Allomyia bifosa, Joe Giersch photoRhyacophila hyalinat, Joe Giersch photoBaetis tricaudatus, Joe Giersch photo

Invertebrates, or animals without backbones, make up 97% of all animal species. The Crown of the Continent supports high invertebrate diversity due to several factors. Major river drainages provide channels for species migration to the region. Complex landscape topologies, encompassing prairies to mountains, offer a variety of life zones necessary to sustain the rich biodiversity of host plants needed to support many invertebrate insects. Wildland fires also play a role, as invertebrates specializing in burned areas thrive in the habitat mosaics which result from fires.

The small size of invertebrates belies their importance as the foundation of the food chain supporting a host of animals across the ecosystem. Insects, crustaceans, and even fresh water sponges found in streams at both high and low elevations are fed upon by larger insects, birds, and even fish. The presence of these aquatic invertebrates is also used as an indicator of water quality.