| BEN |
| BOTANICAL ELECTRONIC NEWS |
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| ISSN 1188-603X |
| No. 499 January 6, 2016 | aceska@telus.net | Victoria, B.C. |
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Phytogeography of Shasta County
Over the years that I've lived in the Pacific Northwest, I've occasionally had the opportunity to drive south on Interstate 5 to California. The transition from the montane forests around Mt. Shasta down to the blue oak savannas in the northern Sacramento Valley has always been one of my favorite parts of the drive. Much of this stretch passes through rugged topography covered by a mix of oaks and pines, colorful in the spring, when the flowering redbuds and young oak leaves paint the landscape with a mix of pink and chartreuse. If you stop to explore a bit, you find a diverse woodland community of conifers, broadleaf evergreen trees, and deciduous broadleaves. Here you can find a number of unusual or distinctive California natives, including many genera with relatives in eastern North America, Europe, or Asia, reflecting a temperate Tertiary flora that has since become discontinuous due to changing climates and continental movements. Some examples include Aesculus californica, Calycanthus occidentalis, Cercis occidentalis, Cornus sessilis, Fraxinus dipetala, Staphylea bolanderi, and Styrax officinalis.
Neviusia cliftonii Shevock, Ertter & D.W. Taylor
This is also the area where the Shasta snow wreath, Neviusia cliftonii, was discovered in 1992 (Shevock et al. 1992, Taylor 1993, Lindstrand III & Nelson 2005, and several other articles in Fremontia 21(3) Jul 1993 [Issued as 22(3)]). This shrubby genus in the Rosaceae was previously known as having only a single species of the southeastern US, though it has since been documented from Eocene leaf fossils from Princeton, in southeastern British Columbia (DeVore 2002). The discovery of_Neviusia in Shasta County was a reminder to the California botanical community that the frontier of botanical discovery had not yet closed, even in this relatively well known region.
Juncus digitatus C.W. Witham & Zika and Brodiaea matsonii R.E. Preston
It turns out that the finding of Neviusia was just the beginning of an extended period of botanical discovery in Shasta County. For example, in 2008, Carol Witham and Peter Zika described Juncus digitatus, a new species that at the time of publication was known only from the foothills of the Cascade Range in Shasta County. It has since been found in Nevada County, and may ultimately prove to be more widespread outside of Shasta County once its full distribution is documented. And, in 2011, Brodiaea matsonii was described from a single locality north of Redding, where it grows in foothill woodland on soils derived from amphibolite schist (Preston 2011).
Shasta Discovery Day - April 3, 2015
But much of the recent inventory of botanical novelties has been focused on the limestone region around Shasta Reservoir in the southeastern part of the Klamath Mountains, just to the north and northeast of Redding. Ongoing investigations have culminated in the publication in the past two years of four new taxa of vascular plants apparently endemic to this region of Shasta County. Many of these populations occur on lands managed by the US Forest Service, so it was only fitting that Forest Service staff, led by long time Forest Botanist Julie Nelson, would hold a sort of a coming out party, a "Shasta Discovery Day", to introduce these new species to the botanical world and the general public.
Shasta Discovery Day was held on April 3rd, 2015, where an audience of several dozen people enjoyed a morning session consisting of presentations at the Redding library, and an afternoon portion involving a field trip to see 3 of the 4 new taxa in the field. The morning session focused on the discovery stories of each of the four species, which was interesting because the presentations included details that are not always included in scientific papers.
Erythronium shastense D.A. York, J.K. Nelson, & D.W. Taylor
Dana York spoke first, telling the story of how he first encountered Erythronium shastense. The story involved a long kayak trip across Shasta Reservoir to explore a prominent limestone ridge that was not readily accessible from roads. Dana found the Erythronium growing in clumps in limestone crevices, an unusual habitat for an Erythronium. However, at that time the plants were in fruit, so he had to wait until the next year to see it blooming. It turned out that Dean Taylor (co-discoverer of Neviusia cliftonii) had actually collected this Erythronium in 1993, and Julie Nelson had observed it in another locality in 2010. A detailed morphological examination showed that Erythronium shastense is most similar to Erythronium helenae, having mottled leaves, white tepals and yellow anthers, and a bent style. Erythronium helenae is another local endemic known from adjacent portions of Lake, Napa, and Sonoma counties, in the Coast Range north of San Francisco. Erythronium shastense differs in having a longer style and longer anthers, and is a generally larger plant that is very strongly clumping due to the production of corm offsets. The flowers are also distinctively outward facing rather than pendant, as is typical in most western North American species of Erythronium. Herbarium research turned up only one old (pre-1993) collection, this in 1935 by Mrs. C.F. Rose. Currently this species is known from about 26 occurrences, patchily distributed over an area of about 60 sq. miles (155 sq. km).
