Life in the Treetops by Jess Haysom
Hello. My name is Jess Haysom, and I study canopy mammals in Borneo. I first came to Borneo in 2013, volunteering for the ground-based mammal team at the Stability of Altered Forest Ecosystems (SAFE) Project in Sabah. It was during this time that I became fascinated by the amount of life there is up in the treetops, and how little we know about it. Borneo’s rainforest canopies are home to over 70 species of mammal – everything from tiny mice and flying squirrels up to orangutans and clouded leopards – and the vast majority of these are barely understood. I won’t bore you with the details but essentially I harped on about this enough times, to enough people, for long enough, that I finally managed to get my own research grant to study them, in the form of a NERC-funded PhD with the University of Kent.
Now that I am able to study canopy mammals, I also finally realise exactly why they are so understudied. Tropical rainforest fieldwork isn’t easy at the best of times. It’s sweaty, muddy, hilly, overgrown and full of little buzzing things whose main goal in life is to bite you, suck your blood, or drive you half to insanity with their incessant attempts to enter your nose. So if you add on that (a) Borneo has the tallest tropical forests in the world with some trees reaching beyond 90m, and (b) most of the mammals living up there are well-camouflaged, fast-moving and don’t really like to be around humans, then you find yourself in the situation where trying to study said canopy mammals is somewhat challenging.
When you are seacrching for something like this….
…..that lives somewhere like this
Part of my research therefore involves testing various possible ways of studying canopy mammals. The other part involves hoping fervently that these are effective so that I will be able to describe the mammal community we would expect to find in the canopy of a “normal” Bornean rainforest, i.e. one that has not been disturbed by human actions such as logging. From this baseline knowledge, I’ll look at what happens to canopy mammals when the forest is logged, with the eventual aim of being able to make recommendations for conservation policy which include the entire mammal community and not just those species that we are familiar with at ground level.
But that’s getting ahead of myself. For the moment, me and the guys I work with are usually to be found stuck on some near-vertical mud cliff carrying ridiculously heavy backpacks stuffed with climbing ropes and camera traps, trying to reach a pre-determined point on the GPS that looked very close on screen but in fact has taken 3 hours of hacking through impenetrable thorn tangles and fording inconveniently-placed rivers to reach. When we get there, we’ll choose a tree which is tall, sturdy, has some nice horizontal branches connecting to adjacent trees and, crucially, shows no signs of termite infestation, wasp nests, rot, or other potentially deadly hazards. We’ll spend an hour or two shooting ropes into the canopy with the aid of a 2m tall slingshot and a fishing rod (I’m not joking) until a couple of branches have been rigged with the climbing ropes. And then it’s harness & helmet ahoy, and up into the treetops we heave ourselves. Well actually the guys shimmy up the ropes as if it’s no effort at all, while I haul and puff my way to the top at the speed of a geriatric snail, shiny with sweat, helmet constantly slipping (no matter how I fasten it – infuriating!) to an angle that makes me look ever-so-slightly deranged…
Rigging the tree
Helmet doing its own thing!
I’ve just realised I didn’t tell you about the trapping methods I’m testing. Firstly, fur traps. These are small plastic funnels, with bait stored at the tapered end which animals can smell but can’t reach. The funnel itself is lined with an adhesive sheet and the idea is that when an animal enters to try and reach the bait, a few hairs will be plucked and remain on the sheet, which will later undergo DNA sequencing in a lab to determine exactly which species have visited. The benefits of these traps are that they are non-invasive (i.e. do not involve trapping or handling the animal, so cause minimum distress), can be left for weeks or months without the need for checking and can, theoretically, obtain samples from many individuals of many different species. In practice however, they have rarely (if at all) been tested in a tropical rainforest that has such a large number of species as in Borneo. It remains to be seen whether the fur traps will be able to attract the same number of species that we could expect to get from cage-trapping or visual surveys, both of which are more traditional and much more labour-intensive ways of studying canopy mammals. And even if they do successfully collect samples, a further question is whether enough DNA will be able to endure the rainforest’s humid conditions long enough to allow accurate species identification months later. So a lot of things to test!
The other method I’m trialling in the canopy is camera traps. These cameras can be set in pretty much any habitat and left to run automatically as they have built-in sensors which trigger when an animal passes. They have been used very successfully in studies of ground-based mammals all over the world, but are only just starting to be tested at height. Like fur traps, they are also non-invasive and can be set and left for months at a time. If they work in the canopy, they will sit as discreet, passive observers, providing snapshots into the secret life of the rainforest – all that stuff that goes on and all those animals that come out to play when we are not around.
