MEPS 127:157-167 (1995)  -  doi:10.3354/meps127157

Spatial and temporal patterns of polychaete communities in a subtropical mangrove swamp: influences of sediment and microhabitat

Hsieh HL

Spatial and temporal patterns of polychaete communities in 2 intertidal flats were examined in a subtropical mangrove swamp, Tan-Shui estuary, Taiwan from 1991 to 1993. The 2 sites appear as distinct microhabitats, differing mainly in sediment granulometry, and consequently in community structure. The 'Creek' site was sandy (0.10 to 0.26 mm, 2 to 30% silt/clay content), while the 'River' site was muddy (0.06 to 0.14 mm, 16 to 60% silt/clay content). A total of 9 species were collected, with 6 species found at both sites. Indices of species diversity and evenness were greater at the Creek site than at the River site, but averaged density was 2 times lower (8317 vs 23325 ind. m-2). Dominance at the Creek site was shared by 2 to 3 species, whereas at the River site a single species, the sabellid Laonome albicingillum, was dominant. Population densities and physical parameters were closely correlated. Malacoceros indicus occurred with large particles, while L. albicingillum increased with small grains. Population densities at both sites varied seasonally, but the timing for increases in densities was 1 to 2 mo earlier at the River site. Effects of shading by mangrove trees at the Creek site were the likely causes of such subtle differences. Abundance in this swamp was greater than those in other tropical mangrove systems. The polychaete populations here may have experienced an environment which was not only nourished by sufficient detrital food, but was also less subject to fluctuation in terms of physical factors. L. albicingillum had high reproductive rates, similar to those of opportunistic species, but differed in its large size and in its life history traits.

Polychaetes . Subtropical mangrove swamp . Sediment

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