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Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits

Species’ tolerance limits determine their capacity to tolerate climatic extremes and limit their potential distributions. Interspecific variation in thermal tolerances is often proposed to indicate climatic vulnerability and is, therefore, the subject of many recent meta-studies on differential capa...

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Autores principales: Pintor, Anna F. V., Schwarzkopf, Lin, Krockenberger, Andrew K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4798272/
https://www.ncbi.nlm.nih.gov/pubmed/26990769
http://dx.doi.org/10.1371/journal.pone.0150408
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author Pintor, Anna F. V.
Schwarzkopf, Lin
Krockenberger, Andrew K.
author_facet Pintor, Anna F. V.
Schwarzkopf, Lin
Krockenberger, Andrew K.
author_sort Pintor, Anna F. V.
collection PubMed
description Species’ tolerance limits determine their capacity to tolerate climatic extremes and limit their potential distributions. Interspecific variation in thermal tolerances is often proposed to indicate climatic vulnerability and is, therefore, the subject of many recent meta-studies on differential capacities of species from climatically different habitats to deal with climate change. Most studies on thermal tolerances do not acclimate animals or use inconsistent, and insufficient, acclimation times, limiting our knowledge of the shape, duration and extent of acclimation responses. Consequently patterns in thermal tolerances observed in meta-analyses, based on data from the literature are based on inconsistent, partial acclimation and true trends may be obscured. In this study we describe time-course of complete acclimation of critical thermal minima in the tropical ectotherm Carlia longipes and compare it to the average acclimation response of other reptiles, estimated from published data, to assess how much acclimation time may contribute to observed differences in thermal limits. Carlia longipes decreased their lower critical thermal limits by 2.4°C and completed 95% of acclimation in 17 weeks. Wild populations did not mirror this acclimation process over the winter. Other reptiles appear to decrease cold tolerance more quickly (95% in 7 weeks) and to a greater extent, with an estimated average acclimation response of 6.1°C. However, without data on tolerances after longer acclimation times available, our capacity to estimate final acclimation state is very limited. Based on the subset of data available for meta-analysis, much of the variation in cold tolerance observed in the literature can be attributed to acclimation time. Our results indicate that (i) acclimation responses can be slow and substantial, even in tropical species, and (ii) interspecific differences in acclimation speed and extent may obscure trends assessed in some meta-studies. Cold tolerances of wild animals are representative of cumulative responses to recent environments, while lengthy acclimation is necessary for controlled comparisons of physiological tolerances. Measures of inconsistent, intermediate acclimation states, as reported by many studies, represent neither the realised nor the potential tolerance in that population, are very likely underestimates of species’ physiological capacities and may consequently be of limited value.
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spelling pubmed-47982722016-03-23 Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits Pintor, Anna F. V. Schwarzkopf, Lin Krockenberger, Andrew K. PLoS One Research Article Species’ tolerance limits determine their capacity to tolerate climatic extremes and limit their potential distributions. Interspecific variation in thermal tolerances is often proposed to indicate climatic vulnerability and is, therefore, the subject of many recent meta-studies on differential capacities of species from climatically different habitats to deal with climate change. Most studies on thermal tolerances do not acclimate animals or use inconsistent, and insufficient, acclimation times, limiting our knowledge of the shape, duration and extent of acclimation responses. Consequently patterns in thermal tolerances observed in meta-analyses, based on data from the literature are based on inconsistent, partial acclimation and true trends may be obscured. In this study we describe time-course of complete acclimation of critical thermal minima in the tropical ectotherm Carlia longipes and compare it to the average acclimation response of other reptiles, estimated from published data, to assess how much acclimation time may contribute to observed differences in thermal limits. Carlia longipes decreased their lower critical thermal limits by 2.4°C and completed 95% of acclimation in 17 weeks. Wild populations did not mirror this acclimation process over the winter. Other reptiles appear to decrease cold tolerance more quickly (95% in 7 weeks) and to a greater extent, with an estimated average acclimation response of 6.1°C. However, without data on tolerances after longer acclimation times available, our capacity to estimate final acclimation state is very limited. Based on the subset of data available for meta-analysis, much of the variation in cold tolerance observed in the literature can be attributed to acclimation time. Our results indicate that (i) acclimation responses can be slow and substantial, even in tropical species, and (ii) interspecific differences in acclimation speed and extent may obscure trends assessed in some meta-studies. Cold tolerances of wild animals are representative of cumulative responses to recent environments, while lengthy acclimation is necessary for controlled comparisons of physiological tolerances. Measures of inconsistent, intermediate acclimation states, as reported by many studies, represent neither the realised nor the potential tolerance in that population, are very likely underestimates of species’ physiological capacities and may consequently be of limited value. Public Library of Science 2016-03-18 /pmc/articles/PMC4798272/ /pubmed/26990769 http://dx.doi.org/10.1371/journal.pone.0150408 Text en © 2016 Pintor et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Pintor, Anna F. V.
Schwarzkopf, Lin
Krockenberger, Andrew K.
Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits
title Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits
title_full Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits
title_fullStr Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits
title_full_unstemmed Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits
title_short Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits
title_sort extensive acclimation in ectotherms conceals interspecific variation in thermal tolerance limits
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4798272/
https://www.ncbi.nlm.nih.gov/pubmed/26990769
http://dx.doi.org/10.1371/journal.pone.0150408
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