Biodiversity indices comparison between 3 sites-Which test is appropriate?

Hi, i would appreciate some help on the following:
I have to compare 3 different farming management systems (Organic, conventional, integrated) in terms of soil fauna (soil arthropod insects)

I have calculated for each management system: Soil fauna's Total catches, mean abundance, Shannon's index (H'), Simpson index (1-D), Pielou's index

The three different management systems imply different level of management intensity (therefore, indepedent variable: Intensity, expressed in 3 levels, Organic=lower to conventional-higher)

What's the best test for the biodiversity indices comparison?

Thank you, i would appreciate any help