School of Biological Sciences and Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA.
Ecology. 2024 Jul;105(7):e4329. doi: 10.1002/ecy.4329. Epub 2024 May 21.
Hundreds of studies now document positive relationships between biodiversity and critical ecosystem processes, but as ecological communities worldwide shift toward new species configurations, less is known regarding how the biodiversity of undesirable species will shape the functioning of ecosystems or foundation species. We manipulated macroalgal species richness in experimental field plots to test whether and how the identity and diversity of competing macroalgae affected the growth, survival, and microbiome of a common coral in Mo'orea, French Polynesia. Compared to controls without algal competitors, coral growth was significantly suppressed across three macroalgal monocultures, a polyculture of the same three macroalgae, and plots containing inert seaweed mimics; coral mortality was limited and did not differ significantly among treatments. One macroalga suppressed coral growth significantly less than the other two, but none differed from the inert mimic in terms of coral suppression. The composition, dispersion, and diversity of coral microbiomes in treatments with live macroalgae or inert plastic mimics did not differ from controls experiencing no competition. Microbiome composition differed between two macroalgal monocultures and a monoculture versus plastic mimics, but no other microbiome differences were observed among macroalgal or mimic treatments. Together, these findings suggest that algal diversity does not alter harmful impacts of macroalgae on coral performance, which could be accounted for by physical structure alone in these field experiments. While enhancing biodiversity is a recognized strategy for promoting desirable species, it would be worrisome if biodiversity also enhanced the negative impacts of undesirable species. We documented no such effects in this investigation.
现在有数百项研究记录了生物多样性与关键生态系统过程之间的积极关系，但随着全球生态群落向新的物种组合转变，人们对不良物种的生物多样性将如何塑造生态系统或基础物种的功能知之甚少。我们在实验野外小区中操纵大型藻类的物种丰富度，以检验竞争大型藻类的身份和多样性是否以及如何影响莫雷阿岛（法属波利尼西亚）一种常见珊瑚的生长、存活和微生物组。与没有藻类竞争者的对照相比，在三种大型藻类的单培养物、相同的三种大型藻类的多培养物以及含有惰性海藻模拟物的小区中，珊瑚的生长明显受到抑制；珊瑚死亡率在处理组之间没有显著差异且受到限制。一种大型藻类对珊瑚生长的抑制作用明显小于另外两种，但在抑制珊瑚方面，它们都与惰性模拟物没有区别。在有活藻类或惰性塑料模拟物的处理中，珊瑚微生物组的组成、分散和多样性与未受竞争影响的对照没有差异。在两种大型藻类的单培养物之间以及单培养物与塑料模拟物之间，微生物组的组成存在差异，但在大型藻类或模拟物处理中没有观察到其他微生物组差异。这些发现表明，藻类多样性不会改变藻类对珊瑚表现的有害影响，这在这些野外实验中仅可以用物理结构来解释。虽然增加生物多样性是促进有益物种的公认策略，但如果生物多样性也增强了不良物种的负面影响，那将令人担忧。在本研究中，我们没有记录到这种影响。
