INTRODUCTION
In a section of the Kalahari desert of Botswana, west of the Central Kalahari Game Reserve (CKGR) there is an ongoing conflict between predators and farmers. In this area of the Ghanzi district during twelve months approximately 500 head of cattle were reported killed by predators, primarily African lions (Panthera leo) and African wild dogs (Lycaon pictus), resulting in approximately $275,000 dollars (US) worth of damage. Wildlife Department officials reported that 54 lions were killed due to potential or actual livestock depredation in the same area. Because African wild dogs are highly protected it is forbidden to kill them but it is suspected that many have also been killed.
In October of 2007 Botswana suspended all lion hunting indefinitely due to concerns over large numbers of lions being killed in defense of livestock.
The farm operations have water resources to support their livestock and due to the dry nature of the CKGR this often draws predators out of the game reserve and onto the private farmlands. As a consequence, lions predate the abundant and easily killed cattle. Then follows an unfortunate dynamic. As lions and wild dogs are shot or poisoned unoccupied territories attract additional predators.
What has been learned over the last several decades is that conflict between large predators in Africa and agriculture is a problem with aspects requiring application of an understanding of proper range management of natural prey, application of proper agricultural practices and application of an understanding of predatory behavior.
MITIGATING CONFLICTS WITH PREY AVERSIONS
The African Continent is the legitimate home of both man and lion, which have coexisted for tens of thousands of years. Clearly, no approach to current conflicts can be expected to succeed unless it benefits both species. In fact, there is a well-known behavioral process that can alter the predatory behavior of large predators in a way that powerfully and permanently dissuades them from predating domestic livestock. This process could create a much-needed buffer between predators and farmers. Since this process modifies only one specific aspect of predatory behavior, predators remain otherwise entirely unchanged and so continue to play their essential role in the natural ecosystem. Since predators are not removed or displaced but are nonetheless dissuaded from attacking livestock, there is no ecological vacuum that continuously brings in new predators. Instead, as intact predator social groups defend their territories they prevent incursions by new individuals that have not been treated by this process. This process is known as Conditioned Taste Aversion.
Conditioned taste aversion (CTA) is a unique and powerful form of learning. It is a natural defensive mechanism enabling predators to survive encounters with prey with toxic anti-predator defenses. When mammalian predators experience nausea after consuming prey with toxic defenses, they form an aversion to the taste and scent of these prey animals. Long after recovering from the effects of a sub-lethal dose of the toxin, predators avoid offending prey wherever they are encountered. Birds also form aversions in this way and tend to avoid dangerous prey on the basis of visual food cues. In this way, predators fortunate enough to survive the first encounter with toxic prey form a rapid and permanent learned aversion to the prey, which reduces the risk of future incapacitation or death.
WILDIZE RESPONDS
Evaluation of the possible application of CTA to wildlife problems has shown that predators acquire and express aversions to prey in a manner that could be of use in mitigating conflicts between lions, for example, and livestock growers. A single meal of food containing a hidden dose of an aversion agent can produce very long lasting aversion to the taste and scent of target prey among mammalian predators.
Currently, WildiZe is undertaking a captive study in the CKGR with 20 lions as study subjects. We are using meat baits to product predatory responses toward cattle with the long-term goal to show the CTA treatment is effective in inhibiting future conflicts between predators and farmers. Denver Zoo Associate Researchers Bill Given and Glyn Maude are conducting this CTA study.
The success of the CTA project in Botswana could have long-term ramifications for projects such as Tsavo and other WildiZe projects by helping remove a large source of on-going Human/Wildlife conflicts.
Expert Action
Bill Given, Condition Taste Aversion (CTA), Botswana
Updated By: Bill Given
We fly out this week to Botswana to do our CTA trial with captive lions. Following obtaining an import permit we were able to ship our aversion agent (a veterinary medication) and it made it fine -- unfortunately there's a lot more to being a conservation biologist then just studying the wildlife! We are excited to test the CTA method for the first time ever on African lions, if we can demonstrate that the lions are successfully averted from eating beef it will be a huge step in moving the method forward as a practical mitigation tool in predator/livestock conflict. Wish us luck.
