Using technology to study and protect elusive wildlife
Sumatra is home to some of the world’s most iconic animals – elephants, tigers, orangutans, and rhinos all co-exist on this remarkable island. As international superstars within the animal kingdom, you might think that scientists and conservationists would have uncovered all there is to know about these animals by now. Unfortunately, we’ve barely scratched the surface! Most population estimates for mammals in Sumatra are based on assumptions about where they should be or out of date surveys. In fact, out of 210 mammal species listed on the IUCN red list and found on Sumatra, only twelve have published population estimates, and only three of these have been published within the last ten years. While this information does give us a good starting point, conservationists desperately need more up to date information on how many individuals are left, where they are now and where they might move to.
To make effective species management plans, there are so many complicated questions we need to find answers to. Are animals stuck in low quality patches of habitat within a sea of oil palm, unable to move somewhere else? Are populations isolated from each other with no gene flow between them resulting in inbreeding depression? How well can they cope with selective logging, and how much logging is too much? Are they utilising human areas and posing a risk to peoples lives and livelihoods? Population monitoring is the first step to answering many of these questions; it also gives us a good baseline to assess our progress and evaluate how well conservation programmes are achieving their goals. For example, if we want to increase the population of a species in decline, we need to know how many animals there are in the first place and be able to monitor how this number changes following the implementation of conservation measures.
In the past, wildlife monitoring relied on direct observations of animals by teams of people out in the field; however, collecting this information is much easier said than done! Despite being relatively large and distinctive, even big mammals such as elephants, tigers and apes, are surprisingly hard to find in remote tropical jungle. They tend to live at low densities, range over large distances and actively avoid people, including scientists. Some researchers have never even directly seen their study species in the wild, despite dedicating years to studying them. Remote areas which are only accessible on foot, extreme and challenging conditions, animals that don’t want to be found, no power to recharge equipment, no GPS signal to stop you getting lost, and no Wi-Fi to google the solutions to problems makes field surveys a serious undertaking requiring a huge investment of time and resources. Times are changing, however, and new technologies are helping us to gather information more effectively and efficiently without disturbing wildlife. Remote monitoring technology, such as motion-activated trail cameras and automated audio recorders, are giving us more and more access to animals, allowing us to monitor them in real time, produce more reliable and up-to-date population estimates and answer those vital questions for conservation.
As part of our ongoing research at LEAP, we wanted to investigate how mammals are adapting to living right at the edge of a protected forest. The village of Aras Napal is located right next to the boundary of the Gunung Leuser National Park in the North Sumatra province. Subsistence farming is the main source of income in this area, and there are smallholder plantations right along the edge of the protected forest. The forest here is recovering from selective logging, which occurred periodically throughout the 1980s and 90s. This area gives us a great opportunity to study forest recovery and how Critically Endangered animals are adapting to living alongside people. The Sumatran Orangutan Conservation Programme have been running the Sikundur monitoring station here, where they have been closely following Sumatran orangutans to monitor their abundance and behaviour since 2013. Apart from that, we know very little about the mammals in this area, other than occasional reported sightings of elephants, tigers, and sun bears. In other words, we know there’s still lots of wildlife, but we have no idea how many animals, or how well they are doing. To start getting a better picture of the mammal community in this forest, we set up a series of remote monitoring stations starting right at the forest edge and moving up to 2km into the interior. These stations used a combination of camera traps and audio recorders to monitor the wildlife in the jungle over a two-month period.
Camera traps are commonly used for studying mammals. They typically run on standard AA batteries and, depending on the design and settings used, cameras will remain operational for several weeks or even months before someone needs to revisit them to replace batteries and memory cards. Long-term camera trap studies have revealed some great information about animal behaviour, movement, and social structure. In total, our cameras were deployed for 1,079 trapping days and recorded 1,384 images. From these images we identified 16 mammal species across 14 families. These included macaques, Thomas’ langur monkeys, elephants, a sun bear and even a tiger!
Cameras work brilliantly for the more conspicuous mammals that live on the ground, but they can only provide information on a small portion of the community in a tropical jungle. Audio recorders are an emerging technology which have not yet been perfected for field deployment, but we are making progress! We worked with specialists from Bournemouth University’s Department of Creative Technology and arts company Invisible Flock to develop a custom-built audio recorder which could capture high-quality sound, made with relatively low-cost components and a robust enough design to survive being left out in the jungle for extended periods. These do not last anywhere near as long as camera traps, but we were able to record around 3,840 hours of the forest soundscape, which can give us more of an insight into what animals are around versus using camera traps alone.
Our results showed that, despite being secondary forest and very close to people, this area is still widely used by wildlife. Almost half of the mammals we identified are considered threatened with extinction according to the IUCN red list (i.e. they are classified as either Vulnerable, Endangered or Critically Endangered), highlighitng the importance of protecting this community. We also noted big differences in the conditions of the forest up to 1km away from the edge. These differences are known as 'edge effects'. These happen due to the increased expsoure to solar radiation and wind, which rasies the temperature and reduces humidity where the dense forest meets the more open farmland. Some animals are better able to cope with these changes than others. Pigs and macaques, for example, are big fans of oranges and visit farms at the forest edge daily; we had by far more detection events of these animals than any other. On the other hand, we picked up very few carnivores, and none were detected close to the edge of the forest. Species which prefer the forest interior over the edge require adequate coverage of continuous forested areas, and these areas must be large enough to shelter them from edge effects. This means that, as well as protecting remaining expanses of primary forest, we must ensure that forest remnants being used as wildlife havens and wildlife corridors are large enough to support the animals we wish to protect.
