Recent pace of change in human impact on the world's ocean: Commercial fishing - demersal non-destructive low-bycatch

These are the stressor and impact data for commercial demersal nondestructive high bycatch fishing for the publication: 'Recent pace of change in human impact on the world's ocean' (Halpern et al. 2019).
This stressor describes tonnes of demersal fisheries catch using nondestructive, but high bycatch, gear types. Catch is standardized by Net Primary Productivity. We describe the stressor intensity of demersal nondestructive high bycatch fishing and the corresponding impact on 21 marine ecosystems over 11 years (2003-2013). To determine annual change in impact, we applied a linear regression model to each raster cell. Code used in analyzing these data is available as a zipped GitHub repository, impact_acceleration-1.0.zip, in this dataset's parent (CITATION HERE).

These data include the following: Raw stressor intensity rasters for 2003 to 2013. These rasters are created using scripts located in the 'stressors' folder of the 'impact_acceleration' Github repository. Rescaled stressor intensity rasters for 2003 to 2013. Raw stressor intensities are rescaled to values between 0 and 1, using either known or estimated ecosystem thresholds or upper quantile values from the distribution of global stressor intensity values across years. These rasters are created using scripts located in the 'stressors' folder of the 'impact_acceleration' Github repository. Impact rasters for 2003 to 2013 which describe the impact of the stressor based on the vulnerability of 21 marine ecosystems to the stressor. The impact of the stressor is estimated by multiplying the stressor's intensity by the corresponding ecosystem vulnerability where the ecosystem occurs. The average impact of each stressor, across all ecosystems, is estimated by summing the stressor-by-ecosystem vulnerability combinations and dividing by the number of ecosystems within each cell. These rasters are created using scripts located in the 'impacts' folder of the 'impact_acceleration' Github repository. A trend raster describing the average annual change in impact from 2003 to 2013. This raster is created using scripts located in the 'trend' folder of the 'impact_acceleration' Github repository. Files describing the cumulative impacts and additional stressors are provided in other KNB datasets.

本数据集为发表于论文《人类对全球海洋影响的近期变化速率》（*Recent pace of change in human impact on the world's ocean*, Halpern et al. 2019）的商业底栖非破坏性高兼捕渔业压力因子与影响数据。
该压力因子表征采用非破坏性但兼捕率较高的渔具类型所产出的底栖渔业捕捞吨数。捕捞量以净初级生产力（Net Primary Productivity）作为标准化基准。本数据集刻画了2003至2013年共11年间，21种海洋生态系统所受底栖非破坏性高兼捕渔业的压力因子强度，及其对应的生态影响。为测算影响的年度变化幅度，我们针对每个栅格（raster）单元应用了线性回归模型。本数据集所用分析代码已打包为GitHub仓库压缩包`impact_acceleration-1.0.zip`，存放于本数据集的父数据集路径中（引用信息详见此处）。

本数据集包含以下内容：
1. 2003年至2013年的原始压力因子强度栅格数据。此类栅格通过`impact_acceleration` GitHub仓库中`stressors`文件夹内的脚本生成。
2. 2003年至2013年的重标化压力因子强度栅格数据。原始压力因子强度将通过已知或估算的生态系统阈值，或是基于全球历年压力因子强度分布的上分位数数值，被重标化至0至1的数值区间内。此类栅格同样通过`impact_acceleration` GitHub仓库中`stressors`文件夹内的脚本生成。
3. 2003年至2013年的影响栅格数据，此类数据基于21种海洋生态系统对该压力因子的脆弱性，刻画了该压力因子所带来的生态影响。压力因子的影响值通过将压力因子强度与对应栅格单元内的生态系统脆弱性相乘得到。各栅格单元的平均影响值则通过累加所有“压力因子-生态系统脆弱性”组合的数值，再除以该单元内的生态系统总数得到。此类栅格通过`impact_acceleration` GitHub仓库中`impacts`文件夹内的脚本生成。
4. 刻画2003年至2013年影响年均变化的趋势栅格数据。此类栅格通过`impact_acceleration` GitHub仓库中`trend`文件夹内的脚本生成。
5. 描述累积影响与其他压力因子的相关文件已在其他KNB数据集中提供。