Ecology and distribution of soft-sediment benthic communities off Viti Levu (Fiji)

Abstract

Information on biodiversity and community structure is vital for monitoring the effects of climate change and other anthropogenic impacts. Benthic ecosystems of 5 sites off Viti Levu (Fiji), comprising 50 stations were sampled quantitatively revealing 13 128 individuals of 230 species at a mean density of 273.5 ind. m -2. Common taxa included polychaetes (89 species), crustaceans (84 species), molluscs (50 species) and echinoderms (7 species). No species occurred in all 50 stations; the maximum distribution range was 45 stations occupied by the polychaete Aglaophamus sp. A total of 81 species (35.2%) were restricted to single sites ('uniques'), highlighting spot endemism. Species richness and rarefaction curves provided high estimates of diversity. Multivariate analyses incorporating biological abundances and environmental factors showed 3 distinct clusters among sites characterising differences in benthic community structure. Strongest determinants of faunal distribution were depth, distance from reef and river, and sand content. The presence of heterogeneous faunal assemblages suggests the interplay of these factors at each site.

Spatio-temporal and functional structure of the amphipod communities off Santos, Southwestern Atlantic

“…However, all of them suggest that the amount of hydrodynamic energy and available organic matter are the main driving forces in structuring the soft-bottom communities, with depth and sediment grain size as secondary correlates. Depth and grain size are intrinsically related factors that act on the variability of the macrofauna diversity, integrating effects of the hydrodynamic environment over time (ELLINGSEN, 2002;JAYARAJ et al, 2008;MOHAMMED;COPPARD, 2008). The results obtained in the present study support these findings, since it was possible to observe 3 spatially distinct groups of amphipods that corresponded to different hydrodynamic areas.…”

Community profiling of the intestinal microbial community of juvenile Hammerhead Sharks (Sphyrna lewini) from the Rewa Delta, Fiji

“…The RD is characterised by strong currents and high wave actions because of the collision between river runoff and incoming waves/tides via the reef channel. This interaction gives the RD estuarine habitat conditions, such as large fluctuating salinities, a freshwater layer, high turbidity, and tidal waves 7,45 , which collectively make 45% of the RD inaccessible for sampling.…”

Fisheries-independent surveys identify critical habitats for young scalloped hammerhead sharks (Sphyrna lewini) in the Rewa Delta, Fiji

“…The RD is characterised by strong currents and high wave actions as a result of the collision between the river runoff and the incoming ocean waves/tides via the reef channel. This interaction gives the RD estuarine habitat conditions such as large fluctuating salinities, a freshwater layer, high turbidity and tidal waves 29 , 70 , which make 40% of the RD inaccessible for sampling. The RD was chosen as the focal point for this study because it is recognised through local ecological knowledge that the Rewa Delta and River are areas of aggregation for juvenile hammerhead and bulls sharks.…”