Ancrenaz M.,HUTAN Kinabatangan Orangutan Conservation Programme |
Sollmann R.,North Carolina State University |
Sollmann R.,Leibniz Institute for Zoo and Wildlife Research |
Meijaard E.,Borneo Futures Project |
And 33 more authors.
Scientific Reports | Year: 2014
The orangutan is the world's largest arboreal mammal, and images of the red ape moving through the tropical forest canopy symbolise its typical arboreal behaviour. Records of terrestrial behaviour are scarce and often associated with habitat disturbance. We conducted a large-scale species-level analysis of ground-based camera-trapping data to evaluate the extent to which Bornean orangutans Pongo pygmaeus come down from the trees to travel terrestrially, and whether they are indeed forced to the ground primarily by anthropogenic forest disturbances. Although the degree of forest disturbance and canopy gap size influenced terrestriality, orangutans were recorded on the ground as frequently in heavily degraded habitats as in primary forests. Furthermore, all age-sex classes were recorded on the ground (flanged males more often). This suggests that terrestrial locomotion is part of the Bornean orangutan's natural behavioural repertoire to a much greater extent than previously thought, and is only modified by habitat disturbance. The capacity of orangutans to come down from the trees may increase their ability to cope with at least smaller-scale forest fragmentation, and to cross moderately open spaces in mosaic landscapes, although the extent of this versatility remains to be investigated. Source
Morrogh-Bernard H.C.,Orangutan Tropical Peatland Project |
Stitt J.M.,Orangutan Tropical Peatland Project |
Yeen Z.,Orangutan Tropical Peatland Project |
Nekaris K.A.I.,Oxford Brookes University |
And 2 more authors.
Primates | Year: 2014
All documented orang-utan-loris interactions have been from Sumatra, where lorises were opportunistically preyed upon by orang-utans. In this paper, we describe two accounts of the Bornean orang-utan (Pongo pygmaeus wurmbii) interacting with the Philippine slow loris (Nycticebus menagensis). The interactions were by two adolescent female orang-utans. No attempts to catch the loris were observed on either occasion. Neither interaction was hostile. During the second observation, which was more detailed, we considered the behaviour to be play rather than aggression or attempted predation. Based upon the lack of interest from the adult females during these rare encounters, we propose that the behaviour represents play or non-aggressive exploration rather than predation. © 2014 Japan Monkey Centre and Springer Japan. Source
Harrison M.E.,University of Leicester |
Zweifel N.,University of Zurich |
Zweifel N.,Tuanan Orangutan Research Project |
Husson S.J.,Orangutan Tropical Peatland Project |
And 19 more authors.
Biotropica | Year: 2016
The timing and frequency of flowering and fruiting events are key tropical forest characteristics that have substantial influence on fauna. Although our understanding of geographic variation in habitat-wide timing and frequency of flowering and fruiting is advancing, corresponding information for individual tree species is limited. Thus, we compared climate and reproductive phenology of 16 tree species over 70 mo at two Bornean tropical peat-swamp forest sites. We found significant inter-site correlations in rainfall and temperature, and only small absolute temperature differences. In both sites, most species exhibited within-site synchrony in flowering and fruiting onset. Broad-scale flowering and fruiting onset frequency classifications showed high congruence between sites. Significant correlations in flowering and fruiting onset timing between sites were found for only 19 and 17 percent of the species, respectively. This remained the case when applying 1- and 2-month lag periods for both sites, with neither site consistently lagging behind. Significant differences in the exact frequency of new flowering and fruiting events were detected for 44 and 58 percent of species, respectively, and no significant relationships between the onset timing synchrony and exact frequency of new reproductive events were found for either flowers or fruit. We conclude that inter-site climatic and ecological similarities do not necessarily lead to high inter-site synchrony in either onset timing or exact frequency of tree reproductive events. Potential reasons for this are discussed, as are the implications for understanding tropical forest ecology and improving forest restoration project seed collections. © 2016 The Association for Tropical Biology and Conservation. Source
