1. Department of Forest, Rangeland and Watershed Stewardship, Colorado State University, Fort Collins, Colorado 80305, U.S.A
2. Present address: Department of Environmental Science, University of California, Davis, California 95616, U.S.A
3. Tetra Tech Inc., Boise, Idaho 83706, U.S.A
4. Herbario de la Facultad de Ciencias (MOL), Universidad Nacional Agraria La Molina, Apdo. 456, Lima, Peru
5. Minera Yanacocha S.R.L., Cajamarca, Peru