Feral Cats as an Invasive Species
Although more commonly known for his expertise with alien plants, Llewellyn Foxcroft's latest collaboration to keep national parks as havens for indigenous species involves claws and teeth rather than thorns and spikes.
Recently Llewellyn, a specialist in alien species with SANParks and research fellow for the DST-NRF Centre of Excellence for Invasion Biology (CIB), with the collaboration of Marna Herbst, also from SANParks, initiated a study to examine the role of feral cats as an invasive species.
Domestic cats can 'invade' by introducing their DNA into the gene pool of the African wildcat population of Kruger National Park (KNP). A proposal was submitted to and accepted for funding by the British Ecological Society Overseas Grants programme.
Llewellyn's interest in the possible hybridisation of feral cats with the African wildcat population started in 1997 when he saw (and heard) a large number of feral and hybrid cats along the boundary of the Phalaborwa section of the park.
His interest was again raised earlier this year, this time as a conservation concern within an invasion biology framework. SANParks colleague Marna studied African wildcat behaviour in the Kalahari National Park. Together with Jaco Le Roux and the molecular lab at the CIB, and with the support of the British Ecological Society, the study has recently started.
The main objective of this project is to clarify the current genetic status of the African wild cat population in terms of its hybridisation with feral domestic cats in KNP. Second, the team hopes to see how far hybridisation has spread into the KNP (eg around staff villages, near towns on the boundary of the KNP and in more remote areas of KNP) to identify focal areas for efficient conservation management strategies.
One of the ways in which biological invasions threaten biodiversity, is through reducing the genetic diversity of species. This is of particular concern to protected areas, whose primary mandate is to protect biological diversity and normal ecosystem processes. The African wild cat (Felis silvestris lybica) has a wide distribution throughout Africa and is generally recognised as the ancestor of the domestic cat.
The identification of genetically pure wild cat populations is imperative for future assessments of the extent of hybridisation and introgression, especially for areas where African wild cats occur in close proximity to domestic and feral cats. Little is known about the genetic status of the African wild cat population in the park, and thus determining the genetic purity of the African wild cat population will assist in determining management strategies.
The British Ecological Society Overseas Grant programme is thanked for their support and contribution to the study. The CIB and SANParks are also thanked for their support.
Photo M. Herbst
By Dr Llewellyn Foxcroft