Phenological shifts of low-latitude frogs over 15 years revealed by passive acoustic monitoring
- 1Graduate School of Science, Kyoto University 1 , Kyoto, Japan
- 2Institute of Agriculture, Tokyo University of Agriculture and Technology 2 , Fuchu, Tokyo, Japan
- 3Department of Biology, Keio University 3 , Yokohama, Japan
Abstract
Phenological responses to climate warming are well-documented, yet limited data come from low latitudes. Because phenological sensitivity may vary with latitude, studies in low-latitude regions are essential to understand global patterns. To fill this gap, we analysed acoustic recordings collected daily over 15 years on Iriomote Island, in Japan's transitional zone between subtropical and tropical biomes. We applied the BirdNET deep learning model to quantify the breeding phenology of seven frog species. Seasonal calling patterns differed among species, with peaks occurring in various seasons while one species called nearly year-round. Among six species analysed for phenological trends, a winter-breeding tree-frog (Zhangixalus owstoni) showed a statistically significant shift in median calling date (3.8 days later per decade), whereas the other species showed no significant shifts of varying magnitude and direction. Sliding time window analysis indicated late-summer temperature—which increased during the study period—best predicted median calling dates in Z. owstoni, suggesting that climate warming delayed the phenology of a winter breeder even where year-round reproduction is possible. The absence of significant phenological advancement in our dataset contrasts with spring advancement commonly reported in temperate regions. These findings reinforce the importance of examining long-term phenological shifts across more sites in low-latitude regions.
Related
- Automated identification of individual birds by song enables multi-year recapture from passive acoustic monitoring data
- A Self‐Supervised Approach for Hainan Gibbon Call Separation in Passive Acoustic Monitoring
- Discovery and promotion of unknown sounds into operational detection targets for underwater passive acoustic monitoring under false alarm constraints
- Sound advice: A calibration framework for defining detection space in passive acoustic monitoring
- Individual recognition and number prediction for Manx shearwater (Puffinus puffinus) by passive acoustic monitoring
BibTeX
@article{kimura2026phenological,
title = {{Phenological shifts of low-latitude frogs over 15 years revealed by passive acoustic monitoring}},
author = {Kaede Kimura and Kinji Fukuyama},
journal = {Royal Society Open Science},
year = {2026},
month = nov,
doi = {10.1098/rsos.261532},
url = {https://royalsocietypublishing.org/rsos/article/13/11/261532/484005/Phenological-shifts-of-low-latitude-frogs-over-15},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Phenological shifts of low-latitude frogs over 15 years revealed by passive acoustic monitoring
AU - Kaede Kimura
AU - Kinji Fukuyama
PY - 2026
DA - 2026/11/04
JO - Royal Society Open Science
DO - 10.1098/rsos.261532
UR - https://royalsocietypublishing.org/rsos/article/13/11/261532/484005/Phenological-shifts-of-low-latitude-frogs-over-15
AB - Phenological responses to climate warming are well-documented, yet limited data come from low latitudes. Because phenological sensitivity may vary with latitude, studies in low-latitude regions are essential to understand global patterns. To fill this gap, we analysed acoustic recordings collected daily over 15 years on Iriomote Island, in Japan's transitional zone between subtropical and tropical biomes. We applied the BirdNET deep learning model to quantify the breeding phenology of seven frog species. Seasonal calling patterns differed among species, with peaks occurring in various seasons while one species called nearly year-round. Among six species analysed for phenological trends, a winter-breeding tree-frog (Zhangixalus owstoni) showed a statistically significant shift in median calling date (3.8 days later per decade), whereas the other species showed no significant shifts of varying magnitude and direction. Sliding time window analysis indicated late-summer temperature—which increased during the study period—best predicted median calling dates in Z. owstoni, suggesting that climate warming delayed the phenology of a winter breeder even where year-round reproduction is possible. The absence of significant phenological advancement in our dataset contrasts with spring advancement commonly reported in temperate regions. These findings reinforce the importance of examining long-term phenological shifts across more sites in low-latitude regions.
SN - 2054-5703
ER -