scholarly journals Thermal ecology of the federally endangered blunt-nosed leopard lizard (Gambelia sila)

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Kathleen N Ivey ◽  
Margaret Cornwall ◽  
Hayley Crowell ◽  
Nargol Ghazian ◽  
Emmeleia Nix ◽  
...  
Keyword(s):  
Climate Change ◽  
Endangered Species ◽  
Thermal Tolerance ◽  
Microhabitat Use ◽  
Thermal Ecology ◽  
Body Temperatures ◽  
Ambient Temperatures ◽  
Open Habitat ◽  
Kangaroo Rat ◽  
Upper Thermal Tolerance

Abstract Recognizing how climate change will impact populations can aid in making decisions about approaches for conservation of endangered species. The blunt-nosed leopard lizard (Gambelia sila) is a federally endangered species that, despite protection, remains in extremely arid, hot areas and may be at risk of extirpation due to climate change. We collected data on the field-active body temperatures, preferred body temperatures and upper thermal tolerance of G. sila. We then described available thermal habitat using biophysical models, which allowed us to (i) describe patterns in lizard body temperatures, microhabitat temperatures and lizard microhabitat use; (ii) quantify the lizards’ thermoregulatory accuracy; (iii) calculate the number of hours they are currently thermally restricted in microhabitat use; (iv) project how the number of restricted hours will change in the future as ambient temperatures rise; and (v) assess the importance of giant kangaroo rat burrows and shade-providing shrubs in the current and projected future thermal ecology of G. sila. Lizards maintained fairly consistent daytime body temperatures over the course of the active season, and use of burrows and shrubs increased as the season progressed and ambient temperatures rose. During the hottest part of the year, lizards shuttled among kangaroo rat burrows, shrubs, and open habitat to maintain body temperatures below their upper thermal tolerance, but, occasionally, higher than their preferred body temperature range. Lizards are restricted from staying in the open habitat for 75% of daylight hours and are forced to seek refuge under shrubs or burrows to avoid surpassing their upper thermal threshold. After applying climatic projections of 1 and 2°C increases to 2018 ambient temperatures, G. sila will lose additional hours of activity time that could compound stressors faced by this population, potentially leading to extirpation.

scholarly journals Contrasting capabilities of two ungulate species to cope with extremes of aridity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Melinda Boyers ◽  
Francesca Parrini ◽  
Norman Owen-Smith ◽  
Barend F. N. Erasmus ◽  
Robyn S. Hetem
Keyword(s):  
Climate Change ◽  
High Water ◽  
Future Climate Change ◽  
Body Temperatures ◽  
Wet Season ◽  
Trade Off ◽  
Ambient Temperatures ◽  
Mammalian Herbivores ◽  
Dry Seasons ◽  
Connochaetes Taurinus

AbstractSouthern Africa is expected to experience increased frequency and intensity of droughts through climate change, which will adversely affect mammalian herbivores. Using bio-loggers, we tested the expectation that wildebeest (Connochaetes taurinus), a grazer with high water-dependence, would be more sensitive to drought conditions than the arid-adapted gemsbok (Oryx gazella gazella). The study, conducted in the Kalahari, encompassed two hot-dry seasons with similar ambient temperatures but differing rainfall patterns during the preceding wet season. In the drier year both ungulates selected similar cooler microclimates, but wildebeest travelled larger distances than gemsbok, presumably in search of water. Body temperatures in both species reached lower daily minimums and higher daily maximums in the drier season but daily fluctuations were wider in wildebeest than in gemsbok. Lower daily minimum body temperatures displayed by wildebeest suggest that wildebeest were under greater nutritional stress than gemsbok. Moving large distances when water is scarce may have compromised the energy balance of the water dependent wildebeest, a trade-off likely to be exacerbated with future climate change.

scholarly journals Intraspecific variation in thermal tolerance differs between tropical and temperate fishes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. J. H. Nati ◽  
M. B. S. Svendsen ◽  
S. Marras ◽  
S. S. Killen ◽  
J. F. Steffensen ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Intraspecific Variation ◽  
Fish Species ◽  
Thermal Tolerance ◽  
Evolutionary History ◽  
Ecological Impacts ◽  
Temperate Species ◽  
Tropical Species ◽  
Upper Thermal Tolerance

