Maps displaying spatial data on invasive plants are essential for planning invasive plant management efforts. Maps showing “quad data” (distribution data based on expert knowledge by USGS 7.5-minute quadrangle) provide important information on regional management opportunities. At the same time, maps showing detailed “occurrence data” from mapping invasive plant populations in the field is necessary to plan the specifics of on-the-ground management. CalWeedMapper and Calflora are set up to integrate both kinds of data. Occurrence data in the Calflora database triggers changes to the quad data shown in CalWeedMapper. Mappers can help strengthen our collective spatial resources by verifying quad data and submitting occurrence data.
Verifying quad data
Verifying quad data in locations where it conflicts with occurrence data can yield important information. If occurrence data exists in a quad where experts have not reported the species’ presence, it is possible that this indicates an early detection target for eradication. The occurrence site(s) should be visited. If the occurrence report is accurate, the population may be a high priority for management. If the occurrence report is inaccurate or outdated, expert knowledge data for the quad can be confirmed. These are the Verify Location quads and are symbolized with a “Q” in the Maps page.
In a few cases, experts lumped multiple species together in their reporting, because they do not distinguish between them. The data in these quads should be verified for each species when possible. These are the Verify Species quads and are symbolized with a “S” in the Maps page.
There are many quads where expert knowledge reports a plant to be present but to date no occurrence data has been reported to Calflora. Submitting occurrence data in these quads will help make statewide mapping (and range modeling) more accurate and thorough. When collecting occurrence data for a population of a plant in a new area, consider submitting a specimen to the state herbarium to make the observation official.
Submitting occurrence data
The Calflora database allows users to submit occurrence data for plants in lots of ways. This occurrence data is important not only for your local efforts, but for other natural resource managers to use in planning their efforts. The data also improves the accuracy of range modeling for each species.
And occurrence data submitted to Calflora will update CalWeedMapper nightly.
- Enter individual occurrence observations using Calflora’s online map, a smartphone, or geotagged photos. (See note above about submitting specimens when appropriate.)
- Upload entire GIS datasets with point, line and polygon features. Use a standard mapping template to streamline sharing your GIS datasets.
Additional mapping resources can be found in the California Weed Mapping Handbook.
Quad data on invasive plant distribution will soon be available in shapefile format from this site. Please be aware that the data is dynamic and data will change as users update their expert knowledge or add occurrence data.