Survey of Rare Plants San Juan Public Lands in Dolores and Montezuma Counties, Colorado Colorado Natural Heritage Program Colorado State University 8002 Campus Delivery Fort Collins, CO 80523-8002 March 2005 Prepared for San Juan National Forest Durango, Colorado By Peggy Lyon and Julia Hanson Colorado Natural Heritage Program Colorado State University 8002 Campus Delivery Fort Collins, CO 80523-8002 [email protected] http://www.cnhp.colostate.edu ©2005 by Colorado Natural Heritage Program ii EXECUTIVE SUMMARY The San Juan Public Lands agencies—Bureau of Land Management and San Juan National Forest—are in the process of revising their management plan. Since one of their missions has been to preserve the biodiversity of the public lands, and particularly to manage to preserve species that have been designated as sensitive, a survey of plant species of special concern is timely. This project is a continuation of surveys conducted by CNHP on the San Juan National Forest from 2001 to 2003, in Archuleta, San Juan and La Plata counties, funded by the San Juan National Forest. Colorado State University contributed by waiving the usual indirect costs associated with the project. CNHP began work in the spring of 2004, by compiling existing data and selecting areas to be inventoried during the field season. Fieldwork was completed from June through September 2004. Thirty-seven new or updated occurrences of plants were documented and evaluated, and added to the CNHP data system. Twenty-three new Potential Conservation Areas (PCAs) were identified, evaluated and mapped to represent the area deemed essential for the protection of these plant occurrences. Three previously identified PCAs are also included in this report. Biodiversity significance of the 26 PCAs is as follows: B1 (Outstanding Significance): 0 B2 (Very High Significance): 5 B3 (High Significance): 10 B4 (Moderate Significance): 6 B5 (General Significance): 5 A profile of each plant species and each PCA is included here, with a map, brief description, ranks and comments regarding urgency of protection and management. This report is accompanied by a GIS coverage of the Potential Conservation Areas. i ACKNOWLEDGEMENTS We owe the existence of this project to many organizations and individuals. Jeff Redders (San Juan National Forest) and Gary Thrash (BLM) have continued to be major supporters of our projects. They have supplied invaluable guidance and advice. Leslie Stewart, USFS botanist, and Marilyn Colyer, Mesa Verde National Park, have generously shared their intimate knowledge of the Four Corners area. Botanists Ken Heil and Arnold Clifford at San Juan College, Farmington, shared results from their extensive surveys in the San Juan Basin. Our staff in Fort Collins, including the botany team--Jill Handwerk, Dave Anderson and Susan Spackman--and Amy Lavender, GIS specialist, all deserve much credit for their patience and work behind the scenes. We were fortunate to have the help of a volunteer, Julie Crawford, on vacation from her position with the National Park Service in Flagstaff during the field season. Karin Freeman, formerly with Colorado Natural Areas Program, volunteered to help with writing PCA profiles. We appreciate the support of our families: Julia’s husband Matthias took over child care of their infant and toddler and household duties while Julia was in the field, and Peggy’s husband Rick was uncomplaining about all the time she spent away from home. Our sincere thanks to all of you! ii Table of Contents EXECUTIVE SUMMARY ...............................................................................................I ACKNOWLEDGEMENTS ............................................................................................ II CHAPTER I. THE NATURAL HERITAGE NETWORK AND BIODIVERSITY . 1 THE NATURAL HERITAGE NETWORK AND BIODIVERSITY................................................ 1 WHAT IS BIOLOGICAL DIVERSITY? .................................................................................. 1 THE COLORADO NATURAL HERITAGE PROGRAM ............................................................ 3 THE NATURAL HERITAGE RANKING SYSTEM .................................................................. 4 LEGAL DESIGNATIONS FOR RARE SPECIES....................................................................... 6 ELEMENT OCCURRENCE RANKING................................................................................... 7 POTENTIAL CONSERVATION AREAS AND THEIR RANKING............................................... 8 OFF-SITE CONSIDERATIONS............................................................................................. 8 RANKING OF POTENTIAL CONSERVATION AREAS ............................................................ 