Weeds, insects, vertebrates, fungi, bacteria - nowhere do all these players come together in a more complex way than in the soil. The soil ecosystem has similar dynamics as the above-ground ecosystem with which we are more familiar - but in miniature! In the Insects section, you collected Berlese funnel samples that allowed extraction of the small fauna that live in the leave litter. These "litter communities" are very different from one habitat to another and provide a fascinating look into the biodiversity of the decomposer world.
From an IPM standpoint, good soil health is critical to prevention of pest problems, especially related to infection of plants from plant pathogens. If plant roots are not functioning properly due to pest damage or poor soil quality, the plant cannot take up water and nutrients well. Sick plants are more susceptible to above-ground pests. There is a correlation between soil life and soil health.
Understanding and promoting certain soil life and use of composting are two good ways to increase soil health and thus prevent pest problems from occuring.