Rangeland Recovery Potential: Soil Seed Content and Seed Viability

In most plant communities, soil contains a seed bank (population of dormant seeds), (Harper 1977), which provides a partial record of past and present vegetation (Major and Pyott 1966, Johnson and Anderson 1986). Seed banks are continuously rejuvenated by a seed rain , from vegetation located on- and off-site. If existing communities are disturbed or destroyed, the seed bank provides a potential source of propagules during succession (Egler 1954, Connell and Slatyer 1977). Consequently, seed banks may serve as an index in predicting what vegetation changes might occur if environmental conditions are favorable for germination (Harper 1977). The objectives of this study are to 1. evaluate the viable seed bank within grazed and relict pinyon-juniper and blackbrush/Indian ricegrass communities in Glen Canyon National Recreation Area (GCNRA), 2. assess the ability of these communities to recover following a disturbance, using their respective seed banks as indicators of recovery potential, and 3. address the suitability of using seed banks to monitor and predict community level composition changes in response to various intensities of grazing