si te Basic Record 

 HUMBUG SPIRES 



From Divide (town), proceed east one mile on State Highway 43 to Interstate 15. Drive under the 

 overpass and park by the fence on the east side of the interstate. The site is along the 

 mountain front, 1.25 miles due east. 



Three major parent material types occur on this site. Limestone outcrops in the north provide 

 habitat for highly-ranked populations of Arabis fecunda. Granitic parent materials dominate 

 most of the remaining part of the site except for the far south, where a schist -dominated ridge 

 occurs. Throughout this site along the western front of the Highland Mountains, forests and 

 woodlands co-dominated by Cercocarpus ledifolius occur. These community types are rare in 

 Montana and, in combination with Arabis fecunda, make this site a significant biodiversity 

 resource. 



COUNTY: Silver Bow 



USGS QUADRANGLE: TUCKER CREEK 

 MELROSE 



TOWNSHIP-RANGE: 001S009W SECTION: 15 



QUARTER/ADDITIONAL SECTIONS: portions of 2, 3, 10, 11, U, 15, 22 and 23 



BOUNDING RECTANGLE: S: 454340N N: 454630N E: 1124025U W: 1124230W 



BOUNDARY JUSTIFICATION: The northernmost boundary encompasses a large population of Arabis fecunda. All 

 other boundaries encompass rare coni fer/Cercocarpus ledifolius communities along 

 the mountain front between Lime Gulch and Moose Creek. 



APPROXIMATE ACREAGE: 1500.00 



GENERAL RATING: 1 



A large, high-quality occurrence of Arabis fecunda is present. 



BIODIVERSITY SIGNIFICANCE: B2 



A large, high-quality occurrence of Arabis fecunda, rare plant communities, and Draba 

 densi folia are present. 



OTHER VALUES: V2 



The highly aesthetic Humbug Spires form the backdrop for portions of this site. 



PROTECTION URGENCY: P2 



Rare species and rare communities are well-represented on the site. Mining withdrawal and 

 protection of sensitive species locations from domestic stock grazing disturbances may be 

 desireable. Water developments have been improved in the area, so enhanced livestock use poses 

 a threat. 



MANAGEMENT URGENCY: M3 



Fencing may be needed to protect sensitive elements. 



CONSERVATION INTENT: Expand the Humbug Spires Primitive Area boundary to encompass the northern 

 portion of this site containing Arabis fecunda. 



PROTECTION COMMENTS: The BLM is aware of the Arabis fecunda occurrences in the northern portion of 

 the site, and is currently considering protection options. 



LAND USE: Mine prospects and shafts are scattered throughout the site and have caused localized 



degradation. Most of the site is relatively steep topography, with low forage volumes and has 

 received low to moderate livestock grazing (relative to heavily-grazed adjacent grasslands and 

 shrublands). Deer browsing of Cercocarpus ledifolius has been heavy in some locations. 

 Occasional tree stumps are present. 



NATURAL HAZARDS: Mine shafts and granite cliffs could be hazardous. 



EXOTICS: No exotic species currently appear to pose a threat to this site. 



OFF-SITE LAND USES: Host of the higher country above the site is within the Humbug Spires Primitive 

 Area and is thus relatively protected and managed in a way that would minimize 



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