So those are my methods and here I am, 30m up a tree in Borneo, armed with traps, bungee cords, memory cards, batteries, bait, nails and a hammer. Setting the fur trap involves wedging myself at a precarious angle stretched out along a branch, trap and nails in one hand, hammer brandished in the other, suddenly very aware that my hands are slippery, the tree is waving in the wind, and there are people below me on the ground. Don’t worry though, I’ve so far set 25 sites and killed nobody! Not even a little bump to the head! I have a protracted battle with the fastening cord, straining to tie it as tight as possible, then fiddle around with the camera angle taking test photos to check its field of vision until finally achieving the Goldilocks Dream of “just right”. Sometimes this alone takes over an hour. Last thing – remember to switch it on! My overriding fear is coming back 3 months later to find the camera sitting merrily in its perfectly-angled position, and off.
Once it is on however, that’s it, job done. All that remains is to glide back down (so much easier than going up! Well, unless you get entangled in vines and/or forget to stop and crash ungracefully to the floor…) Anyway. Then we pack up and start the long trundle home. Once all my sites are set, I have about 3 months to forget the hills, heat and heavy equipment and convince myself it was “quite easy really” before going back to collect them all in again. But even if I don’t quite forget, I can’t lie – I love it. I love the challenge, I love that I never know what we’ll see in the forest, I love the excitement of wondering what we’ll find out from all our efforts. I love that midway up the worst hill of the entire field season (seriously, it takes a full half hour to conquer this beacon of unrelenting steepness) we came across an enormous male orangutan, totally wild, just there, just as he should be. Without wishing to sound too pass-the-bucket clichéd, it made me remember, in the midst of all my cursing and considering calling for a helicopter rescue, why I’m doing this. Forests like this – even the already-logged forest that I was working in that day – hold so much life, and the vast majority of that life we know almost nothing about. It goes back to the age-old question: How can we effectively protect something that we do not understand? So, for my small part, I’m hoping to add a little to our understanding of the rainforest canopy – that place up there of a million shades of green that is so fundamental to the definition of a forest itself, but is so often overlooked because it is just beyond our reach.
The foodwebs of Sabahan bats by Dave Hemprich-Bennett
Borneo’s bats are some of the least–studied in the world. There are at least 100 species here in Sabah; with many more likely yet to be discovered, and yet the rainforest is being cleared at an alarming rate. Over half of Borneo’s forest has been cleared since 1940, with almost half of the remaining jungle being classed as ‘production forest’, so it is crucial for us to better understand these species and how to protect them in this changing landscape.
It’s in this context that Tor Kemp and I are studying the feeding ecology of forest interior bat species for our PhDs. This is a group of particular conservation concern as they are unlikely to be able to survive within the production areas of oil palm plantations. By sampling over a gradient of land-use and fragmentation we are collecting data on the ecology of bats and their relationship to their prey, from primary rainforest to forest that has been severely degraded by successive rounds of selective logging.
We catch our bats by erecting harp traps in the forest: they’re big metal frames with parallel rows of fishing line strung vertically, with a collecting bag at the bottom. Bats fly into the strings and then drop down into the bag, which we then collect them from. After we catch them Tor takes a very small tissue sample from the wing membrane, and we leave the bats in individual holding bags for a short while in the hope that they’ll leave me a sample of their poo when we release them.
Watch our video – Bats Video.
Back in the UK, our work then diverges a lot.
Tor is using stable isotope analysis to look at changes to the trophic position at which bats are feeding to observe how landscape change can alter food web complexity. She will also look at feeding niches of bats by incorporating the contribution of different carbon sources (i.e. fresh leaves, soil) to bat diet, via insect prey, over the period that the wing tissue was grown. Such metrics allow us to look at how foraging of species and communities is altered across diverse systems.
I use the prey DNA from the bat faeces to generate huge food webs, looking at the structure of the interactions between bat species and their prey in our different study sites. Using this we can investigate how robust their ecosystems are to any future extinctions of insect species, how individual bat species change their ecology in habitats of different quality, and gain insights into the diet of some of the worlds least-known bats.
Between our two projects we aim to be able to make recommendations for the conservation of these fantastic animals in the coming decades, including which areas should be high priority for protection to enable their persistence, and which prey groups are particularly important to preserving Borneo’s diverse suite of bats for years to come.
The lesser false-vampire bat (Megaderma lyra)
Into Borneo. Read Sol Milne’s new blog on his first impressions on arriving in Borneo and the SAFE camp to work on LOMBOK’s dung beetle project.
Ute Skiba, Julia Drewer and Melissa Leduning, ably assisted by Arnold and Loly, have been busy setting up chambers at the LOMBOK field sites. These will be used to take regular measurements of greenhouse gas emissions from soils in oil palm and forest. You can see some pictures and learn more about their work on the SAFE web site.