Short-term predicted extinction of Andean populations of the lizard Stenocercus guentheri (Iguanidae: Tropidurinae)

Andrango, María Belén; Sette, Carla M.; Torres‐Carvajal, Omar

doi:10.1016/j.jtherbio.2016.09.012

Cited by 12 publications

(8 citation statements)

References 49 publications

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“…The former intrapopulation sample size is within the range of that used in many studies of lizard thermal tolerance (e.g., Beal, Lattanzio, & Miles, ; Muñoz et al., ). However, we assessed optimal sample size from six datasets, including population CT max from 8 to 25 adult lizards from the Americas, Asia and Europe (Andrango, Sette, & Torres‐Carvajal, ; Belasen et al., ; Buckley, Ehrenberger, & Angilletta, ; Huang & Tu, ; Muñoz et al., ; and unpublished data), and concluded that a sample size of three males should accurately capture the mean population CT max estimated from larger population sizes (Supporting Information Table S2; Figures S4–S9).…”

Section: Methodsmentioning

confidence: 99%

Intraspecific variation in lizard heat tolerance alters estimates of climate impact

Herrando‐Pérez

Ferri‐Yáñez

Monasterio

et al. 2018

Journal of Animal Ecology

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Research addressing the effects of global warming on the distribution and persistence of species generally assumes that population variation in thermal tolerance is spatially constant or overridden by interspecific variation. Typically, this rationale is implicit in sourcing one critical thermal maximum (CTmax) population estimate per species to model spatiotemporal cross‐taxa variation in heat tolerance. Theory suggests that such an approach could result in biased or imprecise estimates and forecasts of impact from climate warming, but limited empirical evidence in support of those expectations exists. We experimentally quantify the magnitude of intraspecific variation in CTmax among lizard populations, and the extent to which incorporating such variability can alter estimates of climate impact through a biophysical model. To do so, we measured CTmax from 59 populations of 15 Iberian lizard species (304 individuals). The overall median CTmax across all individuals from all species was 42.8°C and ranged from 40.5 to 48.3°C, with species medians decreasing through xeric, climate‐generalist and mesic taxa. We found strong statistical support for intraspecific differentiation in CTmax by up to a median of 3°C among populations. We show that annual restricted activity (operative temperature > CTmax) over the Iberian distribution of our study species differs by a median of >80 hr per 25‐km2 grid cell based on different population‐level CTmax estimates. This discrepancy leads to predictions of spatial variation in annual restricted activity to change by more than 20 days for six of the study species. Considering that during restriction periods, reptiles should be unable to feed and reproduce, current projections of climate‐change impacts on the fitness of ectotherm fauna could be under‐ or over‐estimated depending on which population is chosen to represent the physiological spectra of the species in question. Mapping heat tolerance over the full geographical ranges of single species is thus critical to address cross‐taxa patterns and drivers of heat tolerance in a biologically comprehensive way.

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Section: Methodsmentioning

confidence: 99%

Intraspecific variation in lizard heat tolerance alters estimates of climate impact

Herrando‐Pérez

Ferri‐Yáñez

Monasterio

et al. 2018

Journal of Animal Ecology

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“…In 2015, we collected 26 adult specimens of Stenocercus guentheri from Calacalí between May and August, and 21 specimens of S. festae on February, May, and June. Data of 27 adult specimens of S. guentheri from Jerusalem RP were taken from Andrango et al [38]. Specimens were collected under permit N˚003-15 IC-FAU-DNB/MA issued by Ministerio del Ambiente del Ecuador.…”

Section: Specimen and Field Data Collectionmentioning

confidence: 99%

“…CT min and CT max were independently measured by placing each lizard in a clear glass chamber immersed in water cooled and heated at an approximate rate of 1.0-1.5˚C per minute. A T-type thermocouple attached anteriorly to the cloacal area and secure with Micropore surgery tape, recorded the temperature at which the individual was unable to right itself when flipped onto its back [38,40].…”

