Soil water dynamics differ among rangeland plant communities dominated by yellow starthistle (Centaurea solstitialis), annual grasses, or perennial grasses

Abstract

California's interior grasslands have undergone dramatic changes during the last two centuries. Changes in land-use patterns and plant introductions after European contact and settlement resulted in the conversion of perennial-dominated grasslands to exotic annual grasses. More recently, the annual grasslands have been heavily invaded by the deeply rooted late-maturing forb yellow starthistle. This series of invasions and conversions has changed the community structure and phenology of the grasslands. We hypothesized that these changes have resulted in significant differences in soil water–use patterns in the grasslands. We studied soil water depletion and recharge patterns of three grassland community types dominated by perennial grasses, annual grasses, or yellow starthistle with contrasting phenology and rooting depths for 4 yr. Soil moisture measurements were taken every month from March to December in 1998, 1999, and 2000 and every other month in 2001. Measurements were taken with a neutron probe at depths of 30 to 150 cm at 30-cm intervals. The results indicate that the yellow starthistle community maintained a significantly drier soil profile than the annual grass community. The perennial grass community maintained an intermediate soil water content that was not significantly different from either of the other two communities. Significant time by community and depth by community interactions indicated that the yellow starthistle community continued depleting soil moisture later into the season and at deeper depths than the other grass communities. This study demonstrates the effect of plant invasion on soil water recharge and depletion patterns in California grasslands.

Not novel, just better: competition between native and non-native plants in California grasslands that share species traits

“…This ability is lacking in native species (Vivrette and Muller 1977). Dominance of Centaurea solstitialis L. (yellow starthistle), a summer-active annual species, into western North American grasslands is aided by its ability to access deep stores of water that are unexploited by the winter-annual dominant grassland vegetation (Sheley and Larson 1995;Gerlach 2004;Enloe et al 2004). Callaway and Aschehoug (2000) reported that the ability of Centaurea diffusa Lam.…”

The impact of invasion and subsequent removal of an exotic thistle, Cynara cardunculus, on CO2 and H2O vapor exchange in a coastal California grassland

“…The effects of woody-plant removal on local hydrological processes are complex (Hibbert 1983;Seyfried and Wilcox 2006) and likely vary with soil infiltration characteristics, rainfall regime and physiographic setting (Huxman et al 2005). The consequences of removing deeply-rooted, perennial thistles from rangelands on local hydrologic budgets are likely equally complex (Lacey et al 1989;Enloe et al 2004;Gerlach 2004). Nevertheless, these findings suggest that Cynara-removal is associated with a decline in growing season ET and has, at least in the short-term, the potential to increase water yields in rangelands.…”

“…For example, the invasion of species possessing traits such as rapid growth in response to resource availability (Suding et al 2004), high photosynthetic rates (McDowell 2002) and high photosynthetic energy-use efficiency (Nagel and Griffin 2001) have the potential to alter patterns of ecosystem carbon cycling. Likewise, increased active rooting depth (Enloe et al 2004) and increased water use efficiency (McDowell 2002) are traits associated with successful plant invaders that may potentially affect patterns of ecosystem water cycling.…”

Applying the Successional Weed Management Model for Revegetating a Yellow Starthistle-Infested Dryland Pasture in the Chihuahuan Desert

“…Successful revegetation programs should include a combination of species adapted to the study area with different growth forms and growing seasons to maximize resource capture across space and time [14]. Various native and nonnative perennial grass species have been used in revegetation projects to successfully compete with noxious weeds [13,15,30,31]. The native grasses used in our study provided the following warm season (WS)/cool season (CS), and rhizomatous (R)/bunchgrass (B) combinations: WS/B (alkali sacaton), CS/B (squirreltail), WS/R (galleta), and CS/R (western wheatgrass).…”