For a conservation organization, the Nature Conservancy often seems not be very nature friendly, although usually have a political explanation.
Here is the story from the Hays Daily News.
It decribes how they poisoned prairie dogs in Logan County, Kansas. Prairie dogs are a species most groups are trying desperately to conserve. Phostoxin was used without a permit on properties adjacent to their 18,000 acre ranch in Logan County, KA. According to the story, TNC was poisoning prairie dogs that moved from their ranch onto to adjacent ones.
Apparently TNC was responding to pressure from Logan County commissioners who don’t like prairie dogs, which had made a comback on the TNC ranch.
Phostoxin is a non-selective poison. Now TNC is putting pellets of zinc phosphide down the burrows.
I think this is the kind of problem you run into with their method of trying to appease backward local interests when they buy land.