Response of Sublittoral Hard Substrate Invertebrates to Estuarine Sedimentation in the Outer Harbour of Bilbao (N. Spain)   总被引：1，自引：0，他引：1  

J. I. Saiz  Salinas I. Isasi  Urdangarin 《Marine Ecology》1994,15(2):105-131

Abstract. Four sampling stations with relatively similar hard-bottom substrates were investigated to determine if there were differences between the sublittoral invertebrates near the Nervión River mouth (N. Spain) and those closer to the open sea, and if faunal differences could be attributed to the impact of estuarine sedimentation. Four 100 m long transects were surveyed using photographic and quadrat techniques, yielding data on percentage cover of all invertebrates from 136 visual inventories. Data were analysed to determine whether any community response to sedimentation was evident. Ordination (multidimensional scaling) and classification (group-average clustering) based on B ray -C urtis dissimilarity measures separated the stations at three levels based on the different faunal assemblages. The analysis suggests the presence of a gradient along the estuary discharge, mainly affecting the east side of the outer part of Bilbao harbour, since the estuarine plume flows to the east. The influence can be expressed in terms of retrogression of the variety of species and disappearance of the algal fraction, which is progressively replaced by an animal assemblage of tolerant and opportunistic suspension feeders. Several 'indicator' species were identified on the basis of strong density differences between sites; matrix correlations presented here were found to produce complementary and consistent results. The role of estuarine sedimentation disturbance as the main factor controlling subtidal assemblages in outer Bilbao harbour is discussed.  相似文献