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Serge A. Wich - One of the best experts on this subject based on the ideXlab platform.
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Orangutans venture out of the rainforest and into the Anthropocene
Science Advances, 2018Co-Authors: Stephanie N Spehar, Serge A. Wich, Andrew J. Marshall, Marc Ancrenaz, Douglas Sheil, Terry Harrison, Julien Louys, Michael William Bruford, Erik MeijaardAbstract:Conservation benefits from understanding how adaptability and threat interact to determine a taxon’s vulnerability. Recognizing how interactions with humans have shaped taxa such as the critically endangered Orangutan (Pongo spp.) offers insights into this relationship. Orangutans are viewed as icons of wild nature, and most efforts to prevent their extinction have focused on protecting minimally disturbed habitat, with limited success. We synthesize fossil, archeological, genetic, and behavioral evidence to demonstrate that at least 70,000 years of human influence have shaped Orangutan distribution, abundance, and ecology and will likely continue to do so in the future. Our findings indicate that Orangutans are vulnerable to hunting but appear flexible in response to some other human activities. This highlights the need for a multifaceted, landscape-level approach to Orangutan conservation that leverages sound policy and cooperation among government, private sector, and community stakeholders to prevent hunting, mitigate human-Orangutan conflict, and preserve and reconnect remaining natural forests. Broad cooperation can be encouraged through incentives and strategies that focus on the common interests and concerns of different stakeholders. Orangutans provide an illustrative example of how acknowledging the long and pervasive influence of humans can improve strategies to preserve biodiversity in the Anthropocene.
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land cover changes predict steep declines for the sumatran Orangutan pongo abelii
Science Advances, 2016Co-Authors: Ian Singleton, Serge A. Wich, Sri Suci Utami Atmoko, Matthew G Nowak, Gonda Nisam, Sugesti Mhd Arif, Rudi H Putra, Rio Ardi, Gabriella FredrikssonAbstract:Positive news about Sumatran Orangutans is rare. The species is critically endangered because of forest loss and poaching, and therefore, determining the impact of future land-use change on this species is important. To date, the total Sumatran Orangutan population has been estimated at 6600 individuals. On the basis of new transect surveys, we estimate a population of 14,613 in 2015. This higher estimate is due to three factors. First, Orangutans were found at higher elevations, elevations previously considered outside of their range and, consequently, not surveyed previously. Second, Orangutans were found more widely distributed in logged forests. Third, Orangutans were found in areas west of the Toba Lake that were not previously surveyed. This increase in numbers is therefore due to a more wide-ranging survey effort and is not indicative of an increase in the Orangutan population in Sumatra. There are evidently more Sumatran Orangutans remaining in the wild than we thought, but the species remains under serious threat. Current scenarios for future forest loss predict that as many as 4500 individuals could vanish by 2030. Despite the positive finding that the population is double the size previously estimated, our results indicate that future deforestation will continue to be the cause of rapid declines in Orangutan numbers. Hence, we urge that all developmental planning involving forest loss be accompanied by appropriate environmental impact assessments conforming with the current national and provincial legislations, and, through these, implement specific measures to reduce or, better, avoid negative impacts on forests where Orangutans occur.
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Orangutan pongo spp whistling and implications for the emergence of an open ended call repertoire a replication and extension
Journal of the Acoustical Society of America, 2013Co-Authors: Adriano R Lameira, Elisabeth H. M. Sterck, Robert W. Shumaker, Madeleine E Hardus, Bernd Kowalsky, Han De Vries, Berry M Spruijt, Serge A. WichAbstract:One of the most apparent discontinuities between non-human primate (primate) call communication and human speech concerns repertoire size. The former is essentially fixed to a limited number of innate calls, while the latter essentially consists of numerous learned components. Consequently, primates are thought to lack laryngeal control required to produce learned voiced calls. However, whether they may produce learned voiceless calls awaits investigation. Here, a case of voiceless call learning in primates is investigated—Orangutan (Pongo spp.) whistling. In this study, all known whistling Orangutans are inventoried, whistling-matching tests (previously conducted with one individual) are replicated with another individual using original test paradigms, and articulatory and acoustic whistle characteristics are compared between three Orangutans. Results show that whistling has been reported for ten captive Orangutans. The test Orangutan correctly matched human whistles with significantly high levels of per...
