NEVADA NATIVE PLANT SOCIETY
Rare Plant Committee Meeting
2004 MEMBER COMMENTS
http://heritage.nv.gov/nrpw/commnt04.htm
The following comments on 2004 agenda items were offered by participants and/or non-participants prior to the 2004 Workshop, and were made available at the workshop as a handout to participants. Those unable to attend but with thoughts or information to contribute are especially encouraged to submit them!
Member: Jason Alexander
Date: 27 April 2003
Comments: With a taxon as complicated as Astragalus lentiginosus,
we do not yet know if these small [Nevada var. stramineus]
populations with unique morphology are significantly differentiated from the
rest of the complex or are they fully intergradient with neighboring varieties.
Untested hypotheses abound (including, so far, mine) but no concrete data has
ever been researched. It is important to protect the diversity in this variety
in either scenario in a population biology context.
If var. stramineus is a full hybrid, or the Nevada populations are hybrids with var. fremontii, these hybrids swarms are an important conduit for genetic diversity of typical var. stramineus. It is likely that var. stramineus will become genetically depauperate and potentially go extinct if this conduit for genetic diversity is severed. In this case, a conservation plan would encompass populations from Toquop Wash (which are distinguishable from typical stramineus only in having slightly smaller flowers) east to the Beaver Dam Wash. These putative hybrids should be considered var. stramineus until genetic data show otherwise.
If var. stramineus is distinct from other varieties of this complex, the population in Toquop Wash is likely the main source for dispersal in Nevada, having the largest and most widespread extant populations. The others around Mesquite are heavily impacted. In addition, the populations around Beaver Dam are also heavily impacted by past and current development. The remote sandy pockets in washes between Toquop Wash and Beaver Dam Wash are important small populations that promote gene flow and the maintenance of diversity in this species. If this hypothesis is correct, loosing these small populations could cause a loss of genetic diversity and the possible extinction of this variety. In any case, var. stramineus is a taxon in need of some mitigation from habitat loss.
The [Astragalus preussii] var. laxiflorus issue is more problematic. The Muddy Mountains is the central habitat for this species. Those portions in Lake Mead should be monitored by the park service. Future mining applications for Gypsum in the Muddy Mountains should should take this species into consideration. Most of the range of this species is outside of the park. A large gypsum mine in the Anniversary Mine area, Bitter Springs Wash, Lava Butte, or further large mines in the Gale Hills could extirpate the majority of populations of this species, and Arctomecon californica for that matter.
I am very glad to hear that someone in California has looked for the Lancaster population of this species. The location is not an old Jones name, but one from a Dr. Davidson who collected in the vicinity of Lancaster in 1880's. The name A. davidsonii was originally proposed by Rydberg. There is no possible way that var. laxiflorus and this population were a result of separate dispersal event from the same population. I think they are cases of parallel pod development (as Barneby did in 1964). They are probably genetically distinct. A population level morphological and molecular analysis of the Edwards population will likely indicate that this should not be recognized as var. laxiflorus, but as another variety of A. preussii (taxonomic rules would indicate A. preussii var. davidsonii). It should be considered a rare and potentially endangered taxon in California if recognized as a separate variety. It likely previously existed in Lancaster and the rest of Antelope Valley, however, due to development, is now restricted to Edwards.
Member: James Reveal
Date: 14 March 2004
Comments: See the separate handout entitled Rare and Uncommon Eriogonum
(Polygonaceae) in Nevada and some Anticipated Taxonomic Changes and Novelties.
This handout was emailed to all participants and will be available at the
Workshop.
Member: Dana York
Date: 17 March 2004
Comments: Petalonyx thurberi ssp. gilmanii--I don't
know about the Nevada populations, but it is known from at least 20 populations
throughout the park [Death Valley National Park]. Populations range in size from
a few shrubs to over 100.
Astragalus mohavensis var. hemigyrus--Found last year just west of the park [Death Valley National Park] near Darwin. Genetic work on the CA [plants] should be done--there are slight morphological differences from the NV type material.
Sisyrinchium funereum--I question that this species occurs at Ash Meadows. There are no other rare plant correlations between Ash Meadows and Death Valley. This plant only occurs in the springs surrounding the (Death) valley. The populations vary in size (some >100 plants) and seem to be stable, but threats include exotic plants, water extraction, cattle, and burros.
(last updated 30 March 2004)