摘要 : Both seagrasses and bivalves molluscs act as ecosystem engineers in marine systems by forming habitat or modifying environmental conditions. They also have the potential for reciprocal interactions when colocated, through a wide v... 展开 Both seagrasses and bivalves molluscs act as ecosystem engineers in marine systems by forming habitat or modifying environmental conditions. They also have the potential for reciprocal interactions when colocated, through a wide variety of potential mechanisms involving different directions in effect. Pathways mediated by biogenic structure could be facilitative through protection from predation or bioturbators, or by harboring beneficial interactors, or alternatively could result in competition for space or reduced food supply. Other pathways mediated by biological activity could positively link autotrophic roles of seagrass and heterotrophic roles of bivalves, but excessive organic matter production or nutrient release could be damaging. Published studies were compiled for a meta-analysis of field experiments testing bivalve response to seagrass (25 studies) and vice versa (11 studies), as well as for surveys of bivalves in and out of seagrass (39 studies). In experiments, seagrass improved bivalve survival, and bivalves at high cover reduced seagrass density, but seven other response metrics showed no consistent change. In surveys of particular bivalve species, densities were 1.6 times higher in seagrass than out of seagrass. This augmentation did not differ by body size but was especially pronounced in some functional groups, especially lucinid and solemyid bivalves harboring sulfide-oxidizing bacteria. Weak overall directional effects of colocation of seagrass and bivalves reflect weak effects in some individual studies, for instance because of low densities in soft-sediment systems, as well as strong but inconsistent effects because different pathways of interaction dominate. Therefore, generalizations about the outcome of interactions between these two ecosystem engineers when they are colocated cannot be made, although coexistence is typically enabled by weak or positive interactions. Further work is needed, especially outside of some well-studied regions, to explore the specific mechanisms and spatiotemporal scales enabling seagrasses and bivalves to coexist because there are many pathways at work. 收起