All About Animals

Past conservation measures, including strict regulations on trade (CITES), regulation of hunting and regulation of translocations have effectively mitigated the major historical threats responsible for the critical losses in the 19th and first half of the 20th century. However, although the Cape Mountain Zebra has been reintroduced to many formally and privately protected areas, the overall genetic diversity of the population is low. Kamannassie and Gamkaberg Nature Reserves are crucial for the genetic conservation of the subspecies, as these two subpopulations contain two-thirds of the entire genotype. An increase in suitable available habitat is vital for the long-term conservation of these subpopulations, whether it be in the adjacent areas or through translocations to other areas. Mixing of the original subpopulations to ensure increased genetic variation in the metapopulation should be the top priority. Mountain Zebra National Park and Karoo National Park are important as they contain the two largest subpopulations, exist in optimal habitat for the subspecies, and provide large enough areas for a degree of natural seasonal migration to take place.

Thus, a combination of three main interventions is required:

• develop and implement a metapopulation management strategy to maximise genetic diversity and subpopulation growth;

• expand range and number of subpopulations; and

• improve habitat management, to conserve and restore the grass-rich habitats needed by this subspecies.

The development of a Biodiversity Management Plan, underway since 2013, will be strengthened by incorporating findings from the 2015 survey and is nearing completion. The establishment of the herd at Oorlogskloof Nature Reserve serves as a good experiment in adaptive management to investigate disease prevalence as well as the mixing of two genetically isolated and inbred subpopulations. Monitoring this subpopulation is essential to provide knowledge and tools to inform future translocations as part of the metapopulation management plan.

Manging the hybrid threat with both Hartmann’s and Plains Zebra relies on active participation in the Biodiversity Management Plan. Incentives should be developed to encourage private landowner participation in the mooted metapopulation plan. In the private sector, conservation of the subspecies was reportedly the most common motivation behind acquiring Cape Mountain Zebra, while hunting was the least common reason. Most private owners agreed with regulating the possession, translocation and hunting of Cape Mountain Zebra through a permit system (as long as the process is efficient), but around 50% of owners did not agree that the subspecies should be restricted to within their natural distribution range. Such considerations should be taken into account in designing an incentive system. The urgent need to eliminate the threat of hybridisation with Plains Zebra has been recognised by SANParks and plans are in place to remove all remaining Plains Zebra from areas with Cape Mountain Zebra. Furthermore, all individuals captured for translocation from affected SANParks subpopulations will be subject to genetic testing and will be kept in holding camps until confirmed as pure. Hybrid individuals will be euthanised to prevent further genetic contamination. As the genetic integrity of Cape Mountain Zebra depends on their relative abundance to Plains Zebra in a subpopulation, it is important to sustain large subpopulations of Cape Mountain Zebra.

Fire management and access to nutrient-rich lowlands are important management tools to prevent herds from becoming limited by resources (Weel et al. 2015). Although fynbos typically burns at an interval of 12-15 years, burning at shorter intervals to stimulate grass-growth is recommended for Cape Mountain Zebra. Since formally protected areas have a mandate to conserve greater biodiversity, the majority of which is fynbos, management options for properties with Cape Mountain Zebra need to consider the implementation of integrated burn thresholds aimed at maintaining landscape diversity, which includes areas of grassy fynbos. Suitable areas surround many of the formally protected areas, and the establishment of Cape Mountain Zebra on such properties containing reclaimed agricultural fields, provided that adequate natural habitat exists, can be considered as favourable sites for expansion. The primary constraints in achieving this are the costs involved in translocation and establishment, security (fencing), management and monitoring. Additionally, biodiversity stewardship schemes should be established to protected further natural habitat and prevent further transformation, especially in lowland habitats, with effects on Cape Mountain Zebra subpopulations monitored. Management within such conservancies, biodiversity stewardship sites, or leased land should restore grassy habitats and employ ecological stocking rates to reduce grazing competition.

Through such efforts, the chances for the long-term conservation of the subspecies would be greatly enhanced. These recommendations have been passed on to the appropriate authorities and private landowners. Furthermore, it is now possible to access current Cape Mountain Zebra management recommendations and general information from a website dedicated to the subspecies.
Recommendations for land managers and practitioners:

• A Biodiversity Management Plan (BMP) must be drafted and adopted by all stakeholders. There is currently no approved national management plan for Cape Mountain Zebra. SANParks does not have a specific management strategy, but the management of the subspecies follows the general policy for the management of large mammals. According to CapeNature, a conservation management plan is not required, although recommended, for the introduction or keeping of Cape Mountain Zebra on private land. Eastern Cape Parks and Tourism Agency has a management plan for the three subpopulations they manage. A priority for management is thus the development of an integrated Biodiversity Management Plan. A vital component of a successful management plan in the long-term is a sound understanding of population viability. The minimum viable population size has not yet been determined (through a Population Viability Analysis) and management actions required to ensure the viability of subpopulations of various sizes are poorly understood (for example, the number, sex, and frequency of additions/removals required in order to prevent any further loss of genetic variation).

