Salinity tolerances and use of saline environments by freshwater turtles: implications of sea level rise
Salinity tolerances and use of saline environments by freshwater turtles: implications of sea level rise
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DOI：
10.1111/brv.12410
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发表时间：
2018-08-01
影响因子：
10
通讯作者：
Todd, Brian D.
中科院分区：
文献类型：
--
作者：
Agha, Mickey;Ennen, Joshua R.;Todd, Brian D.
预计全球平均海平面将上升，使许多淡水龟种面临盐水侵入淡水生境的风险。淡水海龟比其他类群受到的威胁更大;因此，了解盐度在决定其当代分布和进化方面的作用应该是研究的优先事项。淡水龟是一个缓慢进化的谱系;然而，它们可以在生理或行为上适应不同的盐度水平，因此暂时出现在海洋或半咸水环境中。在这里，我们提供了第一个全面的全球审查淡水龟的使用和容忍咸水生态系统。我们将当前的地理发生，耐盐性，系统发育关系以及生理和行为机制的知识联系在一起，以了解淡水龟对不断变化的盐水环境的反应。我们还审查了淡水龟耐盐性的潜在来源。最后，我们整合2100海平面上升（SLR）的预测，物种分布图，文献收集的咸水利用，并预测暴露的淡水龟预计SLR全球。从我们的综合出版的文献和可用的数据，我们建立了一个框架，沿海淡水龟的空间和系统发育保护优先级。根据我们的文献回顾，70种（类似于30%的沿海淡水龟种），来自10的11个淡水龟科已报告在半咸水生态系统。大多数轶事记录，观察和描述并不意味着淡水龟的长期耐盐性。相反，实验表明，一些物种在生理，行为和生活史特征方面表现出适应和可塑性的潜力，使它们能够忍受不同的时间（例如几天或几个月）和盐水暴露水平。专门生活在半咸水环境中的物种很可能容易受到SLR的影响，因为它们只分布在沿海地区，而且适应的盐度范围很窄。然而，大多数物种没有记录在半咸水栖息地，但也可能是非常脆弱的预计SLR。我们的分析表明，在我们的研究中，大约90%的沿海淡水龟物种将受到影响，全球平均SLR增加1米，到2100年。最危险的是在新几内亚，东南亚，澳大利亚和南北美洲发现的淡水龟，它们可能会失去超过10%的现有地理范围。此外，龟科，Emydidae，和Trionychidae家庭中的海龟物种可能会经历最大的暴露于预计的SLR在其目前的地理范围。更好地了解生存，生长，生殖和人口水平的SLR的反应，将提高特定区域的淡水龟，越来越多地暴露于SLR的人口生存能力预测。整合系统发育，生理和空间框架，以评估预计SLR的影响，可以提高识别脆弱的物种，公会，和需要保护优先的地理区域。我们的结论是，淡水龟的咸淡水和海洋环境的使用提供了线索的进化过程，延长了他们的存在，塑造了他们独特的沿海分布，并可能被证明是有用的，在预测他们对不断变化的世界的反应。
The projected rise in global mean sea levels places many freshwater turtle species at risk of saltwater intrusion into freshwater habitats. Freshwater turtles are disproportionately more threatened than other taxa; thus, understanding the role of salinity in determining their contemporary distribution and evolution should be a research priority. Freshwater turtles are a slowly evolving lineage; however, they can adapt physiologically or behaviourally to various levels of salinity and, therefore, temporarily occur in marine or brackish environments. Here, we provide the first comprehensive global review on freshwater turtle use and tolerance of brackish water ecosystems. We link together current knowledge of geographic occurrence, salinity tolerance, phylogenetic relationships, and physiological and behavioural mechanisms to generate a baseline understanding of the response of freshwater turtles to changing saline environments. We also review the potential origins of salinity tolerance in freshwater turtles. Finally, we integrate 2100 sea level rise (SLR) projections, species distribution maps, literature gathered on brackish water use, and a phylogeny to predict the exposure of freshwater turtles to projected SLR globally. From our synthesis of published literature and available data, we build a framework for spatial and phylogenetic conservation prioritization of coastal freshwater turtles. Based on our literature review, 70 species (similar to 30% of coastal freshwater turtle species) from 10 of the 11 freshwater turtle families have been reported in brackish water ecosystems. Most anecdotal records, observations, and descriptions do not imply long-term salinity tolerance among freshwater turtles. Rather, experiments show that some species exhibit potential for adaptation and plasticity in physiological, behavioural, and life-history traits that enable them to endure varying periods (e.g. days or months) and levels of saltwater exposure. Species that specialize on brackish water habitats are likely to be vulnerable to SLR because of their exclusive coastal distributions and adaptations to a narrow range of salinities. Most species, however, have not been documented in brackish water habitats but may also be highly vulnerable to projected SLR. Our analysis suggests that approximately 90% of coastal freshwater turtle species assessed in our study will be affected by a 1-m increase in global mean SLR by 2100. Most at risk are freshwater turtles found in New Guinea, Southeast Asia, Australia, and North and South America that may lose more than 10% of their present geographic range. In addition, turtle species in the families Chelidae, Emydidae, and Trionychidae may experience the greatest exposure to projected SLR in their present geographic ranges. Better understanding of survival, growth, reproductive and population-level responses to SLR will improve region-specific population viability predictions of freshwater turtles that are increasingly exposed to SLR. Integrating phylogenetic, physiological, and spatial frameworks to assess the effects of projected SLR may improve identification of vulnerable species, guilds, and geographic regions in need of conservation prioritization. We conclude that the use of brackish and marine environments by freshwater turtles provides clues about the evolutionary processes that have prolonged their existence, shaped their unique coastal distributions, and may prove useful in predicting their response to a changing world.