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Learning from Listening to Peat Swamp Forests of Central Kalimantan

Updated: May 15, 2023

By Fredie Poznansky, University of Exeter, UKRI Environmental Intelligence PhD,

Fredie writes about her observations of listening to the soundscapes of Indonesian Tropical Peat Swamp Forest, shifting between field recordings to hearing them in person.

The microphones need to be 5m above ground to capture the vocalisations of canopy dwelling animals such as primates. The field assistants have built ladders so they can easily access the microphones to change over batteries, SD cards and fix faulty devices.

Applications of Acoustic Data for Conservation

Strapping microphones to trees, pressing record and leaving them to run for a month, otherwise known as Passive Acoustic Monitoring (PAM), is a method of generating huge amounts of spatial and temporal acoustic data. Various devices have been engineered for this difficult task of recording acoustic data while withstanding often unforgiving environments, conserving battery life and data storage, whilst maximising data collection. Here, the challenge is less about obtaining data and more processing and interpreting the vast amounts of data obtained - a good challenge to have, many would say! This exciting field is rapidly transitioning from laborious manual methods of signal annotations towards much more efficient machine learning (ML) methods. Commonly acoustic data is used to capture the repertoire of animal vocalisations, to assess anthropogenic impacts and for how I am using it, to monitor ecosystems spatially and temporally.

PAM is considered a conservation tool that can be used for monitoring the impacts of conservation projects, much like camera trapping and drones, as well as non-technological methods such as trapping and visual point counts. Often papers using PAM cite their results as having the potential for being useful for conservation purposes, though arguably many of these statements don’t take into account the complexities of conservation projects and the type of information needed by specific stakeholders/actors. Moreover, they may well be passing over the cost of equipment, field staff, and training for large-scale monitoring projects which are often a limiting factor for conservation project success. So although the valuable research coming out of the ecoacoustic research community does indeed have the potential to inform conservation, there is a gap between this knowledge and the potential end users of it. The aim of my research is to bridge this gap by enquiring into how the data generated from PAM projects can be curated for the needs of different conservation stakeholders. By centralising relevant stakeholders in my research, I hope to:

  1. Identify the gaps between acoustic data collection and the end uses of the data (local stakeholders).

  2. To formulate research questions framed on the needs of local conservation stakeholders – rather than only considering academic notions of conservation.

  3. Uncover potential gaps in ecoacoustic research that can be used to inform technical and methodological development of the field.

  4. Formulate a set of guidelines for aligning PAM research to local conservation needs.

  5. Provide tools and training to local stakeholders to support their participation in acoustic ecology research to fortify and add momentum to the field.

Waterlogged peat swamp forest

The acoustic data I plan to work with is from multiple sites across Central Kalimantan, in Indonesian Borneo. One of the dominant habitats in this area is peat swamp forest. The landscapes I’m working in are culturally and economically valuable to the surrounding communities as well as being of international significance for their role in carbon storage, hydrological regulation, fire prevention and for supporting an abundance of biodiversity. Unfortunately, these habitats are threatened by land conversion and consequent fires from drainage for agricultural expansion. These fires exhibit a socio-ecological-economic-political complexity, involving compromises between many different actors.

One of the datasets I plan to use was collected by Dr Wendy Erb from the University of Cornell and collaborators from Universitas Muhammadiyah Palangka Raya who designed the PAM network in the Rungan Forest initially to monitor orangutans. One of the major advantages of long-term acoustic datasets is that even studies designed for detecting and monitoring a specific species can hold a lot of other valuable information for other research, so it is great to be working within a research community that is willing to share these to explore new opportunities!

With the after-effects of Covid-19 restrictions meaning I have been entirely desk-based up until now, my research questions have been largely based on the literature and very much shaped by existing methodologies. I found that listening to bioacoustics data, without the context of seeing the area myself, led me to oversimplify both the ecology of the sampling area and the social aspects of the conservation problems. I did however gain a good understanding of the state of the acoustic ecology research community.

The field assistants hoisting a large speaker 5 meters into the canopy to carry out an experiment to determine how far primate calls carry in the forest.

Site Visits and KaLi workshop

I visited Central Kalimantan in November to attend the KaLi workshop which had been organised by my supervisor Prof. Frank Van Veen. The workshop facilitated cross-disciplinary conversations about the past, present and future challenges that the Sebangau National Park faces from peat fires. The workshop framed my research in the wider context of land management and drew my attention to the complexity of pressures that Central Kalimantan faces.

For the remainder of the trip I was visiting sites where data I will be potentially using for my project is being collected. One site is a community-owned forest in Tahawa village, where I stayed with my collaborator Kristen Morrow who is the primary researcher collecting this acoustic dataset. Alongside this, she is also conducting an ethnographic study on the community’s relationship with the forest and primates living in this area. The second site is Sebangau National Park, an area set aside from development due to its significant role for conservation of biodiversity such as orang-utans and as a carbon store. The team from Borneo Nature Foundation have established a long-term PAM network, in forested and burnt areas of the National park.

To give you an idea of the environment, stumbling through the swamp forests involved repeatedly sinking waist deep in swampy water and trying to keep my balance climbing and crossing over fallen trees in wellies full of water.

Although exhausting, these site visits meant I was finally able to contextualise the data I have been listening to within the landscape. I began to disentangle the sounds that I struggle to identify from forest sound recordings, for example between insects and frogs, birds and mammals. This was rarely because I was able to see the animals, but mostly due to having members of the field team who are made up of community members and Borneo Nature Foundation (BNF) staff there who recognise the sounds. Capturing vocalisation recordings on my phone meant I will also be able to run them through BirdNet, an app developed by Cornell University for automatic bird identification. Ecologically, I was surprised to hear the contribution of frogs throughout daytime hours in the soundscape. I had not accounted for daytime frog calls when previously analysing the data so it was important to be aware of this. I also reflected on how different the composition of the dawn chorus was to that which I have heard elsewhere.

Finding and visually identifying frogs like this tree frog helped to get a better understanding of what to expect in the acoustic dataset

Whilst visiting the Tahawa site I took advantage of the time I had to spend with the field team. These members of the community are highly invested in the forests protection, as stewards of the ‘Hutan Desa,’ meaning village forest. This meant they were keen to share their experience and knowledge of the history of the area as well as its cultural and ecological significance with Kristen and myself. Kristen’s Indonesian translation enabled me to ask questions to the community about where their interests lie in the acoustic dataset we are collecting. For instance, are there species that they are interested in monitoring? Is the ecological data relevant to them, how can they use this data for their forests protection?


With the exponential growth of big data it may not always be considered essential for researchers to make site visits to the areas their data is from, however I found this experience added so much value to my research. There were some exchanges that I could not have done from home or online. For example, I have had weekly meetings online with Kristen for the past year, but having conversations with her in the context of our planned research whilst working through challenges together as they arose was so much more effective.

The KaLi workshop was an opportunity to link up with UK and Indonesian researchers from multiple universities working on similar research that I would not have met otherwise. It also framed my research in the wider narrative of the challenges, objectives and solutions already happening in this area of research.

Final reflections from this experience that could be useful to consider in your own research:

  • Who could make use of your research?

  • How can your research questions be designed to be useful for those people?

  • How can you ensure that the research is contributing to the area you are working in? This is especially relevant for conservation work when using expensive, often technically inaccessible technology.

  • How can we bridge the disconnection between scientific results and practical solutions by not just simply stating uses of research at the end of papers – this should be prioritised at the start.

  • How to maintain momentum and flow of ideas when living outside of the context?

One of the quiet creatures I would never have found in the sound recordings

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