There and back again: A meta-analytical approach on the influence of acclimation and altitude in the upper thermal tolerance of amphibians and reptiles

Abstract

Realistic predictions about the impacts of climate change onbiodiversity requires gathering ecophysiological data and the critical thermal maxima (CTMax) is the most frequently used index to assess the thermal vulnerability of species. In the present study, we performed a systematic review to understand how acclimation and altitude affect CTMax estimates for amphibian and non-avian reptile species. We retrieved CTMax data for anurans, salamanders, lizards, snakes, and turtles/terrapins. Data allowed to perform a multilevel random effects meta-analysis to answer how acclimation temperature affect CTMax of Anura, Caudata, and Squamata and also meta-regressions to assess the influence of altitude on CTMax of frogs and lizards. Acclimation temperature influenced CTMax estimates of tadpoles, adult anurans, salamanders, and lizards, but not of froglets. In general, the increase in acclimation temperature led to higher CTMax values. Altitudinal bioclimatic gradient had an inverse effect for estimating the CTMax of lizards and anuran amphibians. For lizards, CTMax was positively influenced by the mean temperature of the wettest quarter. For anurans, the relationship is inverse; we recover a trend of decreasing CTMax when max temperature of warmest month and precipitation seasonality increase. There is an urgent need for studies to investigate the thermal tolerance of subsampled groups or even for which we do not have any information such as Gymnophiona, Serpentes, Amphisbaena, and Testudines. Broader phylogenetic coverage is mandatory for more accurate analyses of macroecological and evolutionary patterns for thermal tolerance indices as CTMax.

Acclimation capacity to global warming of amphibians and freshwater fishes: Drivers, patterns, and data limitations

“…Therefore, we assume that the average near‐surface air temperature is a suitable estimate of the temperature of freshwater systems, thereby reflecting the thermal local adaptation of investigated amphibian and freshwater populations. This is in accordance with previous studies testing the effect of thermal adaptation on the thermal physiology of various taxa (e.g., Carilo Filho et al., 2022; Gutiérrez‐Pesquera et al., 2016; Morley et al., 2019; Sinai et al., 2022). Sampling locations were assigned to latitudinal groups based on the absolute latitude (°N/S) and were categorized as either tropical (0–25°), subtropical (>25–40°), temperate (>40–53.55°) or polar (>53.55°; Morley et al., 2019).…”

“…site‐specific temperatures) were not available in original articles or in the WorldClim database. Following previous studies (Carilo Filho et al., 2022; Morley et al., 2019), mean near‐surface air temperature was assumed to reflect the temperature profile of freshwater systems and used to analyze thermal adaptation in both taxa. We are aware that these macroclimatic data as provided by the WorldClim database (representing surface air temperature) present some limitations in reflecting microclimatic data (see Section 5 for methods to improve future studies).…”

Acclimation Capacity to Global Warming of Amphibians and Freshwater Fishes: Drivers, Patterns, and Data Limitations

“…site-specific temperatures) were not available in original articles or in the WorldClim database. Following previous studies (Morley et al 2019; Carilo Filho et al 2022), mean near-surface air temperature was assumed to reflect the temperature profile of freshwater systems and used to analyze thermal adaptation in both taxa. We are aware that these macroclimatic data as provided by the WorldClim database (representing surface air temperature) present some limitations in reflecting microclimatic data (see Conclusion section for methods to improve future studies).…”

“…These macroclimatic data were used as approximations to identify assume that the average near-surface air temperature is a suitable estimate of the temperature of freshwater systems, thereby reflecting the thermal local adaptation of investigated amphibian and freshwater populations. This is in accordance with previous studies testing the effect of thermal adaptation on the thermal physiology of various taxa (e.g.,Gutiérrez-Pesquera et al 2016;Morley et al 2019;Carilo Filho et al 2022;Sinai et al 2022). Sampling locations were assigned to latitudinal groups based on the absolute latitude (°N/S) and were categorized as either tropical (0-25°), sub-tropical (>25-40°), temperate (>40-53.55°) or polar (>53.55°;Morley et al 2019).…”

Seasonal variation of behavioural thermoregulation in the Spotted Salamander (Ambystoma maculatum)

“…Among vertebrate ectotherms, inquiry into the effect of seasonality over thermoregulation is taxonomically biased toward lizards (e.g., Clusella-Trullas and Chown, 2014; Giacometti et al, 2023; Huey and Pianka, 1977). Truly, despite the relatively large number of studies using amphibians as model systems in thermal biology research (e.g., Carilo Filho et al, 2022; Hutchison and Dupré, 1992), the extent to which thermal traits are capable of seasonal acclimation (i.e., response to a single environmental parameter) or acclimatisation (i.e., response to multiple environmental parameters) remains unclear (Navas et al, 2021; but see Pottier et al, 2022). Moreover, amphibian thermoregulation is known to vary extensively both inter- and intra-specifically, and also according to methodological procedures (e.g., acclimation temperatures, photoperiod regime) (Hutchison and Dupré, 1992; Navas et al, 2021).…”