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

景观中物质跨边界交换的机制对生态系统功能至关重要，但尚未得到很好的理解。流动的水是一种强大的力量，可以塑造景观内的空间格局，并为陆地和水生生态系统之间的边界之间的物质运输提供媒介。洪水事件暂时模糊了这一界限，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（浮游生物）的主动迁移，增强了物质通量。空间格局，例如那些由引导水流通过景观的排水渠道的复杂性所定义的格局，可能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在外观上是相似的，但沼泽与淡水系统的不同之处在于，它们的排水渠道经历了潮汐水的双向流动，并且更频繁地淹没了它们的河岸——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，在这里可以探索神经元在景观元素之间的生产运动中的作用，并确定这些通量是否受到景观结构复杂性的影响。拟议的研究将表明沼泽景观内的排水模式是否会通过浮游生物种群影响潮间带生产向潮下河口的转移。这将通过比较物种和大小特定的浮游生物密度、生长、运动、饮食和潮汐动态来完成，这些浮游生物分布在一系列沼泽地，代表着从简单到复杂的一系列排水模式。该研究以一个概念模型为指导，该模型将景观空间模式和潮汐动力学的时间模式与各种时空尺度上的浮游生物生活史、运动和营养相互作用联系起来。研究结果将为景观生态学领域提供所需的经验数据，该领域研究空间格局如何影响景观内跨边界的生态相互作用。该研究直接解决了一个长期存在的问题，即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。它也直接适用于涉及目前创造或恢复已退化或被破坏的沿海沼泽的宝贵功能的努力的成败的问题。由于沼泽缓解工作经常涉及潮汐排水模式的改变，因此需要了解排水复杂性与沼泽在为渔业物种提供营养支持方面的作用之间的关系，以确保成功恢复这些关键河口育苗所失去的一些功能价值。

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.