摘要
延河流域位于黄土高原丘陵沟壑区,水土流失严重。流域中下游人类活动干扰强烈导致生态环境脆弱。流域内不同地貌单元(峁梁丘陵沟壑区、峁状丘陵沟壑区、破碎塬区)水土流失状况不同,本研究于2021年4月(春季)和10月(秋季)对流域底栖动物群落进行调查,通过构建底栖动物生物完整性指数(B-IBI)对流域水生态进行健康评价,并探究不同地貌单元对底栖动物生物完整性的影响。共鉴定底栖动物4门73属113种,两季度中水生昆虫均为绝对优势类群。对26个候选指标进行筛选发现:春季B-IBI由优势分类单元个体相对丰度、科级耐污指数(FBI)、捕食者个体相对丰度3个指标构成;秋季B-IBI由蜉蝣目分类单元数、FBI、捕食者个体相对丰度3个指标构成。B-IBI评价结果显示,上游干支流83.3%的采样点处于健康状态,而中下游干支流仅有28.6%的采样点处于健康状态,流域春季健康状况优于秋季。Kruskal-Wallis非参数检验表明,破碎塬区秋季底栖动物密度、物种数和B-IBI均显著低于春季,且在秋季时显著低于峁梁丘陵沟壑区、峁状丘陵沟壑区,丰水期集中降雨导致水土流失加剧是造成这种差异的主要原因。冗余分析结果显示,影响春季底栖动物群落结构的关键因子为大石底质、叶绿素a、氧化还原电位、浊度、电导率、溶解氧,影响秋季群落结构的关键因子为硝态氮、氧化还原电位、pH。
Yanhe River Basin is located in the hilly gully area of the Loess Plateau with serious soil erosion.Strong human activities in the middle and lower reaches lead to fragile ecological environment.Soil erosion status varies among different geomorphic units within the watershed(loess liang hilly and gully region,loess mao hilly and gully region,and broken platform region).In this study,we surveyed the benthic community from the Yanhe River Basin in April(spring)and October(autumn)of 2021.To evaluate the water ecological health status of the watershed and investigate the effects of different geomorphic units on the benthic integrity of the benthos,we constructed the benthic-index of biotical integrity(B-IBI)based on the biological data.We identified a total of 113 species of 73 genera in 4 phyla of benthic fauna,with aquatic insects as the dominant taxa in both seasons.Through screening 26 candidate indicators,we found that the spring B-IBI consisted of three indicators:relative abundance of individuals of dominant taxonomic units,family biotic index(FBI),and relative abundance of predator individuals,and that autumn B-IBI was composed of the number of taxonomic units of Ephemeroptera,FBI value,and the relative abundance of predator individuals.Results of the B-IBI evaluation showed that 83.3%of the sampling sites in the upper mainstem and tributaries were at a healthy condition,while only 28.6%sampling sites in the middle and lower mainstem and tributaries were at a healthy condition.In addition,the health status of the watershed was better in spring than in autumn.The Kruskal-Wallis nonparametric tests showed that benthic density,species number,and B-IBI percentile scores in the fragmented loess area were significantly higher in spring than in autumn,and significantly lower in autumn than in the loess liang hilly and gully region and loess mao hilly and gully region,being mainly caused by the increasing erosion due to the concentrated rainfall in wet season.Results of the redundancy analysis showed that key environmental factors affecting benthic community structure in spring were boulder substrate,chlorophyll-a,oxidation reduction potential,turbidity,conductivity,and dissolved oxygen,and were nitrate-nitrogen,oxidation reduction potential,and pH in autumn.
作者
贺瑶
孙长顺
侯易明
胡恩
侯湘然
冯治远
张旭达
潘保柱
HE Yao;SUN Chang-shun;HOU Yiming;HU En;HOU Xiangran;FENG Zhiyuan;ZHANG Xuda;PAN Baozhu(State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China,Xi’an University of Technology,Xi’an 710048,China;Shaanxi Provincial Academy of Environmental Science,Xi’an 710069,China)
出处
《应用生态学报》
CAS
CSCD
北大核心
2024年第3期806-816,共11页
Chinese Journal of Applied Ecology
基金
陕西省重点研发计划重点产业链(群)项目(2021ZDLSF05⁃10)资助。
关键词
延河流域
水土流失
底栖动物完整性指数
健康评价
地貌单元
Yanhe River Basin
soil erosion
benthic integrity index
health assessment
geomorphological unit