This study investigated temporal changes in the vertical distribution of invertebrates during periods of low flows in the Tafna wadi, a semi-arid Mediterranean river characterised by a general decline in average flows. The hyporheos was sampled along a 130-m stretch at depths of 0.3, 0.6 and 1 m in a pool-riffle sequence and a lateral gravel bar. Benthic fauna was collected on each sampling occasion from different locations in the studied sections. Sampling was conducted in two consecutive years (2014 and 2015) at the end of the spring (high waters) and over a 2-month period during the low summer flow. The results indicated that high surface water temperatures may initiate the movement of some taxa into the interstitial habitat, thus supporting the hyporheic refuge hypothesis. In the hyporheic zone, the low oxygen rates recorded deeper in the sediment and in the last low-flow months caused significant declines in taxonomic richness, and lower pH values resulted in a reduction in invertebrate abundances. In the benthic zone, high flow velocities increased richness but decreased invertebrate abundances. A large number of taxa were found in the gravel bar section reflecting the more suitable living conditions in this habitat compared with the river reach (high DO rates).

这项研究调查了塔夫纳河谷（Tafna wadi）处于低流量期间无脊椎动物的垂直分布的时间变化。塔夫纳河谷是半干旱的地中海河流，其特征是平均流量普遍下降。沿流水槽序列和侧向碎石棒沿着130m的拉伸段以0.3、0.6和1m的深度采样了流变。在每个采样时机，从研究区域的不同位置收集底栖动物。在春季结束（高水位）连续两年（2014年和2015年）进行取样，夏季低潮期间进行了两个月的采样。结果表明，较高的地表水温度可能会引发一些分类单元向间隙生境的移动，从而支持了流水避难所的假设。在水流带，低氧含量记录在沉积物深处，并且在最近的低流量月份导致生物分类丰富度显着下降，而较低的pH值导致无脊椎动物丰度降低。在底栖地带，高流速增加了丰富度，但无脊椎动物的丰度却降低了。在砾石坝段发现了大量的分类单元，这反映出该栖息地与河段相比具有更高的生存条件（DO较高）。