**This article originally appeared on zoocrew.eu as part of our Conservation Awareness project. **
Rehabilitation Facility and Metapopulations
At its inception the policy of the PDC Rehabilitation Facility was twofold:
1/ It would provide for all Painted dogs that legitimately could not survive in the wild either in short or long term due to human induced circumstances or natural circumstances while the population is still considered endangered.
2/ All dogs that were deemed “fit” enough to be released into the wild would be released (hereinafter called ‘legitimate’ dogs). This decision was made on the basis that PDC would develop strategies and methods to facilitate release into the wild, and that all fit individuals would be part of such a programme.
Up until now PDC has been firmly against breeding from its rehabilitation facility dogs because of the uncertainty of PDC’s capacity to release them into the wild, however since the inception of the rehabilitation facility in 2000 this capacity has changed. Here significant inroads have been made in both captive management in preparation for release, and re-wilding itself. Here PDC has demonstrated that most dogs that come through the facility, to include those that are dug out of dens and captive born animals can be successfully released into the wild. Whilst this fact alone changes the dimension of what PDC can achieve for the purpose of painted dog conservation, it also raises the question as to whether the dogs in the rehabilitation facility should be allowed to breed and if so, what are the arguments and conservation value of doing so.
Painted Dogs are classified as endangered (IUCN Red List). Currently Zimbabwe has three main populations namely Gona re zhou, Zambezi Valley and the Hwange ecosystem and with the large dispersal capability of Painted Dogs, historically these populations would have been contiguous (Childes 1988; Rasmussen 1997). Genetic research on these populations has shown the Zimbabwe population to have the highest genetic diversity in Africa and particularly at the MHC complex level which is responsible for disease resistance (Marsden et al. 2009). Consequently maintenance of this diversity is seen as a high priority particularly as additional research has highlighted cranial and general osteological deformities that are deemed associated with population decline and inbreeding depression in both painted dogs ((Rasmussen 2009) and wolves (Paquet et al 2009).
Whilst research over 22 years on these populations in Zimbabwe has highlighted that the most significant direct threats to painted dog’s are shooting by hunters and ranchers, road traffic accidents, snares, and more recently trafficking of pups, the data also demonstrate that a minimum pack size of six with and optimum of 10 is critical for success (Courchamp et al. 2002; Rasmussen 2009; Rasmussen et al. 2008). Consequently this latter factor has to be taken into consideration when creating release packs, which should ideally be at least seven and ideally 11-12 to allow for initial expected mortality.
With breeding at the PDC rehabilitation facility being focal to considerations, the case in point is that often at the PDC rehabilitation facility there are only 2-3 potential release candidates. This creates the uncomfortable dilemma to either hold them at the facility until more individuals arrive or release them as an “under strength” pack. Unfortunately, experience gained from release programmes has indicated that the older the dogs are at release the longer they take to learn to hunt thus significantly compromising the success of the release.
Consequently, having yearlings bred at the facility to add to the legitimate dogs would not only reduce the time for such dogs to remain in the facility, but also increase release pack size. Resolving both of these factors would greatly enhance the success of any release.
At the Zimbabwe National Action Planning workshop for cheetah and wild dogs, held in Bulawayo on the 10th and 11th of September 2009 a decision was made to “Improve the status of cheetahs and wild dogs, and secure additional viable populations across their range in Zimbabwe”.
Currently the Hwange population is considered to be under significant threat of collapse due to extensive poaching outside the park and collapse in both prey and environmental conditions inside the park (Rasmussen et al. Submitted; Valeix et al. 2008) For this reason it is considered important to have new areas, ideally fenced as meta-populations that could each house at least two or three packs. Such metapopulations exist in South Africa and both from the standpoint of painted dog conservation and an economical standpoint, through greatly enhanced, they have been a resounding success. From the conservation standpoint they have served as valuable reservoirs of painted dogs to the point that they now conservatively represent 34% of the national population Fig. 1 (Data from (IUCN/SSC 2007)). These figures also serve to set at 250 km2 what may be deemed the minimum size of a reserve and thus the minimum conservation unit. It is also salient to note that these reserves have the capacity for a higher density of dogs than in unfenced reserves Fig.1.
These data also reliably demonstrate the importance of reserve size, and how the carrying capacity for this endangered species increases with the size of the fenced reserve Fig 2. The reasons for this are twofold. Namely better protection and secondly, despite the large size of the reserves, painted dogs successfully utilize the fences to increase their hunting success (Romanach and Lindsey 2008). In the smaller reserves this has led to debate whether packs are ‘too successful’ or ‘too many’ inside these reserves and how they should be ‘managed’. Whilst some managers have seen the success of Painted dogs in these areas as a problem, in reality this provides for a readily available stock of dogs to either augment free ranging populations or to colonize new meta-populations.
