Observations on Penstemon Clutei, Coconino National Forest

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Observations on Penstemon clutei, Coconino National Forest

Greg Goodwin Wildlife Biologist September 1979

Goodwin, Greg. 1984. Bulletin of the American Penstemon Society 1984 43(1) 26-31.

Penstemon clutei is a robust, pink-flowered herb that is only found in the vicinity of Sunset Crater, Coconino County. It grows on volcanic cinder from 6500 to 8500 ft. elevation in ponderosa pine forest. Eight of the localities are on Coconino National Forest north of Flagstaff near Sunset Crater. The other locality is in Sunset Crater National Monument.

Penstemon clutei was listed as a Category 3C (delisted because more common than previously thought) by the U.S. Fish and Wildlife Service in the 1980 Notice of Review. It is still listed as a sensitive plant with the U.S. Forest Service. Because the plant is locally abundant and only occurs in a small area that is mostly on Coconino National Forest, the Forest Service has assumed the management and responsibilites for this endemic plant. It should be monitored and considered in management plans for the area.

During August and September a field survey was conducted of the cinder hills area northeast of Flagstaff for the proposed endangered plant, Penstemon clutei. This species is endemic to the cinder hills area and is known only from near Sunset Crater National Monument.

Penstemon clutei is a large robust beardtongue with bright showy deep pink flowers. It is an ecologic endemic (Daubenmier, 1978) having evolved strict habitat requirements. Only the very limited area of the cinder hills can meet these special requirements. A ground search in the area found this beardtongue in several discontinuous populations surrounding Sunset Crater.

The general relief of the cinder hills area is a varied pattern created by numerous volcanic cones, lava flows, and broad, flat valley-like areas between the cones. The soils in the area are well defined, however, they are covered with at least 8-10 inches of raw volcanic cinders (Patton and Meurisse, 1972). The bare raw cinders constitute a relatively widespread blanket of fresh black and red cinders composed of alkali olivine basalt. This material is a recent basalt pyroclastic sheet from the eruption of Sunset Crater in 1064 AD (Moore and Wolfe, 1976). The cinder hills area is part of the San Francisco Volcanic Field and the numerous cinder cones present here make it unique as one of the more recent volcanic fields of the continental United States.

The cinder hills area is predominately a ponderosa pine forest, with scattered pinyon pine and Utah juniper occurring in rather open stands

At lower elevations on the east side, the area is predominantly a pinyon-juniper woodland. Understory vegetation found in ponderosa pine stands on volcanic cinders differ considerably from that found on nearby residual soils. Total plant cover is much lower and the herbaceous flora more depauperate. Stands have little advance pine regeneration and pioneering shrubs such as Fallugia and Chrysothamnus assume much more importance in these xeric areas.

The species most commonaly associated with P. clutei are apache plume (Fallucia paradoxa). rabbit brush (Chrysothamnus spp.), beardtongue (P. barbatus). raullen (Verbascum thapsus). and blue gamma (Bouteloua gracilis).

All populations were found in open pine stands at elevations between 6,500 to 8,500 feet on relatively bare cinders which had virtually no soil accumulation (Table 1). In some areas needle cast constituted as much as 50-60 percent ground cover with generally less than 30 percent vegetative ground cover.

The cinder hills area falls within the Cinder Allotment which is now formally closed to livestock grazing. The last grazing on the allotment occurred in 1969. Some wildlife use in the area was detected, however, it is having no effect on the species.

Penstemon clutei is rather common in a small area on the east side of O'Leary Peak (Sec. 1 T23N, R8E). The population extends along the west side of Forest Road 546 for approximately 1/2 mile. This area has a large amount of apache plume and has had some past logging disturbance. There was some reproduction, however, only four seedlings could be found in a 100 x 100 feet sample area.

The population south of Haywire Crater appears to be in good condition. Plants are scattered across two general areas (Sec. 22 and 26, T23N, R9E) along Forest road 244. A total of 23 mature plants were counted in an area 100 x 100 feet and an estimated 45-50 seedlings were found in the sample area.

The population on the south side of Pinnacle Crater (Sec. 31, T23N, R9E) is small and is presently being severely impacted by off-road vehicle use. Little Cinder Basin and the surrounding cones are receiving very heavy use by ORVs. Large groups of people are camping around Pinnacle Crater and along Forest Road 777 between the Crater and Cinder Lake. This small population will eventually be eliminated by the heavy ORV and dispersed recreation use of the area.

