Ecological status classification systems based on biological elements (e.g., macroinvertebrate communities) are dependent on their response to different pressures. However, there is a need to determine if invasive species should be incorporated to indicator parameters (i.e. metrics based on measurements of richness and diversity) or as a pressure affecting such parameters. Moreover, because ecosystem classification systems are lacking for northwestern Iberian estuaries, there is even the possibility to develop a new metric penalizing presence or abundance of invasive species. To increase our understanding on this topic, we analyze the taxonomic and functional responses of benthic macroinvertebrates to Corbicula invasion along the environmental gradient of 12 northwestern Iberian estuaries. Macroinvertebrate assemblages were described and compared between invaded and uninvaded sections. Additionally, to assess differences in community structure, macroinvertebrate assemblages’ similarity was examined between two distinct estuarine sections (freshwater and oligohaline vs transitional water and mesohaline) and among water body types, including and excluding Corbicula from the analysis. The salinity gradient was the main driver explaining changes in macroinvertebrate assemblages and in functional group distribution. Freshwater and transitional water sections clearly differed in macroinvertebrate assemblages and functional groups composition. In addition, differences among river types in macroinvertebrate composition were found. Corbicula inclusion or exclusion from multivariate community analysis significantly affected the results in functional feeding group composition in the Cantabric-Atlantic siliceous river axis type. Nevertheless, considering Corbicula as a pressure at the regional scale did not provide different results in diversity indices calculation. Hence, we argue that because Corbicula eradication is virtually impossible, it should be included as an additional metric evidencing its presence as a negative indication, or be included within other indicator metrics used in the assessment of the ecological status, for instance in invertebrate abundance metrics were its dominance should be indicative of invasion impairment.

基于生物要素（例如大型无脊椎动物群落）的生态状况分类系统取决于它们对不同压力的反应。然而，需要确定是否应将入侵物种纳入指标参数（即基于丰富度和多样性测量的指标）或作为影响这些参数的压力。此外，由于伊比利亚西北部河口缺乏生态系统分类系统，甚至有可能开发一种新的衡量标准来惩罚入侵物种的存在或丰度。为了增加我们对这个主题的理解，我们分析了底栖大型无脊椎动物对Corbicula的分类和功能反应沿伊比利亚西北部 12 个河口的环境梯度入侵。描述了大型无脊椎动物组合，并在入侵和未入侵部分之间进行了比较。此外，为了评估群落结构的差异，在两个不同的河口部分（淡水和寡盐与过渡水和中盐）之间以及水体类型（包括和不包括Corbicula ）之间检查了大型无脊椎动物组合的相似性从分析。盐度梯度是解释大型无脊椎动物组合和功能组分布变化的主要驱动因素。淡水和过渡水部分的大型无脊椎动物组合和功能组组成明显不同。此外，还发现了河流类型之间大型无脊椎动物组成的差异。多变量群落分析中包含或排除小蚯蚓显着影响坎塔布里克-大西洋硅质河轴型功能性摄食群组成的结果。然而，将Corbicula视为区域尺度的压力并没有在多样性指数计算中提供不同的结果。因此，我们认为因为Corbicula根除几乎是不可能的，它应该作为一个额外的指标来证明它的存在作为一个负面迹象，或者被包括在用于评估生态状况的其他指标指标中，例如在无脊椎动物丰度指标中，它的主导地位应该表明侵袭障碍。