By Fred Roberts, Rare Plant Botanist
CNPS is getting serious about the Locally Rare Plant (LRP) rank. If you haven’t seen it, CNPS now has a web page devoted to Locally Rare Plants: cnps.org/rare-plants/locally-rare. The web page includes a general discussion about the subject focusing on three topics: What are locally rare species, Peripheral populations as refugia, and Legal protection. Additionally, the web page includes a link to several papers, provides example Local Rare Plant lists for four counties (Alameda, Contra Costa (as “Rare, unusual, and significant Plants – you can only access their description page at this point, to see the actual list requires registration), Santa Barbara, and Ventura Counties), and a white paper.
Dave Magney has also established a state level committee on the topic. It was off to a slow start, its first meeting taking place some five years ago but in the last year we have conducted two meetings and a third is proposed for August. The committee’s main purpose is to come up with guidelines to help CNPS chapters and others for what factors determine which species qualify as LR (locally rare) and what methodology should be used to get there.
The LRP concept has largely been proposed to afford some level of conservation status to plant species that while broadly distributed across the state, are scarce at the local level. Ideally, CNPS hopes these species will have a place in future CEQA reviews and local jurisdictional conservation mechanisms. The simplest subunit below the state is a County, but a National Forest, mountain range, or municipality could also be an example of a relevant local level. Different people have come to the table with somewhat different ideas on exactly what an LRP should be and how to arrive at a candidate list. That a species should be relatively uncommon in the local area is a given, but even that is not sharply defined. During our committee meetings plants with populations of five or ten have both been offered as a cut-off for what could be considered an LRP. Others have sought more flexibility to allow for other circumstances then just scarcity. And there is the question, just because a species is known from just a couple sites within a county, should it automatically be placed on the locally rare list?
In Ventura County, the current LRP list also includes plants listed in the CNPS Rare Plant Inventory, but the East Bay chapter does not include officially ranked plants in their “rare, unique, and unusual” plant database, rather maintaining it separately. Everyone on the committee agrees that science should be a driving element and that LRP lists should be as scientifically defensible as possible, especially if CEQA becomes a mechanism of conservation, but the ideas on how to get there and by what means varies. How robust should the list be? Should all sites have a physical voucher? What is the roll of Calflora and iNaturalist observations then? In floristics, botanists often use verified physical voucher specimens as evidence that a species occurs within a region. Photographic observations generally are not considered equivalent. Do we need that same level of robust data for conservation? After all, as many as 70 percent of CNDDB records lack a physical voucher and yet CNDDB is critical to plant conservation in the state of California.
Some counties have turned to modeling. Others are still doing analog research, largely relying on local botanical experts. Modeling has a lot of support in some regions of the state, but it can be time consuming, expensive, and requires expertise not often available to the average chapter.
Stay tuned. There is no formal process in San Diego County at this time to create an LRP candidate list but with resources like the San Diego Plant Atlas, the chapter is in a pretty good position to put together a candidate list. I don’t think we will need any sort of modeling to tell us if a plant belongs on the list or not. Certainly, any plant species with a handful of locations only known west of the I-15 would almost get a guaranteed seat at the table.