Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada, V5A 1S6.
Proc Biol Sci. 2011 Jun 22;278(1713):1823-30. doi: 10.1098/rspb.2010.1295. Epub 2010 Nov 24.
A tenet of macroecology is that physiological processes of organisms are linked to large-scale geographical patterns in environmental conditions. Species at higher latitudes experience greater seasonal temperature variation and are consequently predicted to withstand greater temperature extremes. We tested for relationships between breadths of thermal tolerance in ectothermic animals and the latitude of specimen location using all available data, while accounting for habitat, hemisphere, methodological differences and taxonomic affinity. We found that thermal tolerance breadths generally increase with latitude, and do so at a greater rate in the Northern Hemisphere. In terrestrial ectotherms, upper thermal limits vary little while lower thermal limits decrease with latitude. By contrast, marine species display a coherent poleward decrease in both upper and lower thermal limits. Our findings provide comprehensive global support for hypotheses generated from studies at smaller taxonomic subsets and geographical scales. Our results further indicate differences between terrestrial and marine ectotherms in how thermal physiology varies with latitude that may relate to the degree of temperature variability experienced on land and in the ocean.
宏观生态学的一个基本原理是，生物体的生理过程与环境条件的大尺度地理模式有关。高纬度地区的物种经历更大的季节性温度变化，因此预计能承受更大的温度极端变化。我们使用所有可用的数据，同时考虑到栖息地、半球、方法学差异和分类亲缘关系，测试了变温动物的热耐受幅度与样本所在地纬度之间的关系。我们发现，热耐受幅度通常随纬度增加而增加，而且在北半球增加的速度更快。在陆生变温动物中，上限温度变化不大，而下限温度随纬度降低。相比之下，海洋物种的上下限温度都呈一致的向极地减少的趋势。我们的发现为从小的分类群和地理尺度的研究中产生的假说提供了全面的全球支持。我们的结果还表明，陆地和海洋变温动物的热生理学随纬度变化的差异可能与陆地和海洋上温度变化的程度有关。