Boteti: The Ideal Study Site
An ideal study location will have known conflict between lions and cattle so that post treatment there can be measurable results. The ideal study will occur with a population of lions that are collared so that any spatial shifts in relation to cattle can be determined and it should be in an area where there are other prey species providing feeding choices for lions.
The Boteti River area in Botswana’s Kalahari desert meets all the criteria to do a comprehensive study of free ranging application of CTA on lions and measure the results for mitigation of lion/livestock conflict. There is serious conflict in this area because there is no buffer zone, the east side of the Boteti River is Makgadikgadi National Park and the west side of the river is cattle posts. Lions commonly cross to the cattle posts to prey on livestock and also cattle sometimes enter the national park and are taken there by lions. In turn lions are heavily persecuted in this area and the local population is considered to be the most at risk/endangered within Botswana.
What is completely unique in this area is a large zebra migration (more than 16,000 individuals) uses the Boteti River during the dry season and lions rarely prey on cattle during this time, but when the zebras migrate out of the park then the lions remain behind and conflict with livestock goes up. This situation creates a remarkable opportunity to measure results from CTA treatments. Treated lions will have no reason to cross over to the cattle posts so we expect to be able to examine spatial use as a strong measureable of results. We can also use location data from collars to determine if any treated lions are in the vicinity of cattle reported killed providing us with a second measure to evaluate the success of CTA with lions in the field.
Summary of Conservation Potential
CTA has demonstrated the potential to be a remarkable mitigation tool. CTA is the only management tool that actually changes the feeding desire of a predator, differentiating it from all existing barrier methods. This evolutionary defense mechanism clearly exists and it is a matter of us refining techniques to achieve success with it as a conservation tool. Fortunately it is a low tech solution that is easily transferrable with training to local livestock owners making it a scalable management method if it proves successful in a comprehensive pilot field study.
Who is Involved?
Bill Given, Principal Investigator, Research Associate of the Denver Zoological Foundation. Bill is a conservation biologist with nearly two decades of working with rare and threatened species. He has conducted successful Conditioned Taste Aversion applications with endangered Mexican wolves scheduled for re-introduction by US Fish & Wildlife Service, cougars at the Southwest Wildlife Conservation Center, and African lions at Grasslands Safari Lodge under permit and invitation of the Botswana Department of Wildlife & National Parks.
Lowell Nicolaus, PhD. Lowell is a professor emeritus of Northern Illinois University, and is the world’s living expert on Conditioned Taste Aversion with more than 30 years of experience conducting CTA research with wildlife.
Glyn Maude, PhD. Glyn is the Director of the Makgadikgadi Research Program and the CKGR Predator-Prey Research program in Botswana. He is supervising the effort of local field researchers studying the lion population in the Boteti region.
Keitumetse Ngaka, Masters Student, University of Botswana. Keitumetse is a graduate student working under the supervision of Glyn conducting research on the lion population in the Boteti region.
Project Field Photos:
Kenya Wildlife Service Meeting
WildiZe Foundation, Bill Given, Rick McKenna at the Kenya Wildlife Service meeting with Director Kipeng'etich and Senior Scientists and Wardens
Experimental Lion
We are working with a number of captive lions that were predating on cattle and were going to be shot but instead captured and living in 35 acre enclosures. During September we will be applying our conditioned taste aversion (CTA) method and if all works as it has in our past experiments with Mexican wolves and cougars the treated African lions will no longer eat beef when offered making a strong demonstration of using the tool in the future with free ranging predators.
We have arrived at our Kalahari Research base of Grassland Safari Lodge. Fantastic place to be for research and our lion subjects are magnificent. We are preparing our materials and hope to begin our CTA trials with the lions within days.