A diverse array of aquatic invertebrates occurs in the riparian and aquatic ecosystems of the American Southwest. Springs, seeps, perennial and ephemeral streams, rivers, and playa lakes are some of the habitats available to these important members of the food chain. In the Chihuahuan Desert, for example, there are specialized freshwater assemblages of invertebrates associated with playas (such as clam shrimp, water fleas, and fairy shrimp) that provide food for migrating waterfowl. Monitoring of macroinvertebrates can provide critical insight into degradational changes in water quality and quantity.