An Application of Autonomous Recorders for Gibbon Monitoring

Vu, Thinh Tien; Tran, Long Manh

doi:10.1007/s10764-018-0073-3

Cited by 27 publications

(27 citation statements)

References 31 publications

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“…For vocal primates such as gibbons, morning vocalizations are a fundamental component of their behavior, and quantifying variation in calling behavior has important implications for understanding their ecology and for conservation. Although common in studies of behavior in marine mammals 56 , the use of PAM in primates has been limited, and the majority of studies relying on autonomous acoustic monitoring of primates have focused mostly on occurrence or presence/absence of calling animals 57,58 , and less on the potential for PAM to improve our understanding of primate behavior (but see 59 ). With the improvements in battery-life and data storage capabilities, the use of autonomous recorders has the potential to revolutionize how we study the social behavior of vocal animals 60 .…”

Section: Discussionmentioning

confidence: 99%

Gibbons aren’t singing in the rain: presence and amount of rainfall influences ape calling behavior in Sabah, Malaysia

Clink

Ahmad

Klinck

2020

Sci Rep

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Early morning calling occurs across diverse taxa, which may be related to optimal conditions for sound transmission. There exists substantial inter-and intra-specific variation in calling time which is influenced by intrinsic, social and/or environmental factors. Here, we investigate environmental predictors of calling in gibbons. We hypothesized that male solos-which occur earlier and tend to be longer than duets-would be more influenced by environmental variables, if earlier, longer calling bouts are energetically costly, and therefore limited by overnight energy expenditure. Our top model for male solo events included amount of rain in the previous 24 hours, and explained 30% of the variance, whereas the top model for duet events (which included presence and amount of rainfall) explained only 5% of the variance. Rain the previous night led to a later start time of male solos (~30 minutes), but our top model for duet start time did not include any reliable predictors. Male solo events appear to be more influenced by environmental factors, and duets may be influenced more by social factors. Our results are in line with previous studies that show that changes in overnight conditions-which may alter energy expenditure-can influence early morning calling behavior.

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Section: Discussionmentioning

confidence: 99%

Gibbons aren’t singing in the rain: presence and amount of rainfall influences ape calling behavior in Sabah, Malaysia

Clink

Ahmad

Klinck

2020

Sci Rep

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“…Simple occupancy models have been used to monitor gibbon population (Gray et al, 2010(Gray et al, , 2014, especially in the area with low and medium gibbon density (Vu & Tran, 2019). However, for longterm monitoring program, occurrence probability alone might not fully reveal the true dynamics going on with gibbon population in the forests.…”

Section: Discussionmentioning

confidence: 99%

“…Traditionally, conservationists have focused on estimating absolute gibbon density and population size from vocalization data (e.g., Brockelman & Ali, 1987;Brockelman & Srikosamatara, 1993). The methodological issues with approaches for estimating absolute gibbon density and population size in this way have been discussed in depth by several studies (Cheyne, Thompson, Phillips, Hill, & Suwido, 2008;Rawson, 2010;Vu & Tran, 2019). These methods require the observer to calculate accurate compass bearings and distance estimates for calling gibbon groups as well as differentiate different groups based on vocal characteristics and location data which all have inherent errors.…”

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confidence: 99%

Monitoring occurrence, extinction, and colonization probabilities for gibbon populations

Anh²,

Rawson³

et al. 2020

American J Primatol

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All gibbon species (Family: Hylobatidae) are considered threatened with extinction and recognized on the International Union for Conservation of Nature Red List of Threatened Species. Because gibbons are one of the most threatened families of primates, monitoring their status is now critically important. Long‐term monitoring programs applying occupancy approaches, in addition to assessing occurrence probability, improves understanding of other population parameters such as site extinction or colonization probabilities, which elucidate temporal and spatial changes and are therefore important for guiding conservation efforts. In this study, we used multiple season occupancy models to monitor occurrence, extinction, and colonization probabilities for northern yellow‐cheeked crested gibbon Nomascus annamensis in three adjacent protected areas in the Central Annamites mountain range, Vietnam. We collected data at 30 listening posts in 2012, 2014, and 2016 using the auditory point count method. Occurrence probabilities were highest in 2012 (0.74, confidence interval [CI]: 0.56–0.87) but slightly lower in 2014 (0.66, CI: 0.51–0.79) and 2016 (0.67, CI: 0.49–0.81). Extinction probabilities during the 2012–2014 and 2014–2016 intervals were 0.26 (0.14–0.44) and 0.25 (0.12–0.44), respectively. Colonization probabilities during 2012–2014 were 0.44 (0.19–0.73) and between 2014 and 2016 was 0.51 (0.26–0.75). Although local site extinctions have occurred, high recolonization probability helped to replenish the unoccupied sites and kept the occurrence probability stable. Long‐term monitoring programs which use occurrence probability alone might not fully reveal the true dynamics of gibbon populations. We strongly recommend including multiple season occupancy models to monitor occurrence, extinction, and colonization probabilities in long‐term gibbon monitoring programs.

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“…However, recent advances in bioacoustics have expanded the applications of acoustic sensors for terrestrial species (Blumstein et al, ; Wrege, Rowland, Keen, & Shiu, ). More recently, applications include the study of gibbons Nomascus gabbrielae (Vu & Tran, ), and wolves Canis lupus (Papin, Pichenot, Guérold, & Germain, ) among others. Both methods allow for diverse applications (Burton et al, ; Gibb, Browning, Glover‐Kapfer, & Jones, ; Sugai et al, ), ranging from revealing occurrence and occupancy (Campos‐Cerqueira & Aide, ; Rovero, Collett, Ricci, Martin, & Spitale, ), population size and density (e.g.…”

Section: Introductionmentioning

confidence: 99%

Listening and watching: Do camera traps or acoustic sensors more efficiently detect wild chimpanzees in an open habitat?

et al. 2020

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With one million animal species at risk of extinction, there is an urgent need to regularly monitor threatened species. However, in practice this is challenging, especially with wide‐ranging, elusive and cryptic species or those that occur at low density. Here we compare two non‐invasive methods, passive acoustic monitoring (n = 12) and camera trapping (n = 53), to detect chimpanzees Pan troglodytes in a savanna‐woodland mosaic habitat at the Issa Valley, Tanzania. With occupancy modelling we evaluate the efficacy of each method, using the estimated number of sampling days needed to establish chimpanzee absence with 95% probability, as our measure of efficacy. Passive acoustic monitoring was more efficient than camera trapping in detecting wild chimpanzees. Detectability varied over seasons, likely due to social and ecological factors that influence party size and vocalization rate. The acoustic method can infer chimpanzee absence with less than 10 days of recordings in the field during the late dry season, the period of highest detectability, which was five times faster than the visual method. Synthesis and applications. Despite some technical limitations, we demonstrate that passive acoustic monitoring is a powerful tool for species monitoring. Its applicability in evaluating presence/absence, especially but not exclusively for loud call species, such as cetaceans, elephants, gibbons or chimpanzees provides a more efficient way of monitoring populations and inform conservation plans to mediate species‐loss.

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An Application of Autonomous Recorders for Gibbon Monitoring

Cited by 27 publications

References 31 publications

Gibbons aren’t singing in the rain: presence and amount of rainfall influences ape calling behavior in Sabah, Malaysia

Gibbons aren’t singing in the rain: presence and amount of rainfall influences ape calling behavior in Sabah, Malaysia

Monitoring occurrence, extinction, and colonization probabilities for gibbon populations

Listening and watching: Do camera traps or acoustic sensors more efficiently detect wild chimpanzees in an open habitat?

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