SNFPA Draft Supplemental Environmental Impact Statement

June 2003

Chapter 3: Affected Environment

3.2.2.2. Marten (Martes Americana)

The marten was addressed in the SNFPA FEIS in Chapter 3, Part 4, pp 19-35. A literature survey was conducted to determine whether new information regarding the species, either directly or indirectly, has evolved since the FEIS was completed. Several articles have been published and are described below. This new information deals with recreational activities, fuels reduction, and prey items.

Recreational activities. Recreational effects on marten were addressed in the SNFPA FEIS Chapter 3, Part 4, page 26. Although specific effects of recreational activities on marten have not been conducted, it could be inferred that similar responses could be elicited under similar conditions regardless of species being considered. Over the past decade, methods for non-evasive measurement of glucocorticoid (GC) stress levels in urine and feces have been widely developed to investigate stress physiology in the wild (Wasser et al. 1988, 1997; Creel et al. 1991, 1996; Monfort et al. 1997; Palme et al. 1998). There is a large body of research on captive mammals that shows large prolonged GC elevations typically reduce survival and reproduction (Munck et al. 1984; Sapolsky 1992). Creel et al. (2001) tested for associations between snowmobile activities and fecal GC levels in f populations of elk and wolves in a variety of National Park locations. It was found that for wolves, comparisons among populations and years showed that fecal GC levels were higher in areas and times of heavy snowmobile use. For elk, day-to-day variation in fecal GC level paralleled variation in the number of snowmobiles. There was no evidence that the current level of snowmobile use was affecting the population dynamics of either species in the test locations. Continuous and/or fluctuating levels of GC could be recognized for martens in area of high recreational use, especially during the breeding season.

Fuels reduction. Habitat risk factors are discussed in the SNFPA FEIS in Chapter 3, Part 4, page 23. The FEIS addresses the significance of both down woody material and crown closure as habitat components for marten. Both of these components also play a significant role in providing habitat for marten prey. Both the reduction in down woody material and crown can have an influence on the distribution and abundance of prey items. Bull and Blumton (1999) tested the effects of three different fuels reduction treatments on small mammals populations in lodgepole pine (Pinus contorta) and mixed-conifer stands in northeastern Oregon. A variety of treatments were tested. The harvest activities in lodgepole pine and mixed-conifer stands resulted in fewer post-harvest numbers of red-backed voles and snowshoe hares and an increased number of chipmunks. They found less of a decline in the number of snowshoe hares, no decline in squirrels, and an increase in red-backed voles in the island treatment compared to scattered treatments.

The lack of decline in squirrel detections in the island treatment and in the mixed conifer harvest suggested that those treatments continued to provide suitable habitat for this species. The island treatments retained inlands of logs that provided subnivean structures essential for squirrel survival in winter. The mixed-conifer treatment retained large diameter trees, which could continue to provide a food source for squirrel.

It appeared that the mixed-conifer stands were no longer suitable for snowshoe hares after harvesting. The island treatment that resulted in less of a decline in hares probably provided better habitat than the scattered treatment because the islands contained undisturbed pockets of regeneration as well as logs. In addition, it would be unlikely that marten would venture into the mixed-conifer stands because of reduced canopy closure and stem density. Radio collared martens in the area avoided all harvested stands and stands with less than 50 percent canopy closure.

The declines in red-backed voles, red squirrels, and snowshoe hares in the harvest stands would be detrimental to marten because these species are primary prey items for martens in the Sierra Nevada.

USDA Forest Service · Pacific Southwest Region