Yellowstone's Northern Range - Greater Yellowstone Science ...

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THE NORTHERN RANGE 16 Northern range researchers cannot begin to fully understand the current climate (or the climate of the last half of the last centmy) in Yellowstone without studying the prehistoric climate, which Pielou (1991) summarizes succinctly: The most distinctive climatic interval of the recent past is the Little Ice Age, which lasted from about 1350 to 1870 AD .... Glaciers and ice caps expanded, the ranges of tree species changed, and human beings adapted to the sudden cold that followed the Little Climatic Optimum. Many Rocky Mountain glaciers advanced between one and two kilometers, injuring trees in the process. Many of the trees scarred by ice are still alive .... Trees were also overridden and killed; broken stumps of some of them are now exposed where glacier snouts have receded again, in the climatic warming that began a little over 100 years ago. The only perennial ice yielded by the Little Ice Age was that which was added to preexisting glaciers and ice caps. Elsewhere, winters were colder, summers cooler, and precipitation greater. Ecosystems of all kinds were affected, including those with human beings as members. It is one of the confounding complications of understanding Yellowstone vegetation in historic times that the park was established just as the Little Ice Age was ending. The park landscape was emerging from the effects of the colder winters, cooler summers, and greater precipitation of the Little Ice Age just as the first scientific observers arrived. These observers saw, described, and photographed a Yellowstone that still looked like a Little Ice Age environment, but was about to change in response to a new climatic regime. Yellowstone's climate today is characterized by long, cold winters and short, cool summers. Total annual precipitation is greatest (about 70 inches annually) in the southwest corner of the park. Elsewhere, the park is mostly in a rain shadow and annual precipitation is lower and averages from 30 to 50 inches, depending on elevation. The north entrance at the park's lowest elevation (5,265 feet) is decidedly semiarid and only receives 10 to 12 inches of annual precipitation (Despain 1990). Most of the northern range, to a greater or lesser degree, falls in the semiarid category, which of course is what defines this landscape as ungulate winter range. Climate's influence on a landscape reaches far beyond the effects on individual plants and animals. Climate can cause great fluctuations in ground water levels and springhead outflows that can favor or discourage particular plant species (Figures 2.1, 2.3). Climate is also probably the foremost factor in a landscape's fire history. Evidence of fire history as reflected in sedimentation (due to postfire mudflows and other large movements of soil and other material) in northeastern Yellowstone National Park, along with studies of historic climate records, "imply that the intensity and interannual variability of summer precipitation are greater during warmer periods, enhancing the potential for severe short-term drought, major forest fires, and storm-generated fan deposition" (Figure 2.2) (Meyer et al. 1995). This and several other studies of that portion of the park should, incidentally, provide some reassurance to people who were concerned about mudslides having longterm disastrous effects following the fires of 1988; such debris flows have been typical postfire events for thousands of years here but have since revegetated and are rarely recognized as disastrous events (Balling et aI. 1992a, 1992b; Meyer et al. 1992,1995; Meyer 1993; Bingham 1994; O'Hara 1994). Rangeland climate is a function of temperature, moisture, and wind. Climatic variations from century to century, decade to decade, year to year, and even day to day, can have significant effects on the prosperity of a range and its animal inhabitants. The park's climate has undergone significant variations over the past 12,000 years since the end of the last ice age (Figure 2.2) (Hadly 1990, 1995; Engstrom et al. 1991, 1994, 1996; Whitlock et al. 1991, 1995; Whitlock 1993; Whitlock and Bartlein 1993; Barnosky 1994, 1996; Mullenders and
PREHISTORIC AND EARLY HISTORIC SETTING 17 Miller Well Figure 2.1. Decreasing grol/ndwater levels on the northem range, at the Miller Well (3 miles north of Gardiner, Montana), reveal the apparelll effects of the 1980s drought. Data courtesy of Irving Friedman, U.S. Geological SUJiJey, retired. September-77 September-SO September-83 October-86 October-S9 Year October-92 October-95 Probable fire-related sedimentation Figure 2.2. Calibrated calendaryear chronology of the variability of alluvial activity in northeastern Yellowstone National Parkfor 6,100 years before present. Note wetter and drier climate cycles as expressed by changing sagebrushgrass pollen ratios, Gnd by large variations in alluvial transport. Adapted with pemzission from Meyer et al. (1995).
Page 1: YELLOW"STONE'S NORTHERN RANGE COMPL
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Page 6 and 7: Suggested citation: Yellowstone Nat
Page 8 and 9: c=J Northern Winter Range _ Boundar
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Page 34 and 35: Figure 2.3. Sum ot rotal annual riv
Page 36 and 37: THE NORTHERN RANGE 20 Figure 2.4 Tr
Page 38 and 39: THE NORTHERN RANGE 22 dendrochronol
Page 40 and 41: THE NORTHERN RANGE 24 Figure 2.7. A
Page 42 and 43: THE NORTHERN RANGE 26 et al. (1991)
Page 44 and 45: THE NORTHERN RANGE 28 earlier time,
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Page 60 and 61: Figure 4.1. Northern range, showing
Page 62 and 63: Figure 4.2. Willow distribution in
Page 64 and 65: THE NORTHERN RANGE 48 Figure 4.4. I
Page 66 and 67: THE NORTHERN RANGE 50 public lands,
Page 68 and 69: THE NORTIlERN RANGE 52 Figure 4.5.
Page 70 and 71: THE NORTHERN RANGE 54 able uncertai
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Page 74: THE NORTHERN RANGE 58 RESEARCH RECO
Page 77 and 78: SOIL, EROSION, SEDIMENTS, AND WATER
Page 79 and 80: SOIL, EROSION, SEDIMENTS, AND WATER
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ELK POPULATION ISSUES IS YELLOWSTON
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ange grazing issue, Yellowstone man
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ELK POPULATION ISSUES 71 ... Other
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ELK POPULATION ISSUES 73 1996d), so
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ELK POPULATION ISSUES 75 the northe
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ELK POPULATION ISSUES 77 It has evo
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THE NORTHERN RANGE 82 Competition t
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Figure 7.3. Bison winter range. Sin
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THE NORTHERN RANGE Figure 7.7. Envi
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THE NORTHERN RANGE 88 not aware of
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THE NORTHERN RANGE 90 tion size, an
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THE NORTHERN RANGE 92 activity (95
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THE NORTHERN RANGE 94 pursue the su
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THE NORTHERN RANGE 96 factors were
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THE NORTHERN RANGE Figure 7.13. Num
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THE NORTHERN RANGE 102 complex set
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THE NORTHERN RANGE 104 practically
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THE NORTHERN RANGE 106 appear suppr
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AppendixA. Conferences, Meetings, a
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lJO Year Estimate Comment Source 19
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lJ2 , Estimated # of Elk Year Date
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lJ4 Winter Total Count 1967-68 397
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116 Year Date of Count Parkwide Par
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118 Counts and estimates of mule de
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120 Northern Yellowstone winter ran
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122 Population estimates and reduct
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124 Actual count Inside Outside Est
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Pronghorn counted during spring sur
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128 Year 1939 1940 1941 1942 1943 1
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Ground and aerial counts of bighorn
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REFERENCE LIST NOTES ON THIS REFERE
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Pages 199-210 in Carbyn, L.N., S.H.
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Yellowstone National Park. Technica
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mammal mortality in the 1988 Yellow
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National Park. International Journa
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Mehus, C.A. 1995. Influences ofbraw
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__ , and __ . 1996a. Preburn root b
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Pages 127-138 in F.J. Singer, ed. E
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some northern Yellowstone elk. M.S.
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I I I I I
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