Precipitation Extremes Mark First Years of Plant Community Monitoring in the Marin Headlands

Super bloom of California poppies in the coastal prairies of the Marin Headlands in 2014.

NPS / Eric Wrubel

November 2018 - San Francisco Bay Area Inventory & Monitoring Network scientists began plant community monitoring in network parks in 2015. The year 2015 was also the final year of California’s record-breaking four-year drought. The drought was followed by above average precipitation in 2016 and 2017. In a new article published in the journal Grasslands, network scientists Eric Wrubel and Marie Denn focus in on how those precipitation extremes played out in one particular plant community: the coastal prairies of Golden Gate National Recreation Area’s Marin Headlands.

The prairies, also known as bald hills prairies, are notable for the number of native perennial grasses and forbs they support, despite being dominated by introduced annual species. Monitoring results from 2015-2017 showed that while the amount of ground covered by native perennials stayed fairly stable, non-native annual species covered much more ground in the wet years. The results also showed significant changes in species composition between wet and dry years. Both species richness (the number of unique species) and species diversity (the number of species, plus a measure of how evenly distributed they are) increased during the wet years. That the community can change so much between years helps show the value of long-term monitoring for understanding how a plant community functions, and how it might respond to future conditions.

To learn more, check out the full article titled "Monitoring Long-term Change in Coastal Prairies of the Marin Headlands", or email Eric Wrubel with any questions.

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