Lists of the 26 environment variables.

aVariables used in modeling.bSee http://www.worldclim.org/.cSee http://sedac.ciesin.columbia.edu/.dSee http://www.sage.wisc.edu/atlas/maps.php.Human footprint (HF) is based on the premise that the impact of human influence varies by biogeography and HF expresses as a percentage the relative human influence in every biome on the land’s surface.Human influence index (HII) is a measure showing direct human influence on ecosystems using eight measures of human presence (population density/km2, score of railroads, score of major roads, score of navigable rivers, score of coastlines, score of nighttime stable lights values, urban polygons, and land cover categories).Soil moisture index (SMI) reflects the ability of soil to supply moisture to plants and SMI can identify a quick onset of drought by demonstrating the observed dryness of a soil relative to the plant’s ability to extract water as scaled over the range from field capacity to wilting point.Lists of the 26 environment variables.

a 建模中使用的变量。
b 详见 http://www.worldclim.org/。
c 详见 http://sedac.ciesin.columbia.edu/。
d 详见 http://www.sage.wisc.edu/atlas/maps.php。

人类足迹（Human Footprint, HF）基于“人类活动的影响随生物地理区域而异”这一前提，以百分比形式表征陆地表层各生物群系内的相对人类活动影响强度。

人类影响指数（Human Influence Index, HII）是一项衡量人类对生态系统直接影响的指标，其通过八项人类活动表征因子计算得到：人口密度（人/平方千米）、铁路得分、主要道路得分、通航河流得分、海岸线得分、夜间稳定灯光值得分、城市多边形图层以及土地覆盖分类。

土壤湿度指数（Soil Moisture Index, SMI）可反映土壤为植物供应水分的能力；该指标通过对比观测到的土壤干燥程度与植物在田间持水量至萎蔫点区间内的水分提取能力，能够快速识别干旱的发生。

本数据集包含26项环境变量列表。