Publications by authors named "Serge A Wich"

53 Publications

An Evaluation of the Factors Affecting 'Poacher' Detection with Drones and the Efficacy of Machine-Learning for Detection.

Sensors (Basel) 2021 Jun 13;21(12). Epub 2021 Jun 13.

School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK.

Drones are being increasingly used in conservation to tackle the illegal poaching of animals. An important aspect of using drones for this purpose is establishing the technological and the environmental factors that increase the chances of success when detecting poachers. Recent studies focused on investigating these factors, and this research builds upon this as well as exploring the efficacy of machine-learning for automated detection. In an experimental setting with voluntary test subjects, various factors were tested for their effect on detection probability: camera type (visible spectrum, RGB, and thermal infrared, TIR), time of day, camera angle, canopy density, and walking/stationary test subjects. The drone footage was analysed both manually by volunteers and through automated detection software. A generalised linear model with a logit link function was used to statistically analyse the data for both types of analysis. The findings concluded that using a TIR camera improved detection probability, particularly at dawn and with a 90° camera angle. An oblique angle was more effective during RGB flights, and walking/stationary test subjects did not influence detection with both cameras. Probability of detection decreased with increasing vegetation cover. Machine-learning software had a successful detection probability of 0.558, however, it produced nearly five times more false positives than manual analysis. Manual analysis, however, produced 2.5 times more false negatives than automated detection. Despite manual analysis producing more true positive detections than automated detection in this study, the automated software gives promising, successful results, and the advantages of automated methods over manual analysis make it a promising tool with the potential to be successfully incorporated into anti-poaching strategies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s21124074DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232034PMC
June 2021

Measuring disturbance at swift breeding colonies due to the visual aspects of a drone: a quasi-experiment study.

Curr Zool 2021 Apr 15;67(2):157-163. Epub 2020 Jul 15.

School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool L3 5UG, UK.

There is a growing body of research indicating that drones can disturb animals. However, it is usually unclear whether the disturbance is due to visual or auditory cues. Here, we examined the effect of drone flights on the behavior of great dusky swifts and white-collared swifts in 2 breeding sites where drone noise was obscured by environmental noise from waterfalls and any disturbance must be largely visual. We performed 12 experimental flights with a multirotor drone at different vertical, horizontal, and diagonal distances from the colonies. From all flights, 17% caused <1% of birds to temporarily abandon the breeding site, 50% caused half to abandon, and 33% caused more than half to abandon. We found that the diagonal distance explained 98.9% of the variability of the disturbance percentage and while at distances >50 m the disturbance percentage does not exceed 20%, at <40 m the disturbance percentage increase to > 60%. We recommend that flights with a multirotor drone during the breeding period should be conducted at a distance of >50 m and that recreational flights should be discouraged or conducted at larger distances (e.g. 100 m) in nesting birds areas such as waterfalls, canyons, and caves.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/cz/zoaa038DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8026149PMC
April 2021

Ecological correlates of chimpanzee (Pan troglodytes schweinfurthii) density in Mahale Mountains National Park, Tanzania.

PLoS One 2021 12;16(2):e0246628. Epub 2021 Feb 12.

Department of Anthropology, University College London, London, United Kingdom.

Understanding the ecological factors that drive animal density patterns in time and space is key to devising effective conservation strategies. In Tanzania, most chimpanzees (~75%) live outside national parks where human activities threaten their habitat's integrity and connectivity. Mahale Mountains National Park (MMNP), therefore, is a critical area for chimpanzees (Pan troglodytes schweinfurthii) in the region due to its location and protective status. Yet, despite its importance and long history of chimpanzee research (>50 years), a park-wide census of the species has never been conducted. The park is categorized as a savanna-woodland mosaic, interspersed with riparian forest, wooded grassland, and bamboo thicket. This heterogeneous landscape offers an excellent opportunity to assess the ecological characteristics associated with chimpanzee density, a topic still disputed, which could improve conservation plans that protect crucial chimpanzee habitat outside the park. We examined the influence of fine-scale vegetative characteristics and topographical features on chimpanzee nest density, modeling nest counts using hierarchical distance sampling. We counted 335 nests in forest and woodland habitats across 102 transects in 13 survey sites. Nests were disproportionately found more in or near evergreen forests, on steep slopes, and in feeding tree species. We calculated chimpanzee density in MMNP to be 0.23 ind/km2, although density varied substantially among sites (0.09-3.43 ind/km2). Density was associated with factors related to the availability of food and nesting trees, with topographic heterogeneity and the total basal area of feeding tree species identified as significant positive predictors. Species-rich habitats and floristic diversity likely play a principal role in shaping chimpanzee density within a predominately open landscape with low food abundance. Our results provide valuable baseline data for future monitoring efforts in MMNP and enhance our understanding of this endangered species' density and distribution across Tanzania.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0246628PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7880473PMC
February 2021

