M.C. Davis, former gambler and businessman, stands in his 54,000-acre preserve, Nokuse Plantation, in the Florida Panhandle. It's the largest privately owned conservation area in the southeastern United States. Matt Ozug/NPR hide caption

itoggle caption Matt Ozug/NPR

Hudson River view. Brian Mann/North Country Public Radio hide caption

itoggle caption Brian Mann/North Country Public Radio

A tray of sardines in Costa Mesa, California, in this November 17, 2014 photo. Plummeting sardine populations force a complete ban on sardine fishing off the U.S. West Coast for more than a year. LUCY NICHOLSON/Reuters /Landov hide caption

itoggle caption LUCY NICHOLSON/Reuters /Landov

A baby orangutan wearing a diaper swings through the trees at the Sumatran Orangutan Conservation Program outside Medan, capital of Indonesia's North Sumatra province. The program takes mostly orphaned orangutans, nurses them back to health and releases them back into the wild. Anthony Kuhn/NPR hide caption

itoggle caption Anthony Kuhn/NPR

Volunteer Tom Strain carries debris from an empty lot as part of an Earth Day cleanup effort in Camden, N.J. The Earth Day events celebrated on April 22 promote a sustainable and clean environment. Mel Evans/AP hide caption

itoggle caption Mel Evans/AP

Rufus, 46, now lives on an island in a Florida sanctuary run by Save the Chimps. Before his rescue, Rufus lived in a facility Save the Chimps calls "the dungeon." Courtesy of Save the Chimps hide caption

itoggle caption Courtesy of Save the Chimps

European settlers almost wiped out North America's native wild turkey. But conservation efforts have proved successful. There are now nearly 7 million birds found across 49 states. Larry Price, National Wild Turkey Federation/NWTF.org hide caption

itoggle caption Larry Price, National Wild Turkey Federation/NWTF.org

Dara Arista, 8, holds a photo of Sheila in front of the tiger's cage at the zoo in Jambi, Indonesia. Poachers had slaughtered Sheila during the night. Steve Winter/National Geographic hide caption

itoggle caption Steve Winter/National Geographic

Mixed grasses growing in a parcel of land enrolled in the Conservation Reserve Program is seen near Tribune, Kan. Millions of acres of CRP nationwide will be returned to farmland.

Charlie Riedel/AP hide caption

itoggle caption Charlie Riedel/AP