Living on the Edge: risky or rewarding?

Research Blog

Written by Nora Helal (Gibbon Researcher)

Borneo: a place I’ve visited many times in my wildest dreams, and now it came true. I got the opportunity to study Bornean white-bearded gibbons for five months in Central Kalimantan, Indonesian Borneo. It is a place you simply cannot prepare for.

Sebangau is a peat-swamp forest, a unique but super challenging environment and it is only brave and determined heroes that you find there. I was in Sebangau during the rainy season when the forest becomes flooded, and there is your swamp. While making your way through the vegetation, you are predated on by mosquitos while you inevitably sink into one of the many peat holes (which I found a surprisingly pleasant experience: it is kind of refreshing!). When you’ve spent a day walking through the forest, suddenly you know you can handle everything.

Nora Helal, Gibbon Researcher | BNF | LLG UPT CIMTROP

As a reward, you sit back in one of the hammocks in camp and you enjoy wildlife passing through butterflies and dragonflies sweep by, monitor lizards sunbathing on the boardwalks and cheeky squirrels always ready to steal your biscuit. Various beautiful snakes hang around demanding your respect; this is their home so keep your distance. Living in the jungle for several months definitely gives you a sense of humility: you’re a guest in the wild, so you’d better get a little wild too. So while a gecko drops on your head, you listen to the song of some birds so beautiful you’ve never heard anything like it. You hear the deep long calls of an orang-utan making its way through the forest, and the singing apes in the early morning: gibbons. These funky swinging primates are the reason I came out here in the first place.

My research project focuses on forest edge effects, assessing if gibbon groups living near the forest behave differently to those living deeper inside the forest. Today, with the continuing rates of deforestation, more and more forests are becoming fragmented. This not only causes a great loss in many species, but it also means that the remaining biodiversity in these fragments becomes more exposed to factors from the forest edge. The forest edge is exposed to more sunlight and is more prone to invasive species and hunters. These factors can affect the ecosystem and these effects can reach all the way into the forest interior. How this might affect the behaviour of primates living near a forest edge remains unclear, as various factors can either positively or negatively impact biodiversity. Changing conditions might lead to more growth of vegetation, which could include more food. On the other hand, invasive species and parasites could pose health risks.

During my field research, I investigated two gibbon families, one of which lives near the edge and the other in the forest interior. Does the gibbon group near the edge behave differently? Do they have the same access to fruit trees as the other group, or do they feed on other foods? Is there any indication that fruit trees grow less near the forest edge? And could a difference in feeding behaviour between the groups be explained by these forest edge effects? These are all questions I am trying to answer.

What is clear, though, is that these wonderful gibbons, all with their own unique personalities, show a certain level of resilience. This means that there is still hope for the survival of this endangered species in the future and that we should keep up the hard work in nature conservation to make a safe future a reality.