AbstractHow ectothermic animals will cope with global warming is a critical determinant of the ecological impacts of climate change. There has been extensive study of upper thermal tolerance limits among fish species but how intraspecific variation in tolerance may be affected by habitat characteristics and evolutionary history has not been considered. Intraspecific variation is a primary determinant of species vulnerability to climate change, with implications for global patterns of impacts of ongoing warming. Using published critical thermal maximum (CTmax) data on 203 fish species, we found that intraspecific variation in upper thermal tolerance varies according to a species’ latitude and evolutionary history. Overall, tropical species show a lower intraspecific variation in thermal tolerance than temperate species. Notably, freshwater tropical species have a lower variation in tolerance than freshwater temperate species, which implies increased vulnerability to impacts of thermal stress. The extent of variation in CTmax among fish species has a strong phylogenetic signal, which may indicate a constraint on evolvability to rising temperatures in tropical fishes. That is, in addition to living closer to their upper thermal limits, tropical species may have higher sensitivity and lower adaptability to global warming compared to temperate counterparts. This is evidence that freshwater tropical fish communities, worldwide, are especially vulnerable to ongoing climate change.

scholarly journals Thermal tolerance, acclimatory capacity and vulnerability to global climate change

2007 ◽  
Vol 4 (1) ◽  
pp. 99-102 ◽  
Author(s):  
Piero Calosi ◽  
David T Bilton ◽  
John I Spicer
Keyword(s):  
Climate Change ◽  
At Risk ◽  
Thermal Tolerance ◽  
Global Climate ◽  
Marine Animals ◽  
Vulnerability To Climate Change ◽  
Diving Beetles ◽  
Mountain Systems ◽  
Future Warming ◽  
Upper Thermal Tolerance

Despite evidence that organismal distributions are shifting in response to recent climatic warming, we have little information on direct links between species' physiology and vulnerability to climate change. We demonstrate a positive relationship between upper thermal tolerance and its acclimatory ability in a well-defined clade of closely related European diving beetles. We predict that species with the lowest tolerance to high temperatures will be most at risk from the adverse effects of future warming, since they have both low absolute thermal tolerance and poor acclimatory ability. Upper thermal tolerance is also positively related to species' geographical range size, meaning that species most at risk are already the most geographically restricted ones, being endemic to Mediterranean mountain systems. Our findings on the relationship between tolerance and acclimatory ability contrast with results from marine animals, suggesting that generalizations regarding thermal tolerance and responses to future rapid climate change may be premature.

scholarly journals The CAVEheAT project: climate change, thermal niche and conservation of subterranean biodiversity

2018 ◽  
Vol 1 ◽  
Author(s):  
David Fernandez ◽  
Andrés Millán ◽  
Valeria Rizzo ◽  
Jordi Comas ◽  
Enric Lleopard ◽  
...  
Keyword(s):  
Climate Change ◽  
Environmental Conditions ◽  
Thermal Tolerance ◽  
Evolutionary Biology ◽  
Environmental Changes ◽  
Metabolic Cost ◽  
Behavioural Plasticity ◽  
Microhabitat Use ◽  
Thermal Niche ◽  
Project Climate Change

One of the main challenges in disciplines such as ecology, biogeography, conservation and evolutionary biology is to understand and predict how species will respond to environmental changes, especially within a climate change context. We focus on the deep subterranean environment to minimize uncertainties in predictions, because it is one of the few ecosystems in nature whose environmental conditions are as homogeneous as those in the laboratory and their species cannot accommodate to changing conditions by behavioural plasticity, dispersal or microhabitat use (i.e., their only possibility to cope with climate change is to persist in situ). The hypotheses established for this project are based on the exciting results obtained in some of our previous studies, in which, we found that different subterranean beetle species living under different environmental conditions have identical/similar narrow thermal tolerance ranges, suggesting a lack of evolutionary adjustment to ambient temperature for these species. This could be due to the loss of some of the physiological mechanisms related to thermal tolerance, with a likely high metabolic cost, in a stable environment but with severe resource restrictions. However, the question that remains is to what extent this surprising narrow and homogeneous thermal niche is common for the whole subterranean biodiversity, and how this issue could determine the fate of subterranean biodiversity to climate change. In this project, we are testing for the generality of these exciting previous findings by studying the thermal niche (species acclimation abilities and thermal tolerances) of different lineages of cave beetles with different degrees of specialization to subterranean environments and from different geographical areas (Pyrenees and Cantabrian Mountains) (Suppl. material 1).

scholarly journals Low potential for evolutionary rescue from climate change in a tropical fish

2020 ◽  
Vol 117 (52) ◽  
pp. 33365-33372 ◽  
Author(s):  
Rachael Morgan ◽  
Mette H. Finnøen ◽  
Henrik Jensen ◽  
Christophe Pélabon ◽  
Fredrik Jutfelt
Keyword(s):  
Climate Change ◽  
Danio Rerio ◽  
Thermal Tolerance ◽  
Heat Waves ◽  
Tropical Fish ◽  
Selected Lines ◽  
Thermal Limits ◽  
Evolutionary Rescue ◽  
Hard Limit ◽  
Upper Thermal Tolerance

