J Environ Qual. 2013 Jan-Feb;42(1):239-49. doi: 10.2134/jeq2012.0226.
North America has lost >95% of its native tallgrass prairie due to land conversion, making prairie streams one of the most endangered ecosystems. Research on the basic ecosystem characteristics of the remaining natural prairie streams will inform conservation and management. We examined the structure and function of headwater streams draining tallgrass prairie tracts at Osage Prairie in Missouri and the Konza Prairie Biological Station in Kansas and compared those values with literature values for streams draining agricultural watersheds in the region. We quantified physicochemical and biological characteristics for 2 yr. Streams at Osage and Konza were characterized by low nutrients and low suspended sediments (substantially lower than impacted sites in the region), slight heterotrophic status, and high temporal variability. Suspended sediments and nutrient concentrations were generally low in all prairie streams, but storms increased concentrations of both by 3- to 12-fold. Spring prescribed burns were followed by a slight increase in chlorophyll and decreased nutrients, potentially due to greater light availability. Benthic macroinvertebrate communities at Osage showed seasonal patterns that were probably linked to variable hydrology. We found nine amphibian species using the Osage streams as habitat or breeding sites, but little usage at Konza was probably due to dry conditions and low discharge. Our study indicates that two remnant tallgrass prairie streams along a longitudinal gradient are fairly similar in terms of physicochemical features and have good water quality relative to agricultural watersheds but can differ considerably in macroinvertebrate and amphibian abundance.
由于土地转换,北美已经失去了 >95%的本地高草草原,使得草原溪流成为最濒危的生态系统之一。对剩余的自然草原溪流的基本生态系统特征的研究将为保护和管理提供信息。我们研究了密苏里州奥沙奇草原和堪萨斯州康萨草原生物站的高草草原流域的源头溪流的结构和功能,并将这些值与该地区农业流域溪流的文献值进行了比较。我们在 2 年内量化了物理化学和生物特征。奥沙奇和康萨的溪流以低养分和低悬浮泥沙(明显低于该地区受影响的地点)、轻微的异养状态和高时间变异性为特征。悬浮泥沙和养分浓度在所有草原溪流中通常较低,但风暴会使两者的浓度增加 3 到 12 倍。春季规定的燃烧后,叶绿素略有增加,养分减少,这可能是由于光照增加。奥沙奇的底栖大型无脊椎动物群落表现出季节性模式,可能与可变的水文学有关。我们发现了九种使用奥沙奇溪流作为栖息地或繁殖地的两栖动物,但康萨的使用量很少可能是由于干燥条件和低流量。我们的研究表明,两条沿纵轴的残余高草草原溪流在物理化学特征方面相当相似,与农业流域相比水质较好,但在大型无脊椎动物和两栖动物的丰度方面可能有很大差异。