The pilot reported that while conducting wildlife damage management activities under contract with the U.S. Department of Agriculture, he entered a right 180-degree turn in order to reverse direction and position the airplane. The airplane heading prior to the turn was into a slight right quartering headwind and required a climb due to up-sloping terrain. About 160 degrees into the right turn, the right quartering headwind became a left quartering tailwind. The airplane descended and contacted the ground. On contact, the nose of the airplane pitched forward and struck the ground. The airplane then bounced, cartwheeled, and came to rest approximately 105 ft from the initial ground contact, resulting in substantial damage to the fuselage, both wings, and the empennage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.