Ultramafic Substrates in the California Floristic Province, V1 2026

A continuous, fine-scale geodatabase of ultramafic substrates created to support plant species distribution modeling. The dataset covers the entire California Floristic Province, including California and southwestern Oregon, with a minimum mapping unit of 4,000 m² and an accuracy of ±20 meters. Author Ryan O'Dell produced this version in 2026, aiming to improve upon the accuracy of existing geologic and soil survey maps.

Use Cases

• Modeling species distribution for ultramafic endemic plants based on substrate boundaries.
• Identifying conservation areas for rare plant taxa based on mapped ultramafic masses, landslides, and alluvial deposits.
• Comparing substrate mapping accuracy against older sources like the Geologic Map of California or gSSURGO data.

Strengths

• Designed for high accuracy (±20 m) and fine scale (4,000 m² MMU), addressing gaps in prior maps.
• Covers the entire California Floristic Province, a continuous area including California and southwestern Oregon.
• Explicitly maps ultramafic landslides, alluvial deposits, and glacial till, which were previously missing or mislabeled.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• The dataset is version 1, with a second stage planned for 2026-2030 to add attributes like soil series and rock type.

Provenance

Source

Compiled from the National Geologic Map Database (NGMDB) and the Gridded Soil Survey Geographic Database (gSSURGO).

Collection Method

Polygons were delineated manually using high-resolution satellite imagery to improve boundary accuracy.

Time Range

Data compilation period 2020–2026.

Freshness

Last updated 2026-05-17 21:15:36; freshness should be verified.

Geography

California Floristic Province (California and southwestern Oregon).