Dynamic changes in seagrass assemblages under eutrophication and implications for recovery

摘要: Abstract Over the last 20 years, loss of seagrass beds, often related with increased eutrophication, became a common problem worldwide. In Mondego estuary (Portugal), eutrophication has triggered serious biological changes, which led to an overall increase in primary production and progressive replacement Zostera noltii beds by coarser sediments opportunistic macroalgae. The effects this on benthic assemblages were studied along spatial gradient from 1993 1995. these short temporal small scales, distinct changes structure macrobenthic communities observed. One main structural modifications was decrease species diversity over time, marked impoverishment most disturbed inner area. Other included detritivores decline herbivores together significant deposit-feeding polychaetes. long term, sustained is expected lead complete habitat unvegetated sediments, occasionally covered green macroalgal blooms dominated invertebrate taxa. Recovery situation may not only require reduction nutrient loadings estuary, but also active restoration programmes reverse positive feedback processes thought be presently taking place.