Meadows are important within forest ecosystems because they provide diverse species habitats, facilitate water cycling, help with sediment capture, aid in carbon sequestration, and create natural fire breaks in forested regions. However, fire suppression, poor grazing practices, and climate change have accelerated the encroachment of conifers into historical meadow habitat. This has led to an extensive loss of meadow habitat within the Sierra Nevada and Cascade Mountain Ranges. Therefore, the purpose of this study is to quantify changes in percent soil moisture and groundwater levels following the removal of encroached lodgepole pine (Pinus contorta) in a historic meadow habitat near Lake Almanor, California.
A before-after control-intervention (BACI) study design was used, with Marian Meadow (MM) as the control and Rock Creek Meadow (RCM) as the restored meadow. Soil moisture and groundwater level data was collected one year before (water year 2019), and three years after (water years 2020-2023) the removal of lodgepole pine from RCM in the fall of 2020. This data was then analyzed using multiple linear regression and estimated marginal means (EMMs) models.
Percent soil moisture increased each year after restoration, with significant increases from pre-restoration values occurring in year 2 and year 3 post-restoration. The overall mean soil moisture content increased from 30.69% (pre-restoration) to 40.42% by the 3rd year post-restoration. Groundwater has had a much more mixed response to restoration, with the 1st year post-restoration seeing a significant decrease in groundwater availability. Years 2 and 3 showed gradual recovery of groundwater levels, although on average they were still less than pre-restoration groundwater levels. This can likely be attributed to moderate drought occurring in the 2020 and 2021 water years.
Sources of variability include the 2021 Dixie Fire which burned through both meadows at different severity levels, gaps in the data due to issues with the data loggers, differences in snowmelt timing, and differences in soil attributes. Collectively, however, all these factors converge toward a wetter meadow habitat. Hopefully, the results of this research will help promote a better understanding of how meadow restoration can improve California forestland management.
| Identifer | oai:union.ndltd.org:CALPOLY/oai:digitalcommons.calpoly.edu:theses-4477 |
| Date | 01 June 2024 |
| Creators | Ramirez, Oriana |
| Publisher | DigitalCommons@CalPoly |
| Source Sets | California Polytechnic State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Master's Theses |
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