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Behavioral, Ecological, and Evolutionary Aspects of Meat-Eating by Sumatran Orangutans (Pongo abelii)
International Journal of Primatology, 2012Co-Authors: Madeleine E Hardus, Adriano R Lameira, Han De Vries, Astri Zulfa, S. Suci Utami Atmoko, Serge A. WichAbstract:Meat-eating is an important aspect of human evolution, but how meat became a substantial component of the human diet is still poorly understood. Meat-eating in our closest relatives, the great apes, may provide insight into the emergence of this trait, but most existing data are for chimpanzees. We report 3 rare cases of meat-eating of slow lorises, Nycticebus coucang , by 1 Sumatran Orangutan mother–infant dyad in Ketambe, Indonesia, to examine how Orangutans find slow lorises and share meat. We combine these 3 cases with 2 previous ones to test the hypothesis that slow loris captures by Orangutans are seasonal and dependent on fruit availability. We also provide the first (to our knowledge) quantitative data and high-definition video recordings of meat chewing rates by great apes, which we use to estimate the minimum time necessary for a female Australopithecus africanus to reach its daily energy requirements when feeding partially on raw meat. Captures seemed to be opportunistic but Orangutans may have used olfactory cues to detect the prey. The mother often rejected meat sharing requests and only the infant initiated meat sharing. Slow loris captures occurred only during low ripe fruit availability, suggesting that meat may represent a filler fallback food for Orangutans. Orangutans ate meat more than twice as slowly as chimpanzees ( Pan troglodytes ), suggesting that group living may function as a meat intake accelerator in hominoids. Using Orangutan data as a model, time spent chewing per day would not require an excessive amount of time for our social ancestors (australopithecines and hominids), as long as meat represented no more than a quarter of their diet.
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not by science alone why Orangutan conservationists must think outside the box
Annals of the New York Academy of Sciences, 2012Co-Authors: Erik Meijaard, Serge A. Wich, Marc Ancrenaz, Andrew J. MarshallAbstract:Orangutan survival is threatened by habitat loss and illegal killing. Most wild populations will disappear over the next few decades unless threats are abated. Saving Orangutans is ultimately in the hands of the governments and people of Indonesia and Malaysia, which need to ensure that habitats of viable Orangutan populations are protected fromdeforestationandwellmanagedtoensurenohuntingtakesplace.CompaniesworkinginOrangutanhabitatalso havetoplayamuchbiggerroleinhabitatmanagement.Althoughthemajorproblemsandthedirectactionsrequired to solve them—reducing forest loss and hunting—have been known for decades, Orangutan populations continue to decline. Orangutan populations in Sumatra and Borneo have declined by between 2,280 and 5,250 Orangutans annually over the past 25 years. As the total current population for the two species is some 60,000 animals in an area of about 90,000 km 2 , there is not much time left to make conservation efforts truly effective. Our review discusses what has and has not worked in conservation to guide future conservation efforts.
Andrew J. Marshall - One of the best experts on this subject based on the ideXlab platform.
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Orangutans venture out of the rainforest and into the Anthropocene
Science Advances, 2018Co-Authors: Stephanie N Spehar, Serge A. Wich, Andrew J. Marshall, Marc Ancrenaz, Douglas Sheil, Terry Harrison, Julien Louys, Michael William Bruford, Erik MeijaardAbstract:Conservation benefits from understanding how adaptability and threat interact to determine a taxon’s vulnerability. Recognizing how interactions with humans have shaped taxa such as the critically endangered Orangutan (Pongo spp.) offers insights into this relationship. Orangutans are viewed as icons of wild nature, and most efforts to prevent their extinction have focused on protecting minimally disturbed habitat, with limited success. We synthesize fossil, archeological, genetic, and behavioral evidence to demonstrate that at least 70,000 years of human influence have shaped Orangutan distribution, abundance, and ecology and will likely continue to do so in the future. Our findings indicate that Orangutans are vulnerable to hunting but appear flexible in response to some other human activities. This highlights the need for a multifaceted, landscape-level approach to Orangutan conservation that leverages sound policy and cooperation among government, private sector, and community stakeholders to prevent hunting, mitigate human-Orangutan conflict, and preserve and reconnect remaining natural forests. Broad cooperation can be encouraged through incentives and strategies that focus on the common interests and concerns of different stakeholders. Orangutans provide an illustrative example of how acknowledging the long and pervasive influence of humans can improve strategies to preserve biodiversity in the Anthropocene.
