Desert elephants - nature, nurture, and we love them anyway!
Some things are more important than genetics. The memory of old African savannah elephants is legendary, especially with elephant graveyards where they seem to remember relatives with something similar to affection. The latest research on mtDNA passed on by these matriarchs admits that those distant memories are much more significant to survival than the admittedly essential genetic traits that can be passed on from the same individuals.
Yasuko Ishida and her colleagues from the Universities of Illinois at Urbana-Champaign and Washington, US, San Diego Zoo Global, Queens University in Ontario, the University of New South Wales and Elephant Human Relations Aid (EHRA) have produced the paper, Genetic connectivity across marginal habitats: the elephants of the Namib Desert in
Ecology and Evolution. The Namib is a severe taskmaster. It requires the savannah elephant, Loxodonta africana, to be highly adaptive, existing on (the edge of the species comfort zone) where waterholes are so rare that they must be manufactured.
The results prove that the animals have to regularly shift their ranges in response to an intensive variability in the climate, global warming, and that inevitable hunting pressures we all recognise. This is the evolution of a capable mammal that is unspecialised in feeding and a long range migrater, to suit conditions that would defeat other individuals of the same species. Literally
living on the edge of a vast desert and actually penetrating the arid conditions successfully, despite a lack of survival and reproductive conditions. The elephants have been observed performing amazing feats, including long distance migrations, here since 1793 (van Reenen and Pienaar,) although war and hunters have put paid to several local populations completely!
This research concentrated on checking the molecular genetic markers in order to see how diverse desert-adapted elephants need to be. Dung (with limited DNA quality) and skin samples were used from 6 geographic groups, including 2
desert populations. The only group that differed from the general Namibian standard were the Caprivi Strip population in the far NW of Namibia. These elephants are well-separated from all others and could be seen as long-isolated from other populations. They are not genetically distinctive to any degree of significance, but their maternal (mutating in isolation) mitochondrial DNA does not show the normal haplotypes that are found in all local nuclear DNA because of the roaming habits of male elephants.
Excluding these distinct animals, Namibian elephants do seem themselves to be genetically distinct and isolated to a small extent. 8 out of 9 haplotypes are unique to Namibia . Climate change is highly likely to have ravaged populations for thousands of years, especially in these extreme habitats, where dry periods have occurred 8000 years ago and 3500 years ago. These remarkable creatures are habitat engineers, enabling other species to find water especially, spreading seed of valuable colonisers and fertilizing the ground near waterholes. Even their tracks enable seedlings to survive the conditions better. Long ago we have had articles that show how elephants survive arid conditions, using sand and urine or a few gallons of water under their mouth and in this heat adaptation. However, this new and immensely valuable research indicates they really rely on memory alone for survival. No animals can find the waterholes that they remember over their long lives and pass on to daughters, grandchildren and great-grandchildren. Africa is obsessed with desert ecosystems and these great elephants are irreplaceable in their niche.
Hunters beware- this is the future that is being destroyed by unthinking guns.