Section: Thermophysiological Datamentioning

confidence: 99%

Thermal biology of two tropical lizards from the Ecuadorian Andes and their vulnerability to climate change

et al. 2020

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This study aims to analyze the thermal biology and climatic vulnerability of two closely related lizard species (Stenocercus festae and S. guentheri) inhabiting the Ecuadorian Andes at high altitudes. Four physiological parameters-body temperature (T b), preferred temperature (T pref), critical thermal maximum (CT max), and critical thermal minimum (CT min)-were evaluated to analyze the variation of thermophysiological traits among these populations that inhabit different environmental and altitudinal conditions. We also evaluate the availability of operative temperatures, warming tolerance, and thermal safety margin of each population to estimate their possible risks in the face of future raising temperatures. Similar to previous studies, our results suggest that some physiological traits (CT max and T b) are influenced by environmental heterogeneity, which brings changes on the thermoregulatory behavior. Other parameters (T pref and CT min), may be also influenced by phylogenetic constraints. Moreover, the fluctuating air temperature (T air) as well as the operative temperatures (T e) showed that these lizards exploit a variety of thermal microenvironments, which may facilitate behavioral thermoregulation. Warming tolerance and thermal safety margin analyses suggest that both species find thermal refugia and remain active without reducing their performance or undergoing thermal stress within their habitats. We suggest that studies on the thermal biology of tropical Andean lizards living at high altitudes are extremely important as these environments exhibit a unique diversity of microclimates, which consequently result on particular thermophysiological adaptations.

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“…Cumulative hours when the mean of available temperatures is above or outside the optimal temperature range (hours) (Sinervo et al 2010, Ceia-Hasse et al 2014, Andrango et al 2016.…”

Section: Hours Of Restrictionmentioning

confidence: 99%

“…While different from the original definition by Hertz and colleagues (1993), the formulation of habitat quality we used (Deutsch et al 2008) is the most popular in literature. The conventional hours of restriction index was calculated as the number of hours in each day for which the mean T e across space was above the organism's mean Tpref (Sinervo et al 2010, Ceia-Hasse et al 2014, Andrango et al 2016. To summarise the results across all days, we reported the cumulative hours across the sampling period as a percentage of the total number of hours sampled.…”

Section: Climate Change Vulnerability Indicesmentioning

confidence: 99%

Rethinking the scale and formulation of indices assessing organism vulnerability to warmer habitats

2019

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Ecologists often use indices or proxies to communicate complex ecological entities. Indices commonly known as thermal safety margin, habitat thermal quality and hours of restriction describe species’ vulnerability to climate change by comparing organisms’ thermal limits or preferences to available habitat temperatures. Ready access to temperature data, from global gridded datasets or limited in situ measurements, has made these indices popular for vulnerability assessments across taxonomic groups and regions. However, such coarse descriptions of thermal landscape mask the spatio‐temporal heterogeneity that organisms experience, compromising the value of these indices. Full understanding of how scale affects index estimates is lacking, leaving ecologists and conservation managers with little guidance for applying or interpreting indices. Here, we show that incomplete temperature sampling, in space or time, provides erroneous assessments of vulnerability. Gradually sub‐sampling a long‐term, fine‐scale dataset of operative environmental temperature altered the index estimates for a lizard. Uncertainty associated with the selection of data increased with coarser scales, often leading to contrasting interpretations about the species’ vulnerability to climate change when different data subsets were used. Compressing the environmental temperature data into central or extreme tendencies, as traditionally done to compute these indices, further masked the thermal variation that animals exploit to buffer warming. We suggest the use of improved index formulations that better describe temperature availability at scales that are appropriate to the study organism.

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Short-term predicted extinction of Andean populations of the lizard Stenocercus guentheri (Iguanidae: Tropidurinae)

Cited by 12 publications

References 49 publications

Intraspecific variation in lizard heat tolerance alters estimates of climate impact

Intraspecific variation in lizard heat tolerance alters estimates of climate impact

Thermal biology of two tropical lizards from the Ecuadorian Andes and their vulnerability to climate change

Rethinking the scale and formulation of indices assessing organism vulnerability to warmer habitats

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