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not by science alone why Orangutan conservationists must think outside the box
Annals of the New York Academy of Sciences, 2012Co-Authors: Erik Meijaard, Serge A. Wich, Marc Ancrenaz, Andrew J. MarshallAbstract:Orangutan survival is threatened by habitat loss and illegal killing. Most wild populations will disappear over the next few decades unless threats are abated. Saving Orangutans is ultimately in the hands of the governments and people of Indonesia and Malaysia, which need to ensure that habitats of viable Orangutan populations are protected fromdeforestationandwellmanagedtoensurenohuntingtakesplace.CompaniesworkinginOrangutanhabitatalso havetoplayamuchbiggerroleinhabitatmanagement.Althoughthemajorproblemsandthedirectactionsrequired to solve them—reducing forest loss and hunting—have been known for decades, Orangutan populations continue to decline. Orangutan populations in Sumatra and Borneo have declined by between 2,280 and 5,250 Orangutans annually over the past 25 years. As the total current population for the two species is some 60,000 animals in an area of about 90,000 km 2 , there is not much time left to make conservation efforts truly effective. Our review discusses what has and has not worked in conservation to guide future conservation efforts.
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declining Orangutan encounter rates from wallace to the present suggest the species was once more abundant
PLOS ONE, 2010Co-Authors: Erik Meijaard, Serge A. Wich, Marc Ancrenaz, A H Welsh, Vincent Nijman, Andrew J. MarshallAbstract:Background: Bornean Orangutans (Pongo pygmaeus) currently occur at low densities and seeing a wild one is a rare event. Compared to present low encounter rates of Orangutans, it is striking how many Orangutan each day historic collectors like Alfred Russel Wallace were able to shoot continuously over weeks or even months. Does that indicate that some 150 years ago encounter rates with Orangutans, or their densities, were higher than now? Methodology/Principal Findings: We test this hypothesis by quantifying encounter rates obtained from hunting accounts, museum collections, and recent field studies, and analysing whether there is a declining trend over time. Logistic regression analyses of our data support such a decline on Borneo between the mid-19th century and the present. Even when controlled for variation in the size of survey and hunting teams and the durations of expeditions, mean daily encounter rates appear to have declined about 6-fold in areas with little or no forest disturbance. Conclusions/Significance: This finding has potential consequences for our understanding of Orangutans, because it suggests that Bornean Orangutans once occurred at higher densities. We explore potential explanations—habitat loss and degradation, hunting, and disease—and conclude that hunting fits the observed patterns best. This suggests that hunting has been underestimated as a key causal factor of Orangutan density and distribution, and that species population declines have been more severe than previously estimated based on habitat loss only. Our findings may require us to rethink the biology of Orangutans, with much of our ecological understanding possibly being based on field studies of animals living at lower densities than they did historically. Our approach of quantifying species encounter rates from historic data demonstrates that this method can yield valuable information about the ecology and population density of species in the past, providing new insight into species’ conservation needs.
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Why male Orangutans do not kill infants
Behavioral Ecology and Sociobiology, 2009Co-Authors: Lydia H. Beaudrot, Sonya M. Kahlenberg, Andrew J. MarshallAbstract:Infanticide is widespread among mammals, is particularly common in primates, and has been shown to be an adaptive male strategy under certain conditions. Although no infanticides in wild Orangutans have been reported to date, several authors have suggested that infanticide has been an important selection pressure influencing Orangutan behavior and the evolution of Orangutan social systems. In this paper, we critically assess this suggestion. We begin by investigating whether wild Orangutans have been studied for a sufficiently long period that we might reasonably expect to have detected infanticide if it occurs. We consider whether Orangutan females exhibit counterstrategies typically employed by other mammalian females. We also assess the hypothesis that Orangutan females form special bonds with particular “protector males” to guard against infanticide. Lastly, we discuss socioecological reasons why Orangutan males may not benefit from infanticide. We conclude that there is limited evidence for female counterstrategies and little support for the protector male hypothesis. Aspects of Orangutan paternity certainty, lactational amenorrhea, and ranging behavior may explain why infanticide is not a strategy regularly employed by Orangutan males on Sumatra or Borneo.
