ABSTRACT: An ecosystem engineer’s influence on associated organisms includes 2 components: physical and biological. The physical component is the spatial environment created by the ecosystem engineer, while the biological component is the physiological activity of the engineering species. However, little is known about the ratio between these components. We evaluated this ratio for Mytilus edulis L. by means of a field experiment in which communities of organisms that developed on bare ceramic plates (controls, C) were compared with those that formed on plates carrying patches of live mussels (L) or artificial patches made of mussel dummies (D). The experiment was performed using 2 different age-size groups of mussels and dummies (small-young and large-old). Live mussels had only a weak positive effect on species richness of the associated organisms, but the structure of the communities that formed on tests plates (L, D and C) differed significantly. The similarity of the communities of associated organisms between C and L was 1.5-3 times less than between C and D. Mussel size-age factor had no significant effect on community structure other than on the algal assemblage. The results of this experiment suggest that the influence of mussels on associated organisms cannot be reduced to only the effect of increasing complexity of the spatial environment. The influence of the biological component is significant and can exceed that of the physical component. Thus, in ecosystem engineering, non-living spatial structures cannot serve as an identical substitute for a population of living organisms.

中文翻译：

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贻贝对相关生物影响的生物和物理成分之间的平衡

摘要：生态系统工程师对相关生物的影响包括两个组成部分：物理和生物。物理成分是生态系统工程师创造的空间环境，生物成分是工程物种的生理活动。然而，人们对这些成分之间的比率知之甚少。我们评估了贻贝的这个比率L. 通过田间实验，将在裸陶瓷板上发育的生物群落（对照，C）与在带有活贻贝斑块（L）或由贻贝假人制成的人造斑块（D）的平板上形成的生物群落进行比较. 该实验使用 2 个不同年龄大小的贻贝和假人（小-幼和大-老）进行。活贻贝对相关生物的物种丰富度只有微弱的积极影响，但在测试平板（L、D 和 C）上形成的群落结构存在显着差异。C和L之间相关生物群落的相似性比C和D之间小1.5-3倍。贻贝大小-年龄因子对除藻类组合外的群落结构没有显着影响。该实验的结果表明，贻贝对相关生物的影响不能减少到仅增加空间环境复杂性的影响。生物成分的影响是显着的，可以超过物理成分的影响。因此，在生态系统工程中，非生物空间结构不能作为生物体种群的完全替代品。