Has contemporary climate change played a role in population declines of the lizard Ctenophorus decresii from semi-arid Australia?

Walker, Samantha; Stuart‐Fox, Devi; Kearney, Michael R.

doi:10.1016/j.jtherbio.2014.12.001

Cited by 21 publications

(15 citation statements)

References 60 publications

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“…Instead of physiological adaptation, these species might shift their seasonal timing of activity. In line with that, we showed that with a warming climate, the total activity budget across the year was increasing for the two species investigated as it is the case for other desert species (Walker et al., ). However, the days of high activity budgets shifted to spring and autumn and the species might estivate in hot summer months in the future.…”

Section: Discussionsupporting

confidence: 86%

“…Our findings suggest that in addition to temperature as the most important driver (Cahill et al., ), the availability of vegetation and heterogeneity is highly important factors in determining the warm‐edge range limits for ectotherms. Likewise, Walker, Stuart‐Fox, and Kearney () observed a warm‐edge range restriction in an Australian desert agama which was potentially driven by reduced midsummer activity budgets, not only depending on temperature but water and shelter availability. In addition, Clusella‐Trullas et al.…”

Section: Discussionmentioning

confidence: 96%

“…Nevertheless, it remains unclear how successful desert lizards would be able to change their diurnal or seasonal timing of activity. Generally, reptile species seem to have a large phenotypic plasticity, and an earlier spring and later fall provide a great opportunity for many species to increase their overall activity season (Bradshaw & Holzapfel, , ; Walker et al., ) albeit this will depend on species‐specific genetic adaptation in photoperiodic responses (Bradshaw & Holzapfel, ). Comparably, widespread lizard species already show huge variability between phenological periods across latitudes with species with a shorter hibernation period often producing more and/or larger clutches (Grimm et al., ).…”

Section: Discussionmentioning

confidence: 99%

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Too hot to die? The effects of vegetation shading on past, present, and future activity budgets of two diurnal skinks from arid Australia

Grimm‐Seyfarth

Mihoub

Henle

2017

Ecology and Evolution

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Behavioral thermoregulation is an important mechanism allowing ectotherms to respond to thermal variations. Its efficiency might become imperative for securing activity budgets under future climate change. For diurnal lizards, thermal microhabitat variability appears to be of high importance, especially in hot deserts where vegetation is highly scattered and sensitive to climatic fluctuations. We investigated the effects of a shading gradient from vegetation on body temperatures and activity timing for two diurnal, terrestrial desert lizards, Ctenotus regius, and Morethia boulengeri, and analyzed their changes under past, present, and future climatic conditions. Both species’ body temperatures and activity timing strongly depended on the shading gradient provided by vegetation heterogeneity. At high temperatures, shaded locations provided cooling temperatures and increased diurnal activity. Conversely, bushes also buffered cold temperature by saving heat. According to future climate change scenarios, cooler microhabitats might become beneficial to warm‐adapted species, such as C. regius, by increasing the duration of daily activity. Contrarily, warmer microhabitats might become unsuitable for less warm‐adapted species such as M. boulengeri for which midsummers might result in a complete restriction of activity irrespective of vegetation. However, total annual activity would still increase provided that individuals would be able to shift their seasonal timing towards spring and autumn. Overall, we highlight the critical importance of thermoregulatory behavior to buffer temperatures and its dependence on vegetation heterogeneity. Whereas studies often neglect ecological processes when anticipating species’ responses to future climate change the strongest impact of a changing climate on terrestrial ectotherms in hot deserts is likely to be the loss of shaded microhabitats rather than the rise in temperature itself. We argue that conservation strategies aiming at addressing future climate changes should focus more on the cascading effects of vegetation rather than on shifts of species distributions predicted solely by climatic envelopes.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

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Too hot to die? The effects of vegetation shading on past, present, and future activity budgets of two diurnal skinks from arid Australia

Grimm‐Seyfarth

Mihoub

Henle

2017

Ecology and Evolution

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“…Despite the relative novelty of these patterns, core aspects of lizard behavior and thermal biology suggest a mechanism we proposed is plausible. Metabolic and water-loss costs of high T min may be especially large for small juveniles with low fat stores and high surface-to-volume ratios (Walker, Stuart-Fox, & Kearney, 2015), although other processes may be involved. In ectotherms, metabolic activity rises exponentially with temperature and consumes energy important for growth, reproduction, and other processes, thereby requiring additional activity and risk to acquire lost energy (Adolph & Porter, 1993;Bennett & Dawson, 1976;Huey & Slatkin, 1976).…”

