1. School of Plant and Environmental Sciences Virginia Tech Blacksburg VA 24061 USA
2. School of Resource and Environmental Sciences Wuhan 430079 China
3. Dep. of Ecology Univ. of Innsbruck Innsbruck 6020 Austria
4. Agricultural and Biological Engineering Penn State State College PA 16802 USA
5. Pasture Systems and Watershed Management Research Unit USDA‐ARS University Park PA 16802 USA