Optimising Survey Strategies for the Endangered Romer's Tree Frog (Liuixalus romeri): Effects of Diel, Seasonal and Weather Variation on Acoustic Detection
6 affiliations
- 1School of Health, Sciences and Society University of Suffolk Ipswich UK
- 2Division of Science, Wu Jieh Yee School of Interdisciplinary Studies Lingnan University Hong Kong SAR China
- 3College of Science and Engineering James Cook University Townsville Queensland Australia
- 4Hong Kong Wetlands Conservation Association Hong Kong SAR China
- 5School of Biological Sciences The University of Hong Kong Hong Kong SAR China
- 6School of Natural Sciences University of Tasmania Hobart Tasmania Australia
Abstract
Accurate estimation of species distribution and abundance depends on detection probability, which can vary with environmental conditions. For amphibians, calling activity and detectability are strongly influenced by diel, seasonal and weather conditions. However, these relationships remain poorly quantified for many species, limiting the optimisation of survey planning. We used passive acoustic monitoring (PAM) to investigate environmental factors of call detection in the endangered Romer's tree frog ( Liuixalus romeri ) in Hong Kong. Acoustic data were collected continuously across multiple sites to quantify the effects of time of day, season and weather variables on detection probability. We further compared PAM detections with active call surveys to assess concordance between methods. Detection probability exhibited strong diel and seasonal patterns, peaking during the wet season (June–August) and at night, with highest detection probability during early evening (20:00–22:00) and a secondary peak before dawn (03:00–04:00). Rainfall effects varied across the diel cycle, with positive effects during peak calling periods but negative or neutral effects at other times. Detection probability showed a non‐linear relationship with temperature, peaking at approximately 27.5°C, and declined with increasing wind speed. Agreement between PAM and active call surveys was moderate (Cohen's Kappa = 0.47), with concordant call agreement for 73% of survey nights. This indicates that the two methods are complementary rather than interchangeable. Based on these findings, we recommend conducting manual surveys during peak activity periods (June–August, 20:00–22:00), under conditions of low wind and following recent rainfall. PAM provides a valuable tool for continuous monitoring and detecting temporal changes in call detection, while manual surveys remain important for estimating abundance. Integrating both approaches can improve monitoring protocols for L. romeri and other amphibians.
Versions
Related
- Antibiotic resistance genes in aquaculture: Molecular detection, environmental dynamics, and biological control strategies
- Collapsed Building Detection from Multi-Temporal Pléiades Imagery: Comparing CNN Architectures and Input Data Strategies
- Habitat use by critically endangered North Pacific right whales linked to sea ice dynamics at varying spatial scales
- Optimising Connectivity in Deep‐Sea MPA Networks for Nephrops norvegicus Recovery in NW Mediterranean Sea
- Optimising bat-friendly curtailment algorithms for wind turbines
BibTeX
@article{sung2026optimising,
title = {{Optimising Survey Strategies for the Endangered Romer's Tree Frog (Liuixalus romeri): Effects of Diel, Seasonal and Weather Variation on Acoustic Detection}},
author = {Yik‐Hei Sung and Amy Wing Lam Fok and Hiu Ching Yuen and Franco Ka Wah Leung and Michael Wai‐neng Lau and Jia Huan Liew and Simon Yung Wa Sin and Jonathan J. Fong},
journal = {Ecology and evolution},
year = {2026},
month = oct,
doi = {10.1002/ece3.74491},
url = {https://europepmc.org/article/PMC/PMC13668485},
note = {CC BY},
}
RIS
TY - JOUR
TI - Optimising Survey Strategies for the Endangered Romer's Tree Frog (Liuixalus romeri): Effects of Diel, Seasonal and Weather Variation on Acoustic Detection
AU - Yik‐Hei Sung
AU - Amy Wing Lam Fok
AU - Hiu Ching Yuen
AU - Franco Ka Wah Leung
AU - Michael Wai‐neng Lau
AU - Jia Huan Liew
AU - Simon Yung Wa Sin
AU - Jonathan J. Fong
PY - 2026
DA - 2026/10/01
JO - Ecology and evolution
DO - 10.1002/ece3.74491
UR - https://europepmc.org/article/PMC/PMC13668485
AB - Accurate estimation of species distribution and abundance depends on detection probability, which can vary with environmental conditions. For amphibians, calling activity and detectability are strongly influenced by diel, seasonal and weather conditions. However, these relationships remain poorly quantified for many species, limiting the optimisation of survey planning. We used passive acoustic monitoring (PAM) to investigate environmental factors of call detection in the endangered Romer's tree frog ( Liuixalus romeri ) in Hong Kong. Acoustic data were collected continuously across multiple sites to quantify the effects of time of day, season and weather variables on detection probability. We further compared PAM detections with active call surveys to assess concordance between methods. Detection probability exhibited strong diel and seasonal patterns, peaking during the wet season (June–August) and at night, with highest detection probability during early evening (20:00–22:00) and a secondary peak before dawn (03:00–04:00). Rainfall effects varied across the diel cycle, with positive effects during peak calling periods but negative or neutral effects at other times. Detection probability showed a non‐linear relationship with temperature, peaking at approximately 27.5°C, and declined with increasing wind speed. Agreement between PAM and active call surveys was moderate (Cohen's Kappa = 0.47), with concordant call agreement for 73% of survey nights. This indicates that the two methods are complementary rather than interchangeable. Based on these findings, we recommend conducting manual surveys during peak activity periods (June–August, 20:00–22:00), under conditions of low wind and following recent rainfall. PAM provides a valuable tool for continuous monitoring and detecting temporal changes in call detection, while manual surveys remain important for estimating abundance. Integrating both approaches can improve monitoring protocols for L. romeri and other amphibians.
SN - 2045-7758
ER -