Abstract Detail


Sicangco, Camille Kilayko [1], Regier, Jordyn [2], Hernandez, Mayra [3], Davis, Stephen [4], Holmlund, Helen [4].

Soil respiration varies with vegetative type conversion and water availability in the Santa Monica Mountains.

Vegetation in the Santa Monica Mountains was historically dominated by chaparral but is increasingly being replaced by coastal sage scrub (CSS) and invasive grassland. Intensifying drought and shorter fire return intervals have contributed to this pattern of vegetative type conversion. I measured soil respiration at three sites in various stages of vegetative type conversion before and after irrigation. Sites were historically chaparral, but presently dominated by chaparral, CSS, or invasive grassland. At all three sites, respiration peaked 6-12 hours after irrigation to levels on average 8-25 times their pre-irrigation levels. Sites responded to irrigation distinctly from one another. A week after irrigation, respiration was elevated above dry measurements at all sites and was highest in grassland, followed by CSS, and lastly by chaparral. Respiration varied with aboveground plant composition at the chaparral and grassland sites, but not at the CSS site. Our finding that respiration varied between sites and with water availability indicates the need for further consideration of interactions between vegetative type conversion with hydrology and carbon-cycle dynamics with in the Santa Monica Mountains. Given the rapid type conversion and intensifying drought conditions occurring in the Santa Monica Mountains, understanding soil respiration trends is essential to predicting overall impacts of climate change.

1 - University of Florida
2 - Pepperdine University, Natural Science Division, 24255 Pacific Coast Highway, Malibu, CA, 90263, USA
3 - CSU Dominguez Hills
4 - Pepperdine University

Mediterranean climate
coastal sage scrub

Presentation Type: Poster
Number: PEC008
Abstract ID:638
Candidate for Awards:None

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