A checklist of the vascular flora of Yucca House National Monument and surrounding lands, Montezuma County, Colorado1

Journal of the Torrey Botanical Society, Apr-Jun 2007 by Rink, Glenn R, Cully, Anne C

RINK, G. R. (Northern Arizona University, P.O. Box 5640, Flagstaff, AZ 86001) AND A. C. CULLY (National Park Service Southern Colorado Plateau Network, Box 5765 Northern Arizona University Flagstaff, Arizona 86011). A checklist of the vascular flora of Yucca House National Monument and surrounding lands, Montezuma County, Colorado. J. Torrey Bot. Soc. 134: 289-300. 2007.-Two hundred and sixty-one vascular plant species were documented for Yucca House National Monument and surrounding lands including seven new records for Montezuma County. This work was part of a biological inventory throughout the National Park Service as part of the Natural Resource Challenge, a legislative and administrative mandate. The study area is in the Montezuma Valley, where most land is in private or tribal ownership, and opportunities for plant surveys are limited. The flora includes three species tracked by the Colorado Natural Heritage Program: Centaurium exaltatum (Griseb.) W. Wight ex Piper (desert centaury), Penstemon breviculus (Keck) Nisbet & R.C. Jackson (shortstem beardtongue), and Penstemon lentus Pennell (handsome beardtongue).

Key words: biological inventory, Colorado, flora, Montezuma County, rare plants, Yucca House National Monument.

Yucca House National Monument (YUHO) is located in southwestern Colorado in the Montezuma Valley about 14.5 km (9 mi) southwest of Cortez (Fig. 1 ). The Monument was established to protect Puebloan structures occupied during the Chaco Period (about A.D. 1050 to 1 150 and again from A.D. 1225-1300) (Var�en 1999a, as cited in Glowacki 2001). During its occupation, Yucca House was a large community with a formal, walled ceremonial plaza and structures that were at least three stories high. The site includes a permanent spring that was likely a focus for travelers in this dry region. Yucca House may have been a major trade center, linked to the Mesa Verde Plateau and other sites in the Four Corners region (Stuart 2000).

HISTORY. Yucca House became a National Monument on December 19, 1919 after lands were donated to the National Park Service (NPS) by Henry Van Kleeck of Denver, Colorado at the urging of archaeologist Jesse Walter Fewkes (Glowacki 2001). It was administered by the Superintendent of the Southwestern National Monuments until placed under the care of the Coordinating Superintendent of Mesa Verde National Park (MEVE) on June 30, 1944. The Monument is a National Historic Site and is managed as an Historic Zone (NPS 1984). HaUie Ismay, a local rancher, generously donated additional lands in 1990 (Glowacki 2001) bringing the size of the Monument up to 13.71 ha (33.87 ac) (Fig. 2). Yucca House remains an archaeological reserve, with no visitor services or other development. The site consists of mounds of fallen debris of little interest to the few casual visitors, but is significant in being one of few remaining valley Puebloan sites that are fairly intact. The ranch caretaker's home is next to the entrance to the fenced site, facilitating his watchful eye. During the course of the survey, the ranch was transferred from the Ismay family to new owners.

SITE DESCRIPTION. Lands within the existing Monument boundaries were the original targets for our inventories of vascular plants and vertebrate animals. However, the possibility of adding additional lands to the Monument was raised in 2001, so permission to survey the surrounding Ismay Ranch lands was obtained by the NPS. Consequently, the inventory reported here includes a total of 961.84 ha (2,376.67 ac). The study area falls within latitudes 37� 20' 33'' and 37� 25' 38'' N, and longitudes 109� 38' 21'' and 109� 42' 07'' W. It includes a west parcel that surrounds YUHO with approximate legal description as follows: NW4, Sec25; NE4NE4, S2NS, N2S2, S2SE4, SE4SW4, Sec26; NE4, E2NW4, W2SE4, S2SE4, NE4SW4, Sec35; NW4, E2SW4, Sec36; T35N, R17W and a separate parcel on the east side of Highway 160 with approximate legal description as follows: W2NW4, Sec5; Sec6 E of the Hwy 160ROW; the portion of Sec7, T34N, R16W north of the Old Southern Ute Indian Reservation Boundary; and the N portion of the SE4 of Sec 12, T34N, R17W north of the Old Southern Ute Indian Reservation Boundary. United States Geological Survey 7� minute topographic quadrangles Mud Creek and Towaoc cover the study area, which ranges in elevation from 1780 m (5840 ft) to 1880 m (6160 ft).

The population of Montezuma County was 24,335 in 2003, 4.5 people per square km (1 1.7 per square mile) in 2000 (U. S. Census Bureau 2007a). The population of Cortez, 16 km (10 mi) north of YUHO, was 8,137 in 2003 (U. S. Census Bureau 2007b). Visitation to Yucca House is low, perhaps averaging 100 people per year.

Vegetation is characteristic of Great Basin shrub-steppe dominated by big sage (Artemisia tridentata) and pi�on-juniper (Pinus edulis, Juniperus osteosperma) woodland. Ismay lands have been used for grazing and agriculture for decades. Non-native plants make up a significant component of the vegetation throughout. Some of the non-native plants are invasive, weedy species, and some were introduced for agricultural or landscaping purposes. A portion of the lands donated in 1990 was used as a gravel pit from 1954-1956 (Hallie Ismay, pers. comm., as cited in Glowacki 2001), and remains a weedy, disturbed place.