Understanding the relationship between fruit colour and primate vision requires multiple lines of evidence. A reply to Heymann & Fuzessy.

Proc Biol Sci 2021 01 20;288(1943):20202981. Epub 2021 Jan 20.

Department of Theoretical and Computational Ecology, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, PO Box 94240, Amsterdam, The Netherlands.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1098/rspb.2020.2981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7893271PMC
January 2021

The historical range and drivers of decline of the Tapanuli orangutan.

PLoS One 2021 4;16(1):e0238087. Epub 2021 Jan 4.

Liverpool John Moores University, Liverpool, United Kingdom.

The Tapanuli Orangutan (Pongo tapanuliensis) is the most threatened great ape species in the world. It is restricted to an area of about 1,000 km2 of upland forest where fewer than 800 animals survive in three declining subpopulations. Through a historical ecology approach involving analysis of newspaper, journals, books and museum records from the early 1800s to 2009, we demonstrate that historically Pongo tapanuliensis inhabited a much larger area, and occurred across a much wider range of habitat types and at lower elevations than now. Its current Extent of Occurrence is 2.5% and 5.0% of the historical range in the 1890s and 1940s respectively. A combination of historical fragmentation of forest habitats, mostly for small-scale agriculture, and unsustainable hunting likely drove various populations to the south, east and west of the current population to extinction. This happened prior to the industrial-scale forest conversion that started in the 1970s. Our findings indicate how sensitive P. tapanuliensis is to the combined effects of habitat fragmentation and unsustainable take-off rates. Saving this species will require prevention of any further fragmentation and killings or other removal of animals from the remaining population. Without concerted action to achieve this, the remaining populations of P. tapanuliensis are doomed to become extinct within several orangutan generations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0238087PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7781382PMC
April 2021

The environmental impacts of palm oil in context.

Nat Plants 2020 12 7;6(12):1418-1426. Epub 2020 Dec 7.

Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway.

Delivering the Sustainable Development Goals (SDGs) requires balancing demands on land between agriculture (SDG 2) and biodiversity (SDG 15). The production of vegetable oils and, in particular, palm oil, illustrates these competing demands and trade-offs. Palm oil accounts for ~40% of the current global annual demand for vegetable oil as food, animal feed and fuel (210 Mt), but planted oil palm covers less than 5-5.5% of the total global oil crop area (approximately 425 Mha) due to oil palm's relatively high yields. Recent oil palm expansion in forested regions of Borneo, Sumatra and the Malay Peninsula, where >90% of global palm oil is produced, has led to substantial concern around oil palm's role in deforestation. Oil palm expansion's direct contribution to regional tropical deforestation varies widely, ranging from an estimated 3% in West Africa to 50% in Malaysian Borneo. Oil palm is also implicated in peatland draining and burning in Southeast Asia. Documented negative environmental impacts from such expansion include biodiversity declines, greenhouse gas emissions and air pollution. However, oil palm generally produces more oil per area than other oil crops, is often economically viable in sites unsuitable for most other crops and generates considerable wealth for at least some actors. Global demand for vegetable oils is projected to increase by 46% by 2050. Meeting this demand through additional expansion of oil palm versus other vegetable oil crops will lead to substantial differential effects on biodiversity, food security, climate change, land degradation and livelihoods. Our Review highlights that although substantial gaps remain in our understanding of the relationship between the environmental, socio-cultural and economic impacts of oil palm, and the scope, stringency and effectiveness of initiatives to address these, there has been little research into the impacts and trade-offs of other vegetable oil crops. Greater research attention needs to be given to investigating the impacts of palm oil production compared to alternatives for the trade-offs to be assessed at a global scale.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41477-020-00813-wDOI Listing
December 2020

Grouping behavior of Sumatran orangutans (Pongo abelii) and Tapanuli orangutans (Pongo tapanuliensis) living in forest with low fruit abundance.

