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Nadine Ruppert

Universiti Sains Malaysia, School of Biological Sciences, Faculty Member

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Head of Primate Research and Conservation Lab, USM
Head of Macaca Nemestrina Project
Co-founder & advisor or Langur Project Penang, Night Spotting Project & Gibbons of Peninsular Malaysia (UNGKA)
Member of IUCN Specialist Group Section Small Apes
Scientific Chair of Malaysian Primatological Society

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DR NABILAH ZAINOL

University of Granada

Fredrick Onyancha

Egerton University

Neotropical Primate Conservation

Gilberto Pozo-Montuy

University of Mysore

mohamad fhaizal mohamad bukhori

Universiti Malaysia Sarawak (UNIMAS)

Khansa Kharismawan

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Papers by Nadine Ruppert

Recommendations for the establishment of a trans-island canopy bridge network to support primate movement across Langkawi Island, Malaysia

Oryx

The expansion of transportation and service corridors has numerous, well-documented adverse effec... more The expansion of transportation and service corridors has numerous, well-documented adverse effects on wildlife. However, little research on this topic has been translated into mitigating the effects of habitat fragmentation caused by road development on primates. The establishment of canopy bridges has proven to be an effective conservation intervention. Of the completed primate canopy bridge projects reported in the literature, to our knowledge, all attempt to mitigate the impacts caused by singular, linear infrastructure routes. Here we provide recommendations for the establishment of a network of natural and artificial canopy bridges over roads throughout Langkawi Island, Malaysia, to reduce rates of roadkill and support the movement of primates and other arboreal animals across the island by identifying suitable sites and appropriate tree species to be planted (including Ficus racemosa and Ficus fistulosa), bridge materials and post-installation monitoring. The establishment of...

Rattan litter-collecting structures attract nest-building and defending ants

Plant Signaling & Behavior, May 27, 2019

Rattan is an important climbing palm taxon in Malaysian tropical rain forests. Many rattan specie... more Rattan is an important climbing palm taxon in Malaysian tropical rain forests. Many rattan species have unique structures directly associated with certain ant species. In this study, four rattan species (Daemonorops lewisiana, Calamus castaneus, Daemonorops geniculata and Korthalsia scortechinii) were inspected and documented in a field survey concerning their relationships with several ant species. We noticed that two rattan species (D. lewisiana and C. castaneus) were more likely to be associated with ants compared to their neighbouring rattan (Plectomia griffithii). However, D. lewisiana and C. castaneus did not directly provide shelters for ant colonies, but possessed unique structures: upward-pointing spines and funnel-shaped leaves, which are equipped to collect more litter than P. griffithii. To test our litter collecting hypothesis, we measured the inclination of spines from the stem. Our results showed the presence of ant colonies in the litter-collecting rattans (D. lewisiana and C. castaneus), which was significantly higher compared to a non-litter-collecting rattan (P. griffithii). We propose a complex and novel type of adaptation (litter-collection and provision of nesting materials) for rattans, which promotes interactions between the rattan and ants through the arrangements of leaves, leaflets, and spines. In return, the rattan may benefit from ants' services, such as protection, nutrient enhancement, and pollination.

“Ah Lai’s Crossing” – Malaysia’s first artificial road canopy bridge to facilitate safer arboreal wildlife crossings

Folia Primatologica, Mar 30, 2022

Roads negatively affect wildlife populations globally, causing habitat fragmentation that can fac... more Roads negatively affect wildlife populations globally, causing habitat fragmentation that can facilitate mortality by access to forest for poaching and wildlife collisions with vehicles. Primate habitats are vulnerable to fragmentation exposing them to anthropogenic threats. Endangered dusky langurs (Trachypithecus obscurus) in Malaysia are often found in urban areas and have been frequent victims of vehicle collisions. To mitigate the hazardous impact of a busy asphalt road on wild dusky langurs in Teluk Bahang, Penang, we built the first artificial road canopy bridge in Malaysia in February 2019 to assist arboreal wildlife to move between habitat fragments more safely. Four days after the bridge construction, the first long-tailed macaque (Macaca fascicularis) was recorded via a camera trap crossing the bridge, and plantain squirrels (Callosciurus notatus) and dusky langurs first crossed one and eight months later, respectively. The bridge was upgraded from a single-firehose rope to a double-rope in August 2020 to assess the effectiveness of the two designs. In total, 2128 animal crossings comprising three mammal species were recorded between March 2019 and May 2021. Plantain squirrels crossed the bridge most frequently with 2075 crossings, long-tailed macaques crossed 32 times, and dusky langurs 21 times. There was a significant difference in bridge use according to species between the two designs (Chi-Square, p &lt; 0.001). Since the construction of the bridge, the rate of previously frequently reported primate roadkills near the bridge location has dropped to zero. This successful pilot project has spurred the efforts to implement more canopy bridges country-wide to support primate conservation efforts and better protect arboreal wildlife from the negative impacts of linear infrastructure.

