Ecological Monitoring

  • Ol Pejeta Conservancy
  • Ecological Monitoring on Ol Pejeta

The Ecological Monitoring Department (EMD) on the Ol Pejeta Conservancy aims to identify and monitor key variables necessary to maintain healthy trends in both habitat and animal species.

Consequently the EMD sets appropriate threshold levels for key animal and habitat variables which act as early warnings. Whenever threshold levels are exceeded, either management intervention is recommended or third party researchers (see research opportunities) are engaged to study the underlying reason for change.

In accordance with national strategy and in liaison with the Kenya Wildlife Service, Ol Pejeta has developed a management plan for certain species.

  • Ecological Monitoring on Ol Pejeta
  • Ecological Monitoring on Ol Pejeta
  • Elephant on Ol Pejeta Conservancy

Ecological Monitoring Department Activities:

  1. Habitat Monitoring

    Acacia drepanolobium: Acacia drepanolobium woodlands largely characterize the ecological status of the Ol Pejeta Conservancy and also form a key component of the black rhino diet. A. drepanolobium has been under intense browse pressure from rhino, elephant and giraffe prompting a translocation of 56 elephants in 2001. Currently with the assistance of the EarthWatch Institute, EMD monitors A. drepanolobium growth rates damage and mortality occasioned by elephants, rhinos and giraffes.

    Euclea divinorum: Euclea divinorum covers approximately 27% of the Ol Pejeta Conservancy and its area occurrence is thought to be expanding. This may threaten other woody species especially A. drepanolobium, a key component of black rhino diet. Monitoring is ongoing to establish spatial distribution, the annual rate of spread and to determine rate of conversion into different height classes.

    Acacia xanthophloea: Over the years, elephants have severly impacted the A. xanthophloea (Yellow Fever Trees) woodlands on the Ol Pejeta Conservancy through debarking and pushing-over the mature trees. The EMD works to determine the annual rate of tree loss, and through the implementation of exclusion zones monitor the rate of tree recovery.

    Pasture condition: The Ol Pejeta Conservancy aims at integrating livestock ranching with wildlife conservation and as such careful management of the pasture resource is required. Pasture condition monitoring is undertaken to optimize primary production and efficient forage harvest for both livestock and wildlife grazers on a sustainable basis. The monitoring involves manipulation of cattle-herds and the use of fire to remove moribund grass, improving forage quality, to improve grazing distribution of livestock and wildlife grazers, to create grazing ‘hot spots’ for tourism purposes, and to control bush encroachment.

  2. Species monitoring Knowing the number of individuals in a population is vital for the effective management of that species. Monitoring of the following key species is thus undertaken:

    Rhinos: The Ol Pejeta Rhino Conservation Program was started in 1989 with a founder population of 20 eastern black rhinos (Diceros bicornis michaeli) introduced between 1989 and 1993. This population had increased at an average growth rate of 8.9% to 49 by the end of 2006. In 2006, 7 southern white rhinos (Ceratotherium simum simum) were introduced, mainly from the Lewa Wildlife Conservancy. This was followed with the introduction of a further 27 black rhinos in February 2007 making the Ol Pejeta Conservacny the largest Black Rhino Sanctuary in East Africa. Currently Ol Pejeta has 86 black rhinos, 11 southern white rhinos and 4 northern white rhinos. The rhinos are monitored very intensively and in line with the National Black Rhino Management and Conservation Strategy. The entire conservancy is divided into several patrol sectors each headed by a sector head. The surveillance is complimented by the use of radio tracking devices and aerial surveillance. We aim to see each individual rhino at least once every 5 days.

    Problem Elephants: Monitoring of the problem elephants, that break through our fences to go into community areas, is aimed at identifying troublesome individuals as well as the effectiveness of long-term prevention measures.

    Hartebeest Monitoring: The total population of Jackson’s hartebeest (Alcelaphus busephalus lelwel) is unknown but in Laikipia their numbers are estimated at between 700-1,000 individuals of which the Ol Pejeta Conservancy holds an estimated 21%, or approximately 200. It is estimated that the Laikipia hartebeest population has fallen by 78% since 1991. The Ol Pejeta’s hartebeest population program aims to monitors the reproductive performance of our entire population.

    Grevy’s Zebras: Grevy’s zebra (Equus grevyi) have undergone one of the most substantial reductions of range of any African mammal, now being found only in Ethiopia and Kenya. In the 1970’s it was estimated that there were over 15,000 Grevy’s zebra in Africa. Today only 1,600-2,000 individuals are estimated to remain in Kenya and 126 in Ethiopia. The Ol Pejeta Conservancy is at the very southern tip of the Grevy’s zebra range, with 14 Grevy’s zebras (7 males, 4 females and 3 juveniles). While predation poses the biggest threat to this population, hybridization resulting from the male Grevy’s mating with female Burchell’s zebras is of concern. The hybrids are currently estimated to be 23. In conjunction with the Kenya Wildlife Service, the Ol Pejeta Conservancy will consolidate its Grevy’s zebra population into an area that is free of Burchell’s, hybrids and predators. This founder population will be supplemented with females from another population to create a viable breeding program.

    Burchell’s Zebras: The population dynamics of the Burchell’s zebra population on Ol Pejeta are monitored as a means to estimate predation pressures.

    Primates: Four primate species, the olive baboon (Papio anubis), vervet monkey (Chlorocebus pygerythrus), Patas monkey (Erythrocebus patas), and the Senegal bushbaby (Galago senegalensis) exist on the Ol Pejeta Conservancy. Patas monitoring is done to determine their number and distribution.

    Lions: In every lion (Panthera leo) pride on Ol Pejeta, one female is collared so that the pride can be located easily. When lions are found, each individual in the pride is identified. Individual identification is done using the whisker spot pattern technique. The information obtained from the monitoring is synthesized into home range maps of the different prides and to enable estimates of total population size.

    Spotted Hyenas: Spotted hyenas (Crocuta crocuta) have the potential to negatively impact on the population of prey species and it is therefore important to monitor hyena population. Spotted hyenas live in family groups called clans and each clan has a number of dens. The Ol Pejeta Conservancy's patrol teams report any active dens they come across, which are then monitored to establish hyena usage. Individual hyenas are identified by spot patterns.

    Cheetah Monitoring: Cheetahs (Acinonyx jubatus) are classified as vulnerable for a number of reasons that include a very low genetic diversity which is considered a problem for the long-term adaptability of the species, as well as low cub survival caused by predation. The individual cheetahs comprising the Ol Pejeta population are regularly monitored by means of unique tale patterns.

For more information on Ol Pejeta's ecological monitoring programs, please contact Carol N'gweno at

Ecological Monitoring on Ol Pejeta