The North Etiwanda Preserve is important because it protects one of the few remaining intact Riversidian Alluvial Fan Sage Scrub habitats, which is a rare ecosystem. This habitat runs along the southern base of the Transverse mountain ranges and is characterized by shrub-dominated plant communities adapted to periodic flooding. The preserve contains 473 acres of alluvial shrub habitat and is home to endangered species like the California gnatcatcher bird.