Response of seeded native forb populations to seasonal grazing Sacramento River National Wildlife Refuge, Capay Unit
Graduation Date
2014
Document Type
Thesis
Program
Other
Program
Thesis (M.S.)--Humboldt State University, Natural Resources: Forest, Watershed and Wildland Sciences, 2014
Committee Chair Name
Susan Edinger Marshall
Committee Chair Affiliation
HSU Faculty or Staff
Keywords
Lupinus nanus, Grassland restoration, Grazing, Sacramento River, Grindelia camporum, Acmispon americanus, Floodplains, Eschscholzia californica, Multiyear seeding, USFWS Sacramento River National Wildlife Refuge, Humboldt State University -- Theses -- Natural Resources, Native wildflowers, Habitat restoration
Abstract
An active relay floristic (ARF) design is may be an effective approach to restoration of native forb populations within partially restored native grasslands on the Capay unit of the Sacramento River National Wildlife Refuge. The ARF model is designed to mimic the maturation process of a plant community, similar to ecological succession that is driven by species performance, species availability and site availability. This study examines the efficacy of cattle grazing to improve seeded native forb establishment. Once a month, from March 2013 through October 2013, I measured total species composition and frequency of Spanish lotus (Acmispon americanus), gumplant (Grindelia camporum), sky lupine (Lupinus nanus) and California poppy (Eschscholzia californica) plants that produced reproductive structures. Five treatment areas within a partially restored native perennial grassland at the Capay unit were surveyed: 1) ungrazed and never seeded with forbs, 2) grazed and never seeded with forbs, 3) ungrazed and seeded with forbs in 2010, 4) grazed and seeded with forbs in 2010, and 5) grazed and seeded with forbs in both 2010 and 2012. Thatch depth was measured in October 2013, after the cattle were removed from grazed areas. Cattle grazing increased the cover of Spanish lotus and the frequency of sky lupine plants in flower, but decreased the frequency of gumplant plants in flower or seed. Native forbs likely responded to the disturbance created by trampling and not foraging behavior. None of the native forb species responded positively to the repeated seeding. Sky lupine, the earliest blooming species, had lower cover and fewer flowering plants in the twice seeded site, which is likely due to disturbance to the soil surface from the no-till drill during the germination period. Cattle grazing can be an effective tool for increasing site availability to support successional habitat management of grasslands within the floodplain, as long as the grazing season does not interfere with critical growth phases of the seeded native forbs. A repeated seeding of native forbs as a method for enhancing species availability did not benefit seeded native forb populations.
Recommended Citation
Frediani, Adrian, "Response of seeded native forb populations to seasonal grazing Sacramento River National Wildlife Refuge, Capay Unit" (2014). Cal Poly Humboldt theses and projects. 1715.
https://digitalcommons.humboldt.edu/etd/1715
https://scholarworks.calstate.edu/concern/theses/n870zt37c