Great Sand Dunes National Park and Preserve is an important refuge for Rio Grande Cutthroat Trout and other rare species.
USFWS Photo
The creeks of the Sangre de Cristo Mountains are important habitat for native fish species. The Rio Grande Cutthroat Trout (Oncorhynchus clarki virginalis) historically occupied the Rio Grande Basin and associated drainages in southern Colorado and New Mexico. At present, it only occupies about 15% of that range, mostly in the headwaters of the upper Rio Grande watershed. Medano Creek and Sand Creek serve as important biological refugia for this trout, because these are a closed system where exotic species cannot enter; the creeks are bounded by alpine basins at their source, and the desert valley floor at their terminus.
Rio Grande Cutthroat Trout are catch and release only as they are on the candidate list for threatened/endangered species at the federal level. These trout are currently on the Colorado state list as a Species of Special Concern.
The Rio Grande Sucker (Catostomus plebeius), found along Medano Creek in the National Park and Preserve, is an endangered species in Colorado.