasses , including domestic animals , would have been expected had the pans been contaminated by cyanobacteria . They state that the “ restriction of freshwater supplies that force elephants to use pans as a water source possibly polluted by blue-green algae blooms is a possible cause , but as yet not supported by evidence .”
Most of the elephant carcasses were found within an area administratively
known as NG11 , along the Panhandle region of the Delta – a region where human-wildlife conflict is rife . Neither NG11 nor neighbouring NG12 have protected status and are designated for subsistence agriculture .
These regions neighbour the Kavango- Zambezi Transfrontier Conservation Area that extends over five countries
Figure 2 : NG11 and NG12 administrative blocks have no protected status ( A ). The Seronga area ( NG11 , NG12 , and a part of NG13 ) is cut off from the surrounding landscape by either deep water of the Okavango River and Delta ( blue ) or veterinary or border fences ( dashed lines ) ( B ). The shapefiles for the protected areas were sourced from the World Database on Protected Areas ( https :// www . protectedplanet . net / en ) and for the Okavango Delta from the ESA Climate Change Initiative ( Land Cover project 2017 ).
and is home to the largest population of African bush ( savanna ) elephant in Africa .
The research
The study was authored by members of the Conservation Ecology Research Unit in the Department of Zoology and Entomology at the University of Pretoria and the Nicholas School of Duke University Environment . Their previous research included a long-running research programme in the region , tracking the movements of ten collared elephants within NG11 for several years and those of elephants in neighbouring blocks .
Their research indicates that the elephants within NG11 are restricted by the Okavango River to the west and international border and veterinary fences to the north , east and south . As a result , the elephants cannot disperse when numbers are too high or when environmental conditions are harmful . The population growth rate for the Seronga area since 1995 is exceptionally high , and elephant numbers in NG11 and NG12 are significantly higher than those in neighbouring blocks , though densities are comparable . The report concludes that while a disease is a likely explanation for the mass die-off , this would have been caused by several forces acting in concert , exacerbated by both natural and artificial factors . The restricted movements have resulted in high densities of elephants and , at the same time , confined the death-causing agent to one specific region .
It is also possible that poaching , conflict with people and restricted access to the Okavango Region forced elephants to rely on stagnant water . Increased stress
Grassroots Vol 21 No 1 March 2021 20