Drainage Complexity, Nekton Populations and Production Transfers Across a Marsh Landscape

克内布9629621的物质交换机制对生态系统功能至关重要，但人们对此还不是很清楚。流水是一种强大的力量，可以塑造景观中的空间格局，并为物质跨越陆地和水生生态系统之间的边界提供了一种媒介。洪水事件暂时模糊了这一边界，不仅通过被动颗粒的水力运动，而且通过鱼类和其他水生生物的主动迁徙(Nekton)，增加了物质的通量。空间模式，例如由引导水流通过景观的排水渠道的复杂性所定义的模式，可能会对连接环境组成部分的生态过程产生深远的影响。淡水河流和潮汐沼泽的排水系统在外观上相似，但沼泽湿地与淡水湿地系统的不同之处在于，它们的排水渠道经历了潮水的双向流动，并更频繁地淹没了堤岸--每天多达两次。沼泽环境的这些特征使其成为一个有吸引力的舞台，在这里可以探索Nekton在景观要素之间的生产移动中的作用，并确定这些通量是否受到景观结构复杂性的影响。这项拟议的研究将表明，沼泽景观中的排水模式是否会通过尼克顿种群影响潮间带生产力向潮下河口的转移。这将通过比较特定物种和大小的尼克顿密度、生长、运动、食物和潮汐动态来实现，这些湿地代表了从简单到复杂的一系列排水模式。这项研究是在一个概念模型的指导下进行的，该模型将潮汐动力学的景观和时间模式与一系列时间和空间尺度上的Nekton生活史、运动和营养相互作用联系起来。这些发现将为景观生态学领域提供必要的经验数据，该领域涉及空间格局如何影响景观内边界之间的生态相互作用。该研究直接涉及盐沼在邻近河口和沿海海洋生态系统的营养支持中的功能作用这一长期存在的问题。它还直接适用于涉及目前努力创建或恢复已退化或被破坏的沿海沼泽有价值的功能的成败的问题。由于沼泽缓解努力经常涉及改变潮汐排水模式，因此需要了解排水复杂性如何与沼泽在为渔业物种提供营养支持方面的作用有关，以确保成功恢复这些关键河口苗圃丧失的部分功能价值。

Kneib 9629621 Mechanisms by which materials are exchanged across boundaries within landscapes are crucial to ecosystem functioning, yet are not well understood. Flowing water is a powerful force that can shape spatial patterns within landscapes and provides a medium for the transport of material across the boundary between terrestrial and aquatic ecosystems. Flooding events, which temporarily blur this boundary, enhance material fluxes not only through the hydraulic movement of passive particles but also via the active migrations of fishes and other aquatic organisms (nekton). Spatial patterns, such as those defined by the complexity of drainage channels that direct the flow of water through a landscape, may have profound effects on ecological processes that link components of the environment. Drainages of freshwater rivers and tidal marshes are similar in appearance, but marshes differ from freshwater lotic systems in that their drainage channels experience a bidirectional flow of tidal water and flood their banks more frequently -- as much as twice daily. These features of the marsh environment make it an attractive arena in which to explore the role of nekton in the movement of production between landscape elements, and to determine if these fluxes are affected by complexity in the structure of the landscape. The proposed research will show whether drainage patterns within a marsh landscape influence the transfer of intertidal production to the subtidal estuary via nekton populations. This will be accomplished by comparing species- and size-specific nekton densities, growth, movements, diets and tidal dynamics across a series of marsh sites representing a range of drainage patterns from simple to complex. The research is guided by a conceptual model that links spatial patterns in the landscape and temporal patterns of tidal dynamics with nekton life histories, movements and trophic interactions across a range of temporal and spatial scales. Findings will contribute needed empirical data to the area of landscape ecology that deals with how spatial patterns affect ecological interactions across boundaries within landscapes. The research directly addresses a long-standing issue regarding the functional role of salt marshes in trophic support of adjacent estuarine and coastal ocean ecosystems. It also is directly applicable to questions involving the success or failure of current efforts to create or restore valued functions of coastal marshes that have been degraded or destroyed. Because marsh mitigation efforts frequently involve the alteration of tidal drainage patterns, an understanding of how drainage complexity relates to the role of marshes in providing trophic support for fisheries species is needed to insure success in recovering some of the lost functional value of these critical estuarine nurseries.