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1. Multi‐scale relationships in thermal limits within and between two cold‐water frog species uncover different trends in physiological vulnerability

   https://doi.org/10.1111/fwb.14102  

   Cicchino, Amanda S. ; Shah, Alisha A. ; Forester, Brenna R. ; Dunham, Jason B. ; Ghalambor, Cameron K. ; Funk, W. Chris ( May 2023 , Freshwater Biology)

   1. Critical thermal limits represent an important component of an organism's capacity to cope with future temperature changes. Understanding the drivers of variation in these traits may uncover patterns in physiological vulnerability to climate change. Local temperature extremes have emerged as a major driver of thermal limits, although their effects can be mediated by the exploitation of fine‐scale spatial variation in temperature through behavioural thermoregulation.

   2. Here, we investigated thermal limits along elevation gradients within and between two cold‐water frog species (Ascaphusspp.), one with a coastal distribution (A. truei) and the other with a continental range (A. montanus). We quantified thermal limits for over 700 tadpoles, representing multiple populations from each species. We combined local temporal and fine‐scale spatial temperature data to quantify local thermal landscapes (i.e., thermalscapes), including the opportunity for behavioural thermoregulation.

   3. Lower thermal limits for either species could not be reached experimentally without the water freezing, suggesting that cold tolerance is <0.3°C. By contrast, upper thermal limits varied among populations, but this variation only reflected local temperature extremes inA. montanus, perhaps as a consequence of the greater variation in stream temperatures across its range. Lastly, we found minimal fine‐scale spatial variability in temperature, suggesting limited opportunity for behavioural thermoregulation and thus increased vulnerability to warming for all populations.

   4. By quantifying local thermalscapes, we uncovered different trends in the relative vulnerability of populations across elevation for each species. InA. truei, physiological vulnerability decreased with elevation, whereas inA. montanus, all populations were equally physiologically vulnerable. These results highlight how similar environments can differentially shape physiological tolerance and patterns of vulnerability of species, and in turn impact their vulnerability to future warming.

    

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2. Macroecological predictors of evolutionary and plastic potential do not apply at microgeographic scales for a freshwater cladoceran under climate change

   https://doi.org/10.1093/evlett/qrad042  

   Nadeau, Christopher P. ; Urban, Mark C. ( October 2023 , Evolution Letters)

   Rapid evolutionary adaptation could reduce the negative impacts of climate change if sufficient heritability of key traits exists under future climate conditions. Plastic responses to climate change could also reduce negative impacts. Understanding which populations are likely to respond via evolution or plasticity could therefore improve estimates of extinction risk. A large body of research suggests that the evolutionary and plastic potential of a population can be predicted by the degree of spatial and temporal climatic variation it experiences. However, we know little about the scale at which these relationships apply. Here, we test if spatial and temporal variation in temperature affects genetic variation and plasticity of fitness and a key thermal tolerance trait (critical thermal maximum; CTmax) at microgeographic scales using a metapopulation of Daphnia magna in freshwater rock pools. Specifically, we ask if (a) there is a microgeographic adaptation of CTmax and fitness to differences in temperature among the pools, (b) pools with greater temporal temperature variation have more genetic variation or plasticity in CTmax or fitness, and (c) increases in temperature affect the heritability of CTmax and fitness. Although we observed genetic variation and plasticity in CTmax and fitness, and differences in fitness among pools, we did not find support for the predicted relationships between temperature variation and genetic variation or plasticity. Furthermore, the genetic variation and plasticity we observed in CTmax are unlikely sufficient to reduce the impacts of climate change. CTmax plasticity was minimal and heritability was 72% lower when D. magna developed at the higher temperatures predicted under climate change. In contrast, the heritability of fitness increased by 53% under warmer temperatures, suggesting an increase in overall evolutionary potential unrelated to CTmax under climate change. More research is needed to understand the evolutionary and plastic potential under climate change and how that potential will be altered in future climates.

    

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3. Interaction of hydric and thermal conditions drive geographic variation in thermoregulation in a widespread lizard

   https://doi.org/10.1002/ecm.1440  

   Rozen‐Rechels, David ; Rutschmann, Alexis ; DupouÉ, AndrÉaz ; Blaimont, Pauline ; Chauveau, Victor ; Miles, Donald B. ; Guillon, Michael ; Richard, Murielle ; Badiane, Arnaud ; Meylan, Sandrine ; et al ( January 2021 , Ecological Monographs)

