Reniers Jane, Brendonck Luc, Roberts J Dale, Verlinden Wim, Vanschoenwinkel Bram
Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven, Charles Deberiotstraat 32, 3000, Leuven, Belgium,
Oecologia. 2015 Jul;178(3):931-41. doi: 10.1007/s00442-015-3258-x. Epub 2015 Feb 20.
For many amphibians, high temperatures and limited precipitation are crucial habitat characteristics that limit species ranges and modulate life-history characteristics. Although knowledge of the ability of amphibians to cope with such environmental harshness is particularly relevant in the light of ongoing environmental change, relatively little is known about natural variation in age, maturation and associated life-history traits across species' ranges. We used the analysis of growth rings in bones to investigate the link between environmental harshness and life-history traits, including age and body size distribution, in specimens from 20 populations of the Australian bleating froglet, Crinia pseudinsignifera. Despite the short lifespan of the species, bone slides revealed geographic variation in average age, body size and reproductive investment linked to variation in temperature and rainfall. We found no difference in age at maturation in different climatic harshness regimes. Frogs from harsher environments invested less in their first reproductive event but grew older than their counterparts in more benign environments, thereby allowing for more reproductive events and buffering them against the increased chance of reproductive failure in the harsher environments. For individual frogs, climatic harshness experienced during an individual's life promoted larger body size. Overall, these results illustrate how bone structure analyses from preserved specimens allow both the testing of ecogeographic hypotheses and the assessment of the adaptive potential of species in the light of environmental change.
对于许多两栖动物来说，高温和有限降水是关键的栖息地特征，它们限制了物种分布范围并调节着生活史特征。鉴于当前的环境变化，了解两栖动物应对这种环境恶劣状况的能力尤为重要，但对于物种分布范围内年龄、成熟度及相关生活史特征的自然变异，我们所知甚少。我们通过分析骨骼中的生长环，来研究澳大利亚鸣声姬蛙（Crinia pseudinsignifera）20个种群标本中环境恶劣程度与生活史特征之间的联系，这些特征包括年龄和体型分布。尽管该物种寿命较短，但骨骼切片显示，平均年龄、体型和繁殖投入存在地理变异，这与温度和降雨的变化有关。我们发现，在不同气候恶劣程度的环境中，成熟年龄没有差异。来自更恶劣环境的青蛙在首次繁殖时投入较少，但比生活在更适宜环境中的同类活得更久，从而能够进行更多次繁殖，并缓冲了它们在更恶劣环境中繁殖失败几率增加的影响。对于个体青蛙来说，其一生中经历的气候恶劣程度会促使体型变大。总体而言，这些结果表明，对保存标本进行骨骼结构分析，既能检验生态地理学假设，又能根据环境变化评估物种的适应潜力。
