Laminaria hyperborea kelp forest model in Trondelag

Laminaria hyperborea kelp forest is modelled for the Trondelag coast of Norway (Bekkby et al. 2013). The model was carried out in the projection UTM zone 33N. Kelp forest was defined as the dense kelp forest (see Bekkby et al. 2009), not the scattered occurrences. The model was developed based on 1170 data points and GAM analyses of presence and absence points (presence being kelp forest, absence being absence of kelp at all other densities). Data were collected 2007-2008 by the Norwegian Institute for Water Research (NIVA) and the Institute for Marine Research (IMR), the model was run in 2009 by NIVA. The distribution model is based on depth, slope, terrain curvature, wave exposure and median current speed, wave exposure being the far most important variable (see Bekkby et al. 2009 for explanation of the GIS environmental layers). The input depth, slope, terrain curvature and wave exposure models had a spatial (horizontal) distribution of 25 m, the current speed model was resampled from 500 m resolution. The output model has a spatial (horizontal) distribution of 25 m. Analyses showed that coverage (density of kelp defined as classes) increased with predicted probability. The work was part of the National program for mapping biodiversity – coast, a program that is funded by the Ministry of Climate and Environment and the Ministry of Trade, Industry and Fisheries. The Norwegian Environment Agency is leading the project and NIVA is the scientific coordinator.本研究针对挪威特伦德拉格（Trondelag）海岸的掌状海带（Laminaria hyperborea）林开展了建模研究（Bekkby等，2013）。该模型采用UTM 33N投影坐标系进行构建。本研究中将海带林定义为密集型海带林（参见Bekkby等，2009），而非零星分布的海带个体。本模型基于1170个数据点，以及针对存在点与缺失点的广义可加模型（Generalized Additive Model，GAM）分析构建：其中存在点对应海带林分布点位，缺失点则对应其他所有密度下无海带生长的点位。挪威水研究所（Norwegian Institute for Water Research, NIVA）与挪威海洋研究所（Institute for Marine Research, IMR）于2007-2008年完成了数据采集工作，模型于2009年由NIVA完成运行。该分布模型以水深、坡度、地形曲率、波浪暴露度与平均流速作为驱动变量，其中波浪暴露度为最核心的影响因子（关于地理信息系统（Geographic Information System，GIS）环境图层的详细说明参见Bekkby等，2009）。输入的水深、坡度、地形曲率与波浪暴露度图层的空间（水平）分辨率为25米，流速模型则由500米分辨率的数据源重采样得到。最终输出的模型空间（水平）分辨率为25米。分析结果表明，海带覆盖度（按等级划分的海带密度）随模型预测概率的升高而增加。本研究为《国家海岸生物多样性制图计划》的组成部分，该计划由挪威气候与环境部以及贸易、工业与渔业部联合资助。该项目由挪威环境局牵头，NIVA担任科学协调单位。