Oil palm cultivation critically affects sociality in an endangered Malaysian primate

Authorea (Authorea), Oct 26, 2020

Rattan (Calamoideae) abundance and above-ground biomass at a primary rainforest of Peninsular Malaysia

Plant Ecology & Diversity, Sep 4, 2015

Background: Rattans are widespread throughout paleo-tropical forests; however, there is no inform... more Background: Rattans are widespread throughout paleo-tropical forests; however, there is no information on their contribution to above-ground biomass (AGB). Aims: This study established biomass baseline values for 11 different rattan species in a Malaysian primary forest, and calculated the overall rattan AGB contribution and dynamics during two years. Methods: All rattan stems in five 100 m × 100 m study plots were counted in 2011 and 2013. Biometric non-invasive measurements were carried out on 11 climbing and non-climbing species and total rattan biomass for both years calculated was compared. Results: Rattans contributed with 3.1 Mg ha−1 to the forest AGB. There was no significant change in rattan biomass between the years. Conclusions: These preliminary results are the first published on the AGB contribution of rattans to Malaysian primary forests. Further studies are required to ascertain values across forest types and over time to reliably estimate the contribution of rattan species to ABG and carbon sequestration.

Mother-Infant Interactions in a Wild Population of Macaca nemestrina (Linnaeus)

Until now, mother-infant relationships have not been studied in a wild population of the Southern... more Until now, mother-infant relationships have not been studied in a wild population of the Southern Pig-tailed Macaques Macaca nemestrina. We observed six mother-infant dyads from April 2016 to September 2016 in the Segari Melintang Forest Reserve, Peninsular Malaysia using focal sampling methods from the perspectives of both individuals. We hypothesized that as infant age increased, the same important mother-infant behaviours, previously observed to change in captive pig-tailed macaque mother-infant studies, would also change over time in field conditions. We expected that as the infant ages, mothers would decrease their rates of restraint and retrieval, and increase their rates of punishment. Two separate generalized linear mixed models (GLMM) of mother permissive behaviour and mother-infant contact duration as the outcome variables each showed infant age as the sole significant predictor variable indicating that as infant age increased, maternal behaviours changed as expected above, and mother-infant contact duration decreased. Mothers' interactions with other group members appeared influenced by mothers' associations with their offspring: adult females and juveniles were significantly more likely to be within 1-5 m proximity of mothers as infant age increased. Our data show that mother permissive behaviour, mother-infant contact duration, and proximity are crucial elements to consider when examining wild Southern Pig-tailed Macaque mother-infant relationships and infant independence, similar to what has been observed in captive settings.

Are social media reports useful for assessing small ape occurrence? A pilot study from Peninsular Malaysia

American Journal of Primatology, Feb 21, 2020

Citizen science-based research has been used effectively to estimate animal abundance and breedin... more Citizen science-based research has been used effectively to estimate animal abundance and breeding patterns, to monitor animal movement, and for biodiversity conservation and education. Here, we evaluate the feasibility of using social media observations to assess the distribution of small apes in Peninsular Malaysia. We searched for reports of small ape observations in Peninsular Malaysia on social media (e.g., blogs, Facebook, Instagram, Twitter, YouTube, iNaturalist, etc.), and also used online, radio, print messaging, and word of mouth to invite citizen scientists such as birders, amateur naturalists, hikers, and other members of the public to provide information about small ape observations made during their activities. These reports provided new information about the occurrence of all three species of small apes (Hylobates agilis, Hylobates lar, and Symphalangus syndactylus) in Peninsular Malaysia. Social media users reported observations of small apes in almost every state. Despite the fact that small apes are believed to occur primarily in the interior of large forested areas, most observations were from fairly small (<100 km 2) forests near areas of high traffic and high human population (roads and urban areas). This suggests that most outdoor enthusiasts primarily visit well-traveled and easily accessible areas, which results in biased sampling if only incidental observations reported on social media are used. A more targeted approach specifically soliciting reports from citizen scientists visiting large, less-accessible forests may result in better sampling in these habitats. Social media reports indicated the presence of small apes in at least six habitats where they had not been previously reported. We verified the reported data based on whether reports included a date, location, and uploaded photographs, videos and/or audio recordings. Well-publicized citizen science programs may also build awareness and enthusiasm about the conservation of vulnerable wildlife species.

Time constraints imposed by anthropogenic environments alter social behaviour in longtailed macaques

Animal Behaviour, Apr 1, 2019

Humans and their associated anthropogenic factors may strongly affect the demographics, activity,... more Humans and their associated anthropogenic factors may strongly affect the demographics, activity, and fragmentation of wild animal populations. Yet, the degree and nature of such impact on indicators of animals' social relationships remain largely under-investigated, despite the well-documented importance of strong social ties for an individuals' health and fitness. Here, we examined whether interactions with humans may affect core aspects of social life in a primate species, by constraining the time available for individuals to engage in social interactions. Specifically, we predicted that individuals who spent more time monitoring or interacting with humans reduce their time socializing with conspecifics (i.e., the time constraints hypothesis). Alternatively, human presence may result in increased levels of stress, leading to an increase in social behaviours which serve as a coping mechanism (i.e., the social stress hypothesis). We collected data between September 2016 and September 2017 on four groups of long-tailed macaques in Malaysia at two sites with differing levels of human impact. In support of the time constraints hypothesis, we found that at the site with moderate human impact, monkeys who monitored human activity more frequently engaged less often in grooming. In contrast, at the site with high human impact, we found evidence supporting the social stress hypothesis, as indicators of stress were positively associated with social interactions, although we could not link them to the presence of humans. Our results suggest that the nature of human impact on macaques' social behaviour is dependent upon the intensity of human activity and interaction with the macaques. These findings therefore provide insights into how humans may influence individual fitness and group social structure in animals living in an anthropogenic environment. More broadly, our results may lead to a better understanding of animal behaviour in anthropogenic environments, implementing conservation and population management strategies, and mitigating human-wildlife conflict.

