The non-native solitary ascidian Ciona intestinalis (L.) depresses species richness

摘要: Abstract Non-native ascidians are a dominant feature of many sessile marine communities throughout the world and may have negative effects on species diversity. We tested non-native Ciona intestinalis invertebrate community in San Francisco Bay, where it occurs dense aggregations. In particular, we compared richness between PVC panels from which C. were experimentally removed to with naturally growth, using fouling four sizes (between 49 cm2 1177 cm2) measure effect recruitment species-area relationships. initially deployed 120 (30 each size) at site known populations intestinalis, assigning these three different treatments: (1) Experimental removal, whereby new recruits weekly basis, pulling out water for short time period do so; (2) Manipulated control, week (as experimental removal) but without removal; (3) Unmanipulated remained experiment. After 4 months, all collected analyzed estimate relative abundance (percent cover) invertebrates intestinalis. Across panels, was negatively correlated abundance. The removal produced significantly higher than controls. overall composition treated control also distinctly different, occurring more often absence while others occurred intestinalis-dominated panels. These data suggest that both depress local diversity alter assembly processes fundamentally change composition.