Am J Primatol 2020 05 18;82(5):e23123. Epub 2020 Mar 18.

Sumatran Orangutan Conservation Programme, The PanEco Foundation, Berg am Irchel, Switzerland.

In contrast to the African great apes, orangutans (Pongo spp.) are semisolitary: Individuals are often on their own, but form aggregations more often than expected by chance. These temporary aggregations provide social benefits such as mating opportunities. When fruit availability is high, costs of aggregating should be lower, because competition is less pronounced. Therefore, average party size is expected to be higher when fruit availability is high. This hypothesis would also explain why orangutans in highly fruit-productive habitats on Sumatra are more gregarious than in the usually less productive habitats of Borneo. Here, we describe the aggregation behavior of orangutans in less productive Sumatran habitats (Sikundur and Batang Toru), and compare results with those of previously surveyed field sites. Orangutans in Sikundur were more likely to form parties when fruit availability was higher, but the size of daily parties was not significantly affected by fruit availability. With regard to between-site comparisons, average party sizes of females and alone time of parous females in Sikundur and Batang Toru were substantially lower than those for two previously surveyed Sumatran sites, and both fall in the range of values for Bornean sites. Our results indicate that the assessment of orangutans on Sumatra as being more social than those on Borneo needs revision. Instead, between-site differences in sociality seem to reflect differences in average fruit availability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajp.23123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317506PMC
May 2020

Palm fruit colours are linked to the broad-scale distribution and diversification of primate colour vision systems.

Proc Biol Sci 2020 02 26;287(1921):20192731. Epub 2020 Feb 26.

Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, PO Box 94240, Amsterdam, The Netherlands.

A long-standing hypothesis in ecology and evolution is that trichromatic colour vision (the ability to distinguish red from green) in frugivorous primates has evolved as an adaptation to detect conspicuous (reddish) fruits. This could provide a competitive advantage over dichromatic frugivores which cannot distinguish reddish colours from a background of green foliage. Here, we test whether the origin, distribution and diversity of trichromatic primates is positively associated with the availability of conspicuous palm fruits, i.e. keystone fruit resources for tropical frugivores. We combine global data of colour vision, distribution and phylogenetic data for more than 400 primate species with fruit colour data for more than 1700 palm species, and reveal that species richness of trichromatic primates increases with the proportion of palm species that have conspicuous fruits, especially in subtropical African forests. By contrast, species richness of trichromats in Asia and the Americas is not positively associated with conspicuous palm fruit colours. Macroevolutionary analyses further indicate rapid and synchronous radiations of trichromats and conspicuous palms on the African mainland starting 10 Ma. These results suggest that the distribution and diversification of African trichromatic primates is strongly linked to the relative availability of conspicuous (versus non-conspicuous) palm fruits, and that interactions between primates and palms are related to the coevolutionary dynamics of primate colour vision systems and palm fruit colours.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1098/rspb.2019.2731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7062032PMC
February 2020

Tourist photographs as a scalable framework for wildlife monitoring in protected areas.

Curr Biol 2019 07;29(14):R681-R682

School of Environmental and Life Sciences, University of Newcastle, Newcastle, NSW 2308, Australia; Centre for African Conservation Ecology, Nelson Mandela University, Port Elizabeth, 6031, South Africa.

Protected areas are critical to conservation efforts in the face of rapid biodiversity declines [1]. Yet the resources for conservation are often limited and shared amongst many competing priorities [2]. As a consequence, even basic monitoring surveys are absent within most protected areas [3]. Although a range of wildlife monitoring methods exist, considerable focused survey effort is often required to yield accurate and precise estimates [4]. This makes monitoring difficult to sustain or replicate, limiting access to the data required for evidence-based conservation decisions. Citizen-scientists have been proposed as an important complement to the finite resources available for basic monitoring within protected areas [5]; however, the full potential of this approach has yet to be realised. Wildlife tourists and guides are especially focussed on encountering and photographing fauna and flora, yet the data collected in these efforts is rarely harnessed for conservation monitoring within protected areas. A detailed understanding of photographic tourism's potential role in wildlife monitoring has been lacking, but is essential for the development of new tools to harness the data being collected through tourism. Here, we demonstrate that tourist-contributed data can aid wildlife monitoring in protected areas by providing population estimates of large carnivores comparable to those from traditional survey methods. Our approach could capitalize upon the immense number of wildlife photographs being taken daily as part of the global > 30-billion USD, wildlife-based tourism industry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2019.05.056DOI Listing
July 2019

Orangutan populations are certainly not increasing in the wild.

