1. Dep. of Environ. ScienceAllegheny CollegeMeadvillePA16335
2. Dep. of Natural Resources and Environ. ManagementUniv. of HawaiiHonoluluHI96822
3. Dep. of Earth and Environ. ScienceUniv. of PennsylvaniaPhiladelphiaPA19104‐6316
4. Dep. of Plant and Environ. SciencesUniv. of CopenhagenDK‐1871FrederiksbergDenmark
5. Dep. of Ecology and Evolutionary BiologyUniv. of MichiganAnn ArborMI48109
6. Dep. of Crop and Soil SciencesOregon State Univ.CorvallisOR97331