Invertebrate and microbial responses to inundation in an ephemeral river reach in New Zealand: effects of preceding dry periods
Invertebrate and microbial responses to inundation in an ephemeral river reach in New Zealand: effects of preceding dry periods
复制标题
无脊椎动物和微生物对新西兰短暂河段洪水的反应：之前干旱期的影响
DOI：
10.1007/s00027-007-0930-1
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发表时间：
2007
期刊：
影响因子：
2.4
通讯作者：
C. Robinson
中科院分区：
文献类型：
--
作者：
S. Larned;T. Datry;C. Robinson
摘要：洪水标志着河流从陆地生态系统向水生生态系统的转变。水生无脊椎动物和沉积物微生物对淹没的响应形式和速率取决于干旱前期的抗干燥性。我们评估了无脊椎动物和微生物对淹没的反应，在一个短暂的到达塞尔温河，新西兰的一系列先前的干燥期。微生物响应变量是溶解氧消耗和非特异性酯酶活性。采样点沿着河段已连续干燥1 - 592天前，样品采集。的发病流模拟实验淹没导致水生无脊椎动物在所有样品中的外观，但组合变化与长度的前干燥期。类群丰富度随干旱期长度呈线性下降，而密度则呈指数下降。这些模式表明，大量的干燥敏感类群的个人被淘汰后不久，流停止，和低密度的组合组成的一个小数目的抗干燥类群持续在长期的干燥期。与无脊椎动物密度，沉积物呼吸和非特异性酯酶活性下降与干旱期的长度，其特点是指数衰减函数。淹没实验的结果表明，一个时间的生态过渡区存在约一个星期后，流水消失，陆地系统稳定之前。
Abstract.Inundation marks the shift from a terrestrial ecosystem to an aquatic ecosystem in ephemeral rivers. The forms and rates of responses by aquatic invertebrates and sediment microbes to inundation depend on desiccation resistance during preceding dry periods. We assessed invertebrate and microbial responses to inundation over a range of preceding dry periods in an ephemeral reach of the Selwyn River, New Zealand. Microbial response variables were dissolved oxygen consumption and non-specific esterase activity. Sampling sites along the reach had been continuously dry for 1–592 d prior to sample collection. The onset of flow simulated by an experimental inundation led to the appearance of aquatic invertebrates in all samples, but the assemblages varied with the length of the preceding dry period. Taxon richness decreased linearly with dry period length while density decreased exponentially. These patterns indicate that a large number of individuals from desiccation-sensitive taxa were eliminated soon after flow ceased, and a low-density assemblage composed of a small number of desiccation-resistant taxa persisted during prolonged dry periods. As with invertebrate density, sediment respiration and nonspecific esterase activity decreased with length of dry period, and were characterized by exponential decay functions. The results of the inundation experiments suggest that a temporal ecotone exists for about one week after the disappearance of flowing water, and before the terrestrial system stabilizes.