GRAND JUNCTION — A conservation group is challenging Colorado Parks and Wildlife's plans to reduce predator numbers outside Rifle and in the Upper Arkansas River Valley in order to help mule deer populations improve. WildEarth Guardians said Friday it has sued the agency and the commission that oversees it, The Daily Sentinel reported (http://bit.ly/2jZCdiV). "CPW's plans are not grounded in sound science, violate Colorado's Constitution, and are neither supported by the vast majority of Coloradans nor in the public interest," Stuart Wilcox, staff attorney for WildEarth Guardians, said in a news release.