Applying a Large,Statewide Database to the Assessment,Stressor Diagnosis,and Restoration of Stream Fish Communities

In this report, predictions of the species that were expected to occur at stream sites were generated and probable stressors to fish species that were predicted to occur but were absent were diagnosed. Predictions were generated based on the hierarchical screening method of Smith and Powell (1971, Am. Mus. Novit. 2458, 1–30), using fish abundance in conjunction with 25 environmental variables at 895 sites. The sites were sampled throughout Maryland and represent the entire range of environmental quality from severely degraded to minimally degraded. Stressor variable values that exceeded tolerance thresholds for species that were expected to occur, but were absent, were considered to be probable stressors. This method was tested for efficacy in stream site assessments and stressor diagnosis using an independent data set. Sites that were classified as degraded according to the IBI and to non-biological criteria had fewer predicted species present compared to minimally influenced sites, indicating that the proportion of predicted species present accurately represents the biological integrity of a stream site. The nine stressors that were applied to the test data set accounted for species absences in 43.7% of degraded sites. Impervious land cover was the most common stressor identified. In addition to assessing stream biological integrity and identifying stressors to fish species, this approach also provides tolerance thresholds for predicted fish species that are useful endpoints necessary to plan effective restoration of fish species in Maryland.     

松花江下游底栖动物组成及其环境指示作用

2005—2010年对松花江佳木斯江段3个断面进行大型底栖动物生态调查,共发现大型底栖动物51种,其中水生昆虫33种,软体动物9种,甲壳动物3种,环节动物6种。3个断面均以水生昆虫的种类数为最多,其次为软体动物,两者在各断面的年度监测中均能被观测到,且出现频率较高;环节动物与甲壳动物的种类数较少,且出现频率较低。底栖动物群落特征和水质生物学评价显示,佳木斯江段水质虽呈波动状态,但整体呈不断改善趋势,主要与溶解氧、氨氮以及总磷等指标的不断改善相关。     

调水后东平湖浮游植物群落结构及水质生物评价

东平湖是南水北调东线工程的重要调蓄湖泊,在防洪、灌溉、休闲旅游、水产养殖及水资源供应等方面发挥着至关重要的作用.为了解南水北调东线调水后的东平湖浮游植物群落结构及水体健康状态,于2016年4月(春季)、7月(夏季)、10月(秋季)及2017年1月(冬季)对东平湖不同空间区域(根据调水路线划分为进水区、湖中区和出水区)的...