Spotty calculations? Cheetah numbers may be lower than estimated, says study

London: Current estimates of the number of cheetahs in the wild are ‘guesswork’, researchers including those from India have found, amid fears that the fastest land mammal is racing to extinction. A new study has found that the population in the cheetah stronghold of Maasai Mara, Kenya, is lower than previously thought. In the early 1900s, it was believed that around 1,00,000 cheetahs roamed the Earth. The most recent estimate by the International Union for Conservation of Nature (IUCN), puts the figure at 6,600 — mainly in eastern and southern Africa. However, a team of scientists from the Kenya Wildlife Trust’s Mara Cheetah Project, the University of Oxford in the UK, and the Indian Statistical Institute in Kolkata, said that this number is simply a best guess, given the difficulty of counting cheetahs accurately. [caption id=“attachment_2764800” align=“alignleft” width=“380”]  File photo. Reuters.[/caption] The researchers have now developed a new method to accurately count cheetahs, which in time will help determine the magnitude of the threats they face and assess potential conservation interventions. “The truth is that estimates of cheetah numbers are only best guesses, because cheetahs are a lot harder to count accurately than one might think,” said Dr Femke Broekhuis, Project Director of the Mara Cheetah Project and a post-doctoral researcher at University of Oxford. “They naturally occur at low densities and move large distances, making them difficult to find,” said Broekhuis. “Whatever the exact number, we do know that they are extinct in 20 countries and occupy only 17 percent of their historical range. We also know the major threats facing cheetahs: habitat loss, human-wildlife conflict, depleting prey and the illegal pet trade,” said Broekhuis. During a three-month period, researchers extensively covered the Maasai Mara National Reserve and surrounding wildlife conservancies in search of cheetahs. The team photographed each cheetah that was seen and identified each individual based on its unique coat pattern. These data were then analysed using an advanced Bayesian Spatially Explicit Capture Recapture (SECR) statistical model. This technique, incorporating information such as identity and location, is more powerful than previous methods used to estimate cheetah numbers. The study showed an average of 1.28 adult cheetahs per 100 square kilometres in the Maasai Mara — an average total of 30 animals. This number is lower than previously thought — around half. The results of this study will allow threats and conservation efforts to be quantified and monitored in the future, researchers said. “The method we have used accounts for detection probability and is therefore more accurate than other methods that are currently being used to estimate cheetah numbers,” said Dr Arjun Gopalaswamy, from the Indian Statistical Institute and the Department of Zoology at Oxford. The study was published in the journal PLOS ONE.