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Old 03-02-2011, 04:17 PM
dlmagney dlmagney is offline
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Location: Ojai & Grass Valley
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Default Allium praecox as a locally rare species

The issue of whether Allium praecox should be treated as a rare species in Ventura County has recently been in the news. I have long included this taxon as rare in Ventura County because it is known from only 3 extant and one historic locations in the Ojai Valley. The Ventura County Planning Division maintains a list of locally important species in support of the county general plan, which says that such a list shall be created and maintained, and the County brought together over 40 biologist knowagealbe about Ventura County bio resources. Those biologists, including me, developed rarity criteria to determine which species should be on that list. We agreed upon the G1/S1 ranking of plants with 5 or fewer populations within the county that are declining overall.
The county is currently trying to update their guidelines for conducting biological assessments to satisfy CEQA, and the County has included this treshhold to require assessment of taxa meeting that criterion. The property rights types have combined their resources and formed VC CoLab and hired a biologist from San Diego County, Barry Jones, an ornithologist who says he is a competent botanist too, to fight the County, and has selected Allium praecox as the poster plant. VC CoLab says that they couldn't find any of the local qualified biologists willing to work on their behalf. Hmmm.
Mr. Jones claims that plants like Allium praecox should not be on a locally rare species list because it is common, especially where he is from in San Diego County, but that CEQA REQUIRES the biologist to evaluate the impacts to the species from a statewide perspective. He claims that he believes that there are many more populations of Allium praecox in Ventura County; however, he provided no evidence whatsoever to back up any of his claims.
In my botanizing, and collecting, in Ventura County over the last 37 years, I have found it/collected it only twice, from two locations, both new occurrences not previously reported in the county. One other botanist knowledgeable of the Ventura County flora has collected it once, from one of my collection sites. He knows of no other occurrences. P. Munz collected it in the "Ojai Valley" back in the 1930s.
A search of the Consortium of California Herbaria finds 310 collections for this species. The one for Kern County is a mis-identification of A. peninsulare (confirmed by Dieter Wilken), which means that its known range really is from Santa Barbara, Ventura, Los Angeles, Orange, San Diego, and western Riverside and San Bernardino Counties. Apparently it extends into Baja California del Norte, but how far, I don't know.
Of the 309 collections (eliminating the Kern County collection), 116 are duplicates, leaving possibly 193 occurrences. North of San Diego County, I have identified 4 collections for which the population has been extirpated, based on an examination of current aerial photos using Google Earth. That takes us down to 189 occurrences. Many of the collections from San Diego County were from over 100 years ago and stating the locatity as "San Diego". Knowing that most of the natural vegetation that occurred in the vicinity of San Diego 50 years ago, much less 100 years ago, has long ago been developed, extirpating a vast majority of those historic populations (assuming that all those pioneer botanists didn't all go to the same population to collect their own specimen of the onion that all their colleagues now had in their collections). There are 19 collections that are from "San Diego". There are 57 collections from San Diego County that were made 50 or more years ago, and 39 of them are duplicates or from the same locations of other collections. 124 records occur for San Diego County, and 40 of those are duplicates, leaving only 84 sites where Allium praecox has been historically found. Only 22 of those 124 records (17.7%) were from collections made in the last 10 years, and most are likely extant (although many of them may have been on development sites that have now been extirpated, I haven't checked).
All but 2 of the 66 records from Santa Barbara County are from the Channel Islands (Santa Cruz or Santa Rosa). 28 (42.4%) of the 66 records are duplicates or from occurrences with more than one collection/record.
This situation is repeated for the other counties it has been collected from.
That means that there are probably only about 150 extant occurrences, on the outside, of Allium praecox in California. It is rare on mainland Santa Barbara County, rare in Ventura County, and declining in the more southerly counties.
So, my questions to you are: Is Allium praecox a common species? Should it be given a rarity status warranting protection in those counties where it is rare? Should such species be looked at/assessed under CEQA only from a statewide perspective?
Thanks,
David Magney
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