Thermal and energetic constraints on ectotherm abundance: A global test using lizards
Thermal and energetic constraints on ectotherm abundance: A global test using lizards
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DOI：
10.1890/07-0845.1
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发表时间：
2008-01-01
期刊：
影响因子：
4.8
通讯作者：
Jetz, Walter
中科院分区：
文献类型：
--
作者：
Buckley, Lauren B.;Rodda, Gordon H.;Jetz, Walter
鸟类和哺乳动物的种群密度随着体重的增加而下降，其速度与代谢率的增加速度大致相同，这表明能量需求限制了恒温动物的种群密度。在变温动物中，代谢率随体温呈指数增长，表明环境温度也可能限制种群密度。在这里，我们通过检查483种蜥蜴种群来测试一个生态上重要的异温脊椎动物群体的简单生物能量模型。我们发现蜥蜴种群密度随体重的幂律下降，其斜率近似与代谢率和体重之间关系的斜率相反。能源供应应该会限制人口密度。正如预测的那样，环境生产力对蜥蜴密度有积极影响，加强了蜥蜴密度与体重之间的关系。相比之下，由于行为温度调节、热演化或变温性能的温度依赖性，环境温度的影响最多是微弱的。我们的研究结果初步揭示了在广泛的空间尺度上，能源需求和可用性如何对变恒温动物和恒温动物的密度产生不同的限制。
Population densities of birds and mammals have been shown to decrease with body mass at approximately the same rate as metabolic rates increase, indicating that energetic needs constrain endotherm population densities. In ectotherms, the exponential increase of metabolic rate with body temperature suggests that environmental temperature may additionally constrain population densities. Here we test simple bioenergetic models for an ecologically important group of ectothermic vertebrates by examining 483 lizard populations. We find that lizard population densities decrease as a power law of body mass with a slope approximately inverse to the slope of the relationship between metabolic rates and body mass. Energy availability should limit population densities. As predicted, environmental productivity has a positive effect on lizard density, strengthening the relationship between lizard density and body mass. In contrast, the effect of environmental temperature is at most weak due to behavioral thermoregulation, thermal evolution, or the temperature dependence of ectotherm performance. Our results provide initial insights into how energy needs and availability differentially constrain ectotherm and endotherm density across broad spatial scales.