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Orangutan activity budgets and diet a comparison between species populations and habitats
Morrogh-Bernard H C; Husson S J; Knott C D; Wich S A; van Schaik C P; van Noordwijk M A; Lackman-Ancrenaz I; Marshall A J; Kanamori T; Kuze N; bin Sak, 2009Co-Authors: Helen C Morroghbernard, Serge A. Wich, Andrew J. Marshall, Cheryl D Knott, C P Van Schaik, M A Van Noordwijk, Simon Husson, I Lackmanancrenaz, Tomoko KanamoriAbstract:The chapter examines differences in the activity budgets of wild Orangutans (Pongo spp.) within and between a large number of study sites in Sumatra and Borneo. The authors of the chapter found that each Orangutan population appeared to follow one of two distinct foraging strategies: either (1) ‘sit and wait’, in which Orangutans aim to minimize their energy expenditure by spending long periods of time resting and relatively short periods feeding and travelling; or (2) ‘search and find’ in which Orangutans aim to maximize their energy intake by resting little and mainly feeding or moving in search of food. Orangutans adopt the first strategy in mixed-dipterocarp forests characterized by mast-fruiting events and irregular fruit availability; and adopt the second strategy in swamp forests with a regular supply of fruit, or in dryland forests with high strangling-fig density. The chapter proposes that the determining factor for which strategy is adopted is the temporal availability of fruit in the habitat, as opposed to other possibilities such as Orangutan taxonomy.
Cheryl D Knott - One of the best experts on this subject based on the ideXlab platform.
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Are Male Orangutans a Threat to Infants? Evidence of Mother–Offspring Counterstrategies to Infanticide in Bornean Orangutans ( Pongo pygmaeus wurmbii )
International Journal of Primatology, 2019Co-Authors: Amy M Scott, Cheryl D Knott, Tri Wahyu SusantoAbstract:Sexually selected infanticide by males is widespread in primates. Female primates employ a variety of strategies to reduce infanticide risk. While infanticide has never been directly observed in wild Orangutans (Pongo spp.), their slow life history makes infants vulnerable to infanticide. The mating strategies of female Orangutans include polyandrous and postconceptive mating that may serve to increase paternity confusion, an infanticide avoidance strategy. Here, we investigate whether female Orangutans alter their social interactions with males as another infanticide avoidance strategy. We hypothesize that females with younger offspring avoid males and that the distance between mother and offspring decreases in the presence of males. We use long-term behavioral data collected between 1994 and 2016 from Bornean Orangutans (Pongo pygmaeus wurmbii) in Gunung Palung National Park, Indonesia, to test whether the sexual selection hypothesis for infanticide helps explain aspects of Orangutan social behavior. We found that mothers with offspring 6 yr. old and females without offspring. In addition, the distance between a mother–offspring dyad showed a statistically significant decrease in the presence of males, but not females. Our results are consistent with the hypothesis that female Orangutans employ strategies to reduce infanticide risk in their social interactions. Because Orangutans have a high fission–fusion dynamic, they have flexibility in manipulating social interactions as a counterinfanticide strategy. Our results suggest that infanticide by males is a selective pressure shaping female Orangutan social behavior.
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Orangutan activity budgets and diet a comparison between species populations and habitats
Morrogh-Bernard H C; Husson S J; Knott C D; Wich S A; van Schaik C P; van Noordwijk M A; Lackman-Ancrenaz I; Marshall A J; Kanamori T; Kuze N; bin Sak, 2009Co-Authors: Helen C Morroghbernard, Serge A. Wich, Andrew J. Marshall, Cheryl D Knott, C P Van Schaik, M A Van Noordwijk, Simon Husson, I Lackmanancrenaz, Tomoko KanamoriAbstract:The chapter examines differences in the activity budgets of wild Orangutans (Pongo spp.) within and between a large number of study sites in Sumatra and Borneo. The authors of the chapter found that each Orangutan population appeared to follow one of two distinct foraging strategies: either (1) ‘sit and wait’, in which Orangutans aim to minimize their energy expenditure by spending long periods of time resting and relatively short periods feeding and travelling; or (2) ‘search and find’ in which Orangutans aim to maximize their energy intake by resting little and mainly feeding or moving in search of food. Orangutans adopt the first strategy in mixed-dipterocarp forests characterized by mast-fruiting events and irregular fruit availability; and adopt the second strategy in swamp forests with a regular supply of fruit, or in dryland forests with high strangling-fig density. The chapter proposes that the determining factor for which strategy is adopted is the temporal availability of fruit in the habitat, as opposed to other possibilities such as Orangutan taxonomy.
