How temperature, humidity, and burrow selection affect evaporative water loss in desert tortoises

Bulova, Susan J.

doi:10.1016/s0306-4565(01)00079-1

Cited by 55 publications

(41 citation statements)

References 29 publications

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“…Reduced activity in response to lowered water availability has also been found in adult tortoises and other aridadapted reptiles such as the Gila monster, Heloderma suspectum [2,56]. Lowered activity can benefit aridadapted species by reducing evaporative water loss and other metabolic expenditures when water is scarce [57,58]. Although species such as the desert tortoise can escape some thermal or metabolic challenges created by water scarcity by retreating into burrows, not all arid tortoise species burrow and many species face substantial challenges in metabolic maintenance as habitat is degraded and temperatures increase [59,60].…”

Section: Discussionmentioning

confidence: 96%

Precipitation quantity and timing affect native plant production and growth of a key herbivore, the desert tortoise, in the Mojave Desert

Nafus

Tuberville

Buhlmann

et al. 2017

Clim Chang Responses

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Background: Deserts may be disproportionately vulnerable to changes in precipitation that accompany global climate change due to complex evolutionary relationships of species to historical conditions. Based on current and projected climate scenarios for the southwestern United States, we manipulated rainfall timing and quantity and measured the response by plants and the growth and behavior of the desert tortoise (Gopherus agassizii) to precipitation in the eastern Mojave Desert. Results: We found that winter-dominant rain -the current prevailing pattern in the eastern Mojave Desert -and greater total rainfall correlated with greater cover and species richness of plants. Winter-dominant rain also correlated with a higher proportion of native plants flowering relative to invasive plants. Juvenile tortoises grew more rapidly when they were subjected to rainfall treatments that associated with increased plant abundance and species richness, while their behavior appeared more driven by water availability. Conclusions: Our results suggest that precipitation timing may be as important as rainfall quantity when considering total effects of climate change on arid-adapted systems. Further research should explore how the timing of rainfall may interact with aridity or temperature to influence total effects due to climate change on arid communities.

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Section: Discussionmentioning

confidence: 96%

Precipitation quantity and timing affect native plant production and growth of a key herbivore, the desert tortoise, in the Mojave Desert

Nafus

Tuberville

Buhlmann

et al. 2017

Clim Chang Responses

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“…The benefits of retreat site selection have been examined in species belonging to various lineages [e.g. arachnids, fish, reptiles, mammals and amphibians (Bulova, 2002;Kearney, 2002;Goldsbrough et al, 2004;Kotler et al, 2004;Millidine et al, 2006;Hossie and Murray, 2010;Hossie and Murray, 2011)]. However, previous investigations focused on constraining temperature conditions, i.e.…”

Section: Introductionmentioning

confidence: 99%

Shelter availability, stress level, and digestive performances in the aspic viper

Bonnet

Fizesan

Michel

2012

Journal of Experimental Biology

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SUMMARYThe lack of shelter can perturb behaviors, increase stress level and thus alter physiological performance (e.g. digestive, immune or reproductive functions). Although intuitive, such potential impacts of lack of shelter remain poorly documented. We manipulated shelter availability and environmental and physiological variables (i.e. access to a heat source, predator attack, feeding status) in a viviparous snake, and assessed sun-basking behavior, digestive performance (i.e. digestive transit time, crude estimate of assimilation, regurgitation rate) and plasma corticosterone levels (a proxy of stress level). Shelter deprivation provoked a strong increase in sun-basking behavior and thus elevated body temperature, even in unfed individuals for which energy savings would have been otherwise beneficial. The lack of heat was detrimental to digestive performance; simulated predator attacks worsened the situation and entailed a further deterioration of digestion. The combination of the lack of shelter with cool ambient temperatures markedly elevated basal corticosterone level and was associated with low digestive performance. This hormonal effect was absent when only one negative factor was involved, suggesting a threshold response. Overall, our results revealed important non-linear cascading impacts of shelter availability on stress-hormone levels, behaviors and physiological performance. These results infer that shelter availability is important for laboratory studies, captive husbandry and possibly conservation plans. Supplementary material available online at