Curr Biol 2018 11;28(21):R1241-R1242

Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany.

A recent report, published by the Government of Indonesia with support from the Food and Agricultural Organization and Norway's International Climate and Forest Initiative, states that orangutan populations (Pongo spp.) have increased by more than 10% in Indonesia from 2015 to 2017, exceeding the government target of an annual 2% population increase [1]. This assessment is in strong contrast with recent publications that showed that the Bornean orangutan (P. pygmaeus) lost more than 100,000 individuals in the past 16 years [2] and declined by at least 25% over the past 10 years [3]. Furthermore, recent work has also demonstrated that both Sumatran orangutans (P. abelii) and the recently described Tapanuli orangutan (P. tapanuliensis) lost more than 60% of their key habitats between 1985 and 2007, and ongoing land use changes are expected to result in an 11-27% decline in their populations by 2020 [4,5]. Most scientific data indicate that the survival of these species continues to be seriously threatened by deforestation and killing [4,6,7] and thus all three are Critically Endangered under the International Union for Conservation of Nature's Red List.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2018.09.052DOI Listing
November 2018

Small room for compromise between oil palm cultivation and primate conservation in Africa.

Proc Natl Acad Sci U S A 2018 08 13;115(35):8811-8816. Epub 2018 Aug 13.

Faculty of Science, Liverpool John Moores University, Liverpool L3 5UX, United Kingdom.

Despite growing awareness about its detrimental effects on tropical biodiversity, land conversion to oil palm continues to increase rapidly as a consequence of global demand, profitability, and the income opportunity it offers to producing countries. Although most industrial oil palm plantations are located in Southeast Asia, it is argued that much of their future expansion will occur in Africa. We assessed how this could affect the continent's primates by combining information on oil palm suitability and current land use with primate distribution, diversity, and vulnerability. We also quantified the potential impact of large-scale oil palm cultivation on primates in terms of range loss under different expansion scenarios taking into account future demand, oil palm suitability, human accessibility, carbon stock, and primate vulnerability. We found a high overlap between areas of high oil palm suitability and areas of high conservation priority for primates. Overall, we found only a few small areas where oil palm could be cultivated in Africa with a low impact on primates (3.3 Mha, including all areas suitable for oil palm). These results warn that, consistent with the dramatic effects of palm oil cultivation on biodiversity in Southeast Asia, reconciling a large-scale development of oil palm in Africa with primate conservation will be a great challenge.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1804775115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6126731PMC
August 2018

Orangutans venture out of the rainforest and into the Anthropocene.

Sci Adv 2018 06 27;4(6):e1701422. Epub 2018 Jun 27.

Borneo Futures, Bandar Seri Begawan, BE1518 Brunei Darussalam.

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 ( 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/sciadv.1701422DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6021148PMC
June 2018

Global Demand for Natural Resources Eliminated More Than 100,000 Bornean Orangutans.

Curr Biol 2018 03 15;28(5):761-769.e5. Epub 2018 Feb 15.

The Nature Conservancy (TNC) Indonesia, Jakarta, Indonesia.

Unsustainable exploitation of natural resources is increasingly affecting the highly biodiverse tropics [1, 2]. Although rapid developments in remote sensing technology have permitted more precise estimates of land-cover change over large spatial scales [3-5], our knowledge about the effects of these changes on wildlife is much more sparse [6, 7]. Here we use field survey data, predictive density distribution modeling, and remote sensing to investigate the impact of resource use and land-use changes on the density distribution of Bornean orangutans (Pongo pygmaeus). Our models indicate that between 1999 and 2015, half of the orangutan population was affected by logging, deforestation, or industrialized plantations. Although land clearance caused the most dramatic rates of decline, it accounted for only a small proportion of the total loss. A much larger number of orangutans were lost in selectively logged and primary forests, where rates of decline were less precipitous, but where far more orangutans are found. This suggests that further drivers, independent of land-use change, contribute to orangutan loss. This finding is consistent with studies reporting hunting as a major cause in orangutan decline [8-10]. Our predictions of orangutan abundance loss across Borneo suggest that the population decreased by more than 100,000 individuals, corroborating recent estimates of decline [11]. Practical solutions to prevent future orangutan decline can only be realized by addressing its complex causes in a holistic manner across political and societal sectors, such as in land-use planning, resource exploitation, infrastructure development, and education, and by increasing long-term sustainability [12]. VIDEO ABSTRACT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2018.01.053DOI Listing
March 2018

