1. Several studies of temporary floodplain wetlands suggest that flood history is important to microcrustacean egg bank composition and hatching responses. However, these studies have largely focussed on contrasts among less frequently flooded areas (areas flooded every year to areas flooded once every 10–20 years) and less is known about variation at the more frequently flooded end of the gradient (from multiple floods per year to once every 2 years). Similarly, the effects of flood duration on egg banks have not been examined in detail. Thus, this study examines spatial variation in microcrustacean hatching at higher flood frequencies and in relation to inundation duration.
2. Surface sediment samples were collected from dry anabranches of the Macintyre River floodplain in Australia during February 2018, with a range of flood frequency from approximately four times per year to one in 2 years. Anabranches were selected randomly from predefined flood frequency classes and clustered into three different flood history groups based on flood history variables. Soil samples were collected from deep and shallow locations within anabranches, with depth assumed to be a proxy for the duration of inundation. Sediment samples were inundated in mesocosms and hatched microcrustaceans sampled over 6 weeks.
3. Microcrustacean abundance and assemblage composition varied by sites, relative depth, and duration of inundation. There was no variation by flood history groups. Highest numbers hatched from the deeper areas of anabranches, which is assumed to reflect differences in the egg banks of deep and shallow areas due to the longer duration of inundation in deeper areas. Duration also influenced hatching response from the egg bank, with more microcrustaceans hatching per unit time in the first 2 and final 2 weeks of the 6-week trial than the middle 2 weeks. Species richness also varied by relative depth and duration of inundation with more taxa hatching from the deeper areas of anabranches.
4. The study highlights the critical influence of flood duration on hatching patterns of microcrustaceans from inundated sediments. Therefore, changes to flood duration have the potential to influence microcrustacean assemblages and thus further changes to trophic interactions in temporary floodplain wetlands.

中文翻译：

---

洪水频率和持续时间对旱地河流泛滥平原沉积物中微甲壳动物卵库组成的影响

1. 对临时洪泛区湿地的几项研究表明，洪水历史对微甲壳动物卵库的组成和孵化反应很重要。然而，这些研究主要集中在较不频繁洪水地区（每年被洪水淹没的地区与每 10 到 20 年被洪水淹没一次的地区）之间的对比，而对更频繁被洪水淹没的梯度末端的变化（每年多次洪水）的了解较少每 2 年一次）。同样，洪水持续时间对卵库的影响也没有得到详细研究。因此，本研究检查了在较高洪水频率下微甲壳动物孵化的空间变化以及与洪水持续时间的关系。
2. 表层沉积物样本于 2018 年 2 月从澳大利亚麦金太尔河泛滥平原的干燥亚支流中收集，洪水频率范围从大约每年四次到两年一次。Anabranches 从预定义的洪水频率类别中随机选择，并根据洪水历史变量分为三个不同的洪水历史组。土壤样本是从阿纳分支内的深层和浅层位置收集的，假设深度是洪水持续时间的代表。沉积物样本被淹没在中层生物中，孵化的微型甲壳类动物在 6 周内取样。
3. 微甲壳动物的丰度和组合组成因地点、相对深度和淹没持续时间而异。洪水历史组没有变化。从anabranches 的较深区域孵化的数量最多，这被认为反映了由于较深区域淹没时间较长而导致的深浅区域卵库的差异。持续时间也影响了卵库的孵化反应，在 6 周试验的前 2 周和最后 2 周，单位时间内孵化的微型甲壳动物比中间 2 周多。物种丰富度也因相对深度和淹没持续时间而异，更多的类群从亚分支的较深区域孵化。
4. 该研究强调了洪水持续时间对淹没沉积物中微型甲壳动物孵化模式的关键影响。因此，洪水持续时间的变化有可能影响微甲壳类动物的组合，从而进一步改变临时洪泛平原湿地中的营养相互作用。