Temporal Beta-Diversity in weed communities

This data file provides two beta-diversity indices, namely Jaccard and Bray-Curtis, computed from successive weed communities growing in 493 arable fields distributed over the whole French national territory. Temporal environmental distances, environmental heterogeneity and temporal distance are also furnished. Weeds were surveyed in two kind of plots, without herbicide application (control, "c") and with herbicide application (sprayed, "s"). Each year, weeds were surveyed twice, at the begining (n1) and at the middle (n2) of the cropping season.本数据集提供了两类β多样性指数（beta-diversity indices），即雅卡尔（Jaccard）指数与布雷柯蒂斯（Bray-Curtis）指数，上述指数由分布于法国全境的493块耕地中随时间演替的杂草群落计算得到。同时还提供了时间环境距离（temporal environmental distances）、生境异质性（environmental heterogeneity）与时间距离（temporal distance）三类数据。本调查设置两类样地开展杂草调研：未施用除草剂的对照组（control, "c"）与施用除草剂的喷施组（sprayed, "s"）。每年于作物生长季初期（n1）与中期（n2）开展两次杂草调查。