What happens to orangutans when the forest is taken away from them?

Transcription

1 What happens to orangutans when the forest is taken away from them? By Ian Singleton, Ph.D Director of Conservation PanEco Foundation Sumatran Orangutan Conservation Programme (SOCP) Most people are well aware that Asia s tropical rainforests, particularly in Indonesia, are fast disappearing. For people who have only ever seen orangutans in zoos, or maybe in the forest during visits to Sumatra or Borneo, it might be hard to imagine what happens to orangutans when their habitat is destroyed. We at the SOCP are often asked to explain how forest fragmentation and conversion affects wild orangutans, and how they end up in the SOCP s orangutan quarantine centre. This document is our attempt to explain what we see in the field. Two separate species The Sumatran orangutan (Pongo abelii) is a separate species to its Bornean counterpart (Pongo pygmaeus). Despite looking very similar in appearance, at least to the untrained eye, there are a number of behavioural and ecological differences between them. For example, Bornean orangutans are more often known to travel along the ground, eat more leaves and tree bark (cambium) generally than Sumatran orangutans, and fewer insects like termites and ants, of which Sumatran orangutans are particularly fond. Sumatran orangutans are also known to catch and eat meat, in the form of the small nocturnal primate known as the slow loris (Nycticebus coucang). This has been seen many times now in Sumatra, but to date has never been observed in Borneo. Bornean orangutans tend to exist at lower densities too, reflecting poorer, much older soils in Borneo and a corresponding lower productivity of the forests there. This also means that

2 the females are much fewer in a given area in Borneo, and far more spread out, meaning the adult males find it difficult to maintain exclusive access to them, leading to more conflicts between males, and more frequent changes in the dominant male of an area. Nevertheless, orangutans on both islands have solitary tendencies, especially in areas where food is scarce, but also have a propensity for gregariousness, when food is abundant. Figure 1: Healthy mother and infant Sumatran orangutan in nest in healthy forest. Photo Peter Jaeggi. Daily routine Unlike gorillas, who eat a large amount of highly abundant herbaceous vegetation, orangutans, like chimpanzees, are predominantly frugivores (around 60% of their diet is fruits) and their food supply in the forest is highly patchy. A typical day for a Sumatran orangutan is to wake up just after 6am, when the sun rises, and spend about 3 hours in a nearby fruit tree, eating most of the ripe fruit it contains. They then start to travel, grabbing foods such as stems, insects and other fruits, e.g. of lianas, as they pass by, before finding a suitable tree around midday in which to build a day nest, for a siesta. After about an hour or so rest, they then travel some more, grabbing more tidbits on the way, and tend to find another major fruit patch in which to gorge themselves again before making another, more sturdy nest for the night in a suitable tree nearby, sometime in the late afternoon.

3 Given their food is so patchy, and that they like to eat as much of each tree fruit crop themselves, it is often not in their interest to bring along any friends. Each additional orangutan that does tag along means having to visit more of the scattered fruit trees, and hence travelling farther to obtain sufficient food, adding an unwelcome extra burden on their energy budget. This is in contrast to gorillas, whose varied assortments of food items are generally abundant around them. For them, as there is ample food for everyone in even a large group, it doesn't really matter how many gorillas come along as there is still always plenty to go round. For orangutans, however much they like to hang out with other orangutans, they normally simply just cannot afford it, unless there is an unusual abundance of fruit in the area, as it means they have to travel much too far between food patches to get enough for their daily needs. Home ranges Despite their solitary tendencies, orangutans have highly overlapping home ranges. They are not like gibbons that maintain and defend a territory from any other gibbons that might try to enter it. Orangutans don t defend their home range area and are normally very tolerant of other orangutans using or passing through it. In fact, in one study in the peat swamps of Sumatra it was possible to pick a single location within the forest and potentially find as many as 16 adult females, and many additional males, that would pass through that spot at least occasionally. Orangutan home ranges are also extremely large, ranging from circa 500 ha or so for an adult female in some forests, up to as much as 1,500 ha or so in the peat swamps of Sumatra, where the highest densities of orangutans in the world (as high as 8 individuals per km 2 ) are also found. Adult male home ranges are larger still, and may even be several 1,000 ha in extent. But no matter how large their home ranges are, they are still smaller than most industrial oil palm plantations. So what happens when an oil palm plantation is established in orangutan habitat? Plantations have to clear the forest first, unless of course they are being established on non- forested land, but sadly there are extremely few of those (in fact they are much rarer than orangutans). This is frequently done using heavy machinery (bulldozers and excavators) with some manual help from a few temporary local labourers, hired specially for the task. Naturally, when the forest is completely cleared, all the wildlife, including orangutans, disappears too (see figure 4). Any orangutans resident in the area will either move, or stay and starve to death since their food source has gone. Males tend to be slightly more mobile than females, and therefore may be a little better able to cope with large shifts in their ranging areas (assuming there is some good quality forest remaining nearby).

