台州益顽湾海域主要游泳动物生态位与种间相遇机率

基于2016年10月和2017年4月在台州益顽湾海域(27.9°N～28.6°N和121.1°E～121.9°E)的渔获物调查数据,采用功能群结合种间相遇机率(PIE)与生态位的方法,对主要游泳动物群落特征进行研究。结果显示:春季与秋季主要游泳动物分别有13种与11种,多以短距离洄游种或定居种为主,季节更替率较低;底栖动物/游泳动物食性功能群(FG4)在两季主要游泳动物中占优势地位且营养级偏低;春季与秋季主要游泳动物种间相遇机率总和分别为0.66与0.76,秋季较春季的种间相遇机率高;春秋两季的生态位宽度差异均较大,春季广生态位种4种,中生态位种7种,秋季广生态位种5种,中生态位种4种,窄生态位种两季均为2种;生态位宽度(Bi)与种间相遇机率(PIE)呈显著正相关;三疣梭子蟹(Portunus trituberculatus)在两季相遇机率值最高且生态位宽度值最大,其竞争能力和利用资源的能力最强;春季与秋季种对间生态位重叠值分别为0.14～0.88与0.21～0.91,表明两季种对间重叠程度不均匀。综上,该海域主要游泳动物组成的季节性变化较小,单一功能群占主导且多为中低营养级物种,其生态位宽度值与种间相遇机率值却较大,可能造成了群落数量波动、群落结构与功能稳定性下降。

Niche and PIE of major nekton in Yiwan Bay of Taizhou

This study aimed to investigate the community characteristics of major nekton based on the catch survey data from Yiwan Bay of Taizhou (27.9°N-28.6°N and 121.1°E-121.9°E) in October 2016 and April 2017, through analysis of functional groups along with the niche of and probability of interspecific encounter (PIE) between species. The results showed that there were 13 and 11 species of major nekton in spring and autumn, respectively, most of which were the short-distance migratory species or settler species, with low seasonal turnover rates. In addition, the benthivores/piscivores feeding functional group (FG4) was dominant among the major nekton in spring and autumn, with low trophic levels. Additionally, the total PIE between the major nekton in spring and autumn were 0.66 and 0.76, respectively, and that in autumn was higher than that in spring. There were significant differences in the niche breadth, both in spring and autumn. Specifically, there were four broad niche species, seven meso niche species, and two narrow niche species in spring; conversely, there were five broad niche species, four meso niche species, and two narrow niche species in autumn. In addition, the niche breadth (B_i) was positively correlated with PIE; the portunid (Portunus trituberculatus) was associated with the highest PIE and maximum niche breadth in both seasons, along with the strongest abilities of competition and resource utilization. Moreover, the interspecies niche overlap values in spring and autumn were 0.14-0.88 and 0.21-0.91, respectively, indicating uneven degrees of interspecies overlap in the two seasons. In summary, small seasonal variation was observed in the composition of major nekton in the studied sea area, and a single functional group had taken the dominant place, most of which belonged to the low and middle trophic species, with a large niche breadth and PIE. Thus, this might result in the fluctuations in community numbers, as well as a decline in the structure and functional stability of the communities.