Voelz Neal J, Zuellig Robert E, Shieh Sen-Her, Ward J V
Department of Biological Sciences/MS 262, St. Cloud State University, St. Cloud, Minnesota, USA.
Environ Monit Assess. 2005 Feb;101(1-3):175-202. doi: 10.1007/s10661-005-9147-8.
Water demands in arid and semi-arid areas, coupled with increased human populations and concomitant changes in land use, can greatly alter aquatic ecosystems. A good example of this type of system occurs along the eastern slope of the Colorado Rocky Mountains, U.S.A. Long-term macroinvertebrate metric data from the Big Thompson and Cache la Poudre Rivers, Colorado, were collected at one site above, and three sites in and downstream from urban areas. These data were compared both with regional reference and single reference sites in the respective rivers. Using the surrogate variables of potential urban impact (population and housing units), and the environmental gradient represented primarily by chemical factors, it was determined that there was an effect of urban land use that was reflected in the macroinvertebrate assemblages in both rivers. The most robust results were usually seen when regional reference data were used. However, even using only the upstream reference site in either river indicated some negative impacts from the urban areas. The long-term data, particularly in the Cache la Poudre River, showed that water quality has not been getting worse and there is some evidence of a slight improvement in downstream reaches, even with increased urban development.
干旱和半干旱地区的用水需求，再加上人口增长以及随之而来的土地利用变化，会极大地改变水生生态系统。美国科罗拉多落基山脉东坡就有这样一个典型的系统。从科罗拉多州的大汤普森河和卡什拉普德雷河长期收集大型无脊椎动物指标数据，在城市区域上游的一个地点以及城市区域内和下游的三个地点进行收集。这些数据与各条河流中的区域参考点和单个参考点进行了比较。利用潜在城市影响的替代变量（人口和住房单元）以及主要由化学因素代表的环境梯度，确定城市土地利用对两条河流中的大型无脊椎动物群落都产生了影响。使用区域参考数据时通常能得到最可靠的结果。然而，即使仅使用两条河流中任何一条的上游参考点，也表明城市区域存在一些负面影响。长期数据，特别是卡什拉普德雷河的数据表明，即使城市发展增加，水质并没有恶化，并且有证据表明下游河段略有改善。
