Evolutionary history and the strength of species interactions: testing the phylogenetic limiting similarity hypothesis
Evolutionary history and the strength of species interactions: testing the phylogenetic limiting similarity hypothesis
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DOI：
10.1890/13-0986.1
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发表时间：
2014-05-01
期刊：
影响因子：
4.8
通讯作者：
Oakley, Todd H.
中科院分区：
文献类型：
--
作者：
Fritschie, Keith J.;Cardinale, Bradley J.;Oakley, Todd H.
在群落生态学中，一个长期存在的概念是，近亲物种的竞争比远亲更激烈。生态学家援引这种有限相似性假说来解释生物群落的结构和功能模式，并为保护、恢复和入侵物种管理提供信息。然而，很少有研究已经实证检验的有效性的限制相似性假设。在这里，我们报告了一个实验室微观实验的结果，在这个实验中，我们使用了一个由23种常见的、共同出现的北美淡水绿色藻类组成的模型系统来量化216种成对物种相互作用的强度（单独生长与有其他物种存在时种群密度的差异）沿着一个被操纵的进化相关性梯度（系统发育距离，作为在分子系统发育上分离物种的分支长度的总和）。种间的相互作用在这些浮游植物的双养殖中变化很大，从强烈的竞争（混养与单养的相对产量比1）。然而，我们没有发现任何证据表明物种间相互作用的强度受到它们进化相关性的影响。系统发育距离与平均、最小（劣势竞争者）和最大（上级竞争者）相互作用强度之间没有关系（分别为P = 0.19，P = 0.17，P = 0.14; N = 428）。当我们检查每个个体物种时，只有17%的个体物种的相互作用强度作为系统发育距离的函数而变化，并且在Bonferoni校正多次测试后，这些关系都没有保持显著性（N = 23）。最后，当我们将相互作用分为五种不同的类型时，这些类型的频率与物种对之间的系统发育距离无关（F-4，F-422 = 1.63，P = 0.15）。我们的实证研究增加了其他几个表明竞争的生物基础可能不是进化保守的，因此，生态学家可能需要重新评估以前假设的限制相似性假设的一般性。
A longstanding concept in community ecology is that closely related species compete more strongly than distant relatives. Ecologists have invoked this limiting similarity hypothesis to explain patterns in the structure and function of biological communities and to inform conservation, restoration, and invasive-species management. However, few studies have empirically tested the validity of the limiting similarity hypothesis. Here we report the results of a laboratory microcosm experiment in which we used a model system of 23 common, co-occurring North American freshwater green algae to quantify the strength of 216 pairwise species' interactions (the difference in population density when grown alone vs. in the presence of another species) along a manipulated gradient of evolutionary relatedness (phylogenetic distance, as the sum of branch lengths separating species on a molecular phylogeny). Interspecific interactions varied widely in these bicultures of phytoplankton, ranging from strong competition (ratio of relative yield in polyculture vs. monoculture 1). Yet, we found no evidence that the strength of species' interactions was influenced by their evolutionary relatedness. There was no relationship between phylogenetic distance and the average, minimum (inferior competitor), nor maximum (superior competitor) interaction strength across all biculture communities (respectively, P = 0.19, P = 0.17, P = 0.14; N = 428). When we examined each individual species, only 17% of individual species' interactions strengths varied as a function of phylogenetic distance, and none of these relationships remained significant after Bonferoni correction for multiple tests (N = 23). Last, when we grouped interactions into five qualitatively different types, the frequency of these types was not related to phylogenetic distance among species pairs (F-4,F-422 = 1.63, P = 0.15). Our empirical study adds to several others that suggest the biological underpinnings of competition may not be evolutionarily conserved, and thus, ecologists may need to re-evaluate the previously assumed generality of the limiting similarity hypothesis.