rarefaction and extrapolation of sample coverage based on sample-based abundance data

#R code.txt is the R code for plotting figures and constructing Tables #bciabun1010.txt is the species_by_plot matrix that BCI forest Plot is divided by a plot with size 10m*10m #bciabun2020.txt is the species_by_plot matrix that BCI forest Plot is divided by a plot with size 20m*20m #fus10.txt is the species_by_plot matrix that Fushan forest Plot is divided by a plot with size 10m*10m #fus20.txt is the species_by_plot matrix that Fushan forest Plot is divided by a plot with size 20m*20m #fus20.txt is the species_by_plot matrix that Fushan forest Plot is divided by a plot with size 50m*50m #lhc10.txt is the species_by_plot matrix that Lianhuachi forest Plot is divided by a plot with size 10m*10m #lhc20.txt is the species_by_plot matrix that Lianhuachi forest Plot is divided by a plot with size 20m*20m