RLC is actively involved in the planning, acquisition and management of lands designed to enhance the viability of the Dehli sands flower-loving fly (Rhaphiomidas terminates abdominalis) (DSF). Listed as endangered by the U.S. Fish and Wildlife Service in 1993, this subspecies is endemic to sand dune formations of San Bernardino Valley extending from Colton to Ontario.
The sand dunes, which originally covered an area of about 40 square miles, have dwindled to 2% of their original area. RLC currently holds title or conservation easement on seven properties, totally about 100 acres, which are preserved and managed as DSF habitat.