Section: Effects Of Minimum Daily Air Temperatures (T Min )mentioning

confidence: 99%

Long‐term changes in abundances of Sonoran Desert lizards reveal complex responses to climatic variation

Flesch

Rosen

Holm

2017

Global Change Biology

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Understanding how climatic variation affects animal populations and communities is essential for addressing threats posed by climate change, especially in systems where impacts are projected to be high. We evaluated abundance dynamics of five common species of diurnal lizards over 25 years in a Sonoran Desert transition zone where precipitation decreased and temperature increased across time, and assessed hypotheses for the influence of climatic flux on spatiotemporal variation in abundances. We repeatedly surveyed lizards in spring and summer of each year at up to 32 sites, and used hierarchical mixture models to estimate detection probabilities, abundances, and population growth rates. Among terrestrial species, abundances of a short-lived, winter-spring breeder increased markedly by an estimated 237%-285% across time, while two larger spring-summer breeders with higher thermal preferences declined by up to 64%. Abundances of two arboreal species that occupy shaded and thus sheltered microhabitats fluctuated but did not decline systematically. Abundances of all species increased with precipitation at short lag times (1-1.5 years) likely due to enhanced food availability, but often declined after periods of high precipitation at longer lag times (2-4 years) likely due to predation and other biotic pressures. Although rising maximum daily temperatures (T ) are expected to drive global declines of lizards, associations with T were variable and weak for most species. Instead, abundances of all species declined with rising daily minimum temperatures, suggesting degradation of cool refugia imposed widespread metabolic or other costs. Our results suggest climate warming and drying are having major impacts on lizard communities by driving declines in species with traits that augment exposure to abiotic extremes and by modifying species interactions. The complexity of patterns we report indicates that evaluating and responding to the influence of climate change on biodiversity must consider a broad array of ecological processes.

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“…Some populations of lizards have been proved to go locally extinct because the temperature increase could compromise their physiological performance (Huey et al, ), their activity budgets (Sinervo et al, ), their temperatures in retreat sites and their water balance (Walker, Stuart‐Fox, & Kearney, ).…”

Section: Introductionmentioning

confidence: 99%

Lizards in the mist: Thermal niches constrained by habitat and microclimates in the Andes of southern Bolivia

Jiménez-Robles

Riva

2019

Journal of Biogeography

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Aim To understand how the activity budgets of ectotherms vary in mountain areas with high microclimatic and habitat heterogeneity, and how these factors together with habitat modulate the assemblage of ectotherm communities. Location Tajzara Basin, Cordillera de Sama (3,600–4,300 m a.s.l.), Department of Tarija, Bolivia. Taxon Four lizard species of the genus Liolaemus. Methods After parameterizing the thermal physiology of each species and recording operative temperature time series with dataloggers, we calculated activity budgets for every species across 30 sampling sites. By multimodel inference we evaluated how activity budgets varied across the topography. We also assessed how abundances of each species were predicted by activity budgets, restriction time, temperature deviation, habitat covers and exposure to cold microclimate. Results Activity budgets were not only influenced by elevation but also by the exposure to cold air that comes through saddles from the eastern side of the mountain divide. Although thermal physiological parameters were relatively similar among the species, their abundances were conditioned to different extents by activity budgets, habitat and microclimates. Main conclusions The abundance and distribution of each species across these lizard communities reflect the microclimatic heterogeneity originated by complex topography, which uncouples activity budgets from elevation. Only one species was confined to cold microclimate refugia with higher exposure to Föhn effect. Despite having a relatively similar thermal aspect of fundamental niches, lizards may differ in their realized niches by habitat selection. Habitat specialization could compromise the persistence of some species under global warming by reducing the dispersal possibilities to certain areas where population sustainability might be impaired in the long term. Understanding the heterogeneity of microclimates and habitats and the physiology of the species partially explains their distribution at local scale, and provides insights on how to best confront upcoming climate change effects.

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Has contemporary climate change played a role in population declines of the lizard Ctenophorus decresii from semi-arid Australia?

Cited by 21 publications

References 60 publications

Too hot to die? The effects of vegetation shading on past, present, and future activity budgets of two diurnal skinks from arid Australia

Too hot to die? The effects of vegetation shading on past, present, and future activity budgets of two diurnal skinks from arid Australia

Long‐term changes in abundances of Sonoran Desert lizards reveal complex responses to climatic variation

Lizards in the mist: Thermal niches constrained by habitat and microclimates in the Andes of southern Bolivia

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