The human–primate interface in the New Normal: Challenges and opportunities for primatologists in the COVID‐19 era and beyond

American Journal of Primatology, Jul 20, 2020

The emergence of SARS-CoV-2 in late 2019 and human responses to the resulting COVID-19 pandemic i... more The emergence of SARS-CoV-2 in late 2019 and human responses to the resulting COVID-19 pandemic in early 2020 have rapidly changed many aspects of human behavior, including our interactions with wildlife. In this commentary, we identify challenges and opportunities at human-primate interfaces in light of COVID-19, focusing on examples from Asia, and make recommendations for researchers working with wild primates to reduce zoonosis risk and leverage research opportunities. First, we briefly review the evidence for zoonotic origins of SARS-CoV-2 and discuss risks of zoonosis at the human-primate interface. We then identify challenges that the pandemic has caused for primates, including reduced nutrition, increased intraspecific competition, and increased poaching risk, as well as challenges facing primatologists, including lost research opportunities. Subsequently, we highlight opportunities arising from pandemic-related lockdowns and public health messaging, including opportunities to reduce the intensity of problematic human-primate interfaces, opportunities to reduce the risk of zoonosis between humans and primates, opportunities to reduce legal and illegal trade in primates, new opportunities for research on human-primate interfaces, and opportunities for community education. Finally, we recommend specific actions that primatologists should take to reduce contact and aggression between humans and primates, to reduce demand for primates as pets, to reduce risks of zoonosis in the context of field research, and to improve understanding of human-primate interfaces. Reducing the risk of zoonosis and promoting the wellbeing of humans and primates at our interfaces will require substantial changes from "business as usual." We encourage primatologists to help lead the way.

Activity budget of Southern pigtailed macaques (Macaca nemestrina) in rainforest and oil palm plantations

Rattan (Calamoideae) Diversity and Biomass Change in Different Habitat Types During Two Years

tropical life sciences research, 2017

highest similarity in swamp: plot BC(2011) 0.484, BC(2013) 0.262) and biomass were highest for st... more highest similarity in swamp: plot BC(2011) 0.484, BC(2013) 0.262) and biomass were highest for study plots with the same vegetation types in both years. For rattan biomass, the most similar plot pairs changed during the years: dipterocarp plots A and D were most similar in 2011 (0.509), and swamp plots B and C were most similar in 2013 (0.282). This study helped contribute information regarding the distribution and dynamics of rattans in a primary rainforest of Peninsular Malaysia.

First record of interspecies grooming between Raffles’ Banded Langur and Long-tailed Macaque

Journal of Threatened Taxa, Aug 26, 2021

who focuses on primate ecology and behaviour. He is a trained environmental scientist with intere... more who focuses on primate ecology and behaviour. He is a trained environmental scientist with interest in spatial ecology and conservation of wildlife and their habitats. Andie Ang is a primatologist studying Asian colobines and chairing the Raffles' Banded Langurs Working Group, Singapore. She is a research scientist with Mandai Nature and a visiting researcher to School of Biological Sciences, Universiti Sains Malaysia and member of the IUCN SSC Primate Specialist Group (Asia). Nadine Ruppert is a zoologist focusing on primates, humanwildlife interactions, plant-animal interactions, and conservation issues related to Malaysia. She is a senior lecturer at Universiti Sains Malaysia, vice president of the Malaysian Primatological Society and member of the IUCN SSC Primate Specialist Group Section on Small Apes.

Activity Budgets and Habitat Use of Wild Southern Pig-Tailed Macaques (Macaca nemestrina) in Oil Palm Plantation and Forest

International Journal of Primatology, Apr 1, 2018

Conversion of primary rainforest to agricultural land causes habitat loss and fragmentation and i... more Conversion of primary rainforest to agricultural land causes habitat loss and fragmentation and is a major threat to wild primates worldwide. Conversion of forest to oil palm plantations (Elaeis guineensis) is a particular problem, so it is important to understand whether and how primates use such plantations. Populations of southern pig-tailed macaques (Macaca nemestrina) are declining in Peninsular Malaysia due, in large part, to conversion of primary forests to oil palm plantations. Researchers have observed macaques foraging in plantations but little information is available about how macaques cope with the expansion of plantations into their habitat. We collected GPS data on the home range of a group of wild pig-tailed macaques that foraged in both habitat types in May 2013–May 2015, and compared their use of oil palm plantation and primary rainforest by recording their activity budgets and analyzing their habitat use and diet in both habitat types 4–6 days per week in October 2014–December 2015. The group visited the plantations daily. In 2013–2014, 17% of the group’s overall home range core area (0.6 km2) was in oil palm plantations and in 2014–2015, this increased to 28%. However, the macaques spent most of the day time in the forest and always used a sleeping tree in the forest. Macaque activity budgets in the plantation were significantly different from those in the forest. Feeding and foraging comprised a significantly larger proportion of their activity budget in the plantation, while locomotion, resting, and social behaviors occurred significantly more often in the forest. In both habitats, macaques spent most of their time on the ground and foraged primarily on the ground in the plantation. Of food items eaten in the plantation 85% were oil palm parts, including attached and fallen oil palm fruits and seeds, and flowers. Oil palm plantations serve as additional foraging ground for these macaques, but our results also show that the forest is essential, providing a greater dietary diversity and sleeping sites and allowing resting and social activities. It is not clear to what degree pig-tailed macaque populations can adapt to human-altered environments in the long term. Although our study group used oil palm plantations as regular foraging and feeding ground, pig-tailed macaques are also closely associated with the rainforest habitat, and the protection of natural forest is essential for their conservation.