Morphometric, Behavioral, and Genomic Evidence for a New Orangutan Species.

Curr Biol 2017 Nov 2;27(22):3487-3498.e10. Epub 2017 Nov 2.

School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK.

Six extant species of non-human great apes are currently recognized: Sumatran and Bornean orangutans, eastern and western gorillas, and chimpanzees and bonobos [1]. However, large gaps remain in our knowledge of fine-scale variation in hominoid morphology, behavior, and genetics, and aspects of great ape taxonomy remain in flux. This is particularly true for orangutans (genus: Pongo), the only Asian great apes and phylogenetically our most distant relatives among extant hominids [1]. Designation of Bornean and Sumatran orangutans, P. pygmaeus (Linnaeus 1760) and P. abelii (Lesson 1827), as distinct species occurred in 2001 [1, 2]. Here, we show that an isolated population from Batang Toru, at the southernmost range limit of extant Sumatran orangutans south of Lake Toba, is distinct from other northern Sumatran and Bornean populations. By comparing cranio-mandibular and dental characters of an orangutan killed in a human-animal conflict to those of 33 adult male orangutans of a similar developmental stage, we found consistent differences between the Batang Toru individual and other extant Ponginae. Our analyses of 37 orangutan genomes provided a second line of evidence. Model-based approaches revealed that the deepest split in the evolutionary history of extant orangutans occurred ∼3.38 mya between the Batang Toru population and those to the north of Lake Toba, whereas both currently recognized species separated much later, about 674 kya. Our combined analyses support a new classification of orangutans into three extant species. The new species, Pongo tapanuliensis, encompasses the Batang Toru population, of which fewer than 800 individuals survive. VIDEO ABSTRACT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2017.09.047DOI Listing
November 2017

First integrative trend analysis for a great ape species in Borneo.

Sci Rep 2017 07 7;7(1):4839. Epub 2017 Jul 7.

The Nature Conservancy (TNC) Indonesia, Jakarta, Indonesia.

For many threatened species the rate and drivers of population decline are difficult to assess accurately: species' surveys are typically restricted to small geographic areas, are conducted over short time periods, and employ a wide range of survey protocols. We addressed methodological challenges for assessing change in the abundance of an endangered species. We applied novel methods for integrating field and interview survey data for the critically endangered Bornean orangutan (Pongo pygmaeus), allowing a deeper understanding of the species' persistence through time. Our analysis revealed that Bornean orangutan populations have declined at a rate of 25% over the last 10 years. Survival rates of the species are lowest in areas with intermediate rainfall, where complex interrelations between soil fertility, agricultural productivity, and human settlement patterns influence persistence. These areas also have highest threats from human-wildlife conflict. Survival rates are further positively associated with forest extent, but are lower in areas where surrounding forest has been recently converted to industrial agriculture. Our study highlights the urgency of determining specific management interventions needed in different locations to counter the trend of decline and its associated drivers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-04435-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5501861PMC
July 2017

Vocal fold control beyond the species-specific repertoire in an orang-utan.

Sci Rep 2016 07 27;6:30315. Epub 2016 Jul 27.

Indianapolis Zoo, Indianapolis, IN 46222, USA.

