Friday, February 7, 2014

Yosemite Rare Plants are encountered less-frequently than common plants

Accepting the assumption that a herbarium specimen is randomly gathered (a tenuous proposition), then we can determine if “rare” plants are encountered less often compared to “common” plants (rare plants defined as being on the CNPS list).

In the central Sierra Nevada region centered about Yosemite (Tuolumne, Mariposa, Madera and Mono Conties), with a total of 70,966 herbarium specimens to analyze, the results is that: yes, rare plants are collected less often as compared to common plants.

The difference is significant (using the non-parametric Kolmogorov-Smirnov two-sample test) at p=0.003.  Box plot below...

Those rare plants with the but a single specimen are:
Botrychium paradoxum
Carlquistia muirii
Cuscuta jepsonii
Potamogeton praelongus
Streptanthus gracilis
Viburnum ellipticum

The most frequently collected “rare” plants are (a.. >70 total specimens)
Agnorhiza elata
Astragalus kentrophyta var. danaus
Bolandra californica
Carex congdonii
Ceanothus fresnensis
Diplacus pulchellus
Erythranthe filicaulis
Erythranthe laciniata
Hulsea brevifolia
Lupinus spectabilis

Perhaps being infrequently collected does not diagnose rarity: there are 464 non-rare species in the Yosemite region which have been collected only once.  

Monday, February 3, 2014

2 Million Herbarium Specimen Records for California

Continued efforts to database California vascular plant records in herbaria have narrowed in on the 2-million mark.  As of 31 January 2014, the Consortium of California Herbaria offer up 1,909,005 records.  Major non CCH records are: Consortium of Pacific Northwest Herbaria 29,142 records, and MO-Tropicos 33,098 records.  

A total of 1971,246 specimen records.

Since 2006, the addition of records to the CCH database has averaged 480 records per day, and is trending upwards.  Hard to keep up with...

Taxonomic and floristic studies of the California flora are now greatly facilitated by these riches of data.  The challenge now is not so much data acquisition, but is rather data analysis.  Differences between data providers contributing to CCH need to be standardized.  Nomenclature, which generally reflects the “as filed” taxon name for each specimen, needs attention.   Many CCH data providers use different formats for date, different names for collectors, many have missing data such as the collection number.   Maturation of the herbarium specimen data for California is awaited with baited breath...