4 Females tend to be much more sedentary, and don t readily move and settle in new areas. They are far more likely to try and stay in their home range area, even if it is severely damaged, and risk being killed by plantation workers (which is how most illegal pet infant orangutans are obtained), or malnutrition and eventual starvation (see figure 5). Figure 2: Orangutan at edge of mixed rubber plantation area in Aceh Tamiang, Sumatra, during clearance and conversion to palm oil. Figure 3: Orangutan (top right, in tree) at edge of forest being cleared for palm oil in Kalimantan. Photo Tine Geurts.

5 Figure 4: Prior to planting, soils in new plantation areas are normally barren. Virtually none of the original wildlife living in such areas survives the transition from forest to plantation. The next stage is to burn off all the scrub and debris that is left behind from the logging, even though this is actually illegal under Indonesian National Law. Naturally this creates a lot of smoke. Sometimes these fires burn out of control, especially in peatlands, where they may even burn on for several years. Orangutans near the fires for sure will inhale smoke, until they are able to get far enough away from the fires to breathe smoke free air. If this goes on for a long time they may suffer serious respiratory problems as a result. Do any survive? In some cases, orangutans become trapped during the forest clearing process. Forest conversion seldom follows a neat and tidy pattern, starting at one side and finishing at the other. If it did, some of the larger mammals in those areas (such as deer and pigs etc.) and birds might have a chance to flee into any remaining forested areas nearby, especially if those forested areas are already part of their normal range or territory. Instead, however, forest clearance is often poorly planned, erratic and highly random, resulting in small patches of forest left standing for a time, sometimes of just a few individual trees, being completely cut- off and surrounded by treeless terrain, or land still ablaze.

6 Figure 5: Females in particular do not readily shift their home range, and instead remain in their original area, eventually succumbing to malnutrition and death. This particular adult female Bornean orangutan (Sumi) sadly died not long after this photo was taken. Photo Tine Geurts Figure 6: Illegal forest fires set by palm oil companies in the Tripa swamps, Aceh Province in March Photo Carlos Quiles

7 Figure 7: Often vast swathes of forest are burned at the same time, causing respiratory problems for both people and any wildlife that survives the immediate fire. Photo Carlos Quiles. When orangutans and other wildlife get trapped in such fragments, these are the ones that end up being killed directly, either by people working on the forest clearance, for fun (target practice), or to capture animals for trade (profit), or end up getting burned to death or killed some other way. Some of these orangutans, especially infants, are lucky enough to survive this process, but in virtually every instance their mother is killed before they are taken from the site. It is just such infants that end up being kept as illegal pets or being traded. Ironically, these illegal captives could be considered the lucky ones, even though they are the only surviving refugees from forests that no longer exist. The vast majority are not so lucky; they are killed in the forest clearing process and don t ever make it this far. Those that are able to flee and move to other parts of their home range may have a chance to survive the destruction, depending on where their home range is located relative to present and future forest clearance. Their survival of the current phase of destruction may be only temporary, as plantations continue to expand and new ones are granted. Furthermore, whilst their home ranges are large, they are also finite. As their food resources are lost, due to loss of the forest s fruit trees and other vegetation, orangutans crowding into ever smaller areas are by necessity forced to compete more and more for continuously decreasing resources.

