Wave exposure indices from digital coastlines and the prediction of rocky shore community structure
Wave exposure indices from digital coastlines and the prediction of rocky shore community structure
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DOI：
10.3354/meps07284
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发表时间：
2008-01-01
影响因子：
2.5
通讯作者：
Robb, Linda
中科院分区：
文献类型：
--
作者：
Burrows, Michael T.;Harvey, Robin;Robb, Linda
地形波浪暴露指数可以客观评估沿海地区波浪作用的程度。我们提出了一种基于网格的方法，用于快速计算整个海岸线精细空间分辨率的指数，并评估候选指数在预测岩石海岸群落组成方面的能力。该方法分为 3 个阶段：(1) 使用地理信息系统 (GIS) 软件根据基于矢量的数字海岸线创建网格； (2) 对于每个沿海单元，取波被确定为 16 个角扇区中到最近陆地单元的距离，使用周围单元的粗、中、细分辨率搜索，距离可达 200 公里； (3) 计算邻近沿海站点各扇区的风能（平均风速和出现比例）。我们计算了每个扇区的平均取电量（F）以及取电量与风能的乘积之和（W）。在苏格兰西部 185 个地点总共对 57 个物种进行了调查，以确定波浪指数的趋势。 200 m 尺度网格的平均波提取解释了物种位点丰度矩阵第一主成分中 >50% 的变化，海岸范围解释了另外 10%。将风数据纳入指数对预测能力的影响可以忽略不计。物种多样性解释了第二主成分的 61% 的差异，并从低到高的中上层初级生产力下降。将直接物理效应与生物效应（例如食物供应或放牧）分开可能有助于我们更好地了解在岩石海岸上构建生物群落的过程。
Topographical wave exposure indices allow objective assessment of the degree of wave action at coastal sites. We present a grid-based method for rapidly calculating indices at fine spatial resolutions along whole coastlines, and evaluate the power of candidate indices in predicting composition of rocky shore communities. The method has 3 stages: (1) a grid is created from a vector-based digital coastline using geographical information systems (GIS) software; (2) for every coastal cell, wave fetch is determined as the distance to the nearest land cell in 16 angular sectors, using coarse-, medium- and fine-resolution searches of the surrounding cells up to a distance of 200 km; (3) wind energy (average wind speed and proportional occurrence) in each sector is calculated for nearby coastal sites. We calculated the average fetch in each sector (F) and the sum of products of fetch and wind energy (W). A total of 57 species were surveyed at 185 sites in west Scotland for determination of trends with wave indices. Average wave fetch with a 200 m scale grid explained >50% of the variation in the first principal component of the species-sites abundance matrix, with shore extent explaining another 10%. Incorporating wind data in the indices had a negligible effect on predictive power. Species diversity explained 61% of the variance in the second principal component and declined from low to high pelagic primary productivity. Separating direct physical effects from biological effects, such as food supply or grazing could potentially help us better understand the processes structuring biological communities on rocky shores.