Elephant Home Ranges
EWB continues to monitor elephant home ranges, recording the most variable ever reported for African elephants and ranges categorized by sizes according to age, sex, access to water, types of water sources, vegetation, fences, and human disturbances.
The research has also shown that the elephants of northern Botswana have the largest home ranges (24,828 km2) recorded for African elephants and have conclusively confirmed that the elephants of northern Botswana are part of a large contiguous elephant population encompassing western Zimbabwe, the Caprivi Strip in Namibia, southeast Angola and southwest Zambia. These research findings have complimented and contributed to delineating the area encompassing the largest wilderness area, the Kavango-Zambezi Transfrontier Conservation Area (KAZA TFCA.)
However, the elephant range in Botswana is not a static feature. As the elephant population continues to grow, the northern Botswana elephant range is expanding rapidly. Elephants are re-occupying areas from which they have been absent for many years. During the past 20 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 The most striking expansion of elephant range has occurred south towards the Makgadikgadi, and west of the Okavango Delta. Elephants are now being seen as far south as the Central Kalahari Game Reserve. The movements of elephants, their social dynamics and impacts on people around these periphery regions are currently limited. With further information, we aim to assess human-elephant conflict cases that are occurring on the periphery of the elephant range and suggest appropriate conservation measures. Learn more here: Tracking page
Population Dynamics and Habitat Use
Population dynamics refers to the way populations are affected by birth and death rates, by immigration and emigration into an area, and the biological and environmental processes influencing changes on a population.
EWB has been conducting aerial surveys, to obtain elephant abundance, distribution and herd sizes. Further, combining these data with digital land cover maps, provide the opportunity to develop spatial models of elephant habitat use. Importantly, these models can be used to understand elephant population dynamics, enabling wildlife managers to predict population growth, to assess elephant habitat use to vegetation changes (e.g. fires and drought), and predict the effects of habitat transformations and new infrastructures, such as roads and fences, on elephant numbers and distribution. Further, these models can provide a common information base to discuss elephant management problems and facilitate conflict resolution.
In collaboration with the University of Pretoria, we are also helping to assess the age of individual elephants, birth and death rates, and the population growth rate by using a method called Rapid Elephant Population Assessment (REPA). To do this digital images are taken of herds at a known distance, measured with an infrared range finder. The photos are used to calculate the length of elephant backs and deduce ages based on developed models. From this, reproductive rates can be calculated by assessing the age differences between cows and their calves and age specific survival rates by analyzing age distributions. This can also show expected populations to either grow or decline and repetitive REPAs can demonstrate possible reasons behind population change.
Long-Term Stress Responses
The ability to measure stress hormones in wild animals has improved dramatically in the past decade with the development of fecal metabolite analysis techniques. It’s easy, unobtrusive and accomplished by collecting dung samples then extracting DNA and hormone samples. An EWB study, conducted by MSc student Tanya Lama, is assessing stress hormone levels in elephants and the relationship between environmental stress, temporal differences in food and water availability throughout the seasons, and to provide a comparison between the re-introduced elephants formerly of the Abu herd, the Abu herd that experience daily human interaction, and wild elephant populations. Samples are collected from the Abu study groups, in the Okavango Delta and other regions in northern Botswana, on a weekly or biweekly basis and the hormones are extracted for analysis and quantified.
Read about this project’s progress at http://elephantswithoutborders.org/blog/?p=1485
Reintroduction of Habituated Elephants into the Wild
In NG26 concession of the Okavango delta, a 14 000 sq km oasis in northern Botswana, Abu camp has built up a reputation as a halfway house for disadvantaged elephants. Over the years, the elephant program has sensibly and delicately reintroduced eight African elephants into the Okavango Delta. In 2011, EWB was asked to closely monitor their integration beginning with the reintroduction of a large female, Gika and her daughter Naya, and previously introduced bull Mthondo and cow Nandipa. This important project will shed some critical information on the reintroduction of elephants back into their wild habitat. We aim to provide other projects with guidance on how to conduct successful elephant releases and information on how the elephants have adapted to their releases.
