I comparing fish diversity from the years 2013 to 2018 in a freshwater river system. There are however different species present in some years. Can I still use the Shannon Index to compare diversity? I have attached my calculations below.

Well the index for from 2013 to 2018 can be seen to drop which indicates overall diversity is decreasing over time? Is a stats test required to see if they’re significant?

Put the year and diversity into two columns. Analyse, Regression, Linear. Make Year the independent variable and Diversity the dependent variable. Then look for the p value in the output anova table or the coefficients table