CNDDB News Blog

In December 2019, the Vegetation Classification and Mapping Program (VegCAMP) updated the “map of vegetation maps” in BIOS that shows footprints of fine-scaled vegetation maps: Vegetation (MCV/NVCS) Mapping Projects – California [ds515]. This dataset can help you discover what vegetation types are in your area of interest. California’s Natural Communities are based in the National Vegetation Classification System (NVCS), which is a hierarchical system; and VegCAMP works together with the California Native Plant Society (CNPS) to maintain California’s expression of the system. We publish a list of Natural Communities at the bottom two levels: alliance and association. We also work to rank these communities for rarity, using the same ranking concepts as are used for species in CNDDB. Our published Natural Community lists and other online information were also recently updated. For more information, please see VegCAMP's Natural Communities page (updated November 2019) and CNPS' Online Manual of California Vegetation (updated October 2019).

Where does ds515 come in? If you are working in an area and want to know what vegetation types have been documented there, you can see if there is a mapping project overlapping or near your area of interest. If you click on one of the polygons of ds515 in BIOS, you will see who is responsible for the map, whether it is complete, and how old it is. There are links in ds515 to download the datasets and view the classification and mapping reports. The classification reports have keys that will help you determine vegetation types based on species cover. Since many of the maps are produced at the alliance level, which is coarser than the association level, it is important to know how to identify associations. This is particularly true for those interested in determining whether there are sensitive natural communities present, because there can be sensitive associations within alliances that are broadly distributed that are not considered sensitive. To see ds515, along with other published vegetation datasets, including a newly published, updated map of the Delta (ds2855) and part of the Modoc Plateau (ds2858), please see our BIOS bookmark.

In observance of GIS Day and the CNDDB’s 40th anniversary, let’s take a look back at the technological history of the CNDDB and how geographic information systems help us keep track of the thousands of rare species occurrences in this very diverse state!

The first true GIS, CGIS, was developed in 1960 by Roger Tomlinson to store and analyze the Canada Land Inventory’s extensive map collection. Other GIS systems were developed over the course of the 1960’s and 1970’s, leading to the release of commercially-available desktop software such as Esri’s ARC/INFO in the early 1980’s.

When the California Natural Diversity Database was founded in 1979, GIS was still a relatively new technology and wasn’t widely available. CNDDB staff documented locations of special status species by marking 7.5 minute topographic maps with stickers and writing notes in the map margins. They would fill out forms by hand, in pencil, documenting each element occurrence and index cards documenting each source. In this manner they created an extensive repository of over 15,000 occurrences!

Over the course of the 1980’s and 1990’s, the CNDDB continued to adopt new GIS technologies as they became available. Occurrence locations were digitized into a CAD and occurrence forms were typed into a computer database. Later, the CNDDB adopted a true integrated GIS, and with advances in computer graphics technology they were able to display topographic overlays on their computer screens, mapping element occurrences fully on the computer and recycling the old library of paper maps.

The program distributed sensitive species information to our subscribers at first by printing out map overlays and occurrence reports in response to requests, but by the 1990’s had developed the RareFind software application to allow subscribers to view and display CNDDB data on their own computers.

Today, the CNDDB is the largest natural heritage program database of any state, with over 90,000 element occurrence records. GIS technology has played an integral role in helping the database to keep track of the vast amount of information available on the rare and sensitive species of California.

With the wealth of information accessible on the internet, the explosion of citizen science in recent years, and the increasing risk to sensitive species in a changing climate, it is an incredibly difficult task to keep the database up to date and summarize all observations of a given site into high-quality occurrence records. However, the CNDDB continues to evolve and adapt to new GIS technologies, and we eagerly look ahead to the future, just like the CNDDB staff who began this whole endeavor on pencil and paper, way back in 1979.

Updated November 8, 2019, the list includes vegetation Alliances, Associations, Special Stands, and their respective Global and State rarity ranks. PDF and spreadsheet copies of the full list, sensitive communities, and recent changes - along with information about the legacy Natural Community Element Occurrences still found in CNDDB - can be found on the VegCAMP Natural Communities web page.