Community responses to river drying in an arid-land ecosystem: a field and experimental study

干旱地区生态系统中河流干涸的社区反应：实地和实验研究

• 批准号: 0717047
• 负责人: Thomas Turner
• 金额: --
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0717047&HistoricalAwards=false
• 关键词: Community; responses; river; drying; arid

Rivers that flow through arid lands provide a limiting resource for human population and economic growth while simultaneously supporting a diverse community of plants and animals. Consequently, these rivers are often targets of intensive restoration activities based, perhaps erroneously, on concepts developed for mesic (wetter) rivers. Arid-land systems differ from mesic counterparts in that they experience enormous variability in flows that range from high floods to being nearly dry. Low flows and river intermittency are common occurrences, and drying events may be important for enhancing species diversity by allowing coexistence of organisms that specialize on high- and low-flow conditions, respectively. However, actual effects of seasonal variability in discharge, especially low flows, on aquatic communities remain largely unknown. To address this gap in knowledge, a field and experimental study will be conducted on the Rio Grande in New Mexico. Changes biomass and nutrient composition of the algae, invertebrates, and fishes that make up the river?s food web will be tracked. Macronutrients, such as carbon, nitrogen, and phosphorus, will be used as tracers to understand the dynamics of community changes associated with flow variability and drying in natural river environments. Finally, an experimental study will manipulate key variables that appear to strongly affect species abundance and diversity in drying river environments. The outcomes of this study will aid development of scientifically defensible restoration policies and establishment of minimum flows in arid-land rivers. Development of such policies is of paramount economic importance to arid and semi-arid regions worldwide.

流经干旱地区的河流为人口和经济增长提供了有限的资源，同时支持了多样化的植物和动物群落。 因此，这些河流往往是密集的恢复活动的基础上，也许是错误的，为mesic（潮湿）河流的概念。 干旱地区的系统不同于中温带系统，因为它们经历了从高洪水到近乎干旱的巨大变化。 低流量和河流的不稳定性是常见的现象，干燥事件可能是重要的，以提高物种多样性，允许共存的生物体，专门在高流量和低流量的条件下，分别。 然而，排放量的季节性变化，特别是低流量，对水生生物群落的实际影响在很大程度上仍然未知。 为了填补这一知识空白，将在新墨西哥州的格兰德河进行实地和实验研究。 改变组成河流的藻类、无脊椎动物和鱼类的生物量和营养成分？的食物链将被追踪。 宏量营养素，如碳，氮和磷，将被用作示踪剂，以了解与自然河流环境中的流量变化和干燥相关的群落变化的动态。 最后，一项实验研究将操纵似乎强烈影响干旱河流环境中物种丰度和多样性的关键变量。 这项研究的结果将有助于制定科学合理的恢复政策和建立干旱地区河流的最低流量。 制定这种政策对全世界干旱和半干旱地区具有极其重要的经济意义。