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a survey of the Orangutan pongo pygmaeus wurmbii population in and around gunung palung national park west kalimantan indonesia based on nest counts
Biological Conservation, 2005Co-Authors: Andrea E Johnson, Bhayu Pamungkas, Cheryl D Knott, Monalisa Pasaribu, Andrew J. MarshallAbstract:We conducted the first Orangutan population census of Gunung Palung National Park, West Kalimantan, Indonesia, between April and September 2001. We used a refined line-transect nest-count methodology utilizing transect recounts to survey 69 km at 14 sites within the park and 14.2 km in the buffer zone. We present the first Bornean Orangutan density estimate using complete site-specific parameters and long term monitoring of nest decay rates. Average Orangutan density was 3.0 individuals/km2, with densities ranging from 2.4 ind/km2 in montane forest to 4.1 ind/km2 in primary peat swamp. In addition, we tested alternative approaches to calculation of the nest-duration parameter. The second count of each transect resulted in 30% higher density estimates overall. We conclude that recounts should be incorporated into standard line-transect methodology. We estimate there to be ≈2500 individual Orangutans in Gunung Palung, indicating the importance of this site in plans to conserve a network of viable Orangutan populations. While logging may reduce densities, disturbed forest both inside and adjacent to the park has high conservation value as Orangutan habitat. Further research into long-term Orangutan population persistence in disturbed forest is needed.
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Orangutan population density forest structure and fruit availability in hand logged and unlogged peat swamp forests in west kalimantan indonesia
Biological Conservation, 2003Co-Authors: Annika M Felton, Linda Engstrom, Adam Felton, Cheryl D KnottAbstract:We investigated the population density of Bornean Orangutans Pongo pygmaeus pygmaeus and aspects of habitat quality in a selectively hand-logged peat swamp forest in West Kalimantan, Indonesia, and in a comparable unlogged forest nearby. We conducted Orangutan nest surveys, measured different parameters of forest structure, recorded monthly changes in fruit availability, and noted the sex and the stage of maturity of Orangutans encountered. Nest density, an index of Orangutan population density, was 21% lower in the logged area. The forest, logged 2 years previously, had fewer large food trees and a greater number of canopy gaps. We discuss these differences in relation to the lower Orangutan nest density in the logged forest. Significantly fewer adult Orangutans were observed in the logged study area. We hypothesize that fully adult Orangutans, particularly females, are the most severely affected by hand-logging.
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changes in Orangutan caloric intake energy balance and ketones in response to fluctuating fruit availability
International Journal of Primatology, 1998Co-Authors: Cheryl D KnottAbstract:I used novel quantitative measures to assess the impact of fruit seasonality on changes in diet and energy balance during 4918 hours of observation on <60 Orangutans in Gunung Palung National Park, West Kalimantan, Indonesia, from September 1994 through September 1995. During this period a mast fruiting occurred, resulting in large fluctuations in fruit availability, measured by monitoring of 558 Orangutan fruit trees. Orangutan diet varied tremendously in accordance with these fluctuations. During the month of highest fruit production, 100% of the Orangutan diet was composed of fruit. In contrast, during the fruit-poor period as little as 21% of the diet was fruit, while 37% was bark. Nutritional analyses of 78 of the foods most commonly eaten during this study show that mast foods were significantly higher in caloric content than were nonmast foods, which translates into substantial changes in caloric intake. During the month of highest fruit consumption (January), males consumed an estimated 8422 kcal/day and females consumed 7404 kcal/day. During the month of lowest fruit consumption (May), males consumed 3824 kcal/day and females consumed 1793 kcal/day. These differences were significantly different between the 2 months for both males and females. In May, males ate significantly more kcal/day than females did. Time spent feeding did not differ between the two periods for either males or females. I assessed the impact of these changes in diet and caloric intake on Orangutan physiological functioning by measuring ketones in 257 urine samples collected from adult males and females. Ketones—products of fat metabolism—were present in urine only during the fruit-poor period. These data suggest that Orangutans are highly efficient at storing fat during fruit-rich periods and utilizing the reserves during times of fruit shortfall. This response may have important implications for Orangutan survivorship, reproduction, and behavior.
Erik Meijaard - One of the best experts on this subject based on the ideXlab platform.
