The La Kretz Center facilitates and supports a wide variety of research efforts at Sedgwick, but the full set of projects underway at the reserve is much larger and spans a wide range of disciplines and topics. Every month we will post the title and summary of newly approved and ongoing projects at the reserve. If your project is not listed but should be, or if it is listed incorrectly, please contact the La Kretz Center Director at frankdavis@ucsb.edu.
October 2025
Impacts of prescribed fire on oak recruitment (PI Shane Dewees)
This project focuses on oak recruitment as an important part of maintaining a diverse demography and healthy oak woodlands. Due to periodic mast events, the synchronized large acorn production by most-to all oak trees in an area, seedling recruitment may happen in periodic pulses. As prescribed fires are increasingly being used as a management tool across California, including in oak woodlands, the impact of fire on oak recruitment is important to understand. Here, we propose to take advantage of the recent mast event at Sedgwick and subsequent high presence of first-year seedlings to study the effects on prescribed fire on seedling recruitment and survival. We will conduct seedling surveys in areas that will remain unburned throughout the duration of the study, areas that burned in the 2023 TREX, 2024 TREX, and are scheduled to burn this upcoming fall. Additionally, we will measure microsite temperature and humidity at a subset of these survey locations, along with seedling physiology, to help determine drivers of mortality. These findings will give important insight into both environmental controls on oak seedling survival and the effect of prescribed fire on oak recruitment.
September 2025
Impact of Monarthrum and Pseudopityophthorus Bark Beetles on Varietal Oak Woodlands After Fire Events (PI Brooke Ryan)
Ambrosia and bark beetles, particularly of the genera Monarthrum and Pseudopityophthorus, threaten Southern California oak woodlands by causing bark decay and tree mortality, especially in stressed or dying trees. This project investigates their impact on coast live oaks (Quercus agrifolia) and blue oaks (Quercus douglasii) following prescribed burns, focusing on tree health and pest dynamics. Insights gained through field surveys, pheromone trapping, and analysis will inform improved forest management and fire mitigation strategies.
April 2025
Serpentine influence on plants and streams (PI Piper Lovegreen)
This project focuses on mapping subsurface geology in vegetated landscapes. At Sedgwick Reserve, the heterogeneous Franciscan Complex includes scattered serpentinite outcrops, which influence plant communities through nutrient imbalances, heavy metals, and low water-holding capacity. This project investigates whether remotely sensed plant traits can be used to map subsurface serpentine soils. They compare ground-truthed soil samples with plant trait data collected during the 2022 NASA Surface Biology and Geology High-Frequency Time Series (SHIFT) campaign. In 2024, the Lake Fire burned much of the serpentine-rich portion of the reserve, raising concerns about post-fire mobilization of heavy metals into local waterways. This study links geologic, ecological, and hydrologic processes to understand how subsurface geology affects plant communities and downstream ecosystems.
Soil transport of nitrogen and phosphorus following fire retardant application (PI Iris Holzer)
This project leverages an undergraduate research framework to investigate ammonium and phosphate levels in burned and unburned soils at the reserve, with and without the application of fire retardant, following the Lake Fire. Study sites will span diverse soil types with variable underlying parent materials in locations where fire retardant applied, including the Lisque stream terrace, the Franciscan assemblage, and the Paso Robles Formation, with the objective of addressing the following question: How do phosphate and ammonium concentrations vary by depth across different soil series with and without the application of fire retardant? This will include an assessment of potential bioturbator influence on fire retardant transport and incorporation into soil profiles.
March 2025
Leaf sampling to measure the impacts of the Lake Fire (PI Lily Peck)
In July 2024, the Lake wildfire burned over 16,000 hectares in the Santa Ynez Valley, California, including 40% of the University of California (UC) Sedgwick Reserve. This project wants to understand the impact of the wildfire upon leaf morphology, leaf photosynthetic rate, and genetic and epigenetic factors in valley oak. She will sample leaves from 23 trees inside and outside the Lake Fire burn zone.
GRASS-Net: Establishing drought resilient grassland restoration networks in California (PI Justin Luong)
Ecological restoration projects often use a limited number of common species for planting or seeding efforts. However, common approaches for species selection may fall short of adequately mitigating biodiversity loss and recovering ecosystem functions. Functional traits are measurable plant characteristics that can assist with plant selection as they can inform mechanisms of establishment, guide selection to enhance ecosystem functions, and aid species diversification efforts. This project asked 1) does functional trait diversity contribute to ecosystem functions and 2) what abiotic and biotic conditions influence functional trait responses and species abundance? They assessed plant community composition at three remnant California grassland communities along a latitudinal gradient at three field sites in Humboldt, Sonoma, and San Luis Obispo counties. They measured functional leaf traits and assessed functional diversity metrics related to drought stress and resource use: specific leaf area, lobedness, leaf dry matter content, δ13C, and C:N. They sampled community aboveground biomass via plant clipping, and belowground biomass with root cores. They sourced digital raster data for annual precipitation and vapor pressure deficit. They used climate and soil data to assess environmental relationships with plant abundance, trait expression, functional diversity, and biomass. They expect functional richness or community-weighted trait means to correlate with biomass or plant abundance. These results may identify plant traits suited to local site conditions and inform plant selection to target desired ecosystem functions.