The population near Cinder Lake occurs in a relatively flat open area extending along both sides of the road. Mature plants were counted in a 100 x 100 feet sample area for a total of 40; only 15 seedlings were found. This area is very open and has little understory vegetation, the most common species being Penstemon clutei.

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The largest population of P. clutei is that which extends from the west side of Sunset Crater National Monument west and north up to near the summit of O'Leary Peak. Part of this population was burned in November, 1973 when Burnt Fire burned a large area west of the Monument. The plants in this area are very vigorous and reproduction abundant. Stems on these plants reach as high as 3-4 feet. As a result of the fire relatively dense pole-sized stands of ponderosa pine were opened up and all litter accumulation burned. The bare cinders now support growth and reproduction rates that are considerably higher without competition.

Eggler (1966) reported that there was not evidence that plant succession was taking place at Sunset Crater. It does appear, however, that after a fire succession occurs as species invade the bare cinders and a ponderosa pine forest develops. Penstemon clutei is one of the pioneering species. All species found in the burned area were invaders, Verbascum thapsus. Amaranthus ssp., Sal sol a kali. and Mentzelia ssp.

McDougal (1973) reported that Penstemon clutei occurs at elevations near 7,000 feet, however, this population extends up the south side of O'Leary Peak to near 8,600 feet. Plants become increasingly less abundant at higher elevations occurring only in very open unshaded areas. The optimum growth and abundance seem to occur below 7,500 feet elevation. Common species associated with this beardtongue at 8,000 feet are Fallagia paradoxa, Pericome caudata. Sitanion hystrix. Ribes ssp. and Senecio ssp.

A large part of the cinder hills area was surveyed for this species. No plants could be found south of the Transwestern gas line or in the Maroon Crater area. The area adjacent to Strawberry Crater was also examined but no plants found. The floristic composition and overall physiographic conditions at Strawberry Crater are similar to those areas that contain Penstemon clutei except the area lies at 6,200 feet elevation and 1s a pinyon-juniper woodland.

Penstemon clutei is wide ranging within the limited habitat afforded by bare volcanic cinders and does not meet the criteria for a threatened or endangered species as defined by the Endangered Species Act. The only substantial threats to this species are protection from fire and ORV use. However, the area

east of the 345K transmission line is now in a proposed let-burn area. Plants also seem to be somewhat resistant to trampling if it is only occasional and does not expose the root system from accelerated movement of cinders.

MANAGEMENT RECOMMENDATIONS

1)Areas of Penstemon clutei habitat need to be subjected to fire on a periodic basis. Prescribed burning is obviously a very valuable if not critical management tool for this species.

2)ORV use has the potential to destroy large amounts of habitat and the actual existing populations. Already large areas of the cinder hills show evidence of ORV use. The ORV policy regarding the cinder hills needs to be expanded and strictly enforced. The status of Penstemon clutei could rapidly change if ORV use is not more effectively managed.

LITERATURE CITED

Daubenmire, R.

1978. Plant Geography. Academic Press, 338 pp

Eggler, W.A.

1966. Plant Succession on Recent Volcano, Sunset Crater Plateau, 38: 81-96

McDougal, W.B.

1973. Seed Plants of Northern Arizona. Museum of Northern Arizona. 594 pp

Moore, R.B. and E.W. Wolfe

1976. Geologic Map of the Eastern San Francisco Volcanic Field, Arizona. USGS Map 1-953, Misc. Inves. Series.

Patton, W.W and R.T. Meurisse

1972. Soils Report, Cinder Hills Area, Elden Ranger District, Cocom'no National Forest.

NOTE: Elona Ballou, one of our members in North Las Vegas, NV, learned that one of her forestry professors was working on the effect of perscribed burning on P. clutei. At her request he gave her some names of Forest Service personnel who sent her the article printed above.

TABLE I. SITE DESCRIPTION OF PENSTEMON CLUTEI POPULATIONS IN THE CINDER HILLS AREA

Tree Canopy Basal

Elevation Slope Coverage Area Location (Ft.) (%) Aspect % {Sq. ft.)

Haywire Crater 6,500 10 NE 10 40 Sec. 26, 21, 22 T23N, R8E

O'Leary Peak (East) Sec. 1, T23N. R9E 6,500 10 NE / 10 40
Pinnacle Crater Sec. 31, T23N.R9E 7,000 20 NVI / 6 40

Cinder Lake

Sec. 7, T22N.R9E 6,7005 NW1530

O'Leary Peak

(South)

Sec. 3 T23N.R8E 8,50050S520