Invasive Spartina densiflora Brongn. Reduces primary productivity in a northern California salt marsh

Graduation Date

2012

Document Type

Thesis

Program

Other

Program

Thesis (M.S.)--Humboldt State University, Natural Resources: Environmental and Natural Resource Sciences, 2012

Committee Chair Name

Alison O'Dowd

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Algae, Net ecosystem exchange, Spartina densiflora, Carbon dioxide flux, Humboldt State University -- Theses -- Natural resources, Primary productivity, Invasive species, California, Salt marsh, Humboldt Bay

Abstract

Comprehensive primary productivity measurements of the impact of invasive species are important environmental indicators. This study obtained measurements of the impact of invasive Spartina densiflora on the primary productivity of a Humboldt Bay (California) salt marsh using above and belowground biomass measurements coupled with paired closed-chamber carbon dioxide flux measurements. Compared to samples dominated by native vegetation, samples dominated by S. densiflora displayed higher aboveground net primary productivity, lower belowground net primary productivity, lower net primary productivity, and lower net ecosystem exchange measurements; thus, S. densiflora colonization reduced primary productivity. Benthic macroalgal cover was a strong predictor of net ecosystem exchange. In plots dominated by S. densiflora, less benthic macroalgae was present and less photosynthetically active radiation reached the substratum. Therefore, increased shading of the sediment surface in plots dominated by S. densiflora contributed to lower net ecosystem exchange measurements. These results greatly improve our understanding of the impact of S. densiflora on the primary productivity of Humboldt Bay salt marsh ecosystems.

https://scholarworks.calstate.edu/concern/theses/9593tx452

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