Implementing network approaches to understand the socioecology of human-wildlife interactions

Implementing network approaches to understand the socioecology of human-wildlife interactions.

Is Malaysia’s “mystery monkey” a hybrid between Nasalis larvatus and Trachypithecus cristatus? An assessment of photographs

International Journal of Primatology, Apr 26, 2022

Interspecific hybridization in primates is common but hybridization between distantly related sym... more Interspecific hybridization in primates is common but hybridization between distantly related sympatric primate species is rarely observed in the wild. We present evidence for a possible hybridization event between Nasalis larvatus and Trachypithecus cristatus in the Lower Kinabatangan Wildlife Sanctuary, Sabah, through assessment of photographs. We used a set of categorical characters and metric measurements to compare the putative hybrid with the likely parent species. Nonmetric comparison showed that this "mystery monkey" is intermediate in several characters. Measurements of limb proportions on photographs showed that the brachial, humerofemoral, and intermembral indexes are above 100 for N. larvatus and below 100 for T. cristatus on all photographs, whereas the crural index is higher than 100 in both species and the distributions of this index in the two species overlap. Brachial and intermembral indices of the putative hybrid were similar to those of N. larvatus. Crural and humerofemoral indices were closer to the values for T. cristatus than those of N. larvatus. Multiple observers confirmed the occurrence of mixedspecies groups in the area, and interspecific mating has been photographed. The putative hybrid is now an adult female and was last photographed in September 2020 with an infant and swollen breast, suggesting lactation. We propose further noninvasive fecal sampling for genetic analyses to confirm the origins of this "mystery monkey." This case of hybridization may be related to anthropogenic changes to the landscape, whereby expansion of oil palm plantations confines N. larvatus and T. obscurus to narrow riverine forest patches along the Kinabatangan. This observation therefore also may have conservation implications, indicating limited mate access and dispersal opportunities for these threatened primates.

Primate research and conservation in Malaysia

Cab Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2019

Malaysia is inhabited by ≥25 nonhuman primate species from five families, one of the most diverse... more Malaysia is inhabited by ≥25 nonhuman primate species from five families, one of the most diverse primate faunas on earth. Unfortunately, most Malaysian primates are threatened with extinction due to habitat loss, degradation, and fragmentation, hunting and the synergies among these processes. Here, we review research on primates and issues related to their conservation in Malaysia. Despite the charisma and cultural importance of primates, the importance of primates in ecological processes such as seed dispersal, and the robust development of biodiversityrelated sciences in Malaysia, relatively little research specifically focused on wild primates has been conducted in Malaysia since the 1980s. Forest clearing for plantation agriculture has been a primary driver of forest loss and fragmentation in Malaysia. Selective logging also has primarily negative impacts on primates, but these impacts vary across primate taxa, and previously-logged forests are important habitats for many Malaysian primates. Malaysia is crossed by a dense road network, which fragments primate habitats, facilitates further human encroachment into forested areas and causes substantial mortality due to road kills. Primates in Malaysia are hunted for food or as pests, trapped for translocation due to wildlife-human conflict and hunted and trapped for illegal trade as pets. Further research on the distribution, abundance, ecology and behavioural biology of Malaysian primates is needed to inform effective management plans. Outreach and education are also essential to reduce primate-human conflict and demand for primates as pets. Ultimately, researchers, civil organizations, governmental authorities and local and indigenous communities in Malaysia must work together to develop, promote and implement effective strategies for protecting Malaysian primates and their habitats.

Oil Palm Cultivation Critically Affects Sociality in an Endangered Malaysian Primate

Research Square (Research Square), Dec 21, 2020

Of pig-tails and palm oil: How rat-eating macaques increase oil palm sustainability

TheScienceBreaker, 2020

Implementing social network analysis to understand the socioecology of wildlife co‐occurrence and joint interactions with humans in anthropogenic environments

Journal of Animal Ecology, Sep 6, 2021

Implementing social network analysis to understand the socio-ecology of wildlife cooccurrence and... more

The dual defensive strategy of <i>Amorphophallus</i> throughout its ontogeny

Plant Signaling & Behavior, Sep 21, 2017

Amorphophallus bufo is a rarely studied plant in Malaysian tropical rainforests. We measured the ... more Amorphophallus bufo is a rarely studied plant in Malaysian tropical rainforests. We measured the spectral reflectance of different developmental stages of A. bufo (seedlings, juveniles and adults), background soil/ debris and leaves from other neighboring plant species. Results show that the leaves of A. bufo seedling have a similar reflectance curve as the background soil and debris. Adults and juveniles of A. bufo are similar to other neighboring plants' leaf colors. We hypothesize that the cryptic coloration of A. bufo seedlings plays an important role in camouflage and that the numerous black spots on the surface of the petioles and rachises, may serve as a defensive mimicry against herbivores.

