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2481695 
Book/Book Chapter 
Ecology of Seagrass Communities 
Duffy, JE; Hughes, AR; Moksnes, PerO 
2014 
Sinauer Associates 
Sunderland, MA 
Marine Community Ecology and Conservation 
271-297 
English 
WOS:000333431100012 
Seagrass communities are structured at the most fundamental level by the abundance, diversity, and vigor of the plants that provide their foundation. The seagrasses comprise a polyphyletic group of flowering plants that reinvaded the sea millions of years ago, entering an adaptive zone that formerly had been largely unoccupied by primary producers: marine sediment bottoms. Seagrasses have since diversified and spread to become dominant organisms throughout the world's shallow sediment bottoms around all continents except Antarctica (Figure 12.1 ), primarily in estuaries and more sheltered coastal seas. One genus (the northeastern Pacific Phyllospadix) has even colonized rocky shores (Hemminga and Duarte 2000; Green and Short 2003). Colonization by seagrasses profoundly changed the nature of coastal sediment systems. Being angiosperms, seagrasses are rooted plants, and many form dense mats of rhizomes in the underlying sediments (Figure 12.lB), which reduce the mobility of those sediments and transform their biogeochemistry. Above ground, the often dense vegetation strongly reduces the physical energy of waves and currents; in addition, it provides both food for herbivores and physical structure that shelters a much higher abundance and diversity of animals than do surrounding bare sediments (Figure 12.2; Williams and Heck 2001).