Rahman Mirza A T M Tanvir, Negishi Junjiro N, Akasaka Takumi, Nakamura Futoshi
Laboratory of Watershed Conservation and Management, Graduate School of Environmental Science Hokkaido University Sapporo Japan.
Department of Environmental Sciences Jahangirnagar University Dhaka Bangladesh.
Ecol Evol. 2021 Mar 11;11(9):4656-4669. doi: 10.1002/ece3.7366. eCollection 2021 May.
Hyporheic zone (HZ) locates below the riverbed providing habitat for macroinvertebrates from where the winged adult insects (i.e., hyporheic insects, HIs) emerge and bring out aquatic resources to the riparian zone. This study estimated mean daily flux as dry biomass (BM), carbon (C), and nitrogen (N) deriving from the dominant HI species (Plecoptera, Chloroperlidae) for a 4th-order gravel-bed river during the early-summer to summer periods. We hypothesized that HIs were an important contributor in total aquatic resources to the riparian zone. In 2017 and 2018, we set parallelly (May to August) and perpendicularly (June to October) oriented Malaise traps to catch the lateral and longitudinal directional dispersing winged adults of , and other Ephemeroptera, Plecoptera, Trichoptera, and Diptera from the river and estimated the directional fluxes of them. We further split the directional fluxes as moving away or back to the channel (for lateral) and from down- to upstream or up- to downstream (for longitudinal). was similar to other Plecoptera species and differed clearly from Ephemeroptera and Trichoptera in directional characteristics of resources flux, suggesting that the extent and directions of HZ-derived resource transfer depend on taxon-specific flight behaviors of HIs. Contributions of to the riparian zone in total aquatic C and N transfer seasonally varied and were lower in May (5%-6%) and August (2%-4%) and the highest in July (52%-70%). These conservative estimates largely increased (9% in May) after the supplementary inclusion of Diptera (Chironomidae and Tipulidae), part of which were considered HIs. We demonstrated that HZ could seasonally contribute a significant portion of aquatic resources to the riparian zone and highlighted the potential importance of HZ in nutrient balance in the river-riparian ecosystem.
潜流带（HZ）位于河床下方，为大型无脊椎动物提供栖息地，有翅成虫（即潜流昆虫，HIs）从这里羽化，并将水生资源带到河岸带。本研究估算了一条四级砾石河在初夏至夏季期间，源自优势潜流昆虫物种（襀翅目， Chloroperlidae）的干生物量（BM）、碳（C）和氮（N）的日均通量。我们假设潜流昆虫是河岸带总水生资源的重要贡献者。在2017年和2018年，我们平行设置（5月至8月）和垂直设置（6月至10月）的马氏网诱捕器，以捕获来自河流的横向和纵向定向扩散的有翅成虫，以及其他蜉蝣目、襀翅目、毛翅目和双翅目昆虫，并估算它们的定向通量。我们进一步将定向通量分为离开或返回河道（横向）以及从下游到上游或从上游到下游（纵向）。 与其他襀翅目物种相似，在资源通量的定向特征上与蜉蝣目和毛翅目明显不同，这表明源自潜流带的资源转移的范围和方向取决于潜流昆虫特定分类群的飞行行为。潜流昆虫对河岸带总水生碳和氮转移的贡献随季节变化，5月（5%-6%）和8月（2%-4%）较低，7月最高（52%-70%）。在补充纳入双翅目（摇蚊科和大蚊科）后，这些保守估计大幅增加（5月增加9%），其中部分被视为潜流昆虫。我们证明了潜流带可以季节性地为河岸带贡献很大一部分水生资源，并强调了潜流带在河流 - 河岸生态系统养分平衡中的潜在重要性。
