PS 55-92
Grassland restoration: Analyzing soil moisture to inform species presence during a time of drought
Soil moisture has significant impact on the vegetation of an area, often determining the species composition and relative species presence due to limitations in plants’ ability to tolerate low-moisture conditions. These basic concepts are applied to a California grassland system in which both invasive species and native perennial species are present. By analyzing soil moisture profiles at variable depths using high-capacitance technology, insight may be gained with respect to the impact of soil moisture on the relative abundance of a particular species within an area, as well as the necessary depths at which moisture impacts the growth of various species. In particular, this system uses existing knowledge and plant surveys at the Jasper Ridge Global Change Experiment in conjunction with soil moisture measurements to describe the impact of moisture on various grassland species, with special focus on the current drought conditions in California and the lasting impact on restoration of native perennial species.
Results/Conclusions
Preliminary results have suggested that invasive annual grassland species draw water from shallower depths in the soil profile than their native analogues. This increases fitness of perennial species in the grassland environment. High-capacitance measurements indicate that moisture content at the deeper levels of the soil profile (50-70 cm.) is relatively unaffected by drought conditions compared to shallower levels of the soil profile. Thus, in current drought conditions, perennials are projected to see the same percentage growth and species restoration as in past years, while annuals may be less prolific with respect to biomass production. Coupling these results with previous studies from the Jasper Ridge Global Change Experiment, increased incidence of drought conditions, possibly attributed to global climate change, could increase restoration of perennial grassland species in California.