Home/Species/ Knowlton's Hophornbeam

Ostrya knowltonii

Coville

Knowlton's Hophornbeam

G4Apparently Secure Found in 3 roadless areas NatureServe Explorer →

G4Apparently SecureGlobal Rank

Least concernIUCN

LowThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.145153

Element CodePDBET05020

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

IUCNLeast concern

Endemicendemic to a single nation

KingdomPlantae

PhylumAnthophyta

ClassDicotyledoneae

OrderFagales

FamilyBetulaceae

GenusOstrya

Other Common Names

Knowlton's hophornbeam (EN)

Concept Reference

Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

Conservation Status

Rank MethodLegacy Rank calculation - Excel v3.1x

Review Date2018-07-02

Change Date2018-07-02

Edition Date2018-07-02

Edition AuthorsGardner, P.A. (1989), rev. Treher (2018)

Threat ImpactLow

Range Extent20,000-200,000 square km (about 8000-80,000 square miles)

Number of Occurrences21 - 80

Rank Reasons

Ostrya knowltonii occurs in Texas, New Mexico, Arizona, and Utah. It occurs over a wide range but populations may be small is size and isolated. Threats to this species are low and it is projected to expand it's range based on climate models. Trends are believed to be stable.

Range Extent Comments

Ostrya knowltonii occurs in northeastern Texas, southeastern New Mexico, northern Arizona, and southeastern Utah. In Texas, it occurs in the Trans-Pecos Region including the Guadalupe Mountains of Guadalupe Mountains National Park. In New Mexico, it occurs in the Guadalupe and Sacramento Mountains of Eddy County. In Arizona, it occurs in the Grand Canyon and Oak Creek Canyon near Flagstaff (Ladyman pers. comm. no date; Tesky 1994).

Occurrences Comments

This species is reported from Coconino and Yavapai counties in Arizona, Eddy County in New Mexico (Guadalupe and Sacramento mountains); and in Garfield, Grand, Kane & San Juan Counties in Utah, and in the Guadalupe Mountains of Texas. There are 47 reported occurrences (Utah and Arizona) in the NatureServe Network Database (as of 2018) but this is certainly less than the true number given that some states do not track occurrences for this species. Of these occurrences, twenty-five are historic (not surveyed for 20 or more years) and they should be prioritized for survey.

Threat Impact Comments

Potentially threatened in unprotected areas by water diversion or development. Threats in Utah are believed to be low. Ostrya knowltonii is predicted to have range extensions under projected climates of the 21st century (Notaro et al. 2012).

Ecology & Habitat

Habitat

This species occurs in mesic canyons (over 1,500 meters), moist areas along streams, the bases of monoliths, defiles and hanging gardens in sandstone at 1,225-1,700 meters. "It is commonly found in pinyon-juniper and oak woodlands. At higher elevations it occurs in ponderosa pine and douglas fir communities. In Texas it is also associated with Texas madrone (Arbutus texana), southwestern white pine (Pinus strobiformis), chinkapin oak (Quercus muehlenbergii) and bigtooth maple (Acer grandidentatium) (Stritch 2014)."

Terrestrial Habitats

Forest/WoodlandWoodland - HardwoodWoodland - ConiferWoodland - Mixed

Other Nations (1)

United StatesN4

Province	Rank	Native
Utah	S2	Yes
Texas	S1	Yes
Arizona	S3	Yes
New Mexico	S3	Yes
Navajo Nation	S1	Yes

Plant Characteristics

DurationPERENNIAL, Long-lived, DECIDUOUS

Economic Value (Genus)No

Roadless Areas (3)

New Mexico (3)

Area	Forest	Acres
Ortega Peak	Lincoln National Forest	11,545
South Guadalupe Mountains	Lincoln National Forest	20,930
West Face Sacramento Mountains	Lincoln National Forest	41,176

References (6)

Flora of North America Editorial Committee (FNA). 1997. Flora of North America north of Mexico. Vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford Univ. Press, New York. xxiii + 590 pp.
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Little, E.L., Jr. 1979. Checklist of United States trees (native and naturalized). Agriculture Handbook No. 541. U.S. Forest Service, Washington, D.C. 375 pp.
Notaro, M., A. Mauss, and J. Williams. 2012. Projected vegetation changes for the American Southwest: combined dynamic modeling and bio-climatic envelope approach. Ecological Applications 22(4):1365–1388.
Stritch, L. 2014. Ostrya knowltonii. The IUCN Red List of Threatened Species 2014: e.T194557A2349148. Online. Available: http://dx.doi.org/10.2305/IUCN.UK.2014-3.RLTS.T194557A2349148.en (accessed 02 July 2018).
Tesky, J.L. 1994. Ostrya knowltonii. In: Fire Effects Information System, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Online. Available: www.fs.fed.us/database/feis/plants/tree/ostkno/all.html (accessed 29 June 2018).