Vocal fold control was critical to the evolution of spoken language, much as it today allows us to learn vowel systems. It has, however, never been demonstrated directly in a non-human primate, leading to the suggestion that it evolved in the human lineage after divergence from great apes. Here, we provide the first evidence for real-time, dynamic and interactive vocal fold control in a great ape during an imitation "do-as-I-do" game with a human demonstrator. Notably, the orang-utan subject skilfully produced "wookies" - an idiosyncratic vocalization exhibiting a unique spectral profile among the orang-utan vocal repertoire. The subject instantaneously matched human-produced wookies as they were randomly modulated in pitch, adjusting his voice frequency up or down when the human demonstrator did so, readily generating distinct low vs. high frequency sub-variants. These sub-variants were significantly different from spontaneous ones (not produced in matching trials). Results indicate a latent capacity for vocal fold exercise in a great ape (i) in real-time, (ii) up and down the frequency spectrum, (iii) across a register range beyond the species-repertoire and, (iv) in a co-operative turn-taking social setup. Such ancestral capacity likely provided the neuro-behavioural basis of the more fine-tuned vocal fold control that is a human hallmark.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep30315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4962094PMC
July 2016

Land-cover changes predict steep declines for the Sumatran orangutan (Pongo abelii).

Sci Adv 2016 Mar 4;2(3):e1500789. Epub 2016 Mar 4.

Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.; German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Deutscher Platz 6, 04103 Leipzig, Germany.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/sciadv.1500789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4783118PMC
March 2016

Community motivations to engage in conservation behavior to conserve the Sumatran orangutan.

Conserv Biol 2016 08 6;30(4):816-26. Epub 2016 Apr 6.

Landscape Ecology and Conservation Group, School of Geography, Planning and Environmental Management, The University of Queensland, Brisbane, 4072, Australia.

Community-based conservation programs in developing countries are often based on the assumption that heteronomous motivation (e.g., extrinsic incentives such as economic rewards and pressure or coercion to act) will incite local communities to adopt conservation behaviors. However, this may not be as effective or sustainable as autonomous motivations (e.g., an intrinsic desire to act due to inherent enjoyment or self-identification with a behavior and through freedom of choice). We analyzed the comparative effectiveness of heteronomous versus autonomous approaches to community-based conservation programs through a case study of Sumatran orangutan (Pongo abelii) conservation in 3 villages in Indonesia. Each village had a different conservation program design. We surveyed people (n = 240) to determine their motivations for and behavior changes relative to orangutan and orangutan habitat (forest) protection. Heteronomous motivations (e.g., income from tourism) led to greater self-reporting of behavior change toward orangutan protection. However, they did not change self-reported behavior toward forest (i.e., orangutan habitat) protection. The most effective approach to creating self-reported behavior change throughout the community was a combination of autonomous and heteronomous motivations. Individuals who were heteronomously motivated to protect the orangutan were more likely to have changed attitudes than to have changed their self-reported behavior. These findings demonstrate that the current paradigm of motivating communities in developing countries to adopt conservation behaviors primarily through monetary incentives and rewards should consider integrating autonomous motivational techniques that promote the intrinsic values of conservation. Such a combination has a greater potential to achieve sustainable and cost-effective conservation outcomes. Our results highlight the importance of using in-depth sociopsychological analyses to inform the design and implementation of community-based conservation programs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cobi.12650DOI Listing
August 2016

Locating chimpanzee nests and identifying fruiting trees with an unmanned aerial vehicle.

Am J Primatol 2015 Oct 14;77(10):1122-34. Epub 2015 Jul 14.

Max Planck Institute for Evolutionary Anthropology, Department of Primatology, Leipzig, Germany.

Monitoring of animal populations is essential for conservation management. Various techniques are available to assess spatiotemporal patterns of species distribution and abundance. Nest surveys are often used for monitoring great apes. Quickly developing technologies, including unmanned aerial vehicles (UAVs) can be used to complement these ground-based surveys, especially for covering large areas rapidly. Aerial surveys have been used successfully to detect the nests of orang-utans. It is unknown if such an approach is practical for African apes, which usually build their nests at lower heights, where they might be obscured by forest canopy. In this 2-month study, UAV-derived aerial imagery was used for two distinct purposes: testing the detectability of chimpanzee nests and identifying fruiting trees used by chimpanzees in Loango National Park (Gabon). Chimpanzee nest data were collected through two approaches: we located nests on the ground and then tried to detect them in UAV photos and vice versa. Ground surveys were conducted using line transects, reconnaissance trails, and opportunistic sampling during which we detected 116 individual nests in 28 nest groups. In complementary UAV images we detected 48% of the individual nests (68% of nest groups) in open coastal forests and 8% of individual nests (33% of nest groups) in closed canopy inland forests. The key factor for nest detectability in UAV imagery was canopy openness. Data on fruiting trees were collected from five line transects. In 122 UAV images 14 species of trees (N = 433) were identified, alongside 37 tree species (N = 205) in complementary ground surveys. Relative abundance of common tree species correlated between ground and UAV surveys. We conclude that UAVs have great potential as a rapid assessment tool for detecting chimpanzee presence in forest with open canopy and assessing fruit tree availability. UAVs may have limited applicability for nest detection in closed canopy forest.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajp.22446DOI Listing
October 2015

An estimate of the number of tropical tree species.

