Impacts of climate warming on terrestrial ectotherms across latitude. Proc Nat Acad Sci USA

Program on Climate Change and Department of Oceanography and Department of Biology, University of Washington, Seattle, WA 98195, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 06/2008; 105(18):6668-72. DOI: 10.1073/pnas.0709472105
Source: PubMed


The impact of anthropogenic climate change on terrestrial organisms is often predicted to increase with latitude, in parallel with the rate of warming. Yet the biological impact of rising temperatures also depends on the physiological sensitivity of organisms to temperature change. We integrate empirical fitness curves describing the thermal tolerance of terrestrial insects from around the world with the projected geographic distribution of climate change for the next century to estimate the direct impact of warming on insect fitness across latitude. The results show that warming in the tropics, although relatively small in magnitude, is likely to have the most deleterious consequences because tropical insects are relatively sensitive to temperature change and are currently living very close to their optimal temperature. In contrast, species at higher latitudes have broader thermal tolerance and are living in climates that are currently cooler than their physiological optima, so that warming may even enhance their fitness. Available thermal tolerance data for several vertebrate taxa exhibit similar patterns, suggesting that these results are general for terrestrial ectotherms. Our analyses imply that, in the absence of ameliorating factors such as migration and adaptation, the greatest extinction risks from global warming may be in the tropics, where biological diversity is also greatest.

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    • "In ectotherms, the thermal niche is fundamentally defined by physiological tolerances and defines a population's potential response to changing climates (Deutsch et al., 2008; Huey et al., 2012; Sunday et al., 2011). Thermal tolerances are not fixed, however, but can shift through acclimation based on the environment experienced by the organism (Anneli Korhonen and Lagerspetz, 1996; Claussen, 1977; Somero, 2005). "
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    ABSTRACT: Temperature is one of the primary environmental variables limiting organismal performance, fitness, and species distributions. Yet, understanding temperature effects requires thorough exploration of thermal constraints and organismal responses that can translate to fitness and non-lethal long-term consequences under both constant and changing thermal regimes. We examined the thermal ecology of the fiddler crab Uca panacea, including critical thermal limits, thermal sensitivity of locomotion, operative environmental temperatures, preferred body temperatures, and acclimation ability. Operative environmental temperatures frequently reached the critical thermal maximum (41.8±0.8°C, mean ± s.e.m.), especially in unvegetated microhabitats, indicating the need for behavioral thermoregulation to maintain diurnal activity patterns. Preferred body temperatures (21.1-28.6°C) were substantially below the thermal optimum (30-40°C), although further research is needed to determine the driver of this mismatch. Critical thermal limits shifted 2-4°C in response to exposure to low (20°C) or high (35°C) temperatures, with full acclimation occurring in approximately 9d. This capacity for rapid acclimation, combined with the capacity for behavioral thermoregulation, is a strong candidate mechanism that explains the broad habitat use and could help explain the successful pantropical distribution of fiddler crabs. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · Jun 2015 · Journal of Thermal Biology
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    • "Climate overlap is an index of climate change that can be interpreted as the similarity between historical and future weather in a region. It is useful for vulnerability assessments because (Nadeau and Fuller 2015): (1) it measures changes in multiple weather variables and the correlation between those variables; (2) it measures changes in the means, variation, and probability of extremes of each weather variable; and (3) it takes into account the historical climate variation in a region, which can affect the breadth of species thermal tolerances (Tewksbury et al. 2008, Deutsch et al. 2008) and the likelihood that future weather will fall outside the historical climate variation. Each of these components of climate is important to the persistence of many species (Nadeau and Fuller 2015). "
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    ABSTRACT: Determining where biodiversity is likely to be most vulnerable to climate change and methods to reduce that vulnerability are necessary first steps to incorporate climate change into biodiversity management plans. Here, we use a spatial climate change vulnerability assessment to (1) map the potential vulnerability of terrestrial biodiversity to climate change in the northeastern United States and (2) provide guidance on how and where management actions for biodiversity could provide long-term benefits under climate change (i.e., climate-smart management considerations). Our model suggests that biodiversity will be most vulnerable in Delaware, Maryland, and the District of Columbia due to the combination of high climate change velocity, high landscape resistance, and high topoclimate homogeneity. Biodiversity is predicted to be least vulnerable in Vermont, Maine, and New Hampshire because large portions of these states have low landscape resistance, low climate change velocity, and low topoclimate homogeneity. Our spatial climate-smart management considerations suggest that: (1) high topoclimate diversity could moderate the effects of climate change across 50% of the region; (2) decreasing local landscape resistance in conjunction with other management actions could increase the benefit of those actions across 17% of the region; and (3) management actions across 24% of the region could provide long-term benefits by promoting short-term population persistence that provides a source population capable of moving in the future. The guidance and framework we provide here should allow conservation organizations to incorporate our climate-smart management considerations into management plans without drastically changing their approach to biodiversity conservation.
    Full-text · Article · Jun 2015 · Ecosphere
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    • "Rapid changes in temperature are causing many species to shift their geographic ranges, yet species responses are not uniform (Wilson et al., 2005). Differential responses among taxa are likely to derive from both spatial and temporal variation in the direction and magnitude of temperature change and from species responses to those changes (Deutsch et al., 2008; Mair et al., 2012). The impacts of current temperature change on species and communities may depend strongly on latitude, as factors such as life history and thermal specialization vary with distance from the equator (Huey et al., 2009; Sheldon & Tewksbury, 2014). "
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    ABSTRACT: Aim Identifying factors that limit species distributions is a fundamental question in ecology with implications for understanding global biodiversity patterns and species responses to environmental change. Theory suggests that temperature seasonality may affect range size. Species at higher latitudes and elevations experience greater temperature variation, which should lead to broader thermal tolerances and elevational ranges. Research suggests that realized seasonality, or the seasonality species experience when active, may be a better predictor of distributions than annual seasonality.We tested the seasonality hypothesis by examining relationships between environmental factors and elevational range. Location Argentina. Methods We gathered data on ecology and thermal physiology for 33 Liolaemus lizards (Liolaemidae) and analysed data in phylogenetic comparative analyses using mitochondrial DNA sequences.We used 1000 tree structures and ran phylogenetic generalized least squares analyses on all 33 species and on 23 species in the boulengeri clade to determine if the elevational range of lizards shows a positive relationship with annual and realized seasonality, thermal tolerance, latitude and elevational midpoint of the species distribution. Results Latitude and elevational midpoint were good predictors of elevational range in all models.Annual seasonality was a good predictor of elevational range in models containing 33 species.Variation in phylogenetic tree structure led to differences in the best-fit statistical models. Thermal tolerance and realized seasonality were not good indicators of elevational range. Main conclusions Our findings support some, but not all, of the predictions of the seasonality hypothesis. Species at higher latitudes and elevations have larger elevational ranges, and annual seasonality is partly responsible for this increase.Yet, adult thermal tolerance shows no relationship with elevational range, suggesting that distributions may depend on the physiology of other Liolaemus life stages. Differences in phylogenetic tree structure and the number of species included in analyses can lead to different conclusions regarding the seasonality hypothesis.
    Full-text · Article · Jun 2015 · Global Ecology and Biogeography
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