Effects of pulsed riverine versus non-pulsed wastewater inputs of freshwater on plant community structure in a semi-arid salt marsh
Effects of pulsed riverine versus non-pulsed wastewater inputs of freshwater on plant community structure in a semi-arid salt marsh
复制标题
脉冲河流与非脉冲淡水输入对半干旱盐沼植物群落结构的影响
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
K. Dunton
中科院分区：
文献类型：
--
作者：
Margaret G. Forbes;H. Alexander;K. Dunton
使用处理后的废水恢复干旱和半干旱湿地的淡水输入是一个相对较新的概念，这种做法对植物群落结构的长期影响在很大程度上尚不清楚。我们比较了自 1998 年 10 月以来接收废水排放的恢复地点沿永久横断面的植被组成、孔隙水盐度和土壤湿度与仅通过降水和河流洪水输入淡水的附近三个下游地点。这一时期的当地气候变化很大，包括两次干旱和一个潮湿期，并开始出现一系列大洪水。与下游站点相比，废水站点的孔隙水盐度显着降低，特别是在干旱期间，盐度为 20%.–40%。废水处理场处较低。 1997 年 7 月至 2002 年 7 月期间，废水场的克隆抗逆植物海蓬子 (Salicornia virginica) 的覆盖度从 87% 下降到 33%，而优势克隆博里奇亚 (Borrichia frutescens) 的覆盖度从 5% 增加到 55%。相比之下，同一时期两个下游地点的维吉尼亚 S. virginica 覆盖率有所增加，而 B. frutescens 的覆盖率保持相对稳定。 2002 年夏季发生大洪水后，标志着三年湿润期的开始，所有地点的 B. frutescens 覆盖范围均有所增加。我们得出的结论是，持续的废水添加和气候驱动的潮湿期通过促进克隆优势 B. frutescens 的扩张并抑制耐胁迫物种 S. virginica 的扩张，同样影响了植物群落结构。我们提出了利用废水的独特管理策略：1）增加植物覆盖，2）促进特有植物组合，3）最大限度地提高物种丰富度。
The use of treated wastewater to restore freshwater inputs to arid and semi-arid wetlands is a relatively new concept, and the long-term effects of such practices on plant community structure are largely unknown. We compared vegetation composition, pore water salinity, and soil moisture along permanent transects at a restoration site receiving wastewater effluent since October 1998 to three nearby downstream sites subjected only to freshwater inputs via precipitation and river flooding. Local climate during this period was highly variable and included two droughts and a wet period that began with a series of large floods. Significantly lower pore water salinities were observed at the wastewater site compared to downstream sites, particularly during droughts, when salinities were 20%.–40%. lower at the wastewater site. Between July 1997 and July 2002, cover of the clonal stress-tolerator, Salicornia virginica, decreased from 87% to 33% at the wastewater site, while cover of the clonal dominant, Borrichia frutescens, increased from 5% to 55%. In contrast, S. virginica cover increased at two downstream sites during the same period, while cover of B. frutescens remained relatively stable. Following large floods in summer 2002, which marked the beginning of a three year-wet period, B. frutescens cover increased at all sites. We concluded that constant wastewater additions and climate-driven wet periods affected plant community structure similarly by promoting expansion of the clonal dominant B. frutescens and inhibiting expansion of the stress-tolerant species S. virginica. We propose distinct management strategies for using wastewater to 1) increase plant cover, 2) promote endemic plant assemblages, and 3) maximize species richness.