WATER-TABLE AND PLANT-SPECIES RELATIONSHIPS IN SIERRA-NEVADA MEADOWS

Baseline information on water table fluctuation patterns was collected at Sagehen Creek Field Station, near Truckee, California, from June 1987 through November 1989. Relationships between plant community types and water table patterns were examined. Water table patterns were determined from bimonthly measurements of piezometers. Species composition was determined using a 10-point frame placed randomly near each piezometer. Four distinctive water table patterns were identified based on examination of specific water table variables during 2 growing seasons. Five plant community types were identified, designated Deschampsia caespitosa/Carex nebrascensis, Poa pratensis/Potentilla gracilis, Poa pratensis/Carex, Carex angustata/Poa pratensis and Carex angustata. These plant communities were related to specific water table patterns. The D. caespitosa/C. nebrascensis type experienced the greatest annual fluctuation in water table of any of the types. The P. pratensis/Carex plant community type occupied sites with the smallest water table fluctuation. Water table patterns associated with the P. pratensis/Potentilla gracilis community type indicated dry sites, whereas Carex angustata sites had small overall water table fluctuations and were generally wet to moist sites. The complexity of the physical and biological components of meadow ecosystems was demonstrated, suggesting site variation and changes in meadow species may be predicted by monitoring water table pattern.