Recommendations for the establishment of a trans-island canopy bridge network to support primate movement across Langkawi Island, Malaysia

Oryx

The expansion of transportation and service corridors has numerous, well-documented adverse effec... more The expansion of transportation and service corridors has numerous, well-documented adverse effects on wildlife. However, little research on this topic has been translated into mitigating the effects of habitat fragmentation caused by road development on primates. The establishment of canopy bridges has proven to be an effective conservation intervention. Of the completed primate canopy bridge projects reported in the literature, to our knowledge, all attempt to mitigate the impacts caused by singular, linear infrastructure routes. Here we provide recommendations for the establishment of a network of natural and artificial canopy bridges over roads throughout Langkawi Island, Malaysia, to reduce rates of roadkill and support the movement of primates and other arboreal animals across the island by identifying suitable sites and appropriate tree species to be planted (including Ficus racemosa and Ficus fistulosa), bridge materials and post-installation monitoring. The establishment of...

Rattan litter-collecting structures attract nest-building and defending ants

Plant Signaling & Behavior, May 27, 2019

Rattan is an important climbing palm taxon in Malaysian tropical rain forests. Many rattan specie... more Rattan is an important climbing palm taxon in Malaysian tropical rain forests. Many rattan species have unique structures directly associated with certain ant species. In this study, four rattan species (Daemonorops lewisiana, Calamus castaneus, Daemonorops geniculata and Korthalsia scortechinii) were inspected and documented in a field survey concerning their relationships with several ant species. We noticed that two rattan species (D. lewisiana and C. castaneus) were more likely to be associated with ants compared to their neighbouring rattan (Plectomia griffithii). However, D. lewisiana and C. castaneus did not directly provide shelters for ant colonies, but possessed unique structures: upward-pointing spines and funnel-shaped leaves, which are equipped to collect more litter than P. griffithii. To test our litter collecting hypothesis, we measured the inclination of spines from the stem. Our results showed the presence of ant colonies in the litter-collecting rattans (D. lewisiana and C. castaneus), which was significantly higher compared to a non-litter-collecting rattan (P. griffithii). We propose a complex and novel type of adaptation (litter-collection and provision of nesting materials) for rattans, which promotes interactions between the rattan and ants through the arrangements of leaves, leaflets, and spines. In return, the rattan may benefit from ants' services, such as protection, nutrient enhancement, and pollination.

“Ah Lai’s Crossing” – Malaysia’s first artificial road canopy bridge to facilitate safer arboreal wildlife crossings

Folia Primatologica, Mar 30, 2022

Roads negatively affect wildlife populations globally, causing habitat fragmentation that can fac... more Roads negatively affect wildlife populations globally, causing habitat fragmentation that can facilitate mortality by access to forest for poaching and wildlife collisions with vehicles. Primate habitats are vulnerable to fragmentation exposing them to anthropogenic threats. Endangered dusky langurs (Trachypithecus obscurus) in Malaysia are often found in urban areas and have been frequent victims of vehicle collisions. To mitigate the hazardous impact of a busy asphalt road on wild dusky langurs in Teluk Bahang, Penang, we built the first artificial road canopy bridge in Malaysia in February 2019 to assist arboreal wildlife to move between habitat fragments more safely. Four days after the bridge construction, the first long-tailed macaque (Macaca fascicularis) was recorded via a camera trap crossing the bridge, and plantain squirrels (Callosciurus notatus) and dusky langurs first crossed one and eight months later, respectively. The bridge was upgraded from a single-firehose rope to a double-rope in August 2020 to assess the effectiveness of the two designs. In total, 2128 animal crossings comprising three mammal species were recorded between March 2019 and May 2021. Plantain squirrels crossed the bridge most frequently with 2075 crossings, long-tailed macaques crossed 32 times, and dusky langurs 21 times. There was a significant difference in bridge use according to species between the two designs (Chi-Square, p &lt; 0.001). Since the construction of the bridge, the rate of previously frequently reported primate roadkills near the bridge location has dropped to zero. This successful pilot project has spurred the efforts to implement more canopy bridges country-wide to support primate conservation efforts and better protect arboreal wildlife from the negative impacts of linear infrastructure.

Oil palm cultivation critically affects sociality in an endangered Malaysian primate

Authorea (Authorea), Oct 26, 2020

Rattan (Calamoideae) abundance and above-ground biomass at a primary rainforest of Peninsular Malaysia

Plant Ecology & Diversity, Sep 4, 2015

Background: Rattans are widespread throughout paleo-tropical forests; however, there is no inform... more Background: Rattans are widespread throughout paleo-tropical forests; however, there is no information on their contribution to above-ground biomass (AGB). Aims: This study established biomass baseline values for 11 different rattan species in a Malaysian primary forest, and calculated the overall rattan AGB contribution and dynamics during two years. Methods: All rattan stems in five 100 m × 100 m study plots were counted in 2011 and 2013. Biometric non-invasive measurements were carried out on 11 climbing and non-climbing species and total rattan biomass for both years calculated was compared. Results: Rattans contributed with 3.1 Mg ha−1 to the forest AGB. There was no significant change in rattan biomass between the years. Conclusions: These preliminary results are the first published on the AGB contribution of rattans to Malaysian primary forests. Further studies are required to ascertain values across forest types and over time to reliably estimate the contribution of rattan species to ABG and carbon sequestration.

