Critical Thermal Maximum of Six Species of Eleutherodactylus Frogs in Puerto Rico: Implications for Conservation in a Warming Environment

35 Pages Posted: 29 Aug 2023

See all articles by Ana C. Rivera-Burgos

Ana C. Rivera-Burgos

affiliation not provided to SSRN

Eloy Martinez

Nova Southeastern University

Rafael Chaparro

affiliation not provided to SSRN

Adam J. Terando

affiliation not provided to SSRN

Reetam Majumder

affiliation not provided to SSRN

Jaime Agustin Collazo

affiliation not provided to SSRN

Abstract

Environmental temperatures influence vital physiological processes of amphibians, and determining their thresholds is critical to assess species’ vulnerability to anthropogenic climate change. We determined the critical thermal maximum (CTMax) of six species of Eleutherodactylus frogs in Puerto Rico, representatives of thermal niches occupied by other species in the genus. CTMax was defined as the temperature that prompted the onset of spasms and erratic behavior that may impair predator avoidance. E. wightmanae, a high elevation specialist, had the lowest value (36.30 ± 0.52°C). Species with wider distribution (e.g., E. antillensis) ranged from 38.27 ± 0.21°C to 42.10 ± 0.65°C. The endangered E. juanariveroi, restricted to freshwater wetlands, had a mean value of 40.77 ± 0.28°C. CTMax of E. coqui at a fixed location (147 m) was significantly lower in winter and spring than summer and autumn. CTMax of E. coqui also varied by elevation; value at the lowest location (24 m) was significantly higher than from frogs sampled at 147 and 526 m. Findings aligned well with known distribution and habitat affinities of Eleutherodactylus species, but also highlighted the thermal plasticity of E. coqui. Climate model simulations project that by 2060 the proportion of habitat (≥500 m) exposed to ≥30°C for at least 1 hr/yr during evening hours (1800-2300 hrs) will increase from 6.1-8.1% to 29.3-38.1%. No areas ≥500 m were projected to be exposed to ≥36°C. Our index of warming tolerance pointed at a 13-18°C gap between average frog in-situ temperatures and CTMax. Thus, there is no indication of imminent risk of frogs reaching thermal limits, but an increasing risk of exposure to elevated sub-lethal temperatures. The effects of sub-lethal temperatures on metabolic performance of Eleutherodactylus species needs to be addressed to inform the formulation of climate change adaptation strategies.

Keywords: Critical thermal maximum, Climate Adaptation, Eleutherodactylus, Puerto Rico, Vulnerability, Warming Tolerance

Suggested Citation

Rivera-Burgos, Ana C. and Martinez, Eloy and Chaparro, Rafael and Terando, Adam J. and Majumder, Reetam and Collazo, Jaime Agustin, Critical Thermal Maximum of Six Species of Eleutherodactylus Frogs in Puerto Rico: Implications for Conservation in a Warming Environment. Available at SSRN: https://ssrn.com/abstract=4556214 or http://dx.doi.org/10.2139/ssrn.4556214

Ana C. Rivera-Burgos

affiliation not provided to SSRN ( email )

No Address Available

Eloy Martinez

Nova Southeastern University ( email )

3301 College Avenue
Ft. Lauderdale, FL 33314
United States

Rafael Chaparro

affiliation not provided to SSRN ( email )

No Address Available

Adam J. Terando

affiliation not provided to SSRN ( email )

No Address Available

Reetam Majumder

affiliation not provided to SSRN ( email )

No Address Available

Jaime Agustin Collazo (Contact Author)

affiliation not provided to SSRN ( email )

No Address Available

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