3) Population Status 



The majority of the mule deer population estimates were re- 

 ported in end-of-the-year completion reports by the Montana Depart- 

 ment of Fish and Game or the U.S. Forest Service, and were based on 

 limited field data. Zajanc (1948) estimated there were 2,006 mule 

 deer utilizing 34,000 acres of winter range (0.059 deer/acre) 

 (T^ble 2). This estimate was based on strip counts made within the 

 winter range, and is considered to be a reliable estimate of the 

 mule deer population inhabiting the area along the Kootenai River 

 from Gateway to Jennings during the winter of 1947-48. U.S. Dep. 

 Inter. (1965) estimated there were 1,800 mule deer within the area 

 of influence (the reservoir site and tributary drainages to their 

 headwaters, except the Tobacco River drainage upstream from Eureka). 

 U.S. Dep. Agric. (1965a) observed mule deer were increasing in the 

 Warland District, indicating the estimate based on the density 

 reported by Zajanc (1948) was the absolute minimum population pre- 

 sent during the mid to late 1960's. 



4) Impacts 



Because of their tendency to utilize the higher ranges and the 

 lower population levels inhabiting the impact area, the detrimental 

 impacts to the mule deer population were less than for white-tailed 

 deer. Inundation of the pool area produced a loss of 11,580 acres 

 of mule deer winter range habitat. This loss of winter range was 

 accompanied by a loss of individuals from the population and/or a 

 dispersal of individuals to other habitats. Any dispersal forced 

 the animals to subsist on marginal habitat or concentrate within 

 already occupied habitat. These animals would have been lost from 

 the population during a severe winter, which would have produced 

 further stresses and increased over-winter mortalities. 



The relocation of Highway 37 through the mule deer winter 

 range produced an additional impact on the population. An in- 

 creased loss of habitat resulted, with 580 acres lost to wintering 

 mule deer - determined by adding the acres disturbed (U.S. Dep. 

 Army 1971b, 1971c). In addition, the lengthy sections of highwall 

 created when the highway was constructed act as a barrier to move- 

 ment to the habitats between the road and the reservoir. Increased 

 mortality due to collisions has also resulted. Drumheller (1936) 

 realized the potential impacts of such a road and recommended no 

 road be built along the east side of the Kootenai River as it would 

 traverse the entire winter range and create a loss of habitat. 



Prior to the Libby Dam project, Highway 37 paralleled the west 

 side of the Kootenai River, and impacted approximately 34.7 miles 

 of mule deer winter range. The construction of the Forest Develop- 

 ment Road along the west shore of Lake Koocanusa impacted approxi- 

 mately 29.8 miles of mule deer winter range. This road traversed 

 steeper terrain and more of the mid-slopes than did the original 

 Highway 37. Therefore, even though it impacted less miles of mule 

 deer winter range, the overall impacts were considered to be 



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