The use of camera traps in the jungles of Borneo revealed unknown aspects of wildlife
A significant number of Rain forest research was biased toward terrestrial communities, which live on the ground, and thus the canopy, the tops of the trees, has become an ecological frontier.
This clashes with data from a review of studies that calculates that 76% of vertebrates in these areas are arboreal and spend their lives in the canopy. Primates and rodents, among others, have been among the most analyzed.
Jessica Haysom, from the School of Anthropology and Conservation at the University of Kent, explains that, as an assistant to another investigation in which terrestrial camera traps were used in Borneo, he realized, through the field guides, the number of species that lived in the canopy.
Now she is the co-author of a research in which an inventory of the arboreal mammal community in the tropical forest of Sabah (Borneo) is made, via paired canopy and ground camera traps at 50 different locations.
The results, which have been published in Frontiers in forests and global change, show the detection of 57 mammal species.
Borneo’s rainforests are among the highest in the world and are famous for their arboreal and semi-arboreal mammal fauna. The paired camera traps were installed in two different areas: 25 in unlogged forest in the Maliau Watershed Conservation Area and another 25 in logged forest in the Monte Luisa Forest Reserve, which between 1978 and 2008 saw multiple rounds of logging.
The mean distance between sampling sites was 1.26 km, and paired camera traps were used at each location: one terrestrial and one in the canopy (middle or upper, with an average distance of 25.9 meters above ground). A second camera was placed on 20 of the focal trees over a period of approximately three months.
of the 57 species of mammals detected, 30 were terrestrial, 18 arboreal and 9 semi-arboreal. They were thus determined based on which camera had detected them: the terrestrial ones with the terrestrial trap cameras exclusively, the arboreal ones only with the cameras in the canopy, and the semi-arboreal ones had been seen both by the cameras placed in both strata.
Of the tree species, two were detected thanks to the second camera. However, they were unable to observe 21 species potentially present in the landscape.
The diversity of arboreal mammal species in both types of forests (logged and not) was significantly lower than that achieved at the terrestrial level. Despite this, these mammals perform important functions within the ecosystem, according to the researchers, such as predation, pollination or seed dispersal.
Haysom considers it essential to study this community: “In our area, if you add camera traps in the canopy, you add 30% more species. In addition, we have discovered that these cameras provide new insights into semi-arboreal species.”
Canopy camera traps were especially effective at detecting primates and other gliding mammals. In the terrestrial ones, on the other hand, more individuals of viverrids, mustelids and felids were detected.
Rodents were clearly observed at both levels. The researchers were surprised by the results: “Many tree species (almost all) are physically capable of going down to the ground, like many monkeys or squirrels. I was hoping there would be a lot more mixing communities. This highlights how important it is to sample in the canopy.”.
As for the difference between logged and unlogged forests, the highlight of the study’s conclusions is that, while the arboreal mammal community is comparable in species identity and diversity in both locations, there is greater terrestrial diversity in unlogged forests.
The difficulties to observe any jungle animal are many. Francis Palomares, a researcher in the Department of Conservation Biology of the Doñana Biological Station, considers that what is fundamental is the logistics of the study itself. “When you work in places like this, getting around is very complicated. The territory or the area that can be covered is very little”. In addition, he adds that the animals in these places are very difficult to see and observe.
However, he emphasizes that this is not an exclusive matter of forests, since in Spain there are areas, such as forests or thickets, in which the same thing happens and stresses the need to use indirect techniques to determine the existence of species .
The use of camera traps, he explains, which in addition to letting you know about the existence and characteristics of the species, is also used to estimate its abundance, based on a record of the times and days it appears and using “mathematical techniques of statistics”.
Paul Palencia, which is part of the Hunting Resources Research Institute (IREC-CSIC), specifies that photo-trapping, or the use of camera traps, has more potential in closed environments and also in those species that have more elusive behavior “either because they are nocturnal or because there are few individuals”.
Palencia, together with other researchers, has recently published a study in Journal of Zoology in which he evaluates different brands of this instrument to identify the factors that correspond to the probability of detection and the rate of fire.