乳山近海大型底栖动物功能摄食类群

根据2006年12月至2007年11月对乳山近海的调查样品,报道了该海域大型底栖动物功能摄食类群的生态学状况。结果表明:乳山近海大型底栖动物以食底泥者和肉食者占较大优势,其次为滤食者,食碎屑者、杂食者、植食者相对丰度较小;食底泥者的优势种为中蚓虫、不倒翁虫、丝异蚓虫和轮双眼钩虾,肉食者的优势种为寡鳃齿吻沙蚕、圆筒原盒螺和纽虫,滤食者的优势种为滑理蛤、菲律宾蛤仔、金星蝶铰蛤和江户明樱蛤;各功能摄食类群分布受有机负荷和底质类型限制;基于大型底栖动物功能类群的生态参数评价结果表明,乳山近海大型底栖动物群落健康状况由虚弱趋于不稳定,大部分站位大型底栖动物群落受到轻度扰动,底栖生态质量状况较优良;冗余分析表明,盐度、水温、总氮、悬浮物、溶解氧、总有机碳和硅酸盐等7个因子与乳山近海大型底栖动物功能摄食类群存在较显著的相关性。

Functional feeding groups of macrozoobenthos from coastal water off Rushan

The trophic structure of the benthic communities in the coastal waters off Rushan, situated off the southern coast of the Shangdong Peninsula, in the Yellow Sea, was characterized according to a feeding functional guild approach, based on sampling surveys conducted from December 2006 to November 2007. Macrobenthic organisms were assigned to six distinct trophic groups (herbivores, deposit-feeders, filter-feeders, carnivores, detritus-feeders, omnivores) and the feeding diversity and ecosystem health of the research area was estimated using the Shannon-Wiener index, Pielou''s evenness index, and Infaunal Trophic Index (ITI), applied in conjunction with a Marine Biotic Index (AMBI). The dominance of feeding groups was related to environmental variables using multivariate ordination techniques (Redundancy Analysis). The results show that deposit-feeders and carnivores were the most abundant functional groups, making up 34% and 31% of the benthic communities in terms of relative abundance, respectively, followed by filter-feeders (22%), the detritus-feeders (7%), omnivores (5%), and herbivores (1%). The dominant deposit-feeding species were Mediomastus californiensis, Sternaspis scutata, Heteromastus filiforms and Ampelisca cyclopst while the dominant carnivorous species were Nephtys oligobranchia, Eocylichna cylindrella and Nemertinea sp.; and the dominant filter-feeding species were Theora lubrica, Venerupis philippinarum, Trigonothracia jinxingae and Moerella jedoensis. When seasonal variation was incorporated into the analysis, deposit-feeders had the highest relative abundance (39.3% in December 2006) and mean abundance (107.4 ind/m² in May 2007), followed by carnivores (37.9% in November 2007, 94.7 ind/m² in May 2007) and filter-feeders (27.2% in November 2007, 77.4 ind/m² in May 2007), while herbivores abundance accounted for only 1.1% and 2.9 ind/m2 in December 2006. With regard to spatial distributions, sites G1 and B4 had the highest values of deposit-feeders with relative abundances of 73.3% (recorded in August 2007) and densities of 385 ind/m² (May 2007) respectively. The highest abundance of carnivores was recorded at site A1 (74% and 285 ind/m² in November 2007) whereas sites H1 and D2 exhibited the highest abundance of filter-feeders, with relative abundances of 100% (recorded in August 2007) and densities of 325 ind/m² (May 2007) respectively. The distribution of each functional feeding group was significantly related to organic load and sediment type. Assuming that a healthy environment is characterized by all feeding groups being present, with a clear dominance of deposit-feeders, feeding diversity would be expected to be maximal with the evenness feeding diversity index close to one. Most of the stations in the research area exhibited good or high feeding diversity, corresponding to a healthy ecological state, with the exceptions of stations A1, G1, and I2, that showed occasionally low feeding diversity, ITI and AMBI values. The poor condition at these sites was mainly related to disturbance impacts and natural accumulation of organic matter, with some feeding groups being absent or present at low relative abundances, with one or two groups dominating the community, which was particularly the case with deposit feeders. The redundancy analysis (RDA) results of indicated that salinity, water temperature, total nitrogen, suspended matter, dissolved oxygen, total organic carbon, and silicate were significant predictors of community trophic structure variance (p<0.05).