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Counting marbles: David Macdonald explains how WildCRU’s Bornean team, led by Andrew Hearn has calculated the first estimates of population density for the elusive marbled cat

If you have never heard of a marbled cat – known to science as Pardofelis marmorata – don’t be despondent: very few people have, and nobody knows much about them. These, tropical, forest-dwelling cats were generally invisible until the advent of camera traps which can lie in wait for months at a time until they intercept passing wildlife. Despite being little known, the marbled cat has a broad distribution across much of the Indomalayan ecorealm.

Photo by: Sebastian Kennerknecht/Panthera. Taken at Tawau Hills National Park, Sabah, Borneo, Malaysia

WildCRU’s team conducted large-scale camera trap surveys of eight forest areas and two oil palm plantations in Sabah, Malaysian Borneo, over a period of 8 years. The study sites were selected to be broadly representative of the range of habitat types and the gradient of human disturbance and fragmentation present in contemporary Sabah. You can read the paper at: http://dx.doi.org/10.1371/journal.pone.0151046

The hidden cameras recorded marbled cats from all forest study areas apart from one small, relatively isolated forest patch. On the other hand, there was no trace of them within the plantations. At three study areas we secured enough photos to use a mathematically rather complicated technique called “spatially explicit capture-recapture analysis”. Estimates of population density from the primary, lowland Danum Valley Conservation Area and primary upland, Tawau Hills Park, were 19.57 (SD: 8.36) and 7.10 (SD: 1.90) individuals per 100 km2, respectively, and the selectively logged, lowland Tabin Wildlife Reserve yielded an estimated density of 10.45 (SD: 3.38) individuals per 100 km2. These estimates are an important start in our goal to build a full picture of the natural history of these beautiful cats – watch this space because we are busily secreting camera traps in forests throughout their geographical range, contributing to the three quarters of a million camera trap images of wildlife we have secured of wildlife from Nepal to Kalimantan!

Photo by J Ross and A Hearn: A marbled cat photographed from a selectively logged forest, in Sabah

Andrew Hearn, David Macdonald, and Gilmoore Bolongon