Part 4: Script for NRI analysis and the code needed to run the script

This code takes the NRI values for each of the countries (for each of the plants) and examines the relationship between NRI and invader presence in the transect. The analysis includes simple models and models that account for spatial autocorrelation at the country level.To run this, you need the NRI values that we calculated in the folders labeled Part 2 and Part 3. These values are saved in this folder! You do NOT need to run all the code in Part 2 and Part 3 to run this script.本代码针对各国（各植物类群）的净亲缘关系指数（Net Relatedness Index，简称NRI）值，探究样带中NRI与入侵物种存在情况之间的关联。分析涵盖基础模型与考虑国家层面空间自相关性的模型两类。运行本代码需使用我们在标注为第二部分与第三部分的文件夹中计算得到的NRI值，此类数据已存储于当前文件夹内。您无需运行第二部分与第三部分中的全部代码即可执行本脚本。