Effects of nitrogen on carbon chemistry in chaparral and coastal sage scrub leaf tissue

Background/Question/Methods

Atmospheric N deposition is a main source of pollution to plants, soil and stream water, especially in N limited, semi-arid ecosystems. It is hypothesized that an increase in N levels may cause seasonal and long term effects (4 years) on carbon chemistry within leaf tissue of coastal sage scrub and chaparral plant species, Artemesia californica and Adenostoma fascicuatum, respectively. The C chemistry of a leaf, specifically soluble C, hollocellulose, and lignin, is directly related to the rate of decomposition, N availability, and nutrient cycling. Leaf samples were taken from control and treatment plots, which contain elevated N levels. Nitrogen and carbon chemistry levels were quantified using an elemental analyzer, as well as a series of water/ethanol washes, and sulfuric acid digests.

Results/Conclusions

Initial Artemesia californica data trends show the lowest levels of soluble C and highest levels of holocellulose during winter months; as well as an overall increase in lignin from 2006 to 2010. Initial Adenostoma fascicuatum data trends also show highest levels of holocellulose during winter months but steady levels in soluble C, holocellulose, and lignin throughout the study overall. Further data analysis will be completed shortly using a multivariate repeated measures analysis. The results of this study may reflect how N pollution can affect carbon allocation patterns in California native shrubs.