10.
Riverine Rabbit
(Bunolagus monticularis)
CR
Overview
This rabbit lives in one of the few areas of the Karoo Desert suitable for conversion to agriculture, and as a result has lost virtually all its habitat to farming. Less than 250 individuals survive, and all occur on privately owned land where they come under further pressure from hunting, trapping, and predation by feral dogs and cats. An extremely slow breeder (for a rabbit), the species is finding it almost impossible to recover from these losses, and is in desperate need of conservation attention.
Urgent Conservation Actions
Expansion of the existing conservancy system and the establishment of a biosphere reserve system of core and buffer areas.
Distribution
Karoo Desert of South Africa’s Cape Province.
Associated Blog Posts
20th Apr 15
Lagomorphs are a very distinct group of small mammalian herbivores. The order Lagomorpha (pikas, rabbits, hares and jackrabbits) is defined by small peg-...  Read

9th Apr 12
  EDGE mammal number 10, the riverine rabbit (Bunolagus monticularis), lives in an area of the Karoo Desert in South Africa’s Cape Province that is...  Read

3rd Feb 11
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Media from ARKive
ARKive image - Riverine rabbit
ARKive image - Riverine rabbit sitting upright
ARKive image - Riverine rabbit
ARKive image - Riverine rabbit in scrub vegetation
Evolutionary Distinctiveness
Order: Lagomorpha
Family: Leporidae
The order Lagomorpha contains two families, the Ochotonidae (pikas) and Leporidae (rabbits and hares). These families are thought to have diverged during the late Eocene, 35-38 million years ago. The Leporidae comprises two groups: the jackrabbits and hares of the genus Lepus, and the rabbits in the remaining ten genera. Recent molecular data indicates that most rabbit and hare genera arose from a single rapid diversification event during the Miocene (between 12 and 16 million years ago). Bunolagus monticularis is the sole species in the genus Bunolagus.
Description
Size: 
Head and body length: 337-470 mm:
Tail length: 70-108 mm:
Ear length: 107-124 mm
Weight: 1.0-1.5 kg
This species has large moveable ears, and can be easily identified by the dark brown stripe running from the corner of the mouth and across the cheek towards the base of the ear. Its limbs are short and heavily furred, and it has a broad club-like hind foot. Its fur is cream-coloured on the belly and throat, and it has a uniformly brown woolly tail. Male riverine rabbits weigh approximately 1.5 kg and females 1.8 kg.
Ecology
Predominantly a browser, feeding on wild flowers and leaves from the riparian vegetation found along seasonal rivers in the Karoo Desert. Grass is included in the diet during the wet season. The species is nocturnal, avoiding predators by spending its days resting in a form (a shallow scrape made in the soil under a bush). Individuals are solitary and have a polygamous mating system. Males and females maintain intrasexually exclusive home ranges, with male ranges overlapping those of the female. Unusually for rabbits, this species breeds very slowly, with females giving birth to only one or two young each year. Since they rarely live for more than three years, this means that only around four offspring are produced during each rabbit’s lifetime.
Habitat
A habitat specialist, occupying a very restricted niche. Living amongst the dense riparian vegetation along the seasonal rivers of the central and southern Karoo, it depends on the fine alluvial soil of the floodplains, the only soil in the area suitable for making stable burrows.
Distribution
Endemic to South Africa. Its geographic range is extremely limited, occurring only in the central and southern regions of the Karoo Desert of South Africa’s Cape Province.
Population Estimate
Population size is now estimated to be fewer than 250 mature individuals. Evidence suggests that the population size is currently declining, and it is estimated that over the last 70 years the population has declined by at least 60%. The population is fragmented, with no subpopulation containing more than 50 individuals.
Population Trend
Decreasing
Status
One of South Africa’s most threatened species. Classified as Critically Endangered (CR C2a(i);E) on the 2010 IUCN Red List of Threatened Species.
Threats
The main threat facing this species is habitat loss. The nutrient-rich soils of the alluvial floodplains it inhabits are excellent for conversion to agriculture compared with other soils of the dry Karoo. Crop cultivation and overgrazing by livestock have led to habitat loss and fragmentation and have opened areas up to predators, with an estimated 51-80% decline in habitat size over the last 100 years. Other threats include hunting, trapping, predation from feral cats and dogs, and the construction of dams which dry up rivers.
Conservation Underway
A number of governmental and non-governmental organisations have joined together to form the Riverine Rabbit Conservation Project. The project has focused on identifying areas where the rabbit and its optimum habitat may be found. Through raising public awareness and educating landowners the project aims to reverse the current decline in population. Since almost all the rabbit’s optimal habitat is found on privately owned farmland, its survival depends on the willingness of landowners to adopt more environmentally friendly farming practices. Landowners are therefore being encouraged to participate in conservancies in order to create an informal conservation area to protect remaining populations and potential habitat. These conservancies are recognised by local government and nature conservation bodies. So far three Riverine Rabbit Conservancies have been established in the Karoo: one in the Northern Cape and two in the Western Cape.

