3.1. Epifaunal Community Structure
Grazing invertebrates comprised 53% m-2 of total epifauna recorded in seagrass beds in Langebaan Lagoon (Table 3.1). This group was dominated by the generalist microgastropod Assiminea globulus (31.45% m-2) and the pulmonate limpetSiphonaria compressa (16.12% m-2). The keyhole limpet Fissurella mutabilis was only found in beds in the low shore zone comprising 3.26% m-2 of total epifaunal abundance (Table 3.1). Seagrass beds also supported 43.45% m-2 of predatory species, mainly the non-native anemone, Sargartia ornata (43.38% m-2). Dominant at sites closer to the lagoon mouth, this species was generally found in spring and autumn. In its native habitat (Mediterranean and Western Europe), S. ornata attaches to kelps and rocky shores, however in Langebaan Lagoon it is found among Zostera shoots attached to loose rocks and feeds mainly on amphipods and polychaetes (Robinson & Swart, 2015).
The hermit crab, Diogenes brevirostris had a dual function as grazer and deposit feeder and comprised 2.67% of total abundance. A small percentage (0.83%) of suspension feeding organisms was also encountered, the most abundant being a solitary ascidian, Pyura stolonifera (0.4%), found mainly growing in sediment between seagrass shoots (Table 3.1).