Mother-Infant Interactions in a Wild Population of Macaca nemestrina (Linnaeus)

Until now, mother-infant relationships have not been studied in a wild population of the Southern... more Until now, mother-infant relationships have not been studied in a wild population of the Southern Pig-tailed Macaques Macaca nemestrina. We observed six mother-infant dyads from April 2016 to September 2016 in the Segari Melintang Forest Reserve, Peninsular Malaysia using focal sampling methods from the perspectives of both individuals. We hypothesized that as infant age increased, the same important mother-infant behaviours, previously observed to change in captive pig-tailed macaque mother-infant studies, would also change over time in field conditions. We expected that as the infant ages, mothers would decrease their rates of restraint and retrieval, and increase their rates of punishment. Two separate generalized linear mixed models (GLMM) of mother permissive behaviour and mother-infant contact duration as the outcome variables each showed infant age as the sole significant predictor variable indicating that as infant age increased, maternal behaviours changed as expected above, and mother-infant contact duration decreased. Mothers' interactions with other group members appeared influenced by mothers' associations with their offspring: adult females and juveniles were significantly more likely to be within 1-5 m proximity of mothers as infant age increased. Our data show that mother permissive behaviour, mother-infant contact duration, and proximity are crucial elements to consider when examining wild Southern Pig-tailed Macaque mother-infant relationships and infant independence, similar to what has been observed in captive settings.

Are social media reports useful for assessing small ape occurrence? A pilot study from Peninsular Malaysia

American Journal of Primatology, Feb 21, 2020

Citizen science-based research has been used effectively to estimate animal abundance and breedin... more Citizen science-based research has been used effectively to estimate animal abundance and breeding patterns, to monitor animal movement, and for biodiversity conservation and education. Here, we evaluate the feasibility of using social media observations to assess the distribution of small apes in Peninsular Malaysia. We searched for reports of small ape observations in Peninsular Malaysia on social media (e.g., blogs, Facebook, Instagram, Twitter, YouTube, iNaturalist, etc.), and also used online, radio, print messaging, and word of mouth to invite citizen scientists such as birders, amateur naturalists, hikers, and other members of the public to provide information about small ape observations made during their activities. These reports provided new information about the occurrence of all three species of small apes (Hylobates agilis, Hylobates lar, and Symphalangus syndactylus) in Peninsular Malaysia. Social media users reported observations of small apes in almost every state. Despite the fact that small apes are believed to occur primarily in the interior of large forested areas, most observations were from fairly small (<100 km 2) forests near areas of high traffic and high human population (roads and urban areas). This suggests that most outdoor enthusiasts primarily visit well-traveled and easily accessible areas, which results in biased sampling if only incidental observations reported on social media are used. A more targeted approach specifically soliciting reports from citizen scientists visiting large, less-accessible forests may result in better sampling in these habitats. Social media reports indicated the presence of small apes in at least six habitats where they had not been previously reported. We verified the reported data based on whether reports included a date, location, and uploaded photographs, videos and/or audio recordings. Well-publicized citizen science programs may also build awareness and enthusiasm about the conservation of vulnerable wildlife species.

Time constraints imposed by anthropogenic environments alter social behaviour in longtailed macaques

Animal Behaviour, Apr 1, 2019

Humans and their associated anthropogenic factors may strongly affect the demographics, activity,... more Humans and their associated anthropogenic factors may strongly affect the demographics, activity, and fragmentation of wild animal populations. Yet, the degree and nature of such impact on indicators of animals' social relationships remain largely under-investigated, despite the well-documented importance of strong social ties for an individuals' health and fitness. Here, we examined whether interactions with humans may affect core aspects of social life in a primate species, by constraining the time available for individuals to engage in social interactions. Specifically, we predicted that individuals who spent more time monitoring or interacting with humans reduce their time socializing with conspecifics (i.e., the time constraints hypothesis). Alternatively, human presence may result in increased levels of stress, leading to an increase in social behaviours which serve as a coping mechanism (i.e., the social stress hypothesis). We collected data between September 2016 and September 2017 on four groups of long-tailed macaques in Malaysia at two sites with differing levels of human impact. In support of the time constraints hypothesis, we found that at the site with moderate human impact, monkeys who monitored human activity more frequently engaged less often in grooming. In contrast, at the site with high human impact, we found evidence supporting the social stress hypothesis, as indicators of stress were positively associated with social interactions, although we could not link them to the presence of humans. Our results suggest that the nature of human impact on macaques' social behaviour is dependent upon the intensity of human activity and interaction with the macaques. These findings therefore provide insights into how humans may influence individual fitness and group social structure in animals living in an anthropogenic environment. More broadly, our results may lead to a better understanding of animal behaviour in anthropogenic environments, implementing conservation and population management strategies, and mitigating human-wildlife conflict.

