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Lawson J, Rizos G, Jasinghe D, Whitworth A, Schuller B, Banks-Leite C. Automated acoustic detection of Geoffroy's spider monkey highlights tipping points of human disturbance. Proc Biol Sci 2023; 290:20222473. [PMID: 36919432 PMCID: PMC10015327 DOI: 10.1098/rspb.2022.2473] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
As more land is altered by human activity and more species become at risk of extinction, it is essential that we understand the requirements for conserving threatened species across human-modified landscapes. Owing to their rarity and often sparse distributions, threatened species can be difficult to study and efficient methods to sample them across wide temporal and spatial scales have been lacking. Passive acoustic monitoring (PAM) is increasingly recognized as an efficient method for collecting data on vocal species; however, the development of automated species detectors required to analyse large amounts of acoustic data is not keeping pace. Here, we collected 35 805 h of acoustic data across 341 sites in a region over 1000 km2 to show that PAM, together with a newly developed automated detector, is able to successfully detect the endangered Geoffroy's spider monkey (Ateles geoffroyi), allowing us to show that Geoffroy's spider monkey was absent below a threshold of 80% forest cover and within 1 km of primary paved roads and occurred equally in old growth and secondary forests. We discuss how this methodology circumvents many of the existing issues in traditional sampling methods and can be highly successful in the study of vocally rare or threatened species. Our results provide tools and knowledge for setting targets and developing conservation strategies for the protection of Geoffroy's spider monkey.
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Affiliation(s)
- Jenna Lawson
- Grantham Institute, Imperial College London, UK.,Department of Life Sciences, Imperial College London, UK
| | - George Rizos
- GLAM - Group on Language, Audio, & Music, Imperial College London, UK
| | - Dui Jasinghe
- Department of Life Sciences, Imperial College London, UK
| | - Andrew Whitworth
- Osa Conservation, Conservation Science Team, Washington, DC 20005, USA.,Institute of Biodiversity, Animal Health, and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.,Department of Biology, Center for Energy, Environment, and Sustainability, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Björn Schuller
- GLAM - Group on Language, Audio, & Music, Imperial College London, UK.,EIHW - Chair of Embedded Intelligence for Health Care and Wellbeing, University of Augsburg, Augsburg, Germany
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Aggimarangsee N, Tiansawat P, Brockelman WY. Can electrical wires serve as canopy bridges? A case study of the dusky langur (Trachypithecus obscurus) in Thailand. Folia Primatol (Basel) 2022. [DOI: 10.1163/14219980-20211205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
In many parts of the world, primates and other arboreal and semi-arboreal species use electrical and telecommunication cables to cross open gaps. However, electrocutions can occur when the cables are uninsulated or damaged. Between 2001 and 2002, during a 12-month behavioural study of two dusky langur groups (Trachypithecus obscurus) at the Royal Thai Air Force Base in Prachuap Khiri Khan Province, peninsular Thailand, we recorded langur use of and mortality on electrical and telecommunications cables on an ad libitum basis. Before insulation of the cables in late 2001, five langurs died by electrocution; post insulation, that number decreased to only one case on March 5, 2002. In 2022, we returned to observe the langur groups and saw them continuing to use the cables for crossing and noted damage to the insulation, indicating the importance of maintenance. Electrical cables can provide canopy connectivity for langurs and prevent dangerous encounters with dogs on the ground, but cables must be insulated and inspected regularly. As additional mitigation measures, we suggest providing alternative substrates for travel such as planting more native trees and providing artificial canopy bridges.
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Affiliation(s)
- Nantiya Aggimarangsee
- Behaviour and Ecology of Vertebrates Research Laboratory (BEVRL), Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Pimonrat Tiansawat
- Environmental Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
- Forest Restoration Research Unit, Department of Biology, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Warren Y. Brockelman
- National Biobank of Thailand, National Science and Technology Development Agency, Phaholyothin Road, Khlong Luang, Pathum Thani 12120, Thailand
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phutthamonthon 4 Road, Nakhon Pathom 73170, Thailand
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Saralamba C, José-Domínguez JM, Asensio N. Movement dynamics of gibbons after the construction of canopy bridges over a park road. Folia Primatol (Basel) 2022. [DOI: 10.1163/14219980-20211211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Gibbons (Hylobatidae) are species highly adapted to tree-top living. Thus, their movement can be compromised due to the negative impact roads have on canopy habitats. In this study, we built two single-rope artificial canopy bridges and a ladder bridge at two out of five locations where a group of white-handed gibbons (Hylobates lar) in Khao Yai National Park, Thailand were known to cross a main park road. We compared road crossing frequencies, home-range characteristics, and other ad libitum observations during the periods before and after bridge installation. After bridge construction was complete, the group took 10 weeks to use the single rope bridges to navigate over the road. During 442 group follow observation hours and 539 bridge observation hours, 131 crosses over the road were observed. The adult female usually crossed the road first, and the group showed a clear preference for the single-rope bridges over the ladder bridge (92 crossings versus 5). Gibbons crossed the road approximately once a day and crossed mostly at the bridge locations both before and after bridge construction. There were not significant changes in crossing rates from before (crossing between the tree branches and on the ground) to after bridge installation at both the places where bridges were installed (crossing using the bridges). Nonetheless, with more crossings being in the bridges than on the ground after bridge installation, crossings were presumably safer. These findings suggest that gibbons will cross a road on the ground, risking predation, encountering people, or being hit by a vehicle, but artificial canopy bridges provided a safer crossing option since gibbons no longer crossed on the road or jumped across wide gaps at the two locations where bridges were constructed. Maintaining canopy connectivity over roads using artificial bridges logically improves home range connectivity, potentially gene flow, and safety of canopy dwellers. However, connecting areas which were not previously connected should be considered carefully. The new connection could disrupt group dynamics, particularly for species that defend territories, such as gibbons.
