Please do include it! You can find the logos here: https://www.inaturalist.org/pages/press
The main consideration for using the logo is that it should not be used in a misleading way, e.g. misrepresenting a relationship with iNaturalist.
Using the logo in a graphical abstract to convey how iNaturalist was incorporated into the research is perfectly appropriate, just like using the logo to link to iNaturalist in an editorial or promotional context.