Twenty years after donating $500,000 to The Nature Conservancy in Iowa to acquire the first 642 acres of Iowa's largest remaining native prairie, former Principal Financial Group Inc. chairman and CEO David Hurd and his wife, Trudy, have started a $500,000 endowment fund to help continue the conservation of the now 3,217-acre Broken Kettle Grasslands preserve in Plymouth County, according to a news release. "The Kettle has been here for 10,000 years, but if it isn't properly protected, it will succumb to development," said Hurd. "The value it now brings would be lost. That's why my gift puts emphasis on maintenance of this historic landscape." Located just north of Sioux City, Broken Kettle is The Nature Conservancy's largest preserve in Iowa and is at the core of conservation efforts in the Loess Hills. It's also home to many plant and animal species, including native prairie, American bison, the black billed magpie and the prairie rattlesnake.