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Affiliation(s)
- Chanpen Saralamba
- Conservation Biology Program, School of Interdisciplinary Studies, Mahidol University, Kanchanaburi, 71150, Thailand
| | - Juan Manuel José-Domínguez
- Physical Anthropology Laboratory, Department of Legal Medicine, Toxicology and Physical Anthropology, University of Granada, Avda. de la Investigación, 18016 Granada, Spain
- Conservation Ecology Program, King Mongkut’s University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Norberto Asensio
- Department of Clinical and Health Psychology and Research Methodology, Faculty of Psychology, University of the Basque Country, 20018 Donostia, Gipuzkoa, Spain
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Pang YH, Lappan S, Bartlett TQ, Mohd Sah SA, N Rosely NF, Ruppert N. Population densities of Hylobates agilis in forests with different disturbance histories in Ulu Muda Forest Reserve, Malaysia. Am J Primatol 2022; 84:e23388. [PMID: 35521672 PMCID: PMC9541461 DOI: 10.1002/ajp.23388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 04/05/2022] [Accepted: 04/17/2022] [Indexed: 12/03/2022]
Abstract
Small ape habitat throughout Malaysia is rapidly being lost, degraded, and fragmented, and the effects of these changes on the abundance on this taxon are currently unknown. This study assessed the group density of Hylobates agilis in virgin forest, previously logged forest (1960s–1990s), and recently logged forest (2015–2017) of the Ulu Muda Forest Reserve (UMFR), Kedah, Malaysia. We conducted fixed‐point active acoustic triangulation at nine survey areas to estimate group density. We used vegetation “speed plots” and satellite imagery to quantify habitat characteristics and used model selection to identify ecological predictors of group density variation. The estimated group density of H. agilis in UMFR was 4.03 ± 0.14 groups km−2, with an estimated total of 2927 ± 102 groups in areas below 450 m a.s.l. in UMFR. Group density did not differ significantly among habitat types. The best ecological predictors for group density were canopy cover and proportion of deforested area. Areas with recent deforestation were associated with relatively high group densities, suggesting compression of the populations persisting in these habitat types. The consistently high group densities detected in all forest types emphasizes the importance of degraded forest as habitat for H. agilis. Because of the threats to small apes in Malaysia, and the uncertain status of most populations, we recommend a nationwide population census and regular monitoring to inform conservation planning and implementation. Most urgently, we call for immediate and permanent protection of UMFR and other forests in the Greater Ulu Muda landscape to protect the globally significant populations of H. agilis, as well as other charismatic and threatened megafauna, birds, and flora in the area. This study estimates the population density of Hylobates agilis in Ulu Muda Forest Reserve, part of the largest remaining habitat for the species in mainland Asia. We estimate that lowland forests (<450 m a.s.l.) in Ulu Muda support 2972 ± 102 groups of H. agilis. Our data suggest that recently selectively logged forests support gibbon densities equal to those in undisturbed forest, demonstrating the importance of this landscape.
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Affiliation(s)
- Yi Heng Pang
- School of Biological Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.,Malaysian Primatological Society, Kulim, Kedah, Malaysia
| | - Susan Lappan
- School of Biological Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.,Malaysian Primatological Society, Kulim, Kedah, Malaysia.,Department of Anthropology, Appalachian State University, Boone, North Carolina, USA
| | - Thad Q Bartlett
- Malaysian Primatological Society, Kulim, Kedah, Malaysia.,Department of Anthropology, The University of Texas at San Antonio, San Antonio, Texas, USA
| | | | - Nik Fadzly N Rosely
- School of Biological Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia
| | - Nadine Ruppert
- School of Biological Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia.,Malaysian Primatological Society, Kulim, Kedah, Malaysia
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