Sungai Wain is located within Balikpapan Bay, a biodiversity rich area consisting of interconnecting mosaics of mangrove forests, primary and regenerated rainforests, freshwater rivers and coral reefs.
However, this is a highly developed region in Kalimantan, mainly due to Balikpapan being the second main centre of oil production in Indonesia.
Human activities, such as logging, coal mining and acacia and oil palm plantations, are causing great damage to the ecosystems in Balikpapan Bay, including water pollution, increased sediments on the coral reefs and forest loss.
Sungai Wain is a 100 km sq protected forest; home to several primate species, including orangutans, Bornean gibbons, white fronted langurs and pig-tailed macaques.
Like many other forests on Borneo, during the last few decades large parts of Sungai Wain were destroyed by fires, with only about 40 km sq of core forest remaining intact.
Previous surveys were conducted by Professor Vincent Nijman in 1999-2005.
Seven years later we found that red langurs remained stable and in relatively abundant numbers within the core primary forest of Sungai Wain.
With a density of ~28 individuals per kilometre square, red langurs in Sungai Wain appear to be thriving.
In addition, the number of large trees appeared to be increasing: when we did our surveys in 2012 the trees with a diameter at breast height above 10cm almost doubled compared to previous data from 2001.
Continue reading (Incl. Pics) at: Stronghold of red monkeys discovered on Borneo.