人为干扰条件下白洋淀底栖动物群落变化及其主要环境影响因子分析

底栖动物对维持和稳定湖泊生态系统结构与功能具有重要作用.为了探明长期强人为干扰条件下底栖动物群落结构特征及其主要环境影响因子，本研究分别于2009年和2018年的4月和8月采集和分析了白洋淀8个区水体、沉积物和底栖动物样品.根据人为干扰程度的不同，将白洋淀分为重度干扰区（HD）、中度干扰区（MD）和轻度干扰区（LD），同时分析了3类生境的理化参数和底栖动物群落结构与多样性指数.研究结果表明：1就水体和沉积物理化参数而言，总磷（TP）、总氮（TN）、氨氮（NH₄⁺）、硝酸盐（NO₃^-）、磷酸盐（PO₄^3-）和沉积物总氮（TNs）、总磷（TPs）等理化参数在重度干扰区呈最高值；2就底栖动物群落组成而言，在重度干扰区底栖动物群落物种丰度、生物量、密度均最低，且优势种大多以水生昆虫为主；3就底栖动物群落多样性指数而言，2009年，白洋淀底栖动物群落Margalef丰富度指数D值（0.84）和Shannon-Wiener多样性指数H''值（1.13）均在中度干扰区最高，而Pielou均匀度指数J值（0.53）在轻度干扰区最高，这些指数均与沉积物总氮（TNs）呈显著负相关；2018年，D值（2.02）和H''值（2.21）在轻度干扰区中最高，而J值（0.84）在重度干扰区中最高，D值和H''值与水深（Water depth，WD）呈正相关关系，而与硝酸盐（NO₃^-）和总磷（TP）等呈负相关关系；4RDA分析结果表明，白洋淀底栖动物群落组成的主要环境影响因子在2009年为WD和pH，而在2018年为沉积物中总磷（TPs）.2009-2018年，白洋淀底栖动物群落（主要影响因子从WD和pH变为沉积物总磷）和多样性指数（主要影响因子从TNs变为WD、TN、TP、NO₃^-、TNs等）的主要环境影响因子发生了显著变化.因此，针对主要环境影响因子的时间变化，在不同时期底栖动物群落的恢复需采取不同措施，本研究结果可为白洋淀生态修复提供理论和数据基础.

Changes of benthic invertebrate community in the Baiyangdian Lake and analysis of main environmental factors under the condition of human disturbance

Benthic invertebrate communities play an important role in maintaining and stabilizing the structure and function of lake ecosystems. In order to reveal the structural characteristics of benthic invertebrate communities and the main environmental influencing factors under the condition of long-term strong human disturbance, water, sediments, and biological samples were simultaneously collected and analyzed in Baiyangdian Lake during the period of 2009 and 2018. According to the different degree of human disturbance, Baiyangdian Lake can be divided into heavy disturbance area (HD), moderate disturbance area (MD), and mild disturbance area (LD). In this study, the physical-chemical parameters and the structure and diversity index of benthic invertebrate communities were analyzed among three habitats. The results showed that:1In terms of physical-chemical parameters of water and sediment, such as total phosphorus (TP), total nitrogen (TN), ammonia nitrogen (NH₄⁺), nitrate (NO₃^-), phosphate (PO₄^3-) and sediment total nitrogen (TNs) and total phosphorus (TPs) showed the highest values in HD; 2In terms of the composition of benthic invertebrate communities, the abundance, biomass, and density of benthic invertebrate communities exhibited the lowest values in HD, and the dominant species were aquatic insects; 3 In terms of the diversity indexes of benthic invertebrate communities, in 2009, the Margalef richness index D value (0.84) and Shannon-Wiener diversity index H'' value (1.13) of the benthic community showed the highest values in MD; while the Pielou evenness index J value (0.53) showed the highest value in LD, and all of the indexes were significantly negatively correlated with sediment total nitrogen (TNs); while in 2018, the D (2.02) and H'' (2.21) showed the highest values in LD, while the J (0.84) exhibited the highest value in HD;D and H'' values were positively correlated with WD, while negatively correlated with nitrate (NO₃^-) and total phosphorus (TP); 4The results of RDA analysis showed that WD/pH and sediment total phosphorus (TPs) were the main environmental affecting factors for the benthic invertebrate communities in 2009 and 2018, respectively. From 2009 to 2018, the main environmental influencing factors of benthic invertebrate communities (the main impact factors changed from WD and pH to sediment total phosphorus) and diversity indexes (the main impact factors changed from TNs to WD, TN, TP, NO₃^-, TNs and other factors) were different. Therefore, according to the temporal variation of the main environmental influencing factors, different restoration measures need to be taken in different periods. The study will provide the theoretical and data basis for the restoration of Baiyangdian Lake.