The human–primate interface in the New Normal: Challenges and opportunities for primatologists in the COVID‐19 era and beyond

American Journal of Primatology, Jul 20, 2020

The emergence of SARS-CoV-2 in late 2019 and human responses to the resulting COVID-19 pandemic i... more The emergence of SARS-CoV-2 in late 2019 and human responses to the resulting COVID-19 pandemic in early 2020 have rapidly changed many aspects of human behavior, including our interactions with wildlife. In this commentary, we identify challenges and opportunities at human-primate interfaces in light of COVID-19, focusing on examples from Asia, and make recommendations for researchers working with wild primates to reduce zoonosis risk and leverage research opportunities. First, we briefly review the evidence for zoonotic origins of SARS-CoV-2 and discuss risks of zoonosis at the human-primate interface. We then identify challenges that the pandemic has caused for primates, including reduced nutrition, increased intraspecific competition, and increased poaching risk, as well as challenges facing primatologists, including lost research opportunities. Subsequently, we highlight opportunities arising from pandemic-related lockdowns and public health messaging, including opportunities to reduce the intensity of problematic human-primate interfaces, opportunities to reduce the risk of zoonosis between humans and primates, opportunities to reduce legal and illegal trade in primates, new opportunities for research on human-primate interfaces, and opportunities for community education. Finally, we recommend specific actions that primatologists should take to reduce contact and aggression between humans and primates, to reduce demand for primates as pets, to reduce risks of zoonosis in the context of field research, and to improve understanding of human-primate interfaces. Reducing the risk of zoonosis and promoting the wellbeing of humans and primates at our interfaces will require substantial changes from "business as usual." We encourage primatologists to help lead the way.

Activity budget of Southern pigtailed macaques (Macaca nemestrina) in rainforest and oil palm plantations

Rattan (Calamoideae) Diversity and Biomass Change in Different Habitat Types During Two Years

tropical life sciences research, 2017

highest similarity in swamp: plot BC(2011) 0.484, BC(2013) 0.262) and biomass were highest for st... more highest similarity in swamp: plot BC(2011) 0.484, BC(2013) 0.262) and biomass were highest for study plots with the same vegetation types in both years. For rattan biomass, the most similar plot pairs changed during the years: dipterocarp plots A and D were most similar in 2011 (0.509), and swamp plots B and C were most similar in 2013 (0.282). This study helped contribute information regarding the distribution and dynamics of rattans in a primary rainforest of Peninsular Malaysia.

First record of interspecies grooming between Raffles’ Banded Langur and Long-tailed Macaque

Journal of Threatened Taxa, Aug 26, 2021

who focuses on primate ecology and behaviour. He is a trained environmental scientist with intere... more who focuses on primate ecology and behaviour. He is a trained environmental scientist with interest in spatial ecology and conservation of wildlife and their habitats. Andie Ang is a primatologist studying Asian colobines and chairing the Raffles' Banded Langurs Working Group, Singapore. She is a research scientist with Mandai Nature and a visiting researcher to School of Biological Sciences, Universiti Sains Malaysia and member of the IUCN SSC Primate Specialist Group (Asia). Nadine Ruppert is a zoologist focusing on primates, humanwildlife interactions, plant-animal interactions, and conservation issues related to Malaysia. She is a senior lecturer at Universiti Sains Malaysia, vice president of the Malaysian Primatological Society and member of the IUCN SSC Primate Specialist Group Section on Small Apes.

Activity Budgets and Habitat Use of Wild Southern Pig-Tailed Macaques (Macaca nemestrina) in Oil Palm Plantation and Forest

International Journal of Primatology, Apr 1, 2018

Conversion of primary rainforest to agricultural land causes habitat loss and fragmentation and i... more Conversion of primary rainforest to agricultural land causes habitat loss and fragmentation and is a major threat to wild primates worldwide. Conversion of forest to oil palm plantations (Elaeis guineensis) is a particular problem, so it is important to understand whether and how primates use such plantations. Populations of southern pig-tailed macaques (Macaca nemestrina) are declining in Peninsular Malaysia due, in large part, to conversion of primary forests to oil palm plantations. Researchers have observed macaques foraging in plantations but little information is available about how macaques cope with the expansion of plantations into their habitat. We collected GPS data on the home range of a group of wild pig-tailed macaques that foraged in both habitat types in May 2013–May 2015, and compared their use of oil palm plantation and primary rainforest by recording their activity budgets and analyzing their habitat use and diet in both habitat types 4–6 days per week in October 2014–December 2015. The group visited the plantations daily. In 2013–2014, 17% of the group’s overall home range core area (0.6 km2) was in oil palm plantations and in 2014–2015, this increased to 28%. However, the macaques spent most of the day time in the forest and always used a sleeping tree in the forest. Macaque activity budgets in the plantation were significantly different from those in the forest. Feeding and foraging comprised a significantly larger proportion of their activity budget in the plantation, while locomotion, resting, and social behaviors occurred significantly more often in the forest. In both habitats, macaques spent most of their time on the ground and foraged primarily on the ground in the plantation. Of food items eaten in the plantation 85% were oil palm parts, including attached and fallen oil palm fruits and seeds, and flowers. Oil palm plantations serve as additional foraging ground for these macaques, but our results also show that the forest is essential, providing a greater dietary diversity and sleeping sites and allowing resting and social activities. It is not clear to what degree pig-tailed macaque populations can adapt to human-altered environments in the long term. Although our study group used oil palm plantations as regular foraging and feeding ground, pig-tailed macaques are also closely associated with the rainforest habitat, and the protection of natural forest is essential for their conservation.

Implementing network approaches to understand the socioecology of human-wildlife interactions

Implementing network approaches to understand the socioecology of human-wildlife interactions.

