Seagrasses may enhance the abundance and diversity of benthic invertebrates through trophic facilitation. We investigated this potential ecological function for two seagrasses in SE Brazil: Halodule emarginata, a native species, and Halophila decipiens, a tropical seagrass recently established in the region. At Halophila sites, the organic matter (or carbon) in sediments decreased steadily from seagrass patches to isolated bare grounds, indicating surplus primary production. This was not observed at Halodule sites. At one of the two Halophila sites, localized trophic enrichment was also consistently linked to increased invertebrate abundance within patches, chiefly through increased carrying capacity of small mesoherbivores. Rather than spillover, edge effects were observed at bordering bare habitats, where polychaete predators were abundant. The transition from seagrass edges to isolated bare habitats was marked by an increase of the density of sipunculid worms. The current spread of Halophila may thus change the spatial distribution of benthic ecological functions.

海草可通过营养促进促进底栖无脊椎动物的丰富和多样性。我们调查了巴西东南部两个海草的潜在生态功能：原生种Halodule emarginata和最近在该地区建立的热带海草Halophila decipiens。在嗜盐菌站点，沉积物中的有机物（或碳）从海草斑块到孤立的裸露地面稳步减少，表明初级生产过剩。在Halodule站点未观察到此情况。在两个嗜盐菌之一地点，局部营养的富集也与斑块内无脊椎动物数量的增加一直保持联系，主要是通过提高小型中草食虫的携带能力。在多毛捕食者丰富的边缘裸露栖息地观察到边缘效应，而不是溢出。从海草边缘向孤立的裸露栖息地过渡的特点是剑兰蠕虫的密度增加。嗜盐菌的当前传播可能因此改变底栖生态功能的空间分布。