• Within the BMP, a metapopulation strategy should be detailed. The priority is to mix the relic subpopulations (Mountain Zebra National Park, Gamkaberg and Kamanassie Nature Reserves) to halt the further loss of genetic diversity. Until now, the management plan for the two most genetically important subpopulations, Kamannasie and Gamkaberg, has been to allow these subpopulations to increase before being harvested for translocations into other subpopulations. Unfortunately, both subpopulations are at relatively low numbers—both being less than 100 animals and one being below 50 animals—requiring thorough assessment of the impacts of any removals. This has not been successful though, and actions are now urgently needed to rectify this and reduce the vulnerability of these gene pools. Attempts have been made to increase the suitable habitat available to both populations by incorporating surrounding properties or increasing burning frequencies to promote grassland. This has not yet been achieved due to crucial corridors not being incorporated.

• Translocations and reintroductions within the metapopulation strategy should comprise entire family units, and founder subpopulations should consist of at least 14 individuals to sustain subpopulation growth and genetic diversity. Genetic testing for hybridization should be a pre-requisite for reintroductions. Any hybrid individuals should then be euthanised.

• Reclaimed agricultural lands within the natural distribution range that have been converted to grasslands for livestock can be key resource areas, as such landscapes are likely to be similar to the late Pleistocene when grasslands were widespread and supported large numbers of Cape Mountain Zebra. A habitat suitability index for CMZ has been developed and tested in the Mountain Zebra National Park, and further tested in the Bontebok National Park. These studies indicated that the quality of the habitat for CMZ can be predicted on the basis of the cover of large-tufted, leafy, palatable grass species. However, the habitat suitability index needs further testing over a wider range of habitats. Managers should utilise the habitat suitability index prior to reintroduction and monitor the subsequent habitat use to refine the index. Monitoring habitat suitability should also incorporate drainage lines and kraal lawns, microhabitats favoured by the subspecies.

• A system of collecting genetic samples, such as collecting faecal or hair samples needs to be adopted across all stakeholders. This would create a database of genetic material, which is crucial to determine, monitor, and/or manage genetic heterogeneity within the metapopulation.

• Impacts of reintroduced large predators on Cape Mountain Zebra subpopulations must be researched, and appropriate management interventions developed and implemented to mitigate such impacts.

• Captive breeding and ex-situ management are not necessary.

Research priorities:

• Research to determine effective subpopulation size and minimum viable population size overall. Given that the minimum viable population (breeding individuals) for large mammals is ca 4,000, a more appropriate population target could potentially be as large as 12,000 individuals.

• Analysis of the potential expansion of the population within the available habitat, based on an improved understanding of habitat suitability, is needed. Firstly, the historical distribution range and seasonal movements need to be compared to the current distribution of subpopulations. The degree to which the subpopulation occurs in historic marginal habitat areas can then be determined. Subpopulation performance across a range of habitat types then needs to be assessed to understand habitat suitability and the possible refuge status of the subspecies in fynbos-dominated habitats (such as MaxEnt modelling). Similarly, assessing the effectiveness of using integrated fire thresholds aimed at maintaining diversity inclusive of grassy habitats and subpopulation performance.

• The severity of genetic threats need to be evaluated: for example, the extent of hybridisation with Hartmann’s Mountain Zebra and Plains Zebra; and the extent and consequences of inbreeding, including an improved understanding of how it relates to the Sarcoids virus.- Impacts of reintroduced large predators on Cape Mountain Zebra demographics and behaviour must be determined.

Encouraged citizen actions:

• Citizens can register as an interested party on the website http://www.capemountainzebra-nmmu.co.za where they can read about management recommendations, latest news, and provide sightings data. Private landowners are also encouraged to report their annual count data (with detailed demographic information) to the Cape Mountain Zebra Research Project, Nelson Mandela Metropolitan University. This would greatly enhance the understanding of their subpopulation and appropriate management actions could then be implemented accordingly.

• Any sales/purchases can be reported to keep track of subpopulations, and tissue samples can be collected opportunistically (during captures/hunts) so that researchers can analyse the genetic diversity of the subpopulations. CapeNature has developed a biological sample protocol which can be made available on request.