Is Malaysia’s “mystery monkey” a hybrid between Nasalis larvatus and Trachypithecus cristatus? An assessment of photographs

International Journal of Primatology, Apr 26, 2022

Interspecific hybridization in primates is common but hybridization between distantly related sym... more Interspecific hybridization in primates is common but hybridization between distantly related sympatric primate species is rarely observed in the wild. We present evidence for a possible hybridization event between Nasalis larvatus and Trachypithecus cristatus in the Lower Kinabatangan Wildlife Sanctuary, Sabah, through assessment of photographs. We used a set of categorical characters and metric measurements to compare the putative hybrid with the likely parent species. Nonmetric comparison showed that this "mystery monkey" is intermediate in several characters. Measurements of limb proportions on photographs showed that the brachial, humerofemoral, and intermembral indexes are above 100 for N. larvatus and below 100 for T. cristatus on all photographs, whereas the crural index is higher than 100 in both species and the distributions of this index in the two species overlap. Brachial and intermembral indices of the putative hybrid were similar to those of N. larvatus. Crural and humerofemoral indices were closer to the values for T. cristatus than those of N. larvatus. Multiple observers confirmed the occurrence of mixedspecies groups in the area, and interspecific mating has been photographed. The putative hybrid is now an adult female and was last photographed in September 2020 with an infant and swollen breast, suggesting lactation. We propose further noninvasive fecal sampling for genetic analyses to confirm the origins of this "mystery monkey." This case of hybridization may be related to anthropogenic changes to the landscape, whereby expansion of oil palm plantations confines N. larvatus and T. obscurus to narrow riverine forest patches along the Kinabatangan. This observation therefore also may have conservation implications, indicating limited mate access and dispersal opportunities for these threatened primates.

Primate research and conservation in Malaysia

Cab Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2019

Malaysia is inhabited by ≥25 nonhuman primate species from five families, one of the most diverse... more Malaysia is inhabited by ≥25 nonhuman primate species from five families, one of the most diverse primate faunas on earth. Unfortunately, most Malaysian primates are threatened with extinction due to habitat loss, degradation, and fragmentation, hunting and the synergies among these processes. Here, we review research on primates and issues related to their conservation in Malaysia. Despite the charisma and cultural importance of primates, the importance of primates in ecological processes such as seed dispersal, and the robust development of biodiversityrelated sciences in Malaysia, relatively little research specifically focused on wild primates has been conducted in Malaysia since the 1980s. Forest clearing for plantation agriculture has been a primary driver of forest loss and fragmentation in Malaysia. Selective logging also has primarily negative impacts on primates, but these impacts vary across primate taxa, and previously-logged forests are important habitats for many Malaysian primates. Malaysia is crossed by a dense road network, which fragments primate habitats, facilitates further human encroachment into forested areas and causes substantial mortality due to road kills. Primates in Malaysia are hunted for food or as pests, trapped for translocation due to wildlife-human conflict and hunted and trapped for illegal trade as pets. Further research on the distribution, abundance, ecology and behavioural biology of Malaysian primates is needed to inform effective management plans. Outreach and education are also essential to reduce primate-human conflict and demand for primates as pets. Ultimately, researchers, civil organizations, governmental authorities and local and indigenous communities in Malaysia must work together to develop, promote and implement effective strategies for protecting Malaysian primates and their habitats.

Oil Palm Cultivation Critically Affects Sociality in an Endangered Malaysian Primate

Research Square (Research Square), Dec 21, 2020

Of pig-tails and palm oil: How rat-eating macaques increase oil palm sustainability

TheScienceBreaker, 2020

Implementing social network analysis to understand the socioecology of wildlife co‐occurrence and joint interactions with humans in anthropogenic environments

Journal of Animal Ecology, Sep 6, 2021

Implementing social network analysis to understand the socio-ecology of wildlife cooccurrence and... more

The dual defensive strategy of <i>Amorphophallus</i> throughout its ontogeny

Plant Signaling & Behavior, Sep 21, 2017

Amorphophallus bufo is a rarely studied plant in Malaysian tropical rainforests. We measured the ... more Amorphophallus bufo is a rarely studied plant in Malaysian tropical rainforests. We measured the spectral reflectance of different developmental stages of A. bufo (seedlings, juveniles and adults), background soil/ debris and leaves from other neighboring plant species. Results show that the leaves of A. bufo seedling have a similar reflectance curve as the background soil and debris. Adults and juveniles of A. bufo are similar to other neighboring plants' leaf colors. We hypothesize that the cryptic coloration of A. bufo seedlings plays an important role in camouflage and that the numerous black spots on the surface of the petioles and rachises, may serve as a defensive mimicry against herbivores.

Urban canopy bridges to mitigate human wildlife conflicts

National Conference on Urban Pest NCUP2.0, 2019

Urbanization causes loss of wildlife habitats. In Penang Island, especially primates are threaten... more Urbanization causes loss of wildlife habitats. In Penang Island, especially primates are threatened by habitat loss and fragmentation. They can often be observed feeding by the roadside, in residential areas, orchards or plantations. This may cause conflicts as wildlife moves into residential areas but it also poses a risk to the animals who are exposed to road kills, aggression and disease transmission. Therefore, we are developing a conservation strategy for arboreal animals in urban areas to mitigate the negative effects of habitat fragmentation. We have recently set up the first arboreal wildlife bridge made of recycled firehoses in an urban setting in Malaysia. By using camera traps and direct observations, we are going to monitor the effectiveness of the bridge and, if proven successful, we will propose this model to be used in other high-risk areas in Malaysia.