Abstract: Estuaries are one of the most threatened ecosystems, with a great number of stressors related to pollution, hydromorphological changes, and invasive species. However, the response of the biological indicators proposed for their ecological status assessment is not always well established. When using estuarine vegetation (saltmarshes and seagrasses) as an indicator, there are several theoretical concepts regarding the relationships between the variations of this indicator and hydromorphological stressors. It is precisely these relationships which are presented in this work. To carry out this objective, based on the first intercalibration process, a set of metrics for saltmarsh and seagrass taxonomic compositions (e.g., loss of number of taxa and richness) and abundance (e.g., relative coverage and relative extent) have been selected and applied to different estuaries located in Northern Spain. Additionally, a methodology for the hydromorphological status assessment, based on the analysis of the anthropogenic changes in the hydrodynamic and morphological estuarine characteristics (e.g., the extension of land claim areas or changes in the estuarine perimeter), has been developed and applied to these transitional water bodies in order to find a gradient of pressured sites in which we seek correlations between the vegetation metrics and hydromorphological stressors. As a result, the response of the different vegetation indicators is variable. In some cases, a negative correlation of the indicator with the pressure degree exists, whereas in other cases, the relationship is not as clear. Nonetheless, according to the results, it can be suggested that the placing of anthropogenic structures diminishes the quality of the estuarine vegetation. Therefore, to maintain a suitable environment for the estuarine vegetation seems necessary in order to reduce the number of the hydrodynamic structures which are no longer in use.

Autoría

Descargar referencia