Adiantum shastense Huiet & A.R.Sm.
The second speaker was Layne Huiet. Recognition of Adiantum shastense as distinct from the related the more common California natives A. capillus-veneris and A. jordanii occurred when samples submitted for her global DNA study (as A. jordanii) did not match other samples for either of the two species. This finding led to further herbarium and field studies, which provided morphological characters to uphold the genetic distinctiveness. The most obvious character distinguishing Adiantum shastense from the two other related California species is its evergreen leaves - in fact, the fronds seem to persist for two years, in contrast to the summer deciduous A. jordanii and the semi-evergreen A. capillus-veneris. Adiantum shastense also has very strongly angular, rhomboidal fertile pinnules, contrasting particularly with the fan-shaped fertile pinnules of A. jordanii. Adiantum shastense is larger than the other two species, often forming large (presumably old) clumps with many fronds. Chromosome counts show that this is a diploid species, like A. capillus-veneris and A. jordanii.
Apparently this species is known from only one old herbarium collection, by Milo Baker in 1894; otherwise, the oldest collection was by Dean Taylor in 1992. I might add here that I collected Adiantum shastense in March 2005, when I was in the area looking (unsuccessfully) for erythroniums(!), and immediately recognized it as unusual for being evergreen, but did not undertake any further study. Currently this species is now known from about 50 occurrences over an area of about 675 sq. miles (1748 sq. km).
In 2014 I visited Shasta County and collected spore-bearing material to distribute to a number of fern growers, so hopefully this species will soon be available in the horticultural trade. It remains to be seen how adaptable Adiantum shastense will be in garden settings outside its native range, but if it is hardy and garden-tolerant it will be an excellent addition to our garden flora, being an evergreen fern quite unlike other hardy species.
Erythranthe taylorii Nesom
Third up was Dean Taylor, to talk about Erythranthe taylorii, which he first collected in 1993. But Dean's story starts in 1972, when he was a student of Ledyard Stebbins at UC Davis and visited the area to recollect an undescribed Eupatorium (now Ageratina cf. Kling & Robinson, 1980) that Stebbins originally found at Shasta Caverns in 1959. Eupatorium shastense was described as a new species in 1978 (Taylor and Stebbins 1978); this early experience was Dean's first introduction to the flora of the Shasta County limestones.
The next phase of Shasta County included the discovery of Neviusia cliftonii, and it was during these efforts that the Erythranthe was first collected. The Erythranthe was also collected by Julie Nelson in 2010, and subsequently these collections were recognized as a new species by Guy Nesom (2013), who is authoring the Phrymaceae treatment for Flora of North America.
Erythranthe taylorii is one of the annual monkeyflowers now placed in Erythranthe sect. Mimulosma, related to the more widely distributed E. pulsiferae. It differs from that species in its more strongly bilabiate corolla; larger, more ovate leaves, and differences in pubescence. According to Nesom, Erythronium taylorii is closest to E. ampliata, an Idaho endemic that was synonymized under Mimulus washingtonensis in Vascular Plants of the Pacific Northwest (Hitchcock et al. 1959).
Erythranthe taylorii is a species of open rock crevices, primarily though not exclusively limestone, between 1070 and 3200 ft. elevation. At the time of publication it was known from only 3 collections, but subsequent inventory work has documented a total of 40 occurrences over an area of about 390 sq. miles (1010 sq. km).
