Thermal tolerance and the importance of microhabitats for Andean frogs in the context of land use and climate change

• Published in: The Journal of animal ecology 2020-11, Vol.89 (11), p.2451-2460
• Main Authors: González‐del‐Pliego, Pamela, Scheffers, Brett R., Freckleton, Robert P., Basham, Edmund W., Araújo, Miguel B., Acosta‐Galvis, Andrés R., Medina Uribe, Claudia A., Haugaasen, Torbjørn, Edwards, David P., Marske, Katharine
• Format: Article
• Language: English
• Subjects: amphibian conservation; Amphibians; Animals; Anura; Buffers; Climate; Climate Change; Colombian Andes; CTmax; Ecosystem; Exposure; Forests; Frogs; Global warming; Habitats; Land use; Landscape preservation; Microenvironments; Microhabitats; Phylogeny; Regrowth; secondary forest regeneration; Sensitivity; Species; Temperature; Temperature tolerance; Thermal protection; Thermal stress; thermal tolerance limits; tropics
• ISSN: 0021-8790; 1365-2656
• DOI: 10.1111/1365-2656.13309

Global warming is having impacts across the Tree of Life. Understanding species’ physiological sensitivity to temperature change and how they relate to local temperature variation in their habitats is crucial to determining vulnerability to global warming. We ask how species’ vulnerability varies across habitats and elevations, and how climatically buffered microhabitats can contribute to reduce their vulnerability. We measured thermal sensitivity (critical thermal maximum—CTmax) of 14 species of Pristimantis frogs inhabiting young and old secondary, and primary forests in the Colombian Andes. Exposure to temperature stress was measured by recording temperature in the understorey and across five microhabitats. We determined frogs’ current vulnerability across habitats, elevations and microhabitats accounting for phylogeny and then ask how vulnerability varies under four warming scenarios: +1.5, +2, +3 and +5°C. We found that CTmax was constant across species regardless of habitat and elevation. However, species in young secondary forests are expected to become more vulnerable because of increased exposure to higher temperatures. Microhabitat variation could enable species to persist within their thermal temperature range as long as regional temperatures do not surpass +2°C. The effectiveness of microhabitat buffering decreases with a 2–3°C increase, and is almost null under a 5°C temperature increase. Microhabitats will provide thermal protection to Andean frog communities from climate change by enabling tracking of suitable climates through short distance movement. Conservation strategies, such as managing landscapes by preserving primary forests and allowing regrowth and reconnection of secondary forest would offer thermally buffered microhabitats and aid in the survival of this group. Resumen Para determinar la vulnerabilidad de las especies al calentamiento global es indispensable considerar la tolerancia fisiológica de las especies al cambio de temperatura y las condiciones ambientales a las que están expuestas. En este estudio exploramos la vulnerabilidad de especies a través de diferentes hábitats y altitudes y examinamos si ciertos microhábitats contribuyen a reducir la vulnerabilidad al calentamiento global. Medimos la tolerancia térmica (CTmax) de catorce especies de ranas Pristimantis en bosques secundarios jóvenes y viejos, y bosques primarios en los Andes tropicales. Registramos la temperatura a la que estas especies están expuestas en el soto