Proc Natl Acad Sci U S A 2015 Jun 1;112(24):7472-7. Epub 2015 Jun 1.

Center for Tropical Conservation, Duke University, Durham, NC;

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼ 40,000 and ∼ 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼ 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼ 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1423147112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4475970PMC
June 2015

Alternative futures for Borneo show the value of integrating economic and conservation targets across borders.

Nat Commun 2015 04 14;6:6819. Epub 2015 Apr 14.

Australian Research Council Centre of Excellence for Environmental Decisions, School of Biological Sciences, The University of Queensland, Brisbane 4072, Queensland, Australia.

Balancing economic development with international commitments to protect biodiversity is a global challenge. Achieving this balance requires an understanding of the possible consequences of alternative future scenarios for a range of stakeholders. We employ an integrated economic and environmental planning approach to evaluate four alternative futures for the mega-diverse island of Borneo. We show what could be achieved if the three national jurisdictions of Borneo coordinate efforts to achieve their public policy targets and allow a partial reallocation of planned land uses. We reveal the potential for Borneo to simultaneously retain ∼50% of its land as forests, protect adequate habitat for the Bornean orangutan (Pongo pygmaeus) and Bornean elephant (Elephas maximus borneensis), and achieve an opportunity cost saving of over US$43 billion. Such coordination would depend on enhanced information sharing and reforms to land-use planning, which could be supported by the increasingly international nature of economies and conservation efforts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ncomms7819DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403346PMC
April 2015

Acoustic models of orangutan hand-assisted alarm calls.

J Exp Biol 2015 Mar;218(Pt 6):907-14

Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands.

Orangutans produce alarm calls called kiss-squeaks, which they sometimes modify by putting a hand in front of their mouth. Through theoretical models and observational evidence, we show that using the hand when making a kiss-squeak alters the acoustics of the production in such a way that more formants per kilohertz are produced. Our theoretical models suggest that cylindrical wave propagation is created with the use of the hand and face as they act as a cylindrical extension of the lips. The use of cylindrical wave propagation in animal calls appears to be extremely rare, but is an effective way to lengthen the acoustic system; it causes the number of resonances per kilohertz to increase. This increase is associated with larger animals, and thus using the hand in kiss-squeak production may be effective in exaggerating the size of the producer. Using the hand appears to be a culturally learned behavior, and therefore orangutans may be able to associate the acoustic effect of using the hand with potentially more effective deterrence of predators.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1242/jeb.110577DOI Listing
March 2015

Speech-like rhythm in a voiced and voiceless orangutan call.

PLoS One 2015 8;10(1):e116136. Epub 2015 Jan 8.

Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands.

The evolutionary origins of speech remain obscure. Recently, it was proposed that speech derived from monkey facial signals which exhibit a speech-like rhythm of ∼5 open-close lip cycles per second. In monkeys, these signals may also be vocalized, offering a plausible evolutionary stepping stone towards speech. Three essential predictions remain, however, to be tested to assess this hypothesis' validity; (i) Great apes, our closest relatives, should likewise produce 5Hz-rhythm signals, (ii) speech-like rhythm should involve calls articulatorily similar to consonants and vowels given that speech rhythm is the direct product of stringing together these two basic elements, and (iii) speech-like rhythm should be experience-based. Via cinematic analyses we demonstrate that an ex-entertainment orangutan produces two calls at a speech-like rhythm, coined "clicks" and "faux-speech." Like voiceless consonants, clicks required no vocal fold action, but did involve independent manoeuvring over lips and tongue. In parallel to vowels, faux-speech showed harmonic and formant modulations, implying vocal fold and supralaryngeal action. This rhythm was several times faster than orangutan chewing rates, as observed in monkeys and humans. Critically, this rhythm was seven-fold faster, and contextually distinct, than any other known rhythmic calls described to date in the largest database of the orangutan repertoire ever assembled. The first two predictions advanced by this study are validated and, based on parsimony and exclusion of potential alternative explanations, initial support is given to the third prediction. Irrespectively of the putative origins of these calls and underlying mechanisms, our findings demonstrate irrevocably that great apes are not respiratorily, articulatorilly, or neurologically constrained for the production of consonant- and vowel-like calls at speech rhythm. Orangutan clicks and faux-speech confirm the importance of rhythmic speech antecedents within the primate lineage, and highlight potential articulatory homologies between great ape calls and human consonants and vowels.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0116136PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4287529PMC
January 2016

