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.