01 03/01/2019

Surveying carnivorous plants in Indonesia

We supported the survey of Nepenthes, a group of carnivorous plants, in West Kalimantan, Indonesia. The pitcher plants are facing various threats in this region such as habitat destruction due to forest fires, oil palm plantation and mining and also their overexploitation for commercial purposes.

Surveying carnivorous plants in Indonesia
© Indonesian Institute of Sciences

Nepenthes (also known as pitcher plants), are carnivorous plants that trap and digest insects in their pitcher-like leaf. Almost half of the 139 species of Nepenthes that have been identified across the globe are found in Indonesian islands such as Sumatra, Java, Papua, Maluku, Sulawesi and Kalimantan making the country a stronghold for those quirky plants.

Our field partner, Muhammad Mansur from the Indonesian Institute of Sciences, has a passion for the botanical world and more specifically pitcher plants. He has been collecting herbarium specimen for years and carefully stored them inside the Herbarium Bogoriense, a botanical museum in Bogor which currently holds 2,135 sheets of 72 species if Nepenthes collected from Indonesia and abroad. Mr Mansur also keeps a living collection of 15 species of Nepenthes in a small green house, which he opens to students to learn about the plants.

Surveying carnivorous plants in Indonesia
Dr Muhammad Mansur © Indonesian Institute of Sciences

One of the Indonesian provinces, West Kalimantan, is especially known to be rich in Nepenthes diversity with various species having been recorded nowhere else in the world. Those endemic species include N. clipeata, N. veitchii, N. hirsuta and N. bicalcarata. However, conservationists are worried that threats such as land conversion for agriculture and mining, as well as the overexploitation of those rare pitcher plants might have an important toll on those endemics.

Mr Mansur believed that conducting an inventory and a distribution survey of these species in West Kalimantan is crucial to ensure that adapted conservation programmes are put in place. One of the Critially Endangered species of Nepenthes is known to only grow on Mount Kelam, a large granite outcrop and another species threatened by illegal gold and coal mining is classified as Endangered and is known to be present in the Mandor Nature Reserve.

Surveying carnivorous plants in Indonesia
Mount Kelam © Indonesian Institute of Sciences

Supported by Chester Zoo, Mr Mansur and his team were able to conduct a 12-days inventory of Nepenthes species in both those sites allowing them to lay the basis for in situ and ex situ conservation of the pitcher plants occurring there. The main objectives of this study were to record all the species found on those sites to get a population estimate alongside a habitat description for each of them.

Surveying carnivorous plants in Indonesia
Dr Mansur and his team. © Indonesian Institute of Sciences

On Mount Kelam, Dr Mansur and his team recorded a total of 10 Nepenthes species which included one species of natural hybrid and managed to collect 130 sheets of specimen ((Nepenthes and trees leaves)  to bring back to the Herbarium Bogoriense for further analysis. For each taxa recorded, the team noted information such as its family, species, locality, latitude and longitude, and altitude but also the habitat the plant was found in.

A total of ten species, which included four natural hybrids, was found in the Mandor Nature Reserve across three main habitats: heath forest, thin peat swamp, and swamp forest. The team was very excited to find individuals of the threatened and endemic N. bicalcarata growing clustered in thin peat swamps. The species is protected by law and is currently being conserved in ex situ conditions to prevent its extinction.

Surveying carnivorous plants in Indonesia
© Indonesian Institute of Sciences

Mr Mansur’s team also conducted an ethnobotany study around Mandor and interviewed a range of local people to assess their traditional knowledge and use of Nepenthes. 90% of the villagers surveyed stated that the Nepenthes population around their village had decreased compared to 10 years ago and they indicated changes in forest area function, illegal logging, illegal mining, and forest fires as the main reasons behind the decline.

The local community reported using Nepenthes plant to cook rice in the past and using different parts of the plant such as the root and the liquid enclosed in the pitcher as traditional medicine but did not report any mystical stories related to the pitcher plants.

While in the field, the team of conservationists collected seeds from some of the species they encountered and brought them back to the Nepenthes collection at the Indonesian Institute of Sciences to allow for cultivation and propagation.

Surveying carnivorous plants in Indonesia
© Indonesian Institute of Sciences

Dr Johanna Rode-Margono, Field Programme Coordinator for South East Asia at Chester Zoo adds:

“We hope that we can repeat the survey in West Kalimantan to investigate changes over time, and to add similar surveys in other places in Indonesia to provide assessments for other highly threatened species.

In the future, it is our dream to build a small Nepenthes conservation centre at Mr Mansur’s institution that would allow for a combination of cultivation of threatened species, training and research opportunities for students and researchers, as well as serve as a base for a variety of field conservation studies. With this holistic approach we hope to secure the future of as many of these fascinating plants as possible!”

Surveying carnivorous plants in Indonesia
© Indonesian Institute of Sciences