Tvärminne Zoological Station, University of Helsinki, Hanko, Finland; Departamento de Biología, Instituto Universitario de Investigación Marina (INMAR), University of Cádiz, Spain; Baltic Sea Centre, Stockholm University, Stockholm, Sweden.
Department of Biology, University of Southern Denmark, Odense, Denmark.
Mar Environ Res. 2021 May;167:105321. doi: 10.1016/j.marenvres.2021.105321. Epub 2021 Mar 30.
The contributions of habitat-forming species to the biodiversity and ecosystem processes of marine and terrestrial ecosystems are widely recognized. Aquatic plants are considered foundation species in shallow ecosystems, as they maintain biodiversity and sustain many ecosystem functions such as primary production and respiration. Despite the increasing amount of biodiversity-ecosystem functioning experiments in seagrass habitats, the effects of benthic variability on ecosystem functioning are rarely investigated across spatially variable aquatic plant habitats. Here, we quantitatively link seasonal variability in seafloor metabolism (i.e. gross primary production and community respiration) with major benthic community components (i.e. microphytobenthos, aquatic plants and macrofauna) across a structural complexity gradient of habitat-forming species (in terms of shoot density and biomass), ranging from bare sand, to a sparse mixture of plants to a dense monospecific seagrass meadow. The increasing complexity gradient enhanced the magnitude of the relationships between benthic community and seafloor metabolism. The daily average seafloor metabolism per season at the bare site was similar to the sparse site, highlighting the role of microphytobenthos for seafloor metabolism in shallow unvegetated sediments. The contribution of the associated macrofauna to the seafloor respiration was similar to the aquatic plant community contribution. Infauna was the main macrofaunal component significantly explaining the seasonal variability of seafloor respiration. However, benthic community-metabolism relationships were stronger within the plant community than within the macrofauna community (i.e. steepest slopes and lowest p-values). Understanding these relationships are a priority since climate change and biodiversity loss are reducing habitat complexity around the world, jeopardizing valuable ecosystem functions and services.
生境形成物种对海洋和陆地生态系统生物多样性和生态系统过程的贡献已得到广泛认可。水生植物被认为是浅海生态系统的基础物种，因为它们维持生物多样性并支撑着许多生态系统功能，如初级生产和呼吸作用。尽管在海草草甸生境中进行了越来越多的生物多样性-生态系统功能实验，但很少有研究调查底栖生物变异性对跨空间变化的水生植物生境中生态系统功能的影响。在这里，我们定量地将海底代谢（即总初级生产力和群落呼吸）的季节性变化与主要底栖群落组成部分（即微型生物、水生植物和大型动物）联系起来，这些组成部分在生境形成物种的结构复杂性梯度上具有不同的特征（以茎密度和生物量表示），从裸露的沙滩到稀疏的植物混合物到密集的单一种海草草甸。复杂性增加的梯度增强了底栖群落和海底代谢之间关系的强度。每个季节在裸露地点的海底代谢的日平均值与稀疏地点相似，这突显了微型生物在浅无植被沉积物中的海底代谢中的作用。相关大型动物对海底呼吸的贡献与水生植物群落的贡献相似。底栖动物是主要的大型动物组成部分，它显著解释了海底呼吸的季节性变化。然而，在植物群落内，底栖群落-代谢关系比在大型动物群落内更强（即最陡峭的斜率和最低的 p 值）。了解这些关系是当务之急，因为气候变化和生物多样性丧失正在减少世界各地的生境复杂性，危及宝贵的生态系统功能和服务。
