Systems Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany
Departamento de Biología y Ecología Animal, Universidad de Vigo, Vigo, Spain.
Proc Biol Sci. 2018 May 30;285(1879). doi: 10.1098/rspb.2018.0621.
Trait diversity, a key component of biodiversity, mediates many essential ecosystem functions and services. However, the mechanisms behind such relationships at large spatial scales are not fully understood. Here we adopt the functional biogeography approach to investigate how the size composition of phytoplankton communities relates to primary production and export production along a broad latitudinal gradient. Using phytoplankton size distribution data and a trait-based model, we find an increase in the average phytoplankton size, size diversity, primary production and export when moving from low to high latitudes. Our analysis indicates that the interplay between spatio-temporal heterogeneities in environmental conditions and a trade-off between the high affinity for nutrients of smaller cells and the ability to avoid predation by larger cells are the main mechanisms driving the observed patterns. Our results also suggest that variations in size diversity alone do not directly lead to changes in primary production and export. The trade-off thus introduces a feedback that influences the relationship between size diversity and ecosystem functions. These findings support the importance of environmentally mediated trade-offs as crucial mechanisms shaping biodiversity and ecosystem function relationships at large spatial scales.
性状多样性是生物多样性的一个关键组成部分，它介导着许多重要的生态系统功能和服务。然而，在大的空间尺度上，这些关系背后的机制还不完全清楚。在这里，我们采用功能生物地理学的方法来研究浮游植物群落的大小组成如何沿宽纬度梯度与初级生产和输出生产相关。我们利用浮游植物大小分布数据和基于性状的模型，发现从低纬度到高纬度，浮游植物的平均大小、大小多样性、初级生产和输出都会增加。我们的分析表明，环境条件的时空异质性与较小细胞对养分的高亲和力和较大细胞逃避捕食的能力之间的权衡之间的相互作用是驱动这些模式的主要机制。我们的研究结果还表明，大小多样性的变化本身并不会直接导致初级生产和输出的变化。这种权衡因此引入了一个反馈，影响了大小多样性与生态系统功能之间的关系。这些发现支持了环境介导的权衡作为在大空间尺度上塑造生物多样性和生态系统功能关系的关键机制的重要性。