   Behavioral thermoregulation is an efficient mechanism to buffer the physiological effects of climate change. Thermal ecology studies have traditionally tested how thermal constraints shape thermoregulatory behaviors without accounting for the potential major effects of landscape structure and water availability. Thus, we lack a general understanding of the multifactorial determinants of thermoregulatory behaviors in natural populations. In this study, we quantified the relative contribution of elevation, thermal gradient, moisture gradient, and landscape structure in explaining geographic variation in thermoregulation strategies of a terrestrial ectotherm species. We measured field‐active body temperature, thermal preferences, and operative environmental temperatures to calculate thermoregulation indices, including thermal quality of the habitat and thermoregulation efficiency for a very large sample of common lizards (Zootoca vivipara) from 21 populations over 3 yr across the Massif Central mountain range in France. We used an information‐theoretic approach to compare eight a priori thermo‐hydroregulation hypotheses predicting how behavioral thermoregulation should respond to environmental conditions. Environmental characteristics exerted little influence on thermal preference with the exception that females from habitats with permanent access to water had lower thermal preferences. Field body temperatures and accuracy of thermoregulation were best predicted by the interaction between air temperature and a moisture index. In mesic environments, field body temperature and thermoregulation accuracy increased with air temperature, but they decreased in drier habitats. Thermoregulation efficiency (difference between thermoregulation inaccuracy and the thermal quality of the habitat) was maximized in cooler and more humid environments and was mostly influenced by the thermal quality of the habitat. Our study highlights complex patterns of variation in thermoregulation strategies, which are mostly explained by the interaction between temperature and water availability, independent of the elevation gradient or thermal heterogeneity. Although changes in landscape structure were expected to be the main driver of extinction rate of temperate zone ectotherms with ongoing global change, we conclude that changes in water availability coupled with rising temperatures might have a drastic impact on the population dynamics of some ectotherm species.

    

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4. Local climate determines vulnerability to camouflage mismatch in snowshoe hares

   https://doi.org/10.1111/geb.13049  

   Zimova, Marketa ; Sirén, Alexej P. K. ; Nowak, Joshua J. ; Bryan, Alexander M. ; Ivan, Jacob S. ; Morelli, Toni Lyn ; Suhrer, Skyler L. ; Whittington, Jesse ; Mills, L. Scott ; Morellato, ed., Patricia ( December 2019 , Global Ecology and Biogeography)

   Phenological mismatches, when life‐events become mistimed with optimal environmental conditions, have become increasingly common under climate change. Population‐level susceptibility to mismatches depends on how phenology and phenotypic plasticity vary across a species’ distributional range. Here, we quantify the environmental drivers of colour moult phenology, phenotypic plasticity, and the extent of phenological mismatch in seasonal camouflage to assess vulnerability to mismatch in a common North American mammal.

   North America.

   2010–2017.

   Snowshoe hare (Lepus americanus).

   We used > 5,500 by‐catch photographs of snowshoe hares from 448 remote camera trap sites at three independent study areas. To quantify moult phenology and phenotypic plasticity, we used multinomial logistic regression models that incorporated geospatial and high‐resolution climate data. We estimated occurrence of camouflage mismatch between hares’ coat colour and the presence and absence of snow over 7 years of monitoring.

   Spatial and temporal variation in moult phenology depended on local climate conditions more so than on latitude. First, hares in colder, snowier areas moulted earlier in the fall and later in the spring. Next, hares exhibited phenotypic plasticity in moult phenology in response to annual variation in temperature and snow duration, especially in the spring. Finally, the occurrence of camouflage mismatch varied in space and time; white hares on dark, snowless background occurred primarily during low‐snow years in regions characterized by shallow, short‐lasting snowpack.

   Long‐term climate and annual variation in snow and temperature determine coat colour moult phenology in snowshoe hares. In most areas, climate change leads to shorter snow seasons, but the occurrence of camouflage mismatch varies across the species’ range. Our results underscore the population‐specific susceptibility to climate change‐induced stressors and the necessity to understand this variation to prioritize the populations most vulnerable under global environmental change.

    

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5. How will climate change shape climate opinion?

   https://doi.org/10.1088/1748-9326/ab466a  

   Howe, Peter D. ; Marlon, Jennifer R. ; Mildenberger, Matto ; Shield, Brittany S. ( October 2019 , Environmental Research Letters)

   As climate change intensifies, global publics will experience more unusual weather and extreme weather events. How will individual experiences with these weather trends shape climate change beliefs, attitudes, and behaviors? In this article, we review 73 papers that have studied the relationship between climate change experiences and public opinion. Overall, we find mixed evidence that weather shapes climate opinions. Although there is some support for a weak effect of local temperature and extreme weather events on climate opinion, the heterogeneity of independent variables, dependent variables, study populations, and research designs complicate systematic comparison. To advance research on this critical topic, we suggest that future studies pay careful attention to differences between self-reported and objective weather data, causal identification, and the presence of spatial autocorrelation in weather and climate data. Refining research designs and methods in future studies will help us understand the discrepancies in results, and allow better detection of effects, which have important practical implications for climate communication. As the global population increasingly experiences weather conditions outside the range of historical experience, researchers, communicators, and policymakers need to understand how these experiences shape-and are shaped by-public opinions and behaviors.

    

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