As a consequence of the status of Painted dogs in Hwange and surrounds it is considered essential that two categories of areas be designated and fenced under the umbrella of painted dog conservation. The first category relates to Metapopulation Management Areas (MMAs), which are at least 250 km2 and can hold viable packs in the longer term with minimal management. The Matobo National Park being the first under consideration with others in the Midlands and perhaps in the northwest hopefully to be identified. The second category relates to Rehabilitation Introduction Areas (RIAs), which are smaller areas that serve as a site for the first stage of release for dogs from the PDC Rehabilitation Facility. Previously PDC has utilised Starvation Island on Lake Kariba for this purpose. Whilst Starvation Island has been a successful location in so far as dogs from the PDC Rehabilitation facility have bonded as a pack, and hunted successfully before being released elsewhere, crocodiles have been the cause of unacceptable dog losses. Consequently RIAs were sought with the Victoria Falls Private Game Reserve (VFPGR) being the first under consideration.
It is anticipated that these metapopulations would be exclusively populated with dogs from the PDC rehabilitation facility for the following reasons.
1/ There would be no impingement on existing wild populations.
2/ As the provenance of all the rehab dogs is known, the metapopulations could be representative of the three known Zimbabwe populations. This would facilitate genetic reinforcement in areas where populations had declined rapidly in recent history (Childes 1988; Marsden et al. 2009; Rasmussen 2009), for the above reasons, limited and selective breeding at PDC would be required. It will however also require PDC to simultaneously work towards fulfilling the action plan goal to secure additional release sites.
It is intended that these packs would be monitored by PDC in collaboration with Zimbabwe Parks and Wildlife Management Authority.
As it is to be anticipated that packs inside the fenced reserves would, as in South Africa, do well consideration has to be given as to what should happen to the fenced packs as they increase past what is considered an acceptable carrying capacity. At this juncture considering the genetic arguments mentioned this stock would be best utilized to augment existing populations, which are rarely at saturation. In the case of Hwange, should the conditions that have caused the current population to collapse be reversed, such stock would be a welcome addition. However, the goal of establishing a metapopulation as well as sorting out the huge issues facing Hwange need to be addressed simultaneously.
At this point, as genetics are highlighted as an issue through both cranial morphology (Rasmussen 2009), as well as through the finding that at the MHC complex level (MHC complex responsible for disease resistance) the dogs are genetically depauperate (Marsden et al. 2009), it makes sense to utilize the genetic diversity of the of the dogs in the rehabilitation unit. Consequently then it will be of conservation value to initially breed no more than one or two litters and monitor the success of the release of these dogs into the wild. To maximise on the success of such an operation PDC has now secured access to Victoria Falls Private Game Reserve (VFPGR) which will be fenced to be dog proof to provide for the first releases of any pups born at the rehabilitation unit in conjunction with any legitimate dogs that are in the rehabilitation facility. Should this be achievable then the conservation value of the PDC Rehabilitation Facility will be immeasurably enhanced.
Childes, S. L. 1988. The Past History Present Status and Distribution of the Hunting Dog Lycaon pictus in Zimbabwe. Biological Conservation 44:301-316.
Courchamp, F., G. S. A. Rasmussen, and D. W. Macdonald. 2002. Small pack size imposes a trade-off between hunting and pup-guarding in the painted hunting dog Lycaon pictus. Behavioural Ecology 13:20-27.
IUCN/SSC. 2007. Regional conservation strategy for the Cheetah and African wild dog in southern Africa
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Rasmussen, G. S. A. 1997. Conservation status of the painted hunting dog Lycaon pictus in Zimbabwe, Pages 47pp, Ministry of Environment & Tourism. Harare, Zimbabwe, Department of National Parks & Wildlife Management.
—. 2009. Anthropogenic factors influencing biological processes of the Painted Dog Lycaon pictus , Oxford University, Oxford.
Rasmussen, G. S. A., S. Canney, F. Courchamp, and D. W. Macdonald. Submitted. Breaking the Camels Back. Can Energetic Cost Cascades help quantify extinction vortices? Ecological monographs.
Rasmussen, G. S. A., M. Gusset, F. Courchamp, and D. W. Macdonald. 2008. Achilles Heel of Sociality Revealed by Energetic Poverty Trap in Cursorial Hunters. American Naturalist 172:508-518.
Romanach, S. S., and P. A. Lindsey. 2008. Conservation implications of prey responses to wild dogs Lycaon pictus during the denning season on wildlife ranches. Animal Conservation 11:111-117.
Valeix, M., H. Fritz, S. Chamaillé-Jammes, M. Bourgarel, and F. Murindagomo. 2008. Fluctuations in abundance of large herbivore populations: insights into the influence of dry season rainfall and elephant numbers from long-term data. Animal Conservation 11:391-400
This article has been provided by: Stichting Painted Dog Conservation (http://www.painteddogconservation.nl/)