Anticipated climate and land-cover changes reveal refuge areas for Borneo's orang-utans.

Glob Chang Biol 2015 Aug 6;21(8):2891-904. Epub 2015 Jan 6.

Leibniz Institute for Zoo and Wildlife Research (IZW), Alfred-Kowalke-Straße 17, 10315, Berlin, Germany.

Habitat loss and climate change pose a double jeopardy for many threatened taxa, making the identification of optimal habitat for the future a conservation priority. Using a case study of the endangered Bornean orang-utan, we identify environmental refuges by integrating bioclimatic models with projected deforestation and oil-palm agriculture suitability from the 1950s to 2080s. We coupled a maximum entropy algorithm with information on habitat needs to predict suitable habitat for the present day and 1950s. We then projected to the 2020s, 2050s and 2080s in models incorporating only land-cover change, climate change or both processes combined. For future climate, we incorporated projections from four model and emission scenario combinations. For future land cover, we developed spatial deforestation predictions from 10 years of satellite data. Refuges were delineated as suitable forested habitats identified by all models that were also unsuitable for oil palm - a major threat to tropical biodiversity. Our analyses indicate that in 2010 up to 260,000 km(2) of Borneo was suitable habitat within the core orang-utan range; an 18-24% reduction since the 1950s. Land-cover models predicted further decline of 15-30% by the 2080s. Although habitat extent under future climate conditions varied among projections, there was majority consensus, particularly in north-eastern and western regions. Across projections habitat loss due to climate change alone averaged 63% by 2080, but 74% when also considering land-cover change. Refuge areas amounted to 2000-42,000 km(2) depending on thresholds used, with 900-17,000 km(2) outside the current species range. We demonstrate that efforts to halt deforestation could mediate some orang-utan habitat loss, but further decline of the most suitable areas is to be expected given projected changes to climate. Protected refuge areas could therefore become increasingly important for ongoing translocation efforts. We present an approach to help identify such areas for highly threatened species given environmental changes expected this century.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/gcb.12814DOI Listing
August 2015

Effect of repeated exposures and sociality on novel food acceptance and consumption by orangutans.

Primates 2015 Jan 20;56(1):21-7. Epub 2014 Sep 20.

Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands,

Hundreds of rehabilitant great apes have been released into the wild, and thousands await release. However, survival rates after release can be as low as 20%. Several factors influence individuals' survival rates, one of which is the capacity to obtain an adequate diet once released. Released individuals are faced with a mixture of familiar and novel foods in an unfamiliar forest; therefore, it is important to understand how they increase acceptance and consumption of novel foods. This is especially vital for omnivorous species, such as wild great apes, which consume several hundred species of different foods. We assessed the effects of repeated exposures and sociality (i.e. co-feeding in the presence of one or more other individuals) on the acceptance and consumption of novel foods by captive orangutans (Pongo sp). Repeated exposures of food (novel, at first) did not cause an increase of acceptance of food; in other words, the orangutans did not start to eat a food item after being exposed to that food more often, but repeated exposures of food increased consumption (i.e. quantity). After repeated exposures, the orangutans also became gradually more familiar with the food, decreasing their explorative behaviour. The presence of co-feeding conspecifics resulted in an increased acceptance of the novel food by orangutans, and they ate a larger amount of said foods than when alone. Repeated exposure and sociality may benefit rehabilitant great apes in augmenting and diversifying diet and, once practiced before release, may accelerate an individuals' adaptation to their new habitat, improving survival chances. Great ape rescue, rehabilitation and reintroduction require large financial and logistic investments; however, their effectiveness may be improved at low cost and low effort through the suggested measures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10329-014-0441-3DOI Listing
January 2015