Climate change is increasing global temperatures and intensifying the frequency and severity of extreme heat waves. How organisms will cope with these changes depends on their inherent thermal tolerance, acclimation capacity, and ability for evolutionary adaptation. Yet, the potential for adaptation of upper thermal tolerance in vertebrates is largely unknown. We artificially selected offspring from wild-caught zebrafish (Danio rerio) to increase (Up-selected) or decrease (Down-selected) upper thermal tolerance over six generations. Selection to increase upper thermal tolerance was also performed on warm-acclimated fish to test whether plasticity in the form of inducible warm tolerance also evolved. Upper thermal tolerance responded to selection in the predicted directions. However, compared to the control lines, the response was stronger in the Down-selected than in the Up-selected lines in which evolution toward higher upper thermal tolerance was slow (0.04 ± 0.008 °C per generation). Furthermore, the scope for plasticity resulting from warm acclimation decreased in the Up-selected lines. These results suggest the existence of a hard limit in upper thermal tolerance. Considering the rate at which global temperatures are increasing, the observed rates of adaptation and the possible hard limit in upper thermal tolerance suggest a low potential for evolutionary rescue in tropical fish living at the edge of their thermal limits.

scholarly journals Intraspecific variation in thermal tolerance differs between tropical and temperate fishes

2020 ◽  
Author(s):  
J.J.H. Nati ◽  
M.B.S. Svendsen ◽  
S. Marras ◽  
S.S. Killen ◽  
J.F. Steffensen ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Intraspecific Variation ◽  
Fish Species ◽  
Thermal Tolerance ◽  
Evolutionary History ◽  
Ecological Impacts ◽  
Tropical Fish ◽  
Tropical Species ◽  
Upper Thermal Tolerance

AbstractHow ectothermic animals will cope with global warming, especially more frequent and intense heatwaves, is a critical determinant of the ecological impacts of climate change. There has been extensive study of upper thermal tolerance limits among fish species but how intraspecific variation in tolerance may be affected by habitat characteristics and evolutionary history has not been considered. Intraspecific variation is a primary determinant of species vulnerability to climate change, with implications for global patterns of impacts of ongoing warming. Using published critical thermal maximum (CTmax) data on 203 marine and freshwater fish species, we found that intraspecific vsariation in upper thermal tolerance varies according to a species’ latitude and evolutionary history. Notably, freshwater tropical species have lower variation in tolerance than temperate species in the northern hemisphere, which implies increased vulnerability to impacts of thermal stress. The extent of variation in CTmax among fish species has a strong phylogenetic signal, which may indicate a constraint on evolvability to rising temperatures in tropical fishes. That is, in addition to living closer to their upper thermal limits, tropical species may have higher sensitivity and lower adaptability to global warming compared to temperate counterparts. This is evidence that tropical fish communities, worldwide, are especially vulnerable to ongoing climate change.

Life at the interface: ecology of Prionodactylus oshaughnessyi in the western Amazon and comparisons with P. argulus and P. eigenmanni

2003 ◽  
Vol 81 (2) ◽  
pp. 302-312 ◽  
Author(s):  
Laurie J Vitt ◽  
Teresa Cristina S. Avila-Pires ◽  
Peter A Zani ◽  
Maria Cristina Espósito ◽  
Shawn S Sartorius
Keyword(s):  
Rain Forest ◽  
Null Model ◽  
Prey Type ◽  
Microhabitat Use ◽  
Body Temperatures ◽  
Insect Larvae ◽  
Ambient Temperatures ◽  
Forest Sites ◽  
Amazonian Rain Forest ◽  
Arboreal Habitat

The gymnophthalmid lizard Prionodactylus oshaughnessyi was studied at two Amazonian rain-forest sites. These lizards live at the interface of the terrestrial habitat and arboreal habitat, are active throughout the day at relatively low body temperatures, and maintain body temperatures (29.0 ± 0.34°C) slightly higher than ambient temperatures. Grasshoppers and crickets, roaches, insect larvae, and spiders dominate their carnivorous diet. Sexual size dimorphism is not apparent but differences in coloration and relative head size exist, with males having brighter and more vivid coloration and a relatively larger head. Differences in activity time, prey type, prey size, and microhabitat use exist between populations. A comparison of three species of Prionodactylus from Amazonian rain forest revealed some ecological similarity. However, differences in microhabitat use and diet exist. Differences in Baupläne were consistent with differences in microhabitat use. Dietary overlaps were relatively low; nevertheless, diets of the Prionodactylus species were more similar to each other than expected, based on a null model analysis in which a sampling of all diets was used for comparison.

scholarly journals Variation in upper thermal tolerance among 19 species from temperate wetlands

2021 ◽  
Vol 96 ◽  
pp. 102856
Author(s):  
Marco Katzenberger ◽  
Helder Duarte ◽  
Rick Relyea ◽  
Juan Francisco Beltrán ◽  
Miguel Tejedo
Keyword(s):  
Thermal Tolerance ◽  
Temperate Wetlands ◽  
Upper Thermal Tolerance
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