A captive breeding programme was attempted in 1987 but has now been abandoned due to the high mortality of rabbits in captivity and the fact that they were introduced into a national park which contained no suitable habitat.
Conservation Proposed
The future of the species depends on the protection and effective management of its natural habitat. At present none of the riverine rabbit habitat is protected within a provincial nature reserve or national park in the Karoo region. This lack of formal habitat protection requires the expansion of the existing conservancy system to cover a wider range of the rabbits’ distribution, with the ultimate goal being to develop a biosphere reserve system of core and buffer areas. At the IUCN/SSC Conservation Breeding Specialist Group CAMP South Africa workshop, additional conservation actions recommended included further research into the life history of the species, increased public awareness, and the establishment of a second captive breeding programme.
Links
Riverine Rabbit Conservation Project
Consists of a wide variety organisations dedicated to conservation of the riverine Rabbit and its habitat. The main role players in the conservation project include the Endangered Wildlife Trust’s Riverine Rabbit Working Group (EWT-RRWG), Western Cape and Northern Cape nature conservation departments (CapeNature and Northern Cape Department of Nature and Environmental Conservation), Conservancy members, South African National Parks, Departments of Agriculture as well as Academic Institutions (University of Pretoria and University of Stellenbosch).

The Endangered Wildlife Trust’s Riverine Rabbit Working Group (EWT-RRWG)
Established in August 2003 and now delegating and coordinating all conservation efforts on the Riverine Rabbit and its habitat. The group aims to conserve the species by undertaking transect surveys and habitat evaluation and mapping exercises, environmental education and awareness, habitat management and rehabilitation, conservation stewardship programmes, population monitoring, research within the distribution range of the species as well as publicity.
References

Duthrie, A. G. and Robinson, T. J. 1990. The African Rabbits. In: Chapman, J.A. & Flux, J.E.C. (eds.). 1990. Rabbits, Hares and Pikas: Status Survey and Conservation Action Plan. IUCN/SSC Lagomorph Specialist Group. IUCN, Gland. pp: 121-127.

Duthie, A. G., Skinner, J. D and Robinson, T. J. 1989. The distribution and status of the riverine rabbit, Bunolagus monticularis, South Africa. Biological Conservation 47(3): 195-202.

Matthee, C. A., Jansen van Vuuren, B., Bell, D. and Robinson, T. J. 2004. A Molecular Supermatrix of the Rabbits and Hares (Leporidae) Allows for the Identification of Five Intercontinental Exchanges During the Miocene. Systematic Biology 53(3): 433-447.

Nowak, R.M. 1999. Walker's Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.

Riverine Rabbit Conservation Project

Robinson, T. J. and Skinner, J. D. 1983. Karyology of the riverine rabbit, Bunolagus monticularis, and its taxonomic implications. Journal of Mammalogy 64(4): 678-681.

South African Mammal CAMP Workshop 2008. Bunolagus monticularis. In: 2010 IUCN Red List of Threatened Species. Version 2010.4. Downloaded on 12 November 2010.

Distribution map based on data provided by the IUCN Global Mammal Assessment.

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