Use Of Wildlife Crossing Structures On Us Highway 93 On The Flathead Indian Reservation

Abstract

In the 1990s, Montana Department of Transportation (MDT) proposed an expansion of U.S. Highway 93, in an area entirely within the Flathead Indian Reservation (FIR), home to the Confederated Salish and Kootenai Tribes (CSKT). In December 2000, the CSKT, MDT, and Federal Highway Administration (FHWA) signed a memorandum of agreement that enabled its expansion. It included wildlife mitigation measures to both mitigate impacts to wildlife and natural processes associated with the widening of US93 as well as to address the safety of the traveling public. Mitigation measures include 41 fish and wildlife-crossing structures, including 40 underpasses and one overpass, wildlife fencing, jumpouts, and wildlife crossing guards across 56 mi of highway. Crossing structures were placed in areas that have a history of wildlife crossings and wildlife mortality, and/or locations where the surrounding landscape and land use was best suited for the crossing structures. Research is underway to determine the effectiveness of the mitigation (see www.mdt.mt.gov/research/ projects/env/wildlife_crossing.shtml). Between May 2008 and December 2009, eleven underpasses were monitored for wildlife use. Wildlife use of the structures was substantial with 3,000 deer crossings, 1500 coyote crossings, 300 bobcat crossings, 200 raccoon crossings, and 200 black bear crossings. Other species that used the crossings include mountain lion, elk, grizzly bear, moose, badger, river otter, muskrat, beaver, skunk, rabbit, and various bird species. For the wildlife mitigation measures to be considered successful, goals have been set by the CSKT, MDT, and FHWA, and more data need to be collected and analyzed before the researchers can conclude whether the mitigation measures have indeed reached those goals.