Vaccinium shastense J. K. Nelson & L. Lindstrand III
The last speaker of the morning session was Len Lindstrand, to talk about Vaccinium shastense. Vaccinium shastense is a tall shrub with twigs that are green and strongly 4-angled, like V. parvifolium (and the shorter V. scoparium). However, Vaccinium shastense has dark blue fruits, unlike the red fruits of the latter two species. Julie Nelson first observed this plant in 1991, during an inspection trip to an abandoned mine site. Finding a Vaccinium growing on an exposed slope with acid mine seepage seemed odd. Similar plants were later found in other locations in western Shasta County. Shasta County botanists heard through the botanical grape vine of "blue fruited Vaccinium parvifolium" growing in the Sierra Nevada mountains as well, which resulted in the initiation of a research program to better understand the limits of morphological and geographic variation in this complex.
The conclusions of the ensuing morphological and genetic studies was that there were actually two undescribed entities within this complex in California, both of which are allopatric relative to each other as well as to Vaccinium parvifolium. The authors chose to describe a new species, Vaccinium shastense, with two subspecies, subsp. shastense and subsp. nevadense. The former is endemic to Shasta County, where it grows within the "Copper Belt", on acidic rocks of volcanic origin. The latter subspecies is actually fairly widespread, though sporadic, on the western slopes of the Sierra Nevada. There is, however, a gap of over 85 mi (137 km) between the NW extent of subsp. nevadense and the SE extent of subsp. shastense, and a 50 mi (80 km) gap between V. shastense subsp. shastense and the nearest V. parvifolium. The two subspecies of V. shastense differ in the stronger pink color of the corolla of subsp. shastense, as well as features of the calyx scar and growth habit. They were also found to differ in a study of microsatellite loci (DeWoody et al. 2012). From Vaccinium parvifolium, which in California is a more coastal species, V. shastense differs in its blue fruit color, wider hypanthium scar, and the presence of cilia along the entirety of the leaf margins. I found myself wondering whether a pie made from the fruits of V. shastense would have as superior a flavor profile as a Vaccinium parvifolium fruit pie. Further research is needed.
Herbarium research turned up only a few specimens of Vaccinium shatense subsp. shastense collected prior to the Nelson collection in 1991, the earliest being a 1900 collection by Milo Baker, who did record in his field notes an impression that the Shasta County plant was different from V. parvifolium. Interestingly, while V. shastense subsp. shastense is known from only 25 occurrences over an area of about 18 sq. miles (47 sq. km), it has been able to colonize areas disturbed by past mining activities. Because of this resilience, the authors do not consider it threatened or endangered, though it definitely warrants ongoing monitoring.
Field trip
After the talks concluded, we spent the remainder of the morning reviewing poster displays of each species and chatting individually with the authors. After lunch, the group re-convened at the Shasta-Trinity NRA office north of Redding to carpool to the field trip site along the McCloud Arm of Shasta Reservoir, where we were hoping to observe the Adiantum, Erythronium, And Erythranthe in the wild. Len Lindstrand, who led the field trip portion, has been conducting field surveys for the Shasta County endemics to inform thedecision-making process for a proposal to raise the height of Shasta Dam.
These surveys have actually been range-wide, because it is important to know the extent of both the populations that would be impacted by the project, and the extent of the populations that would not be impacted. Consequently, resource managers already have a much more complete knowledge of the new species' ranges and status than is typical for most newly described species.
Just a short distance from our parking area we crossed the road and bushwhacked a couple hundred meters across a forested north-facing slope. Before too long we encountered clumps of both Adiantum shastense and Erythronium shastense, growing under a dense shrub layer of Neviusia cliftonii. The Adiantum was looking good with its new growth fully emerged; due to the drought and early spring season this year, the Erythronium was already in fruit, though we could still see the large leaves and strongly clumping habit.
Returning back to the paved road, we walked for 10 minutes up the road to a rock outcrop, where Erythranthe taylorii was blooming for us. Participants spent some time scrambling on the cliffs until we realized that a rattlesnake was also sharing the outcrop with the Erythranthe! It was fun to see these three new species growing in such close proximity, and interesting to contemplate how many of us (myself included) had driven past this site without realizing what we were missing.
Shasta Co. endemics - Conservation issues
Rarity and threats were a topic of conversation throughout the day. Many of the populations of the new species are located on public lands, where management can incorporate the needs of the new species. One potential threat is the proposal to raise the height of Shasta Dam by up to 18.5 ft (5.6m) to increase reservoir storage, which would flood about 5000 ac (2023 ha) of land and impact some populations of the newly described species. Much of the recent botanical inventory work that has been done for the new species has happened to provide data to evaluate the impact of the higher dam on the status of rare species. Future wildfires are another potential concern for the future survival of the new species, depending upon their scale and severity.