Right now I’m still at at my first research site, Sikundur, in North Sumatra, looking out over Gunung Leuser National Park. Normally at this time of year the view would be fairly clear, and I’d hear gibbons and siamangs calling, instead I’m staring at a silent cloud of thick smoke from massive forest fires further South in Riau and Jambi provinces. Actually, I’m fortunate in a way; Leuser isn’t burning to the same extent, and though the smoke is an annoyance, we can still follow orangutans. By now though, I should have moved to work with the University of Palangka Raya Centre for International Cooperation in Sustainable Management of Tropical Peatlands (CIMTROP) and Orangutan Tropical Peatland Project (OuTrop) at my second research site, Sabangau, in Borneo, but research has stopped for fire-fighting, and the scale of the destruction and emergency of the situation in Kalimantan (Indonesian Borneo), mean that I won’t be getting there any time soon. Over the last two months, nearly 100,000 fires have been raging across Indonesia, the thick blankets of toxic smoke suffocating the region are being inhaled by an estimated 40 million people, and have caused acute respiratory infections in almost half a million people to date. The haze is forcing schools offices, and airports to close. Its spread is creating diplomatic tension between Indonesia and its neighbours Singapore and Malaysia. It is predicted that the cost of this crisis will total as much as $50 billion, about 5% of Indonesia’s GNP, wiping out the country’s economic growth for the year. And, it’s not just a regional problem. Since September burning jungle has been releasing more carbon on a daily basis than the entire US economy, giving total emissions of about a billion tons of CO or 3% of the World’s yearly global fossil fuel emissions. It’s one of the biggest environmental disasters of my lifetime, and Erik Meijaard (a conservation scientist coordinating the Borneo Futures initiative), goes so far as to call it “The Biggest Environmental Crime of the 21st Century”. Each year, at the end of the dry season, fires are deliberately set for a number of reasons: to clear land for agriculture, for hunting, to settle land disputes, and, in some cases, just for fun. While large-scale oil palm and timber plantations are typically presented as being responsible for the burning, studies in Kalimantan and Sumatra show the majority of fires are set outside concession boundaries, and these are the ones that spread out of control. Usually, the monsoon rains would have started by now, putting out the flames naturally, however, with a major El Niño event occurring this year, Indonesia is currently in a prolonged drought, the fires are yet to be subdued, and will likely continue into the coming months. The most frustrating thing is this all could have been avoided. During the last major El Niño event in 1997, the exact same thing happened, an estimated 25 million acres of land burned, 20 million Indonesians suffered from respiratory problems, and there were 19,800-48,100 premature mortalities. Doubtless the numbers will be similar this year, and scientists have for a long time predicted this year’s events, including the El Niño. Given this timeline, policy development and actual law enforcement, along with better land usage and spatial planning, could have mitigated a lot of the damage. Instead, while large swathes of the country have been in states of emergency for over a month (though as of yet it’s not national), the official response has been lacklustre; there’s yet to be a national ban on starting fires, the government initially turned down offers of International help, choosing to send out the country’s small fleet of helicopters and water-bombers, along with a few soldiers to dig canals (not a good idea). The president, Joko “Jokowi” Widodo, has since reversed this position, sending out thousands of troops, and accepting fire-fighting planes from Singapore, Malaysia, and Australia. However, rather than anyone taking responsibility, the forests have continued to burn. As noted in Brittany Patterson / ClimateWire’s Scientific American article last week, some of the worst fires are happening in areas of peatland, like the swamps of Sabangau, where I got my start studying orangutans. You’d think a swamp couldn’t burn, but, as OuTrop’s Managing Director, Mark Harrison, explains, “In their undisturbed, flooded state, peatland forests are naturally fire-resistant. But decades of poor management practices, including extensive forest clearance and canal construction, has drained the peat, putting the whole region at high fire risk when the inevitable droughts occur.” Bornean lowland forests contain huge amounts of already endangered and endemic biodiversity, including clouded leopards, hornbills, gibbons, and, of course, my own species of focus, orangutans. The fires are currently