8 Figure 8: A few lucky individuals may survive the forest conversion and end up as illegal pets, often in insanitary conditions. The mothers of any captured infants are always killed during the capture. This photo shows staff of the Sumatran Orangutan Conservation Programme cleaning up an infant during confiscation. Photo SOCP. Figure 9: Even some larger animals are captured on occasions, often sustaining injuries in the process, sometimes quite horrific. This orangutan originated from the Tripa peat swamp forests in Aceh province, Sumatra and eventually had to have his left arm amputated due to irreparably damaged nerves. Photo SOCP

9 Orangutan home ranges are large for a reason. The home range is the area of forest an individual needs to survive and reproduce in the long term. In the short term they may be able to survive in a much smaller area, depending on fruit abundance, how many other orangutans are already there, and other factors, but in the long run they have lost some of their food resources and will find it harder to find enough to sustain them as a result. As the overall forest area is also reduced, the orangutans are forced to crowd together more, and therefore must compete with each other for food and other resources. This is what happens when a forest is above its so- called carrying capacity for orangutans, meaning that the number of individuals it contains is more than the forest can actually support. This places a huge level of stress on a population and some casualties are inevitable, due to long- term starvation and malnutrition. If left alone, the forest conversion stops and does not continue any further, some of the orangutans surviving in the now more compacted population will still almost certainly die over the next few years, even if not immediately, and the population will gradually decrease until equilibrium is once again reached at the level of the remaining forests new carrying capacity. But if the forest conversion continues, eventually all of the forest will be gone, and all of the orangutans and other species will no longer be able to live there. Every one of them will die, except for a few lucky survivors that are captured and kept as pets, or are rescued by NGO s and taken to safety, either being quickly released elsewhere or entering a medical facility for treatment before eventual return to the wild at a later date. Assuming these animals are physically and mentally healthy enough to be returned to the wild, their genes (DNA) can still contribute to the conservation of the species in the future. But all those that are lost in the devastation make no further contribution at all. Figure 10: The unlucky orangutans do not survive the process. Photo BOSF.

10 Figure 11: This adult male Bornean orangutan was reportedly burned alive deliberately by palm oil concession workers in Kalimantan, who first doused him with petrol before setting him alight. Photo BOSF Figure 12: This orangutan was found by the Centre for Orangutan Protection after being killed and buried by plantation workers, in an attempt to hide the evidence of their crime. Photo COP.

11 Please help us! The Sumatran Orangutan Conservation Programme (PanEco and Yayasan Ekosistem Lestari) and a coalition of other NGO s are currently fighting a last ditch battle to save the remaining Sumatran orangutans and forests of the Tripa peat swamps, on the West coast of Aceh Province, Indonesia. These forests probably contained up to as many as 3,000 orangutans in 1990, but today only around 200 are thought to remain. It is also considered that as many as 100 perished in the 12 months prior to April 2012, due to rapid forest clearance and fires, especially in March this year. Tripa s forests are being converted by just a handful of companies, owned by a relatively few extremely wealthy people, for large- scale oil palm plantations. The legality of the concession of one of the companies, PT Kallista Alam, is being contested in a high profile legal case since it contravenes National Spatial Planning Laws. This company and the others in Tripa are also being challenged for illegal clearance and illegal burning within their concessions, which continues even now, and for the illegal establishment of huge drainage canals that drain this unique wetland ecosystem of its principal life force. To stop these crimes, the SOCP and its partners have been working hard on media campaigns and publicity to push the authorities to enforce Indonesia s National Laws. Thanks to the support of thousands of people around the world, we are now at last starting to see real progress, but there is a still a long way to go. Naturally, all these efforts cost money, and we are already even spending money that we don t currently have. We therefore urgently need to raise considerable funds to continue the fight, to keep collecting evidence, developing the legal cases, lobbying officials and for preparing media materials. If you, your family, friends or colleagues are in a position to help financially, please do not hesitate to visit and donate to the Paypal account. Alternatively, feel free to contact myself directly at mokko123@gmail.com if you are interested in other methods of making a donation.