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“…Moreover, the small size of the temperature logger (3 g) and quadrupled memory capacity (Thermochron iButton model DS1922L offers 8kB of memory) increase the versatility of TBAE for use in a variety of active foraging species that rely on thermally insulated refugia-like red foxes (Vulpes vulpes), badgers (Meles meles), and cactus wrens (Campylorhynchus brunneicapillus) (Fenn and MacDonald, 1995;Moore and Roper, 2003;Ricklefs and Hainsworth, 1968). Arid environments offer ideal conditions in which to use TBAE since (1) the refugia of resident animals as diverse as arachnids (Polis, 1980;Shillington, 2002), birds (Ricklefs and Hainsworth, 1968), mammals (Jackson et al, 2002;Moore and Roper, 2003;Randall, 1993;Rezende et al, 2003), and reptiles; (Beck and Jennings, 2003;Bradshaw, 1997;Bulova, 2002;Grant and Dunham, 1988) are notably buffered from extreme fluctuations in T air , and thus present the thermal dichotomy required for TBAE and (2) many animals use water-conserving behaviors, including extended inactivity periods and temporally constrained activity (i.e., nocturnality), which improve the accuracy of TBAE (this study). TBAE can also identify the date and time of key annual events such as initiation and cessation of seasonal dormancy (J.…”

Section: Discussionmentioning

confidence: 99%

“…Refuge use is common in all taxa and obligatory in many species since refugia often provide living, nesting, and socializing locations, protection from predation (Blumstein et al, 2001;Davis and Theimer, 2004;Martin and Lopez, 2000;Polis, 1980), and, perhaps most notably, a significant buffer from challenging environmental conditions including drought (Beck and Jennings, 2003;Bulova, 2002) and both high (Grant and Dunham, 1988;Rezende et al, 2003;Ricklefs and Hainsworth, 1968) and low (Buck and Barnes, 1999;Dorcas and Peterson, 1998;Peterson, 1987) air temperature extremes. These benefits become increasingly valuable in arid environments because aridity is often accompanied by challenging air temperatures making behaviors that benefit both water conservation and thermoregulation (e.g., shifting activity from diurnal to nocturnal, decreasing overall surface activity, hibernation/active-season dormancy) essential for survival.…”

Section: Introductionmentioning

confidence: 99%

“…The general dichotomy that exists in temperate-zone climates between highly fluctuating T air and milder, more stable temperatures in thermally insulated refugia-like sub-terranean burrows (Bulova, 2002;Rezende et al, 2003;Shenbrot et al, 2002) and water (Grayson and Dorcas, 2004) led us to test the hypothesis that environmental thermal heterogeneity can be used to predict animal surface activity. We predicted that the thermal dichotomy between air and sub-surface temperatures influences the T b of free-ranging reptiles in a predictable manner such that T b can be used to distinguish surface activity from refuge occupation.…”

Section: Introductionmentioning

confidence: 99%

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An automated temperature-based option for estimating surface activity and refuge use patterns in free-ranging animals

Davis

Taylor

DeNardo

2008

Journal of Arid Environments

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Accurately assessing free ranging animals' patterns of surface activity and refuge use is critical, yet fundamentally challenging for biologists and wildlife managers. We evaluate the accuracy of an automated technique temperature based activity estimation (TBAE) in estimating surface activity and refuge use patterns of two sympatric reptiles, the western diamond backed rattlesnake (Crotalus atrox) and the Gila monster (Heloderma suspectum) in the Sonoran Desert. TBAE derived from a comparison of body temperature to shaded air temperature was effective in estimating the overall percent surface activity for both rattlesnakes (observed surface activity 51.8%, TBAE estimated surface activity 48.2%) and Gila monsters (observed 22.3%, TBAE 24.5%). There was, however, considerable interspecific difference in the effectiveness of TBAE in predicting surface activity at specific time points; TBAE was far more accurate for Gila monsters than for rattlesnakes (96% vs. 66% time point specific accuracy, respectively). We assert that, when validated, TBAE can be used to yield concurrent and accurate body temperatures and activity estimates for multiple free ranging animals, particularly in arid environments, which improves our understanding of animal biology and can be used to inform management decisions.

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How temperature, humidity, and burrow selection affect evaporative water loss in desert tortoises

Cited by 55 publications

References 29 publications

Precipitation quantity and timing affect native plant production and growth of a key herbivore, the desert tortoise, in the Mojave Desert

Precipitation quantity and timing affect native plant production and growth of a key herbivore, the desert tortoise, in the Mojave Desert

Shelter availability, stress level, and digestive performances in the aspic viper

An automated temperature-based option for estimating surface activity and refuge use patterns in free-ranging animals

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