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shifting apes conservation and welfare outcomes of bornean Orangutan rescue and release in kalimantan indonesia
Journal for Nature Conservation, 2020Co-Authors: Julie Sherman, Marc Ancrenaz, Erik MeijaardAbstract:Abstract For more than 50 years, Critically Endangered Bornean Orangutans (Pongo pygmaeus) have been rescued from poachers or captors, rehabilitated, and released into natural habitats. Wild Orangutans are also translocated—intentionally captured from habitat patches and insecure situations for the purpose of releasing them into areas considered to be safer. Although these activities are widely applied, data on Orangutan conservation and welfare effects are lacking. Our study improves understanding of these outcomes through analysis of Bornean Orangutan rescues and releases conducted in Kalimantan, Indonesia between 2007 and 2017. We collected data on Orangutan rescues (n = 1517) and releases (n = 1219) from rescue facility reports, newspaper articles, and scientific publications, and assessed outcomes in relation to action plans, international standards for wildlife releases, law enforcement, and wild Orangutan population and habitat conservation. High levels of Orangutan killing and illegal possession drove rescue facility intake, while deforestation, actual or potential human-Orangutan interactions, and fires drove large-scale wild Orangutan translocations. We found rescue facilities held 1112 Orangutans in 2017, a number largely unchanged since 2007 despite 1219 reported releases including 605 ex-captive Orangutans and a minimum of 523 translocated wild Orangutans. Rescue has not facilitated notable changes in law enforcement, nor forestalled wild Orangutan losses. Translocations in particular pose serious risks to conservation of Orangutan metapopulations and individual welfare. Substantial changes in law enforcement, human attitudes and behaviors toward Orangutans, and improved management of human-Orangutan coexistence are needed to disrupt the current cycle of Orangutan killing and illegal possession followed by rescue and release. These changes would enable a much-needed renewed focus on protecting wild Orangutans in their natural habitats.
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Orangutans venture out of the rainforest and into the Anthropocene
Science Advances, 2018Co-Authors: Stephanie N Spehar, Serge A. Wich, Andrew J. Marshall, Marc Ancrenaz, Douglas Sheil, Terry Harrison, Julien Louys, Michael William Bruford, Erik MeijaardAbstract:Conservation benefits from understanding how adaptability and threat interact to determine a taxon’s vulnerability. Recognizing how interactions with humans have shaped taxa such as the critically endangered Orangutan (Pongo spp.) offers insights into this relationship. Orangutans are viewed as icons of wild nature, and most efforts to prevent their extinction have focused on protecting minimally disturbed habitat, with limited success. We synthesize fossil, archeological, genetic, and behavioral evidence to demonstrate that at least 70,000 years of human influence have shaped Orangutan distribution, abundance, and ecology and will likely continue to do so in the future. Our findings indicate that Orangutans are vulnerable to hunting but appear flexible in response to some other human activities. This highlights the need for a multifaceted, landscape-level approach to Orangutan conservation that leverages sound policy and cooperation among government, private sector, and community stakeholders to prevent hunting, mitigate human-Orangutan conflict, and preserve and reconnect remaining natural forests. Broad cooperation can be encouraged through incentives and strategies that focus on the common interests and concerns of different stakeholders. Orangutans provide an illustrative example of how acknowledging the long and pervasive influence of humans can improve strategies to preserve biodiversity in the Anthropocene.
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It’s Not Just Conflict That Motivates Killing of Orangutans
PLoS ONE, 2013Co-Authors: Jacqueline Davis, Marc Ancrenaz, Kerrie Mengersen, Nicola K. Abram, Jessie A. Wells, Erik MeijaardAbstract:We investigated why Orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill Orangutans. Those who reported having personally killed an Orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an Orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons Orangutans were killed was fear of Orangutans or in self-defence. A similar pattern was evident among reports of Orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether Orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 Orangutans were killed in Kalimantan within the respondents’ active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI) and between 26,361 and 41,688 for non-conflict reasons (95% CI). These findings confirm that habitat protection alone will not ensure the survival of Orangutans in Indonesian Borneo, and that effective reduction of Orangutan killings is urgently needed.
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not by science alone why Orangutan conservationists must think outside the box
Annals of the New York Academy of Sciences, 2012Co-Authors: Erik Meijaard, Serge A. Wich, Marc Ancrenaz, Andrew J. MarshallAbstract:Orangutan survival is threatened by habitat loss and illegal killing. Most wild populations will disappear over the next few decades unless threats are abated. Saving Orangutans is ultimately in the hands of the governments and people of Indonesia and Malaysia, which need to ensure that habitats of viable Orangutan populations are protected fromdeforestationandwellmanagedtoensurenohuntingtakesplace.CompaniesworkinginOrangutanhabitatalso havetoplayamuchbiggerroleinhabitatmanagement.Althoughthemajorproblemsandthedirectactionsrequired to solve them—reducing forest loss and hunting—have been known for decades, Orangutan populations continue to decline. Orangutan populations in Sumatra and Borneo have declined by between 2,280 and 5,250 Orangutans annually over the past 25 years. As the total current population for the two species is some 60,000 animals in an area of about 90,000 km 2 , there is not much time left to make conservation efforts truly effective. Our review discusses what has and has not worked in conservation to guide future conservation efforts.
