Aside from managing reintroductions to the rainforest and monitoring rehabilitated orangutans in the Kehje Sewen forest, BOS Foundation also conducts regular surveys of plants, fruits, and food trees. The surveys are conducted to evaluate whether the rainforest areas can sustain its wildlife, including its orangutans. The surveys are critical to the study of orangutan habitats and the understanding of the release sites’ ecology, and thus to the orangutans’ survivability in given rainforest areas. The following is a brief report from a recent survey.

The BOS Foundation monitoring team from the Nles Mamse camp in Kehje Sewen, East Kalimantan, conducts thorough plant phenology surveys in the third and fourth weeks of every months. ’Plant phenology’ is the study of the timing of life history events and cycles in plants. It is crucial to the understanding of the release sites’ ecology since the phenology of given release sites may affect the survivability of the released orangutans.

The monitoring team is particularly interested in when the orangutans’ food sources are flowering and fruiting. If the monitoring team knows that food sources in a given area are low, they can monitor the orangutans in that area more closely, they can intervene if the risk of starvation is high, or they can reduce the number of releases into that area temporarily.

Fruits on a Baccaurea tree. Photo by the monitoring team. (BOS Foundation, RHOI)

2018 was a rich year

The latest phenological survey, BOS Foundation’s monitoring team conducted, revealed that numerous tree sorts are flowering or fruiting, including the Macaranga, Baccaurea, Ficus, Shorea, Polyalthia, and Vitex trees.

Baccaurea, Knema, Artocarpus, Ficus, Vitex, and Shorea trees, among several other sorts, are producing fruit in large quantities at the moment (December/January) – which is great news for the orangutans!

Normally, the phenological surveys take up to two weeks to conduct, however, thanks to extra staff and volunteers lending a hand, the monitoring team in Kehje Sewen conducted the latest survey in just two days. Fortunately, the phenological data from 2018 revealed there are enough food resources to sustain the orangutans in the area.

Fruits on a Ficus tree. The Ficus’ fruits are very popular among the orangutans. (BOS Foundation, RHOI)

El Niño threatens 2019

2019 may well be a more critical year for both the monitoring team and the orangutans. Experts warn of an El Niño climate pattern (increased average temperature and less precipitation) in 2019. Historically, an El Niño climate pattern has resulted in drought and thus increased risk of forest fires and irregularities in the phenology of Kehje Sewen and the rest of Borneo.

Read more about the El Niño climate pattern threat in 2019 from Mongabay’s news site >>

Consequently, BOS Foundation has to obtain access rights to additional forest areas to be used as release sites for rehabilitated orangutans in East Kalimantan as quickly as possible in case the caring capacity of Kehje Sewen is reduced due to shortage of food.

Naturally, BOS Foundation continues their fight to protect the orangutan in 2019, and they work to maximise their results and mitigate any threats to this goal. Save the Orangutan will of course follow the development closely and support BOS Foundation in any possible way, both in terms of the regular monitoring of protected orangutan habitats and in terms of the need for new orangutan habitats.