Effects of nitrogen deposition on multiple ecosystem services of the California oak savanna

Abstract

The influence of enhanced nitrogen (N) deposition on key ecosystem services provided by oak woodlands was experimentally investigated. Fertilizer was applied for 2 years to paired plots in the oak understory and adjacent open grassland. Treatments simulated four N deposition levels and effects on forage productivity, biodiversity, and soil N supply were measured. At each treatment level, understory plots received twice the N fertilizer of paired open plots to simulate a deposition hotspot effect of the oak canopy. Soils in the open had lower inorganic N concentrations than the understory regardless of fertilizer level. Productivity largely did not respond to fertilization except at the highest level, where it declined by 34 percent and 25 percent relative to control plots in understory and open areas, respectively. Understory and open plots lost an average of two and one species under high N, respectively. These results indicate oak woodlands are resistant to the effects of N deposition on these ecosystem services up to 100 to 200 kg/ha/yr, which is a much higher level than currently received or expected. The different contributions by understory and open areas to these ecosystem services highlight the need to consider both habitats when predicting response to environmental change.

Parent Publication

• Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world

Citation

Tulloss, Elise M.; Cadenasso, Mary L. 2015. Effects of nitrogen deposition on multiple ecosystem services of the California oak savanna. In: Standiford, Richard B.; Purcell, Kathryn L., tech. cords. Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world. Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 199-208.