CHAIHER 2: Al-FKtMEt) lilNVIRONMENT 



In other areas of the state, wolves are expected to prey primarily on elk, mule deer, and moose. In 

 southwestern Montana, wolf packs seem to prey on elk more frequently than mule deer or moose (Smith 

 et al. 2001 ; Gude and GaiTolt unpubl. data). Of the three species most likely to be killed by wolves in the 

 Yellowstone area, elk are the most closely studied. Elk are important to human hunters as well. 



The northern Yellowstone elk herd has always gotten a great deal of public attention because it is one of 

 the largest and best known elk herds in the country, it is associated with YNP, and it provides a unique 

 and very popular elk hunting opportunity during the .so called "Gardiner late elk hunt." Since the 1970s, 

 the northern Yellowstone elk herd has nuctuated up and down from less than 9,000 elk to about 19,000 

 elk, based on winter counts. The annual winter count changes 10-20% from year to year, but sometimes 

 it changes by 30-40%. Compared to other Montana elk populations, northern Yellowstone herd counts 

 are dynamic and very chaotic. During this same period, elk herds in other parts of southwestern Montana 

 that are managed primarily by hunting, fluctuated 5-15% per year, with a clear long term trend toward 

 increasing elk numbers. Most elk herds in southwestern Montana currently have two to four times as 

 many elk now as they had in the mid-1970s. 



Periodic, but significant winterkill events are the greatest single factor affecting elk numbers in the 

 northern herd, with the last two occurring in 1989 and 1997. Winterkills of such magnitude do not occur 

 in other Montana elk populations, even in severe winters. Yellowstone elk are predisposed to higher 

 winter mortality due to harsher winter conditions, an older age structure in the population, high elk 

 densities, and lack of an agricultural forage base to fall back on during hard winters. 



Historically, northern range elk counts do not exhibit clear, long term trends. The northern herd has been 

 surveyed from the air since 1967. Beginning in more recent years, two surveys are conducted - one in 

 December and one in the spring. The purpose of the December survey is determine overall population 

 trends by counting total elk numbers, using four fixed-wing aircraft simultaneously. These surveys yield 

 trend information and are flown at the same time each year, regardless of counting conditions so that the 

 count itself becomes an index to reflect changes in the elk population over time. The total count in 

 December 2002 was 9,215 elk, with approximately 75% of the herd inside YNP. The previous count in 

 December 2001 was 1 1,969, compared to a long temi average of 13,846 elk from 1968-2002 (Table 9) 

 (FWP 2002). Poor counting conditions likely contributed to an under count of the actual number of elk in 

 the northern Yellowstone population for the 2002 count. Lack of snow cover, the wide distribution of elk 

 at higher elevations, and difficulty in detecting elk were noted by observers. In previous instances of poor 

 counting conditions, the previous or the following year's trend estimate were more consistent with long 

 term averages. However, biologists concluded that the December 2002 data suggest that elk abundance 

 has decreased since 1988 (Northern Yellowstone Cooperative Wildlife Working Group, 2003). Factors 

 contributing to the decrease likely include predation, drought-related effects on pregnancy and calf 

 survival, periodic substantial winterkill owing to severe snow pack, and human harvest during the 

 Gardiner area late hunt. The second survey is flown in the spring (usually March) to determine how 

 many elk wintered north of YNP and Dome Mountain and to classify the elk population to obtain an 

 estimate of calf recruitment, expressed as the number of calves observed for every 100 cows (calf:cow 

 ratio) (Table 9). 



The northern herd demon.strates the natural ability to recover from periodic population declines. The 

 mo.st significant recovery started in 1968, following the end of deliberate elk reductions inside YNP and 

 the end of largely unregulated elk hunting. The population increased from about 3,200 elk to over 12,000 

 just eight years later. Elk numbers have since recovered from major winterkills within five to six years. 

 Wolves, however, are a new and significant source of mortality that will reduce total elk numbers. The 

 exact extent of those overall population reductions, how wolf predation affects population growth rates, 

 and the variation from year to year is unknown. FWP is concerned that during severe winters, more elk 

 will be vulnerable to predation, and the combination of winterkill and predation could be significant. 



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