Aerial Survey of Mammoth Importance
Elephants Without Borders (EWB), with the support of San Diego Zoo Global, recently completed flying an aerial survey, counting elephants and wildlife species, over northern Botswana. The team flew over three months, approximately 250 hours in small, single-engine plane for the survey.
The distance covered was approximately 26,719 miles (43,000 km), encompassing the entire elephant range in northern Botswana of approximately 72,000 square miles (115,800 km2)over Botswana’s varied terrain. Over high-density wildlife areas, the sampling coverage was about 22%, making this Botswana’s first aerial survey conducted with such a high sampling intensity. The distance covered is longer than the circumference of the Earth at the Equator!
Wildlife species counted included large and small herbivores: elephants, roan, sable, zebra, giraffe, eland, kudu, impala, lechwe, springbok, buffalo, wildebeest, hartebeest, tsessebe, waterbuck, warthog, and hippos, selected large birds and nesting sites (critically endangered wattled crane, lappet-faced vultures, ground hornbill, ostrich, saddle-bill storks, fish eagles, and bateleurs); predators were also noted when seen. Other observations included elephant bull or family groups, elephant carcasses and bones, and, if possible, whether tusks were intact or missing.
Due to the growing concern about the impact that elephants and fire are having on large trees in Botswana, the team also counted Baobab trees, documenting their size and extent of damage to each tree observed. Additional notes were taken on environmental conditions, such as the extent of bush fires and the structural integrity of Botswana’s veterinary fence lines and whether livestock or wildlife had crossed them.
The information on elephant and wildlife numbers, distribution, and demographic characteristics from this study will be incorporated into population models to better understand a variety of research and management questions relating to wildlife ecology and conservation management in Botswana. Other management issues where this study may contribute important information include illegal hunting, veterinary control measures, hunting quotas, and habitat monitoring. The results of this project may also help promote conservation efforts that seek to ultimately enhance economic opportunities for rural communities in the region.
During the past 15 years the elephant range in Botswana has expanded by 53%, causing increasing concern about the impact of elephants on biodiversity, the viability of other species and the livelihoods and safety of people living within the elephant range. There is growing concern over the recent habitat changes, as well. The movements of elephants, their social dynamics, and their impact on people around the regions are currently limited.
A few of the areas we are focusing studies on are the pristine Okavango Delta, west of the Delta, the harsh environment of the Makgadikgadi and the recent flows of both the Savute and Boteti rivers. After 27 dry years, in May 2009, the Savute Channel started to flow again, and by January 2010, water was entering the Savute Marsh. Elephants now make use of this river along its entire length, feeding on the surrounding vegetation as they move between the now-flowing river systems.
We aim to assess human-elephant conflict cases that are occurring within the elephant range and suggest appropriate counter-measures, while providing reliable information on the role of elephants on the vegetation in the regions where elephants are now occurring.
We also hope to answer questions about how much of the structural and compositional change of the tree community is attributed to elephants and how much may be attributed to other herbivores and possibly fires and climate change. We would like to address the question of how elephants affect the density and diversity of other wildlife species. In combination with monitoring elephant herd movements, assessing the wildlife populations and proposed vegetation studies, we will be able to provide the needed information critical for land-use planning and habitat protection.
Photos by Kelly Landen, Elephants Without Borders