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.

流经干旱土地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动植物群落。 因此，这些河流常常成为密集恢复活动的目标，这些活动的基础可能是错误的，是基于为中湿（湿润）河流开发的概念。 干旱地区系统与中湿地区系统的不同之处在于，它们经历了从高洪水到几乎干旱的巨大流量变化。 低流量和河流间歇性是常见现象，干旱事件可能对增强物种多样性很重要，因为它允许分别专门适应高流量和低流量条件的生物共存。 然而，流量季节变化（特别是低流量）对水生群落的实际影响仍然很大程度上未知。 为了解决这一知识差距，将在新墨西哥州的格兰德河进行实地和实验研究。 构成河流食物网的藻类、无脊椎动物和鱼类的生物量和营养成分的变化将被跟踪。 大量营养素，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动态变化。 最后，一项实验研究将操纵似乎强烈影响干涸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确定干旱地区河流的最低流量。 制定此类政策对于全世界干旱和半干旱地区具有至关重要的经济意义。