decimating orangutan strongholds across Borneo. My site, Sabangau contains the world’s largest contiguous population of nearly 7,000 wild orangutans, and is under serious threat of total destruction. Already over 500 hectares of jungle has been devoured, and in the last week alone, using NASA satellite imaging, 358 fire hotspots were detected inside the forest’s boundaries. Trees are crashing down as their roots are burnt away from beneath them, and thick plumes of smoke spiral into the atmosphere. The fires have already reached the research area, and recently the Patrol Team house we use as a staging point burned down just 1km from camp. Showing exceptional bravery in the face of such overwhelming adversity, a small, locally led fire-fighting team, including research staff from the field site, is desperately battling to hold back the flames. With no standing water because of the drought, they painstakingly drill bores 20 metres down to pump out groundwater. Because peat fires reach such high temperatures, and burn beneath the surface, huge amounts of water, up to 200 litres for just 1m2 of Peatland, are needed to extinguish the flames. The conditions on the ground are utterly horrific; the air quality index (PM10) is regularly over 2500 (healthy is 0-50; above 300 is hazardous), and there aren’t enough masks to go around. They need help with equipment, and to get more people on the ground fighting the fires (Donations to support OuTrop’s fire-fighting campaign can be received online via MyDonate). To us here in Indonesia at least, there also seems to be a lack of international attention. OuTrop’s founder and director of conservation, Simon Husson, summarizes the situation: “People are choking in the smoke, and one of the world’s last, great rainforests is burning down. The only way to tackle this is with huge manpower on the ground, supported by intensive and sustained aerial water bombing. Mobilising these resources requires raising international awareness of the catastrophe unfolding in Sabangau. Eventually the rains will come, and only then we will see how bad the damage really is. But simply waiting for the rains is not a solution. We need the eyes of the World on Indonesia, we need more support and we need it now.” My field season in Borneo is probably gone, but that doesn’t matter in comparison to the on-going environmental and humanitarian disaster that is occurring. Long-term, the conservation, economic, and health impacts will be huge. The Indonesian government has a responsibility to implement widespread changes. According to Meijaard these should include “a complete and enforced fire ban; a major scale-up of firefighting efforts, using all available means, national and international; and a prohibition on further peat development and funding for peat restoration.” My only hope is that some change for good can occur as result of this destruction, that these events, and increased international pressure (especially given the vast carbon emissions), act as a catalyst for improved environmental laws and their enforcement in Indonesia. My thoughts are with everyone in Kalimantan and South Sumatra. I hope it rains soon. Donations to support OuTrop’s fire-fighting campaign can be received online via MyDonate
Vogel E.R.,Rutgers University |
Harrison M.E.,University of Leicester |
Zulfa A.,National University of Indonesia |
Bransford T.D.,Rutgers University |
And 10 more authors.
PLoS ONE | Year: 2015
Bottom-up regulatory factors have been proposed to exert a strong influence on mammalian population density. Studies relating habitat quality to population density have typically made comparisons among distant species or communities without considering variation in food quality among localities. We compared dietary nutritional quality of two Bornean orangutan populations with differing population densities in peatland habitats, Tuanan and Sabangau, separated by 63 km. We hypothesized that because Tuanan is alluvial, the plant species included in the orangutan diet would be of higher nutritional quality compared to Sabangau, resulting in higher daily caloric intake in Tuanan.We also predicted that forest productivity would be greater in Tuanan compared to Sabangau. In support of these hypotheses, the overall quality of the diet and the quality of matched dietary items were higher in Tuanan, resulting in higher daily caloric intake compared to Sabangau. These differences in dietary nutritional quality may provide insights into why orangutan population density is almost two times greater in Tuanan compared to Sabangau, in agreement with a potentially important influence of diet quality on primate population density. © 2015 Vogel et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source