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unexpected ecological resilience in bornean Orangutans and implications for pulp and paper plantation management
PLOS ONE, 2010Co-Authors: Erik Meijaard, Marc Ancrenaz, Guillaume Albar, Yaya Rayadin, Stephanie N SpeharAbstract:Ecological studies of Orangutans have almost exclusively focused on populations living in primary or selectively logged rainforest. The response of Orangutans to severe habitat degradation remains therefore poorly understood. Most experts assume that viable populations cannot survive outside undisturbed or slightly disturbed forests. This is a concern because nearly 75% of all Orangutans live outside protected areas, where degradation of natural forests is likely to occur, or where these are replaced by planted forests. To improve our understanding of Orangutan survival in highly altered forest habitats, we conducted population density surveys in two pulp and paper plantation concessions in East Kalimantan, Indonesia. These plantations consist of areas planted with fast-growing exotics intermixed with stands of highly degraded forests and scrublands. Our rapid surveys indicate unexpectedly high Orangutan densities in plantation landscapes dominated by Acacia spp., although it remains unclear whether such landscapes can maintain long-term viable populations. These findings indicate the need to better understand how plantation-dominated landscapes can potentially be incorporated into Orangutan conservation planning. Although we emphasize that plantations have less value for overall biodiversity conservation than natural forests, they could potentially boost the chances of Orangutan survival. Our findings are based on a relatively short study and various methodological issues need to be addressed, but they suggest that Orangutans may be more ecologically flexible than previously thought.
Marc Ancrenaz - One of the best experts on this subject based on the ideXlab platform.
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shifting apes conservation and welfare outcomes of bornean Orangutan rescue and release in kalimantan indonesia
Journal for Nature Conservation, 2020Co-Authors: Julie Sherman, Marc Ancrenaz, Erik MeijaardAbstract:Abstract For more than 50 years, Critically Endangered Bornean Orangutans (Pongo pygmaeus) have been rescued from poachers or captors, rehabilitated, and released into natural habitats. Wild Orangutans are also translocated—intentionally captured from habitat patches and insecure situations for the purpose of releasing them into areas considered to be safer. Although these activities are widely applied, data on Orangutan conservation and welfare effects are lacking. Our study improves understanding of these outcomes through analysis of Bornean Orangutan rescues and releases conducted in Kalimantan, Indonesia between 2007 and 2017. We collected data on Orangutan rescues (n = 1517) and releases (n = 1219) from rescue facility reports, newspaper articles, and scientific publications, and assessed outcomes in relation to action plans, international standards for wildlife releases, law enforcement, and wild Orangutan population and habitat conservation. High levels of Orangutan killing and illegal possession drove rescue facility intake, while deforestation, actual or potential human-Orangutan interactions, and fires drove large-scale wild Orangutan translocations. We found rescue facilities held 1112 Orangutans in 2017, a number largely unchanged since 2007 despite 1219 reported releases including 605 ex-captive Orangutans and a minimum of 523 translocated wild Orangutans. Rescue has not facilitated notable changes in law enforcement, nor forestalled wild Orangutan losses. Translocations in particular pose serious risks to conservation of Orangutan metapopulations and individual welfare. Substantial changes in law enforcement, human attitudes and behaviors toward Orangutans, and improved management of human-Orangutan coexistence are needed to disrupt the current cycle of Orangutan killing and illegal possession followed by rescue and release. These changes would enable a much-needed renewed focus on protecting wild Orangutans in their natural habitats.
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combining behavioural and lidar data to reveal relationships between canopy structure and Orangutan nest site selection in disturbed forests
Biological Conservation, 2019Co-Authors: Marc Ancrenaz, Andrew B Davies, Felicity Oram, Gregory P AsnerAbstract:Abstract Primary tropical forests are becoming increasingly disturbed and fragmented, making it critically important to understand the conservation value of degraded forests. Many populations of even the largest and most iconic species are now found outside of primary habitats, and the long-term survival of these and many other species depends on appropriate management of degraded areas, whether protected or not. However, for conservation in degraded habitats to be successful, an adequate understanding of the minimal ecological requirements necessary for species persistence within them is required. We combined ground and helicopter nest surveys of critically endangered Bornean Orangutans with high-resolution measurements of forest canopy structure from airborne Light Detection and Ranging (LiDAR) to understand Orangutan nest site selection across multiple spatial scales in degraded forests of the Lower Kinabatangan region, Malaysian Borneo. We found Orangutans to be selective when choosing nest sites, with nests more likely to be observed in canopies of tall and uniform height and closer to full canopy gaps, which was consistent across spatial scales and Orangutan age and sex classes. These sites likely offer Orangutans an improved vantage point and/or shelter from wind and rain. In contrast, no discernible relationships between nest site selection and canopy complexity, or nest abundance and landscape forest structure or aboveground carbon density were recorded. Our findings suggest that although Orangutans do nest across a range of forest conditions, their optimum requirement for nesting strongly depends on forest patches with sufficient tall canopy of uniform height. These results serve to inform degraded forest conservation strategies across Borneo, particularly where Orangutans are a focal species.
