An ecotope map of the trilateral Wadden Sea

These data present the first digital, publicly available, ecotope map of the trilateral Wadden Sea covering the Netherlands, Germany and Denmark. This ecotope map, representative for the time period 2008-2012, was developed on the basis of bathymetry, salinity, flow velocity, exposure time, sediment composition, hard substrates and salt marshes. Ecotopes are discrete classes of the physical environment based on the distributions of communities in an ecosystem. An ecotope map can give a first–order estimate of the potential spatial distribution of species and communities. The use of a single, consistent and well-defined ecotope system makes it possible to compare the proportions of the different ecotopes and compare properties of the tidal basins over the entire trilateral Wadden Sea.

This ecotope map of the trilateral Wadden Sea area followed the ecotope system for coastal waters ZES.1 typology that was developed in the Netherlands. This ecotope system is based on the notion that local physical environmental factors and processes are main determinants of communities. The main physical environmental factors and processes in the ZES.1 system were mean and variability of salinity, substratum type, mean water depth, and hydrodynamics. Class boundaries were used to classify the continuous variables in order to define the ecotopes. The ZES.1 ecotype system hierarchically arranges the ecotope variables on the basis of the dominance of the physical environmental factors and processes in determining community composition.

CORRIGENDUM. In version 1 of June 2019 an error has been made. The class boundary between shallow sublittoral and low intertidal was not set to 4% mean exposure but to 0.001%. This resulted in a too low cover of sublitoral areas. In Version 2 this is corrected. The data file is a zipped file "EctpWZ3L_gpkg.zip" containing a GeoPackage, holding the geographical data (polygons etc.):
i. EcotopeWS3_mp = polygon geodata of ecotope map
ii. bivbeds_focc = geodata for eco-element bivalve beds (polygon)
iii. eelgrass_presence = geodata for eco-element seagrass aka eelgrass presence (polygon)
iv. EcotopeWS3CodeInterpretation, table explaining how fields in ecotope map should be interpreted
v. ZESsmpleCode2Legend, table expanding ZESsimple from code to full legend text.
and includes:
2) a set of QML-files (symbology definition files for QGIS),
3) a set of SLD-files (symbology layer definition files for GeoServer),
4) three PNG-files to provide the different textures/patterns used in the symbolising the sediment types.

本数据集提供了首份数字化、可公开获取的、覆盖荷兰、德国、丹麦三国的瓦登海三方跨界海域的生境（ecotope）地图。该生境地图代表2008-2012时段，基于水深地形、盐度、流速、暴露时长、沉积物组成、硬质底质与盐沼构建而成。
生境（ecotope）是基于生态系统中群落分布划分的物理环境离散分类单元。生境地图可对物种与群落的潜在空间分布提供一阶估算结果。采用单一、统一且定义明确的生境系统，可对整个三国跨界瓦登海海域内不同生境类型的占比，以及各潮盆的属性开展对比分析。

本三国跨界瓦登海生境地图采用荷兰研发的ZES.1沿岸水生生境分类系统。该生境系统的核心理念为：局地物理环境因子与过程是决定群落分布的主要因素。ZES.1系统中的核心物理环境因子与过程包括盐度平均值与变异性、底质类型、平均水深以及水动力条件。通过设定分类阈值，对连续变量进行分类以界定生境类型。ZES.1生境系统依据物理环境因子与过程在群落组成决定中的主导地位，对生境变量进行层级化排布。

勘误说明：2019年6月发布的V1版本存在一处错误：浅海亚潮带与低潮间带的分类阈值被误设为0.001%平均暴露时长占比，而非原定的4%，这导致亚潮带区域的覆盖范围被严重低估。V2版本已修正该问题。

本数据集的压缩文件名为"EctpWZ3L_gpkg.zip，内含一个地理数据包（GeoPackage），存储各类地理数据（多边形要素等）：
i. EcotopeWS3_mp：生境地图的多边形地理要素数据
ii. bivbeds_focc：双壳类床生态要素的多边形地理数据
iii. eelgrass_presence：海草（又称鳗草）床生态要素的存在范围多边形地理数据
iv. EcotopeWS3CodeInterpretation：生境地图字段释义表，用于说明生境地图各字段的解读方式
v. ZESsmpleCode2Legend：ZESsimple代码转图例表，用于将ZESsimple代码转换为完整图例文本

此外还包含：
2. 若干QML文件（QGIS符号系统定义文件）
3. 若干SLD文件（GeoServer符号图层定义文件）
4. 三张PNG格式文件，用于提供沉积物类型符号化所需的各类纹理/图案。