在自然和人工湿地中精心管理的水文时段可能会提供理想的防洪服务和高生态功能的组合。为了探索休斯顿典型的淡水湿地管理方式,得克萨斯州地区将对不同的水文状况做出反应,如果湿地被排干,预计大雨将无法实现,我们进行了一个中观实验,有六个洪水深度和七个干旱持续时间,随后是七个月的恢复。我们发现,中间宇宙干燥的速度是初始水深的函数,最初设定的mesocoss具有更大的水深(30厘米),需要〜38天的时间才能变干,而完全排水的湿地则为零。单个植物物种(种植14种;恢复期结束时常见的8种)受到干旱长度的影响,洪水深度,或者他们的互动,尽管这些反应的细节因物种而异。干旱期结束时植物群落的组成受到干旱长度的强烈影响,干旱长度处理的效果持续了七个月的干旱后恢复,80天和160天的干旱处理与较短的干旱处理差异最大。植物的地上和地下生物量不受处理的影响,但是地上死亡生物量(凋落物)随着干旱长度的增加而减少。蚊子幼虫的密度,蜗牛和t在时间上是可变的,并且在治疗期间和恢复早期受到的影响大于恢复后期的干扰事件。我们的结果表明,德克萨斯州东南部的管理湿地对持续时间长达40天的干旱期具有很强的适应性,特别是在干旱开始时水没有完全排干的情况下。此外,即使干旱长达160天,许多物种也会在有管理的湿地中持续存在。这表明,通过保留更长时间的水以增加生态功能来管理人工滞留池的水文周期具有相当大的潜力。很少甚至没有损失防洪服务,并通过在预期降雨之前排干自然湿地以增加防洪服务来管理自然湿地的水文期,几乎没有生态功能的损失。
Thoughtfully managed hydroperiods in natural and artificial
wetlands could potentially provide a combination of desirable flood control services and high ecological functions. To explore how managed freshwater
wetlands typical of the Houston, Texas area would respond to different hydrological regimes that might occur if
wetlands were drained in anticipation of a heavy rain that did not materialize, we conducted a mesocosm experiment with six flooding depths and seven drought durations, followed by seven months of recovery. We found that the speed in which mesocosms dried out was a function of initial water depth, with mesocosms initially set with greater water depths (30 cm) taking ~ 38 days to dry out versus zero days for wetlands that were completely drained. Individual plant species (14 species planted; 8 species common at the end of the recovery period) were affected by drought length, flooding depth, or their interaction, although details of these responses varied among the species. The composition of the plant community at the end of the drought period was strongly affected by drought length, and the effect of the drought length treatment persisted through seven months of post-drought recovery, with the 80- and 160-day drought treatments diverging most strongly from shorter drought treatments. Above- and below-ground biomass of plants was not affected by the treatments, but above-ground dead biomass (litter) decreased with increasing drought length. Densities of mosquito larvae, snails and tadpoles were temporally variable, and were affected more during the treatment period and early in recovery than after a disturbance event late in recovery. Our results indicate that managed
wetlands in southeast Texas would be quite resilient to dry periods of up to 40 days in duration, especially if water was not completely drained at the beginning of the drought. In addition, many species would persist in managed
wetlands even with droughts of up to 160 days. This indicates considerable potential for managing the hydroperiods of artificial detention ponds by retaining water longer to increase ecological function, with little to no loss of flood control services, and for managing the hydroperiods of natural wetlands by draining them in advance of anticipated rains to increase flood control services, with little to no loss of ecological function.