De Guzman, M. E. , Tobin, M.F. , Jacobsen, A. L. , O'Mara, H. P. , Pratt, R. B. .
Leaf and canopy level carbon assimilation rates of post-fire resprouting chaparral shrub species that display different life history types.
The chaparral vegetation that dominates the foothills of the Mediterranean-type climate region of California experiences wildfires as part of a natural fire regime. Chaparral shrub species display different life history types that are partially defined by their post-fire response. Facultative sprouters (FS) resprout from an underground lignotuber after fire and also recruit new seedlings post-fire from a dormant, fire stimulated seed bank. Obligate sprouters (OS) resprout following fire, but unlike FS do not recruit new seedlings post-fire because their seeds are short lived and intolerant of fire. Canopy removal by fire limits the ability of plants to acquire carbon, and forces plants to rely on limited root and lignotuber stores for maintenance respiration and early growth. This project focused on a critical plant trait, photosynthetic rate (net carbon assimilation rate; Anet), and its ability to predict post-fire resprout success and survival. Measurements of Anet were made on co-occurring burned and unburned plants at both the leaf and canopy levels in the first year following fire in the Angeles National Forest in southern California. We hypothesized that Anet and life history type would be linked, such that OS species would have greater Anet than FS, because OS species must successfully resprout in order to maintain population stability. Results showed that burned plants had greater rates of Anet compared to unburned plants at both the leaf and canopy levels (p < 0.001 for all comparisons). The life history types did not differ in Anet at any scale (p > 0.05 for all comparisons). The vigorous recovery of the OS life history type cannot be explained by greater rates of Anet, but maybe linked to greater underground stores of carbon compared to FS species.
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1 - California State University, Bakersfield, Biology, 9001 Stockdale Highway, Bakersfield, CA, 93311, USA
2 - California State University Bakersfield, Biology, 9001 Stockdale Hwy, Bakersfield, CA, 93311, USA
3 - California State University, Bakersfield, Department of Biology, 61 Sci, 9001 Stockdale Hwy, Bakersfield, CA, 93311, USA
4 - California State University, Bakersfield, Biology, 9001 Stockdale Hwy, Bakersfield, CA, 93311, USA
Presentation Type: Oral Paper:Papers for Topics
Location: 551B/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 2:15 PM