Efficient implementation of nematodes-based indices for ecological quality assessment requires fundamental knowledge on their biodiversity and functional patterns along with the drivers that generate these patterns. Though, it is still unclear if nematodes taxonomical attributes are driven by the same environmental drivers as their functional (biological traits) counterparts, or if their taxonomical diversity is also enhanced by their functional diversity. To fill this knowledge gap, we investigated taxonomical (based on nematode genera abundances dataset) and functional attributes: trophic groups (TG) and life history strategies (LHS) of benthic nematodes collected from 35 sampling stations along the Sado Estuary, SW Portugal. Along with biological samples we measured environmental variables in the water and sediments as well as sediment grain size.

Our results demonstrated that taxonomy-based assemblages were mainly structured by the salinity gradient and further by the interplay of granulometry and organic matter content. Contrastingly, trait-based distribution patterns were largely driven by the variations in the above sediment dissolved oxygen concentration. This finding largely draw attention to the role that above sediment dissolved oxygen concentration exerts on nematode assemblages and their functional distribution patterns. Consequently, our results demonstrate that biological traits introduce a new dimensionality in multivariate data that otherwise could not be detected using solely taxonomical information, thereby enhancing our knowledge on ecological gradients existing within an estuary.

Additionally, we found a strong correlation between functional richness (based on the combination of TG and LHS traits) and diversity taxonomic metrics (species richness, Simpson and Shannon diversity), although no correlation was found between taxonomic diversity indices and single nematode ecological indices (ITD index of trophic diversity and MI Maturity Index). Therefore, the combined use of functional traits and its derived metrics was demonstrated to effectively reflect taxonomical diversity presenting reliable and highly complementary information for the assessment and monitoring of marine coastal sediments using benthic nematodes.

有效实施基于线虫的指数进行生态质量评估需要有关其生物多样性和功能模式的基本知识，以及产生这些模式的驱动因素。虽然，目前尚不清楚线虫的分类学特征是否由与其功能（生物学特性）对应物相同的环境驱动因素驱动，或者其分类学多样性是否也因其功能多样性而得到增强。为了填补这一知识空白，我们调查了分类学（基于线虫属丰度数据集）和功能属性：从葡萄牙西南部佐渡河口的35个采样站收集的底栖线虫营养类群（TG）和生活史策略（LHS）。

我们的结果表明，基于分类学的组合主要由盐度梯度构成，并且进一步由粒度分析法和有机物含量的相互作用构成。相反，基于特征的分布模式主要受上述沉积物溶解氧浓度变化的驱动。这一发现在很大程度上引起了人们对以上沉淀物溶解氧浓度对线虫组合及其功能分布模式的作用的关注。因此，我们的结果表明，生物学特征在多变量数据中引入了新的维度，否则只能使用分类信息无法检测到，从而增强了我们对河口内生态梯度的认识。

此外，我们发现功能丰富度（基于TG和LHS性状的组合）与多样性分类指标（物种丰富度，辛普森和香农多样性）之间存在很强的相关性，尽管在分类学多样性指标和单个线虫生态指标之间未发现相关性（营养多样性的ITD指数和MI成熟度指数）。因此，功能性特征及其衍生指标的组合使用被证明可以有效地反映分类学多样性，从而为使用底栖线虫评估和监测海洋沿海沉积物提供可靠且高度互补的信息。