禁捕初期菜子湖两种典型生境底栖动物群落结构研究

COMMUNITY STRUCTURE OF MACROZOOBENTHOS IN TWO TYPICAL HABITATS OF CAIZI LAKE DURING THE EARLY PERIOD OF THE “10-YEAR FISHING BAN”

  • 摘要: 为了解禁捕初期菜子湖大型底栖动物群落结构, 本研究于2022—2024年对菜子湖两种典型生境(湖滨带和敞水区)开展了季节性调查。研究结果表明, 共采集底栖动物83种, 隶属于3门7纲17目32科, 其中中国淡水蛏(Novaculina chinensis)和背瘤丽蚌(Lamprotula leai)为菜子湖首次记录的国家二级保护动物。整个调查区域底栖动物的平均密度和生物量分别为208 ind./m2和75.8 g/m2, 且呈现出明显的空间分布差异; 菜子湖西侧湖区及出湖河流长河底栖动物现存量明显高于其他区域。两种不同生境相比, 湖滨带共采集底栖动物66种, 以小划蝽(Micronectra sp.)和环足摇蚊(Cricotopus sp.)为主要优势种; 敞水区共采集44种, 主要以小摇蚊(Microchironomus sp.)和长足摇蚊(Tanypus sp.)优势度最高。湖滨带平均生物量占比以十足目(虾类)最高, 且不同功能摄食类群的相对丰度变化较大; 敞水区平均生物量占比主要以软体动物最高, 且不同功能摄食类群相对丰度较为恒定。然而, 双因素方差分析结果表明生境类型、季节及其交互作用均对菜子湖底栖动物的现存量没有显著影响。单因素相似性分析结果显示, 两种典型生境底栖动物群落明显分离且差异显著; 不同季节底栖动物群落虽有一定重叠, 但也存在显著差异。植被盖度、底质类型和水温是造成不同季节两种典型生境底栖动物群落差异的主要影响因素。与禁捕前历史数据相比, 此次调查底栖动物种类数和现存量明显增加, 但敞水区主要优势种已由摇蚊幼虫、寡毛类和软体动物共存演变为摇蚊幼虫为主。后续研究中仍需持续跟踪监测, 从而为底栖动物资源恢复和禁捕效果评估提供科学依据。

     

    Abstract: In order to understand the community structure of macrozoobenthos in Caizi Lake during the early period of the “10-year fishing ban”, seasonal investigations of two typical habitats (littoral area and offshore area) were conducted during 20222024. The results showed that a total of 83 macrozoobenthos species were collected, belonging to 3 phyla, 7 classes, 17 orders, and 32 families. Among these, Novaculina chinensis and Lamprotula leai were the first recorded national second-class protected species in Caizi Lake. The average density and biomass of macrozoobenthos in the whole survey area were 208 ind./m2 and 75.8 g/m2, respectively, revealing obvious spatial distribution differences. Biomass was obviously higher in the western lake area and the Changhe River. In terms of species number and predominance, 66 macrozoobenthos species were collected in the littoral area, where Micronectra sp. and Cricotopus sp. were the predominant taxa; 44species were collected in the offshore area, where the Microchironomus sp. and Tanypus sp. were the predominant taxa. Decapoda (shrimp) contributed the highest proportion of the average biomass in the offshore area, whereas, the relative abundance of different functional feeding groups varied greatly. In contrast, Mollusca contributed the highest proportion to the littoral average biomass, and the relative abundance of different functional feeding groups was comparatively constant. As to the statistical analysis, the results of the Two-way ANOVA showed that none of habitat, season, and the interactions of the two significantly affected the biomass of macrozoobenthos in Caizi Lake. Analyses of similarity showed that the macrozoobenthos communities in two typical habitats differed significantly. Although the macrozoobenthos communities in different seasons had a certain overlap, significant differences were revealed. Vegetation coverage, substrate type, and water temperature were the main influencing factors resulting in the differences of macrozoobenthos communities in two typical habitats among different seasons. Comparing with the historical data before the “10-year fishing ban” policy implemented, the species number and standing crop of macrozoobenthos in this study increased obviously. However, the predominant taxa in the offshore area had changed from the coexistence of chironomidae larvae, oligochaeta, and mollusca to chironomidae larvae. Future studies should focus on continuous monitoring to provide a scientific basis for the restoration of macrozoobenthos resources and ecological evaluation of the “10-year fishing ban” policy.

     

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