9 PROTECTION URGENCY RANKS...................................................................................... 10 MANAGEMENT URGENCY RANKS .................................................................................. 10 CHAPTER II. ASSESSMENT OF CRITICAL BIOLOGICAL RESOURCES OF LA PLATA COUNTY .................................................................................................... 12 PURPOSE OF THE STUDY................................................................................................. 12 INVENTORY METHODS ................................................................................................... 12 COLLECTING INFORMATION........................................................................................... 12 IDENTIFYING RARE OR IMPERILED SPECIES AND SIGNIFICANT PLANT COMMUNITIESPOTENTIALLY OCCURRING IN THE PROJECT AREA.................................. 12 IDENTIFYING TARGETED INVENTORY AREAS................................................................. 13 CONDUCTING FIELD SURVEYS ....................................................................................... 16 RESULTS OF BIOLOGICAL INVENTORY ........................................................................... 16 DELINEATING POTENTIAL CONSERVATION AREAS ........................................................ 16 CHAPTER III. DESCRIPTION OF STUDY AREA ................................................. 18 LOCATION AND ECOREGION........................................................................................... 18 SIZE AND ELEVATION .................................................................................................... 18 MUNICIPALITIES ............................................................................................................ 19 CLIMATE........................................................................................................................ 19 GEOLOGY....................................................................................................................... 19 VEGETATION/PLANT COMMUNITIES .............................................................................. 20 CLIMATIC ZONES ........................................................................................................... 21 ECOLOGICAL SYSTEMS OF SAN JUAN PUBLIC LANDS .................................................... 23 CHAPTER IV. RARE AND IMPERILED PLANTS OF SAN JUAN PUBLIC LANDS IN DOLORES AND MONTEZUMA COUNTIES ....................................... 25 ADIANTUM CAPILLUS-VENERIS (SOUTHERN MAIDENHAIR FERN) ................................... 27 ALSINANTHE MACRANTHA (HOUSE’S STITCHWORT)...................................................... 28 iii AMSONIA JONESII (JONES BLUE-STAR)........................................................................... 28 AMSONIA JONESII (JONES BLUE-STAR)........................................................................... 29 ASTRAGALUS CRONQUISTII (CRONQUIST’S MILKVETCH) ............................................... 30 ASTRAGALUS DETERIOR (CLIFF PALACE MILKVETCH)................................................... 31 ASTRAGALUS NATURITENSIS (NATURITA MILKVETCH).................................................. 32 ASTRAGALUS NEWBERRYI (NEWBERRY’S MILKVETCH)................................................. 33 BOTRYCHIUM ECHO (REFLECTED MOONWORT).............................................................. 34 CALOCHORTUS FLEXUOSUS (WEAK-STEMMED OR WINDING MARIPOSA LILY)................ 36 DRABA BOREALIS (BOREAL WHITLOW-GRASS) .............................................................. 37 DRABA GRAMINEA (SAN JUAN WHITLOW-GRASS).......................................................... 38 DRABA STREPTOBRACHIA (COLORADO DIVIDE WHITLOW-GRASS) ................................ 39 EPIPACTIS GIGANTEA (GIANT HELLEBORINE)................................................................. 40 ERIOGONUM SCABRELLUM (WESTWATER WILD BUCKWHEAT) ...................................... 42 ERIOPHORUM ALTAICUM SSP. NEOGAEUM (ALTAI COTTONGRASS) ................................ 43 GILIA HAYDENII (SAN JUAN GILIA)................................................................................ 44 ILIAMNA GRANDIFLORA (LARGE-FLOWER GLOBE-MALLOW; WILD HOLLYHOCK)........... 45 MACHAERANTHERA COLORADOENSIS (COLORADO TANSY-ASTER) ............................... 46 PENSTEMON BREVICULUS (SHORT-STEM BEARDTONGUE).............................................. 47 PENSTEMON LENTUS (ABAJO PENSTEMON) .................................................................... 48 PENSTEMON UTAHENSIS (UTAH BEARDTONGUE ) .......................................................... 49 STELLARIA IRRIGUA (ALTAI CHICKWEED)...................................................................... 50 TOWNSENDIA