Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky University Oldenburg, Schleusenstrasse 1, Wilhelmshaven, Germany.
PLoS One. 2012;7(6):e37856. doi: 10.1371/journal.pone.0037856. Epub 2012 Jun 6.
Food webs may be affected by evolutionary processes, and effective evolutionary time ultimately affects the probability of species evolving to fill the niche space. Thus, ecosystem history may set important evolutionary constraints on community composition and food web structure. Food chain length (FCL) has long been recognized as a fundamental ecosystem attribute. We examined historical effects on FCL in large lakes spanning >6 orders of magnitude in age. We found that food chains in the world's ancient lakes (n = 8) were significantly shorter than in recently formed lakes (n = 10) and reservoirs (n = 3), despite the fact that ancient lakes harbored much higher species richness, including many endemic species. One potential factor leading to shorter FCL in ancient lakes is an increasing diversity of trophic omnivores and herbivores. Speciation could simply broaden the number of species within a trophic group, particularly at lower trophic levels and could also lead to a greater degree of trophic omnivory. Our results highlight a counter-intuitive and poorly-understood role of evolutionary history in shaping key food web properties such as FCL.
食物网可能会受到进化过程的影响，有效的进化时间最终会影响物种进化以填补生态位空间的概率。因此，生态系统历史可能对群落组成和食物网结构施加重要的进化限制。食物链长度 (FCL) 长期以来一直被认为是一个基本的生态系统属性。我们研究了跨越 6 个数量级的年龄的大湖对 FCL 的历史影响。我们发现，尽管古老湖泊的物种丰富度高得多，包括许多特有物种，但世界上古老湖泊（n=8）的食物链明显短于最近形成的湖泊（n=10）和水库（n=3）。导致古老湖泊中 FCL 缩短的一个潜在因素是营养级杂食动物和草食动物的多样性增加。物种形成可能只是拓宽了一个营养组内的物种数量，特别是在较低的营养水平，也可能导致更高程度的营养级杂食性。我们的研究结果强调了进化历史在塑造关键食物网特性（如 FCL）方面的反直觉和理解不足的作用。
