When it comes to ecology, there is one field where having illustrations really helps improve accessibility and understanding. That field is Theoretical Ecology. Theoretical ecologists look at complex interactions in nature and transform them into mathematical frameworks. It can be challenging to effectively communicate theory to a broader audience. I know I'm not the only one who glazes over when they see a paper full of equations! This is where an illustration can really work to give biological context to the math.
My husband is a theoretical ecologist, and I've created a number of illustrations for his papers. This latest one took his equation for incorporating mutualisms into coexistence theory, and broke it into parts that I then explained visually using watercolor illustrations of each component of the equation. The figure helps show how each biological interaction is incorporated into the theory.
You can read Christopher Johnson's paper in Ecology here.