Dynamics of Habitat Structure in Seagrass Landscapes; Ecosystem Implications

9318130贝尔在强调生态系统功能的海洋植被生境模型中，大型植物植被通常不被认为与更高的营养水平有直接联系。 相反，植物被视为重要的重要营养贡献者的碎屑池。 在本研究中，我们扩展了对植物作用的认识，并考虑了由水生植物提供的生境结构，无论是作为物理或捕食者的避难所，还是作为资源积累的场所，对生态系统功能都可能是重要的。 这项研究的目的是：1）探索已知与营养相关的动物群（即小型留居鱼和附生端足类动物）与植物覆盖、高度和植物在空间尺度上的排列的关系; 2）建立一个描述影响海草斑块发育和维持的沉积过程的模型。 1994年春季和1995年秋季将在佛罗里达的坦帕湾对24个大小和形状各异的海草床进行取样。 海草斑块的物理属性将在景观水平（从航空照片），并在子景观水平（即在景观，斑块水平）的特点。 回归分析技术将被用来调查海草床的物理属性之间的关系，在景观和亚景观尺度。 还将利用回归分析技术研究动物群组成与河床物理属性之间的关系。 在同样的24个海草床中，将在四个罗盘航向中的每一个测量沉积速率，并每月记录床缘的扩张/收缩。 这些综合数据应使我们能够确定沉积作用在定义海草斑块特征，斑块特征是否有重要的影响动物群，因此，生态系统功能发挥了重要作用。 我们的技术和结果应该是普遍感兴趣的生态系统研究计划，其中水生植物是占主导地位的植被，包括淡水和盐沼。 鉴于水生植物占主导地位的地区往往是那些报告提供关键栖息地为较高的营养级作为喂养/避难/筑巢地点，生境结构在这些生态系统中发挥的作用可能是类似的海草床。 预计我们的研究结果可以用来建立一个预测基础，确定生态系统水平的影响栖息地退化。

9318130 Bell In models developed for marine vegetated habitats which emphasize ecosystem function, macrophytic vegetation is not generally considered to have major direct links to higher trophic levels. Instead, plants are veiwed as important important trophic contributors to the detrital pool. In the study proposed here we expand the veiw of the role of plants and consider how habitat structure provided by macrophytes, either as physical or predator refuge, or as a site of resource accumulation, might be important to ecosystem function. %%% This study is proposed to 1) explore the relationship of fauna known to be trophically-linked (i.e. small resident fish and epiphytal amphipods) to plant cover, height, and arrangement of plants across spatial scales and 2) develop a model depicting sedimentation processes that influence seagrass patch development and maintenance. Twenty four seagrass beds of varying size and shape will be sampled during the Spring and Fall of 1994 and 1995 in Tampa Bay, Florida. Seagrass patches will be characterized for physical attributes on a landscape level (from aerial photographs), and on a sub-landscape level (i.e. within a landscape, patch level). Regression analyses techniques will be used to investigate relationships between the physical attributes of the seagrass beds at both landscape and sub-landscape scales. The relationship of faunal components and bed physical attributes will also be examined using regression analysis techniques. In the same 24 seagrass beds, sedimentation rates will be measured at each of the four compass headings and expansion/contraction of bed margin recorded monthly. These combined data should allow us to determine if sedimentation plays a major role in defining seagrass patch characteristics, whether patch characteristics have important influence on fauna, and hence, ecosystem function. %%% Our techniques and results should be of general interest to ecosystem research programs where macrophytes are the dominant vegetat ion, including freshwater and salt marshes. Given that macrophyte-dominated areas are often those reported to provide critical habitat for higher trophic levels as feeding/refuge/nesting sites, the role habitat structure plays in these ecosystems may be similar to that in seagrass beds. It is anticipated that results from our study can be used to build a predictive basis for determining the ecosystem level implications of habitat degradation.