Orangutan numbers are not increasing despite what the Indonesian Government claims

In a new publication in Current Biology we explain that orangutan numbers are still declining despite what the Indonesian Government suggests and that there is a strong need to collaborate to set up a solid monitoring system for orangutans.



Small room for compromise between oil palm cultivation and primate conservation in Africa

We just published a new paper in PNAS on the potential expansion of oil palm in Africa and its potential impacts on primates. See the abstract here:


Despite growing awareness about its detrimental effects on tropical biodiversity, land conversion to oil palm continues to increase rapidly as a consequence of global demand, profitability, and the income opportunity it offers to producing countries. Although most industrial oil palm plantations are located in Southeast Asia, it is argued that much of their future expansion will occur in Africa. We assessed how this could affect the continent’s primates by combining information on oil palm suitability and current land use with primate distribution, diversity, and vulnerability. We also quantified the potential impact of large-scale oil palm cultivation on primates in terms of range loss under different expansion scenarios taking into account future demand, oil palm suitability, human accessibility, carbon stock, and primate vulnerability. We found a high overlap between areas of high oil palm suitability and areas of high conservation priority for primates. Overall, we found only a few small areas where oil palm could be cultivated in Africa with a low impact on primates (3.3 Mha, including all areas suitable for oil palm). These results warn that, consistent with the dramatic effects of palm oil cultivation on biodiversity in Southeast Asia, reconciling a large-scale development of oil palm in Africa with primate conservation will be a great challenge.



Locating emergent trees in a tropical rainforest using data from an Unmanned Aerial Vehicle (UAV)

We have a new paper out on the usage of drones to locate emergent trees. Please see the link here. The highlights are below:

Emergent trees are used as ‘sleeping’ trees by endangered primates such as gibbons.
A method is developed to detect emergent trees in a rainforest using data from UAVs.
Relative heights are used instead of canopy heights to identify emergent trees.

Emergent figure

Counting crocs from the sky

Here’s a link to a new paper led by Gokarna Thapa on counting crocs with a drone.

Here’s the abstract:

Technology is rapidly changing the methods in the field of wildlife monitoring. Unmanned aerial vehicle (UAV) is an example of a new technology that allows biologists to take to the air to monitor wildlife. Fixed Wing UAV was used to monitor critically endangered gharial population along 46 km of the Babai River in Bardia National Park. The UAV was flown at an altitude of 80 m along 12 pre-designed missions with a search effort of 2.72 hours of flight time acquired a total of 11,799 images covering an effective surface area of 8.2 km2 of river bank habitat. The images taken from the UAV could differentiate between gharial and muggers. A total count of 33 gharials and 31 muggers with observed density (per km2) of 4.64 and 4.0 for gharial and mugger respectively. Comparison of count data between one-time UAV and multiple conventional visual encounter rate surveys data showed no significant difference in the mean. Basking season and turbidity were important factors for monitoring crocodiles along the river bank habitat. Efficacy of monitoring crocodiles by UAV at the given altitude can be replicated in high priority areas with less operating cost and acquisition of high resolution data.