Wolverine Reintroduction: Sangre de Cristo Mountains

With USFWS approval, CPW will move forward with reintroducing wolverines in CO. The USFWS will label these reintroduced wolverines a nonessential experimental population. Over the next three years, forty-five wolverines will be introduced. CPW plans to release these wolverines in three zones: north of I70, between I70 and HWY50, and in the southern San Juan Mountains. The introduction plan should include a fourth zone, the Sangre de Cristo Wilderness area. 

Wolverines were native to the Sangre de Cristo mountains and the surrounding area. Frey concluded that historically, the southern limit of wolverine distribution in the Rocky Mountains may have been northern New Mexico (2006).  Aubry et al. documented wolverine reports in the Sangre de Cristo Mountains (2007). 

Aubry et al. suggest that wolverine's historic distribution patterns were closely tied to spring snow cover (2007).  Records of wolverine in the contiguous United States were often where snow cover persisted through the spring denning period. Aubry et al. used EASE-Grid snow cover data to predict the probability of snow cover during the latter portion of the denning period (2007). Results suggest a 76-100% probability for the Sangre de Cristo mountains (Aubry et al. 2007).

Banci suggests wolverines are generally found in remote areas away from human development (1994). Wolverine habitat associations are based on isolation from human presence and association with subalpine habitats (Aubry et al. 2007). According to Copeland et al., wolverines favored high elevations (2007). The Sangre de Cristo wilderness area provides 900 km2 of remote habitat away from human development. Human development along the base of the range is sparse. The wilderness area is also contiguous with the Great Sand Dunes National Park and Preserve, which provides 170 km2 of remote land suitable for wolverines in the park's Preserve section, excluding the dune field. Human use of these two federally managed land systems is light because the terrain is rough; after steep climbs from the valley floor, most trails end at high-altitude cirques surrounded by technical rock climbing. The units are remote from any substantial cities or towns. 

The Sangre de Cristo mountains and surrounding preserve provide Kuchler’s Alpine Meadows vegetation type and Holdridge’s Alpine life zones, which Aubry et al. suggest are vital to wolverines (2007). The Sangres provide large expanses of alpine vegetation or climatic conditions needed to sustain a reintroduced wolverine population.  Wolverines are associated with boreal and subalpine forests, talus, and tundra habitats and prefer areas with snow on the ground in winter (Banci, 1994). At the southern edge of their range in the western US, wolverines are limited to mountainous regions associated with remote high-elevation habitats, especially during summer (Banci 1994). The historical range may have extended more regularly below the subalpine forest into the lower-elevation mixed conifer zone (Frey 2006).

Male wolverines' home range size varies from 422 to 1,506 km2 (The Wolverine Foundation 2014). Female wolverines' mean home range size varies from 73 to 335 km2 (TWF 2014). The Sangre de Cristo Wilderness could support multiple males with strategic introduction, one male introduced north of Hayden Pass and another male introduced in the Willow Lake area. Additionally, another male could be introduced at the southern end of the range in the GSDNP's Preserve section near Tijeras Peak/Upper Sand Creek Basin or further south in the Blanca Massif.  The area could support five to ten females. Introductions at the headwaters of the range's significant streams would provide ample range and separation for each female.  

Male and female wolverines may disperse long distances (TWF 2014). The Sangre de Cristo range provides connectivity to more mountain ranges with suitable habitat. Frey indicates that the lower elevation forest type at Poncha Pass between the Sangre de Cristos and the remainder of the Southern Rocky Mountain does not hinder wolverine dispersal (2006).  Dispersing individuals can move north across Poncha Pass into the Sawatch Range and suitable habitats along the Continental Divide, such as the Powderhorn Wilderness and the La Garita Wilderness, or south across La Veta Pass into the Culebra Range, a privately held mountain range providing 9,689 km2 of high-altitude habitat.  

Literature Cited:

AUBRY, K.B., MCKELVEY, K.S. and COPELAND, J.P. 2007. Distribution and Broadscale Habitat Relations of the Wolverine in the Contiguous United States. The Journal of Wildlife Management, 71: 2147-2158. <https://doi.org/10.2193/2006-548>.

Banci, Vivian. 1994. Chapter 5: Wolverine. In: Ruggiero, Leonard F.; Aubry, Keith B.; Buskirk, Steven W.; Lyon, L. Jack; Zielinski, William J., tech. eds. The scientific basis for conserving forest carnivores: American marten, fisher, lynx, and wolverine in the western United States. Gen. Tech. Rep. RM-254. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. p. 99-127

COPELAND, J.P., PEEK, J.M., GROVES, C.R., MELQUIST, W.E., MCKELVEY, K.S., MCDANIEL, G.W., LONG, C.D. and HARRIS, C.E. (2007), Seasonal Habitat Associations of the Wolverine in Central Idaho. The Journal of Wildlife Management, 71: 2201-2212. <https://doi.org/10.2193/2006-559>.

Frey, J. K. 2006. Inferring species distributions in the absence of occurrence records: An example considering wolverine (Gulo gulo) and Canada lynx (Lynx canadensis) in New Mexico. Biological Conservation 130:16–24 <https://doi.org/10.1016/j.biocon.2005.11.029>.

The Wolverine Foundation | Spatial use. 2014. The Wolverine Foundation. <https://wolverinefoundation.org/spatial-use#:~:text=Wolverine%20home%20range%20size%20varies,Magoun%201985%2C%20Whitman%20et%20al.>.