Southern Seas Ecology Laboratories, School of Biological Sciences, and The Environment Institute, DX 650 418, The University of Adelaide, Adelaide, SA 5005, Australia.
Southern Seas Ecology Laboratories, School of Biological Sciences, and The Environment Institute, DX 650 418, The University of Adelaide, Adelaide, SA 5005, Australia.
Sci Total Environ. 2018 Dec 15;645:615-622. doi: 10.1016/j.scitotenv.2018.07.168. Epub 2018 Jul 18.
Niche segregation allows competing species to capture resources in contrasting ways so they can co-exist and maintain diversity, yet global change is simplifying ecosystems and associated niche diversity. Whether climate perturbations alter niche occupancy among co-occurring species and affect species diversity is a key, but unanswered question. Using CO vents as natural analogues of ocean acidification, we show that competing fish species with overlapping diets are partially segregated across microhabitat niches and differently-orientated substrata under ambient CO conditions. Under elevated CO, benthic microhabitats experienced a significant increase in non-calcifying turf and fleshy algae but a sharp reduction in calcareous algae. The increased availability of turf and fleshy algae supported increased densities of a competitively dominant species, whilst the reduction in calcifying algal microhabitats decreased densities of several subordinate species. The change in microhabitat availability also drove an increased overlap in microhabitat use among competing fishes at the vents, associated with a reduced fish species richness on horizontal substrates. We conclude that loss of preferred microhabitat niches, exacerbated by population proliferation of competitively dominant species, can drive population losses of less common and subordinate species, and reduce local species richness. The indirect effects of ocean acidification on microhabitat availability can therefore impair maintenance of species populations, and drive changes in local community and biodiversity patterns.
生态位隔离使竞争物种以不同的方式获取资源，从而能够共存并维持多样性，但全球变化正在简化生态系统及其相关的生态位多样性。气候干扰是否会改变共存物种的生态位占据情况并影响物种多样性，这是一个关键但尚未解决的问题。利用 CO 喷口作为海洋酸化的自然模拟物，我们表明，具有重叠饮食的竞争鱼类物种在微生境生态位和环境 CO 条件下不同取向的基质中部分隔离。在高 CO 下，底栖微生境中非钙化的草皮和肉质藻类的数量显著增加，但钙化藻类的数量急剧减少。草皮和肉质藻类的增加可用性支持了竞争力强的物种密度的增加，而钙化藻类微生境的减少降低了几个从属物种的密度。微生境可用性的变化也导致了喷口处竞争鱼类之间微生境利用的重叠增加，与水平基质上鱼类物种丰富度的降低有关。我们的结论是，由于竞争力强的物种数量的增殖导致首选微生境生态位的丧失，可能会导致较少见和从属物种的种群损失，并降低当地物种丰富度。因此，海洋酸化对微生境可用性的间接影响可能会损害物种种群的维持，并导致当地群落和生物多样性模式发生变化。
