Invasion
Invasion Description
1st record: Cronulla Wharf, Port Hacking (Sydney area)/New South Wales/Gunnamatta Bay, Tasman Sea (2000, Millar 2004)
Geographic Extent
Cronulla Wharf, Port Hacking (Sydney area)/New South Wales/Gunnamatta Bay, Tasman Sea (2000, Millar 2004; Galsby 2012); Jervis Bay/New South Wales/Lake Conjola (Tasman Sea) (2000, Millar 2004; West and West 2007); New South Wales/Quibray Bay, Botany Bay (2001, Millar 2004; Glasby 2012); New South Wales/Lake Conjola (Gribben et al. 2013)
Vectors
| Level | Vector |
|---|---|
| Alternate | Aquatic Plant Shipments |
| Alternate | Hull Fouling |
| Alternate | Fisheries Accidental (not Oyster) |
Regional Impacts
| Ecological Impact | Competition | |
| In experiments, Caulerpa taxifolia colonized cleared areas within meadows of the seagrass Posidonia australis, and persisted but did not replace the grass. Effects on another seagrass, Zostera capricorni were harder to interpret, because of the decline of Z. capricorni in both experimental and control plots (Glasby 2013), | ||
| Ecological Impact | Habitat Change | |
| Effects of Caulerpa taxifolia on benthic communities were complex and sometimes contradictory. Overall, the dense physical structure of the C. taxifolia beds, increases deposition of silt and organic material, and reduces water movement, contributing to anoxia in the sediments, to a greater degree than found in native seagrass beds (Posidonia oceanica, Zostera capricorni ). Caulerpa taxifolia beds had similar meiofaunal species richness to native seagrass beds, but had many species absent in the seagrass sediments (Galluci et al. 2012). The bivalve Anadara trapezia had somewhat reduced predation in C. taxifolia beds, due to shelter, but had reduced health and predator resistance, due to anoxia, sulfide, and bacteria (Byers et al. 2010). Recruitment of A. trapezia was good, probably due to lack of predation, but reproductive output of females were reduced (Gribben and Wright 2006a; Gribben and Wright 2006b; Gribben et al. 2009; Gribben et al. 2013). In response to hypoxia in the sediments in C. taxifolia beds, A. trapezia altered its behavior, emerging from the sediment (Wright et al. 2010), but also showed morphological adaptations (shell morphology, gill mass, and palp mass), possibly due to natural selection (Wright et al. 2012). Overall, the composition and abundance of the epifauna was positively associated with C. taxifolia biomass, but abundance of infauna was negatively correlated (McKinnon et al. 2009; Gribben et al. 2013). Benthic communities receiving high doses of detritus from plots colonized by C. taxifolia had reduced abundance of deposit-feeding animals, after 4 months of incubation, compared to those receiving equal doses of seagrass detritus (P. oceanica or Z. capricorni). The C. taxifolia detritus is especially prone to develop hypoxia, compared to the seagrass detritus (Bishop and Kelaher 2013). Fish abundance was similar, but species diversity was reduced in Caulerpa taxifolia beds compared to seagrass beds. Gobiid fishes were more abundant in C. taxifolia, but sygnathids (seahorses and pipefishes) and monacanthids (filefies) were reduced (York et al. 2006). | ||
| Ecological Impact | Food/Prey | |
| In Australia, several herbivorous organisms, including a fish (Girella tricuspidata), an amphipod (Cymadusa setosa), and a sea hare (Aplysia dactylomela strongly preferred other algae to Caulerpa tiaxifolia as food. A polychaete, Platynereis dumerilii antipoda did survive well while feeding on C. taxifolia, but fed at much higher rates on other algae (Gollan and Wright 2006). Extracts of C. taxifolia added to agar disks, had weak negative effects on the feeding of snails and fishes (Davis et al. 2005). Detritus from C. taxifolia, added to sediment, reduced the abundance and species richness of infaunal communities, possibly because of deterrent chemical compounds (Tanner et al. 2010). | ||