MINNEAPOLIS — The federal government is considering adding the Blanding’s turtle to the endangered species list, as the yellow-throated reptile that once thrived throughout the Upper Midwest can now only be found in large numbers in parts of Minnesota and Nebraska.

The sand dunes, marshes and backwaters of the upper Mississippi River, including the Weaver Dunes of southeastern Minnesota, hold one of the largest remaining populations of the Blanding’s turtle, which the Minnesota Department of Natural Resources already classifies as threatened. A population in Valentine National Wildlife Refuge in northern Nebraska, where the species is classified as at-risk, is more secure but still vulnerable.