Vegetation monitoring in the Santa Monica Mountains and Simi Hills region: 2014–2020 annual report

Mendelsohn M, Tiszler J, Sagar T. 2023. Vegetation monitoring in the Santa Monica Mountains and Simi Hills region: 2014–2020 annual report. Natural Resource Report. NPS/MEDN/NRR–2023/2598. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2300992

Our Inventory & Monitoring team surveyed over 200 Terrestrial Native Vegetation Monitoring Plots in the Santa Monica Mountains and Simi Hills (SAMO) Region over the first seven years of this program’s history, 2014–2020. During this period, the park experienced a large wildfire in 2013 followed by historic drought, and then in 2018 the largest wildfire in the region’s recorded history, succeeded by well-timed rainfall. The goal of this monitoring program is to detect and understand the nature of vegetation change, for example in drought or post-fire environments, providing a knowledge base for developing effective management strategies. Our metrics include vegetation cover, species richness, shrub/tree abundance, survival, and recruitment. In general, SAMO experienced widescale native shrub dieback during the extended drought. Dry shrublands that subsequently burned to the ground in 2018 converted into a rich and widespread green-up with the substantial rains received in 2019, producing a very diverse assemblage of wildflowers (including many fire followers not seen in many years) and a strong recruitment of our native shrubs via resprouting and seedlings into 2020 across most of the park’s more pristine areas. We documented post-fire expansions in several populations of the federally endangered Braunton’s milkvetch. Non-native herbaceous species such as mustards dominated previously disturbed lands and expanded their coverage following the 2018 wildfire. The data we collected will be available for advancing the science of fire ecology, and informing future park management and interpretation programs.

Type
Published Report
Authors
Mendelsohn, Mark; Tiszler, John; Sagar, Tarja
Date of Issue
2023-11
Publisher
National Park Service
DOI
10.36967/2300992
Units
MEDN , NRSS , SAMO
Keywords
Braunton’s milkvetch, chaparral, coastal sage scrub, dieback, Native Plant Community Monitor, post-fire, Woolsey Fire
Subjects
Ecological Framework: Biological Integrity | Focal Species or Communities | Shrubland Communities , Ecological Framework: Biological Integrity | Focal Species or Communities | Forest/Woodland Communities

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