For my expedition, I went to Borneo, where I stayed at Danau Girang Field Centre, located just off the Kinabatangan river, surrounded by the jungle. During the 5 days we were there, we were with PTYs (students from Cardiff University, doing their Professional Training Year), learning from them, and from the PhD student, Ritch.
Starting in the ‘80’s, the Bornean jungle was rapidly converted to oil palm plantations. The wildlife sanctuaries were created to protect the forest, especially around the river. However, people have decreased the land for the forest, and expanded the land set aside for timber, oil palm, and other plantations, creating this fragmented habitat. This fragmentation has impacted many of the native animals inhabiting the rainforest.
Distribution of land use around the area of Danau Girang (1)
Ritch, the student doing his PhD on reticulated pythons, gave us a presentation on the very first day, focusing on the area, and its history, and briefly talked about the overall effects of the palm oil plantations on animals. What interested me was how animals like monitor lizards are affected by them. By simply looking at the food chain, we can see these effects. Rats are attracted to the plantations, because of the steady availability of the oil palm fruit. Monitor lizards are attracted to the plantations because of all the rats (a steady source of food for them). When a source of food is abundant in a place, a predator will stay there, as the food is not only easier to catch, but also reliable. In the case of the relationship between the rats and lizards, the rats have become the main component of the lizards’ diets. This is a problem because the rats are consuming the oil filled fruits; making them a less nutritious food source for the lizards. This means that the lizards are essentially only consuming fatty oil, impacting their health.
Oil palm fruit (2)
A group of animals specifically impacted by the fragmentation itself is the native primates: Proboscis monkeys, Silver leaf monkeys, Orangutans, and Macaques. This is because the plantations aren’t on the banks of the Kinabatangan, so boat access points are carved out of the jungle for quick, easy harvesting and transportation (of people, machinery and goods). To get across from the area on one side of the man made bank to the other, the primates have to swim across, where crocodiles and other natural predators lurk. Because they are isolated in a smaller area of land, they inbreed, creating genetic mutations. It also creates more competition for resources, as well as territory.
Although humans have created this problem of fragmentation, impacting the native wildlife, some people are trying to come up with solutions. In the case of the primates, about a decade ago, rope bridges, connecting tall trees from both sides of the water, were implemented, allowing them to cross without having to go in the water, acting as an artificial vine. So far, it seems to be successful. In the case of the lizards, however, a solution hasn’t been implemented, although researchers are actively trying to find one.
Proboscis monkey using a rope bridge (3)
Sources for the images:
(1) Ancrenaz , Marc. “Map of the Lower Kinabatangan Wildlife Sanctuary.” Www.researchgate.net, www.researchgate.net/figure/Map-of-the-Lower-Kinabatangan-Wildlife-Sanctuary_fig1_226120941.
(2) Lego, Rob. “Palm Oil Fruit .” Www.pbase.com/rob_lego, www.pbase.com/rob_lego/image/85102202/original .
(3) Ling, C S. “Proboscis Monkeys – Family Crossing River.” Wildlife.cslingphotography.com, wildlife.cslingphotography.com/portfolio/borneo-proboscis-monkeys-family-crossing-river/.