Data from: Wildfire interacts with land cover to influence mercury concentrations in juvenile steelhead (Oncorhynchus mykiss) in coastal California watersheds
Data files
Mar 30, 2026 version files 103.40 KB
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README.md
6.33 KB
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WILC_Hg_data.xlsx
73.38 KB
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WILC.Rmd
23.69 KB
Abstract
This dataset contains muscle tissue mercury concentration measurements from juvenile steelhead, lichen, soil, and water samples collected from burned and unburned watersheds along the central California coast in 2021. Associated spatial covariates include geology, land cover, and burn severity metrics derived from field and remote sensing data. These data support analyses of wildfire and land cover effects on mercury bioaccumulation presented in Abbott et al. The dataset includes raw measurements, metadata, and R code used for data processing and statistical modeling.
Author(s): Morgan M. Abbott, David Boughton, Stephanie M. Carlson, Andrew Dittman, Maryam Kamran, Joseph Kiernan, Thomas H. Williams, Peter Weiss-Penzias, Eric Palkovacs
Date: October 7, 2025. Corresponding author: Morgan M. Abbott (morgan.abbott@ucsc.edu).
Associated publication: Abbott et al. (accepted for publication). Wildfire interacts with land cover to influence mercury concentrations in juvenile steelhead (Oncorhynchus mykiss) in coastal California watersheds. Canadian Journal of Fisheries and Aquatic Sciences.
Overview
This dataset contains mercury concentration measurements from juvenile steelhead trout (Oncorhynchus mykiss), lichen, soil, and water samples collected in burned and unburned watersheds along the central California coast in 2021.
The dataset supports analyses of wildfire and land cover effects on mercury bioaccumulation in juvenile steelhead presented in Abbott et al.
File list
- WILC_Hg_data.xlsx – Primary dataset containing all sample information and spatial covariates.
- WILC.Rmd – R Markdown file with data cleaning, compositional transformations, statistical modeling, and figure generation.
Variable descriptions (WILC_Hg_data.xlsx)
Units & conventions: Unless noted, concentrations are ng/g dry weight; land cover, burn severity, and geology are percent of watershed; missing values are NA. The sex of the fish is Male or Female if not identified entered as NA.
| Column Name | Description | Units |
|---|---|---|
| Sample_ID | Unique identifier for each sample | — |
| Sample_Type | Sample category (Fish, Lichen, Soil, Water) | — |
| Site | Watershed code (BCR = Big Creek, CRR = Carmel River, PES = Pescadero Creek, SLR = San Lorenzo River) | — |
| Burn_Status | Burn condition (B = Burned, U = Unburned) | — |
| Area | Size of the spatial unit | ha or km² |
| Slope | Average terrain slope | degrees |
| Avg_Precip | Average annual precipitation | mm |
| Mass | Fish wet mass | g |
| Length | Fish fork length | mm |
| Ni–Hg | Trace metal concentrations in tissue | ng/g (dw) |
| MeHg | Methylmercury concentration | ng/g (dw) |
| Sandstone–Schist | Geologic composition of the watershed (Sandstone, Igneous, Serpentinite, Schist) | % |
| Fire | Name of wildfire event affecting the area (if any) | — |
| Burn_Area | Proportion of area burned | % |
| Unchanged–High | Burn severity classes based on RdNBR (Unchanged, Low, Moderate, High) | % |
| Forest–Developed | Land cover proportions (Forest, Shrub, Developed; NLCD 2019) | % |
| mean_burn_sev | Weighted mean burn severity | — |
Data collection and analysis
Fish muscle, lichen, soil, and water samples were analyzed for total mercury (THg). Total Hg (THg) was quantified with a direct mercury analyzer (DMA-80, Milestone Corp.) (Gabriel et al., 2014). This instrument was calibrated with liquid Hg standards (diluted from NIST-3133) and checked daily with standard reference materials (DOLT-4 dogfish liver and DORM-4 fish protein). Percent recovery of the THg in the reference materials was between 94-110%. Between 0.02–0.03 g of dried fish tissue was weighed into nickel boats and run on the DMA-80.
Spatial covariates (geology, land cover, burn severity) were derived from Landsat 8 imagery and public GIS datasets.
Statistical analyses were performed in R version 4.2.2 (2022-10-31 -- "Innocent and Trusting") using GLMMs with a negative binomial distribution (glmmTMB package). All data transformations (centered log-ratio), PCA generation, and model scripts are documented in WILC.Rmd.
Ethical and legal compliance
Ethics approval was obtained from the University of California, Santa Cruz Institutional Animal Care and Use Committee (IACUC Protocol #Kierj1904, approved May 22, 2019). Field collections were conducted under California Department of Fish and Wildlife Scientific Collecting Permit #S-201120001-20127-001 and S-201120001-20147-002 and National Marine Fisheries Service Section 10(a)(1)(A) permit numbers 17219-3R and 17292-2A.
Please cite this dataset as:
Abbott et al., 2026. Wildfire interacts with land cover to influence mercury concentrations in juvenile steelhead (Oncorhynchus mykiss) in coastal California watersheds, in the Canadian Journal of Fisheries and Aquatic Sciences. Dryad Digital Repository. https://doi.org/10.5061/dryad.fj6q5747j
Contact
Questions about data use or interpretation can be directed to:
Morgan M. Abbott
Department of Ecology and Evolutionary Biology
University of California, Santa Cruz
mmabbott@ucsc.edu