watervulnerability

Helena National Forest Watershed Vulnerability Assessment, Northern Region (R1)
Bull trout
• Listed as a Threatened Species throughout their range under the Endangered Species Act since
1999.
• Have important habitat on the Helena National Forest west of the continental divide in the
headwaters of the Columbia River.
• Require colder water temperatures than most salmonids.
• Require the cleanest stream substrates for spawning and rearing.
• Need complex habitats, including streams with riffles and deep pools, undercut banks, and lots of
large logs.
• Rely on river, lake, and ocean habitats that connect to headwater streams for annual spawning and
feeding migrations.
Cutthroat trout
• One of two subspecies of native cutthroat found in Montana.
• Montana’s state fish.
• Historic range was west of the Continental Divide as well as the upper Missouri River drainage.
• Range has been seriously reduced due to hybridization with rainbow and/or Yellowstone
cutthroat and habitat loss and degradation.
• Designated a Montana Fish of Special Concern in Montana.
• Common in both headwaters lake and stream environments.
Infrastructure
• Roads, campgrounds near streams and rivers, water diversions, bridges, etc.
• Can become a safety concern for all forest users recreating in areas where streams are subject to
higher flows, flash floods, etc.
• Important financial investment for the Forest Service.
EXPOSURE
Information on predicted climate changes anticipated on the Helena National Forest came from a variety
of sources. Published reports from the Rocky Mountain Research station were used to describe the
general projections for the region including the projected change in the climate variable, the anticipated
watershed response, and the potential consequences to watershed services (Table 1) (Rieman and Isaak,
2010). Generally, predictions agree on a warmer and sometimes drier climate (Rieman and Isaak, 2010).
This will include an increase in summer maximum temperatures of approximately 3 °C by the mid-21 st
century, and an increase in spring and summer precipitation accompanied by a decrease in fall and winter
precipitation.
49 Assessing the Vulnerability of Watersheds to Climate Change