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Orangutans venture out of the rainforest and into the Anthropocene
Science Advances, 2018Co-Authors: Stephanie N Spehar, Serge A. Wich, Andrew J. Marshall, Marc Ancrenaz, Douglas Sheil, Terry Harrison, Julien Louys, Michael William Bruford, Erik MeijaardAbstract:Conservation benefits from understanding how adaptability and threat interact to determine a taxon’s vulnerability. Recognizing how interactions with humans have shaped taxa such as the critically endangered Orangutan (Pongo spp.) offers insights into this relationship. Orangutans are viewed as icons of wild nature, and most efforts to prevent their extinction have focused on protecting minimally disturbed habitat, with limited success. We synthesize fossil, archeological, genetic, and behavioral evidence to demonstrate that at least 70,000 years of human influence have shaped Orangutan distribution, abundance, and ecology and will likely continue to do so in the future. Our findings indicate that Orangutans are vulnerable to hunting but appear flexible in response to some other human activities. This highlights the need for a multifaceted, landscape-level approach to Orangutan conservation that leverages sound policy and cooperation among government, private sector, and community stakeholders to prevent hunting, mitigate human-Orangutan conflict, and preserve and reconnect remaining natural forests. Broad cooperation can be encouraged through incentives and strategies that focus on the common interests and concerns of different stakeholders. Orangutans provide an illustrative example of how acknowledging the long and pervasive influence of humans can improve strategies to preserve biodiversity in the Anthropocene.
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canopy structure drives Orangutan habitat selection in disturbed bornean forests
Proceedings of the National Academy of Sciences of the United States of America, 2017Co-Authors: Andrew B Davies, Marc Ancrenaz, Felicity Oram, Gregory P AsnerAbstract:The conservation of charismatic and functionally important large species is becoming increasingly difficult. Anthropogenic pressures continue to squeeze available habitat and force animals into degraded and disturbed areas. Ensuring the long-term survival of these species requires a well-developed understanding of how animals use these new landscapes to inform conservation and habitat restoration efforts. We combined 3 y of highly detailed visual observations of Bornean Orangutans with high-resolution airborne remote sensing (Light Detection and Ranging) to understand Orangutan movement in disturbed and fragmented forests of Malaysian Borneo. Structural attributes of the upper forest canopy were the dominant determinant of Orangutan movement among all age and sex classes, with Orangutans more likely to move in directions of increased canopy closure, tall trees, and uniform height, as well as avoiding canopy gaps and moving toward emergent crowns. In contrast, canopy vertical complexity (canopy layering and shape) did not affect movement. Our results suggest that although Orangutans do make use of disturbed forest, they select certain canopy attributes within these forests, indicating that not all disturbed or degraded forest is of equal value for the long-term sustainability of Orangutan populations. Although the value of disturbed habitats needs to be recognized in conservation plans for wide-ranging, large-bodied species, minimal ecological requirements within these habitats also need to be understood and considered if long-term population viability is to be realized.
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It’s Not Just Conflict That Motivates Killing of Orangutans
PLoS ONE, 2013Co-Authors: Jacqueline Davis, Marc Ancrenaz, Kerrie Mengersen, Nicola K. Abram, Jessie A. Wells, Erik MeijaardAbstract:We investigated why Orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill Orangutans. Those who reported having personally killed an Orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an Orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons Orangutans were killed was fear of Orangutans or in self-defence. A similar pattern was evident among reports of Orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether Orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 Orangutans were killed in Kalimantan within the respondents’ active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI) and between 26,361 and 41,688 for non-conflict reasons (95% CI). These findings confirm that habitat protection alone will not ensure the survival of Orangutans in Indonesian Borneo, and that effective reduction of Orangutan killings is urgently needed.