Matthews Blake, Mazumder Asit
Water and Watershed Research Program, Department of Biology, University of Victoria, P.O. Box 3020 STN CSC, Victoria, British Columbia, Canada, V85 3N5.
Oecologia. 2004 Jul;140(2):361-71. doi: 10.1007/s00442-004-1579-2. Epub 2004 Apr 29.
Individual variation in the diet of consumers is common in many ecological systems and has important implications for the study of population dynamics, animal behavior, and evolutionary or ecological interactions. Ecologists frequently quantify the niche of a population by intensive analyses of gut contents and feeding behaviors of consumers. Inter-individual differences in delta13C signature can indicate long term differences in feeding behavior, often unattainable by a single snapshot analysis of gut contents. If a consumer's food sources have unique delta13C signatures, then the intrapopulation variation in delta13C may be useful for quantifying diet variation and detecting isotopic evidence of individual specialization. However, intrapopulation variation in delta13C can underestimate or overestimate dietary variation, and therefore is not directly equivalent to a dietary based niche. In this paper we show that intrapopulation variability of delta13C in consumers critically depends on the isotopic range and distribution of food sources. Our analyses fundamentally challenge how we interpret the intrapopulation isotopic variance of delta13C, and how we evaluate isotopic evidence of individual specialization.
在许多生态系统中，消费者饮食的个体差异很常见，这对种群动态、动物行为以及进化或生态相互作用的研究具有重要意义。生态学家经常通过深入分析消费者的肠道内容物和摄食行为来量化种群的生态位。δ13C特征的个体间差异可以表明摄食行为的长期差异，而这通常是通过对肠道内容物的单次快照分析无法实现的。如果消费者的食物来源具有独特的δ13C特征，那么种群内δ13C的变化可能有助于量化饮食差异并检测个体特化的同位素证据。然而，种群内δ13C的变化可能会低估或高估饮食差异，因此并不直接等同于基于饮食的生态位。在本文中，我们表明消费者体内δ13C的种群内变异性关键取决于食物来源的同位素范围和分布。我们的分析从根本上挑战了我们如何解释δ13C的种群内同位素方差，以及我们如何评估个体特化的同位素证据。
