Possible Impact of Climate Change and Environmental Health on the Geographical Distribution of Sarawak Frogs

• Main Author: Eugenie Clare, Kaboi
• Format: Thesis
• Language: English; English; English
• Published: UNIVERSITI MALAYSIA SARAWAK 2025
• Subjects: QL Zoology
• Online Access: http://ir.unimas.my/id/eprint/49952/

Climate change, together with habitat loss, represents a major threat to global biodiversity, with frogs particularly at risk because of their ectothermic nature, reliance on specific microhabitats, and heightened sensitivity to environmental variation. This study investigated the impacts of climate and habitat change on the physiology and distribution of frogs in Sarawak by addressing three related questions: (i) how microhabitat conditions shape body temperatures and thermoregulatory strategies, (ii) how habitat quality and human disturbance influence species diversity and microhabitat use across protected and altered sites, and (iii) how projected temperature increases may shift the future range of Fejervarya limnocharis, used here as a model species to anticipate broader distributional responses among Bornean frogs. Field surveys were carried out between November 2022 and May 2023 at five study locations: Bung Jagoi, Matang Wildlife Centre, UNIMAS West Campus, Kampung Telok Melano, and Mulu National Park. There were 261 individuals in all, representing 40 species across six families. Results from Chapter 4 demonstrated the thigmothermic nature of frogs by showing a close correlation between their body temperatures and substrate temperatures. The higher body temperatures of frogs in non flowing aquatic environments compared to those in streams and terrestrial habitats have significant implications for physiological function and disease susceptibility, especially with relation to Batrachochytrium dendrobatidis. Chapter 5 revealed that protected sites like Mulu National Park, Matang Wildlife Centre, and Bung Jagoi supported healthier ecosystems and higher frog diversity due to the availability of intact microhabitats, while disturbed sites like Telok Melano and UNIMAS West Campus showed signs of habitat degradation and lower diversity. These results highlight the critical role of microhabitat variety and community-driven conservation in maintaining amphibian populations. Chapter 6 applied species distribution models (SDMs) for Fejervarya limnocharis, showing that its suitable habitat is likely to expand significantly by 2050 under both moderate (SSP2-4.5) and high (SSP5-8.5) climate scenarios. This reflects the high adaptability of this generalist species, yet also highlights potential risks to more sensitive native frog species. Overall, the results indicate that Bornean frogs respond to environmental changes through physiological regulation, alterations in species assemblages, and shifts in distribution, emphasising their susceptibility in a rapidly changing climate. By combining information on thermal ecology, habitat quality, and species distribution predictions, this study delivers comprehensive insights into amphibian vulnerability and adaptability, providing practical guidance for conservation planning, management of protected areas, and climate adaptation strategies in Sarawak.