Plant Ecology

, Volume 184, Issue 1, pp 53–63

Shrub establishment under experimental global changes in a California grassland


DOI: 10.1007/s11258-005-9051-x

Cite this article as:
Zavaleta, E.S. Plant Ecol (2006) 184: 53. doi:10.1007/s11258-005-9051-x


Accelerating invasion of grasslands by woody species is a widespread global phenomenon. The native shrub Baccharis pilularis has recently increased in abundance in some California grasslands, with large local community and ecosystem effects. I investigated potential contributions of (1) future global climate and atmospheric changes and (2) variation in moisture and nutrient availability to increased Baccharis germination and early establishment rates. I examined responses of Baccharis seeds and seedlings to simulated warming (+ 1−2 °C) and elevated CO2 (+ 300 ppm) in a 2-year field experiment. Warming and CO2 treatments were applied at ambient and increased water and nitrogen levels chosen to simulate future increases in precipitation (+ 50%) and N deposition (+ 7 gN  m−2 y−1). Elevated CO2 and water addition each increased or accelerated germination. Herbivory strongly reduced seedling populations during the winter wet season; drought further reduced seedling survival in the spring. Overall Baccharis survivorship was extremely low (<0.1%) across all treatments, complicating the interpretation of global change effects.


Baccharis pilularisClimate changeColonizationElevated CO2Nitrogen fertilizationShrub

Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  1. 1.Environmental Studies DepartmentUniversity of CaliforniaSanta CruzUSA