Evaluation of the new species' global status ranking and California Rare Plant Ranks (CRPR) is currently in progress for most of the new taxa. In 2013 Erythranthe taylorii was assigned a CRPR of 1B.1, and a global rank of G1G2. Erythronium shastense is in the process of ranking; as of August 10, 2015 recommendations are for a global rank of G2, and a CRPR rank of 1B.2. Adiantum shastense ranking has not yet been initiated; the authors of the species recommended a CRPR of 4.3. Vaccinium shastense ranking has not been initiated yet either. The authors recommended CRPR rank of 1B.3 for subsp. shastense, and no conservation rank for subsp. nevadense - with 100+ populations across ten counties in the Sierra Nevada, most of them in relatively remote areas, they thought no ranking was warranted.
One might easily ask the question of why there is such a concentration of local endemic plant taxa in the southeastern Klamath Mountains, and why their existence is only now fully coming to light. After all, William Brewer passed through this area on his way to Mt. Shasta in September 1862. And, today, all four new taxa grow within about 15 air miles of the city of Redding, which has a population of nearly 90,000. Shasta Reservoir is an extremely popular recreation area, and the Interstate 5 freeway passes right through the region. In fact, the type locality for Adiantum shastense is only a 5 minute drive from an exit off I-5. So this is not a remote wilderness. On the other hand, the topography of this area is extremely rugged, and poison-oak is nearly everywhere. Rattlesnakes are a definite presence (as we found), and temperatures regularly exceed 100 degrees F (ca. 38 degrees C). While these conditions do not necessarily invite off-trail exploration, it can be done!
The presenters at the morning session kept coming back to a combination of circumstances - presence of unusual limestone bedrock formations, a relatively old geological regions, and relatively high average annual precipitation (at least, for lower elevations of inland California) as factors helping to explain the presence of these endemic species within this limited area. To this one can certainly add the sustained, collaborative efforts of agency, private sector, and academic botanists. These are lessons that all of us can take from this case study, to apply to wherever we work - the importance of geology, climate, and refugia in plant evolution and biogeography.
PLATES - http://mpb.ou.edu/ben/499/shastaendemics.pdf
On Thu 17/09/2015 Barbara wrote to the BEN Editor: "BTW, I was just in touch with Julie Nelson, and she indicated that half the known Neviusia cliftonii populations will be wiped out if the proposed dam increase goes into effect. Of course, we'll never know how much the original population was flooded when the original dam was built."
I attended Oliver Sacks' memorial service. Do you remember I mentioned in the article the "baggy pants" he always wore to Fern Society meetings. One of the speakers at the memorial service said that those were actually pajamas given to him as a Christmas present! I don't know that Oliver ever realized they were not pants, or cared. He thought they were comfortable.
The Organization for Tropical Studies will be offering Tropical Plant Systematics next summer in Costa Rica. The course is an intensive, five-week field introduction to the identification, inventory, classification, and phylogenetic analysis of tropical vascular plants. It is intended primarily for graduate students in plant systematists but will interest anyone-ecologists, zoologists, and conservation biologists-whose research requires a broad knowledge of plant relationships and classification. The course visits all major vegetation types in the country, from mangrove swamps at sea level to páramos at 3400 m. The course is led by Robbin Moran (New York Botanical Garden), Amanda Grusz (Smithsonian) and Mauricio Bonifacino (Univ. Uruguay).
Program Details Where: OTS Stations in Costa Rica, La Selva, Las Cruces, Palo Verde, Cuericí, and herbaria in San José When: Jun 9 to Jul 12, 2016 Duration: 5 weeks Accreditation: 6 credits Application Deadline: Feb 10, 2016 (Early applications may be sent by December 10, 2015).
Tuition: $4000 for OTS-consortium applicants; $6500 for non-consortium applicants. A limited number of partial scholarships are available.
For more information please visit: http://education.tropicalstudies.org/en/education/graduate-opportunities/programs/tropical-plants-systematics.html
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