Teagasc, Environmental Research Centre, Johnstown Castle, Wexford, Ireland.
Teagasc, Spatial Analysis Unit, Ashtown, Ireland.
Sci Total Environ. 2016 Dec 1;572:618-625. doi: 10.1016/j.scitotenv.2016.04.011. Epub 2016 May 14.
High ecological status at river sites is an indicator of minimal disturbance from anthropogenic activities and the presence of ecologically important species and communities. However, a lack of clarity on what factors cause sites to lose high ecological status is limiting the ability to maintain the quality of these sites. Examination of ecological status records at 508 high status river sites throughout the Republic of Ireland revealed that 337 had fallen below high status at some point between 2001 and 2012 due to changes in invertebrate communities. A geographical information system was used to characterise land use and environmental variables in the catchment, riparian and reach areas upstream of the sites. The relationships between these variables at the three spatial scales and whether or not river sites had maintained high ecological status were then estimated by multiple logistic regression and propensity modelling. The results indicated that grassland at either catchment or riparian scales had a greater negative impact on high ecological status than at the reach scale. This effect appeared to be strongest for upland, steeply sloping rivers that are subject to high rainfall, possibly due to the presence of sensitive biota and/or a greater potential for erosion. These results highlighted the need for better management of grassland upstream of the high status sites, with a focus on river alterations and critical source areas of nutrients, sediments and pesticides that are hydrologically connected to the river. Sustainable management practices and land use planning in those areas will need to be considered carefully if the aim of maintaining high ecological status at river sites is to be achieved.
河流站点的高生态状况是指示人类活动干扰最小以及存在生态重要物种和群落的指标。然而，对于哪些因素导致站点失去高生态状况，还存在一些不明确的地方，这限制了维持这些站点质量的能力。对爱尔兰共和国 508 个高生态状况河流站点的生态状况记录进行检查后发现，由于无脊椎动物群落的变化，自 2001 年至 2012 年期间，有 337 个站点的生态状况已降至低水平。使用地理信息系统对流域、河岸带和站点上游河道区域的土地利用和环境变量进行了描述。然后，通过多项逻辑回归和倾向评分模型，对三个空间尺度上的这些变量与河流站点是否保持高生态状况之间的关系进行了估计。结果表明，与河道尺度相比，无论是在流域尺度还是河岸带尺度上，草地对高生态状况的负面影响更大。这种影响对于受到高降雨影响的高海拔、陡坡河流似乎最为强烈，这可能是由于存在敏感生物群和/或更大的侵蚀潜力。这些结果突出表明，需要更好地管理高生态状况站点上游的草地，重点关注与河流相连的河流改造和营养物质、沉积物和农药的关键源区。如果要实现维持河流站点高生态状况的目标，就需要仔细考虑这些地区的可持续管理实践和土地利用规划。