Read more about this project at http://elephantswithoutborders.org/blog/?p=1469
EWB was also proud to be part of the post-monitoring team for Mary, the largest female in a herd of 9 elephants that were once captured and found to be mistreated. The Zimbabwe SPCA (ZNSPCA) approached the Minister of Environment and Natural Resources, Honorable Minister Nhema, and officials from the Ministry of Environment and Natural Resources and National Parks and Wildlife Management Authority (NPWMA) to discuss the dilemma of the elephants. It was agreed that the captive elephants would be trans-located and released back into the wild. The elephants were released in Hwange National Park in Zimbabwe on Nov 3 2009. EWB, working in collaboration with Roger Parry and the Victoria Falls Wildlife Trust, Mary was fitted with a satellite collar to monitor the herd. We markedly witnessed the herd’s progress and interactions with wild herds and Mary had given birth. Mary and the “Hwange 9” are no longer monitored as they successfully integrated back into the wild.
Savute Channel Elephant Project
In 1982, water in the Savute Channel and Savute Marsh began to dry and eventually soon disappeared. In an effort to bring relief to wildlife in the region the Botswana Department of Wildlife and National Parks (DWNP) drilled five boreholes to augment water by pumping artificial water points in the heart of the Chobe National Park. Since then, a known attraction of Savute has been its artificial waterholes and big elephant tuskers who seek refuge around these water points during the hot dry season. However, in May 2009, the Savute Channel started to flow again and by January 2010, water returned to the Savute Marsh. The Linyanti Swamps feed the Savute Channel, which meanders in an easterly direction for some 100km until it reaches the Savute Marsh. The full channel now acts as a giant water trough running through the arid sands of Botswana’s northern Kalahari. Elephants now make use of this river along its entire length; thus, the DWNP has stopped providing water. This study investigates the effects of the availability of water in the Savute Channel on elephant movements in the region. With support received from the Wilderness Wildlife Trust, we deployed satellite collars on elephants along the Savute Channel. This long-term movement study will provide important information on the spatial ecology of elephants in this dynamic system and will enable us to compare it in temporal changes and elephant movements in other regions.
Elephant Thermoregulation and Spatial Use
How does temperature affect an elephant’s behavior? This research is examining temperatures, both that of the environment and climatic conditions and at the same time, the internal temperatures of an elephant’s body and how these affect an elephant’s behavior and use of space, which could have consequences for habitat selection and the impact elephants have on a chosen landscape.
Michael Mole and Shaun D’Araujo, both MSc students at the University of Pretoria’s Conservation Ecology Research Unit are studying the affects of the thermal determinants of how elephants use their space. Michael’s research focuses on the potential influence of climate on shade seeking, water use, large tree interactions and fine scale path movements of tame free-ranging elephants. While complimenting this, Shaun is trying to determine the effect of the thermal envelope on the skin and core temperature within an elephant and discern the thermal determinants of shade seeking by the physiological consequences of sun, shade, swimming and mud bathing for elephants under natural conditions.
To read more about this interesting work: http://elephantswithoutborders.org/blog/?p=1412
Additional supported Projects:
DNA Sequencing & confiscated ivory
In support of research being conducted by Adam Brandt and Dr. Alfred Roca at the University of Illinois, EWB is providing samples of dung to extract DNA to help identify distinct genetic elephant populations. The elephant DNA can then be compared to DNA of confiscated ivory to help trace the ivory’s origin.
Recent advances in next generation sequencing technology has developed methods to extract DNA as nuclear genetic markers from degraded DNA sources such as dung or ivory. These markers can be used to examine the population structure of elephants, analyzing genetic patterns between different geographic locations. The analyses of such DNA are expected to provide information relevant to the conservation of elephants, including establishing the genetic diversity of elephants at a location; their status as forest or savanna elephants; relationship to elephants at other locations; and status as a genetically distinctive population. Ultimately this research should prove useful for establishing conservation genetic priorities for African elephants, and for efforts to trace the origins of confiscated ivory.
Both Asian and African elephants are at risk for the infectious diseases of tuberculosis and herpes virus infections. Both diseases have emerged as significant health risks for captive and wild elephants in the last 20 years.
A family of Elephant Endotheliotropic Herpesvirus (EEHVs) was discovered when a captive animal died of acute, sudden onset hemorrhagic disease An additional 47 cases with 90% fatality have subsequently been identified across North America, Europe, and Asia.
EWB is contributing to an important study with Virginia Pearson from Princeton University and host of other collaborative researchers on identifying genetic factors influencing susceptibility to infection and disease progression. Such results can assist captive breeding programs, contribute toward understanding disease transmission, and guide the movement of animals both in the wild and in captivity.