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

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THE NORTHERN RANGE 64 channels in these reaches, it would be necessary to re-establish the woody species, primarily willow." Rosgen attributed these "out of balance" situations to what he regarded as historical increases in elk numbers beyond what had existed in the park area prehistorically. Rosgen's interpretations appear to fall under the category described earlier in this report, under the WIllows discussion, of presuming a full understanding of how a particular setting "should" look. The Colorado streams he used for comparison and contrast (that is, the streams he believes northern range streams "should" resemble) are managed by humans to look a certain way. Rosgen concluded that changes in climate over the past century did not cause the changes he measured in Lamar River drainage, but did not introduce any climate data to support his position. He presented no riparian data to support his interpretations, which appear to have been based on undocumented assumptions about ungulate effects on this watershed. Rosgen also based his interpretations of current sediment conditions in the Lamar Valley on the elToneous conviction that "large herds of elk did not inhabit the greater Yellowstone ecosystem until the late l800s." As the present volume demonstrates, large herds of elk were in fact present in the park area prior to the late l800s. As the present volume also has explained, willow, elk, and willow thrived together in this setting in the late 1800s. This means that another explanation must be found for what Rosgen describes as the "dramatic conversion" of willows to grass communities along some Lamar Valley streams. CONCLUSIONS Soils normally erode in wildland settings, and often do so on a grand geological scale. The Yellowstone we see today is a relatively young landscape. Flowing water, wind, gravity, and other forces still carve the park's canyons, shift stream channels, and relocate soils. One look at the Grand Canyon of the Yellowstone River would convince most observers that this is true. As well, ungulates do move soil, and at times contribute to sediment loads in park streams. But even if there were no ungulates at all on the northern range, the rivers would become muddy, especially during the period of spring snowmelt, during high-intensity summer thunderstorms, and following fires when vegetative cover is reduced or eliminated. The sedimentation process is clearly geologically and climatically driven. Dire interpretations of erosion processes on the northern range, such as given by Rosgen (1993), are not yet persuasive because they so totally reject any factor being involved other than ungulates. RESEARCH RECOMMENDATIONS: EROSION AND SEDIMENTATION To date, studies of erosion and its role in northern range ecological and hydrological processes have concentrated on the grand scale of entire watersheds, starting on the highest, steepest, and most easily eroded slopes and working down the drainages to the dver valleys. Research has now resolved that most of the material that muddies park streams originates in steep and geologically unstable areas where the activities of ungulates are not a significant factor in movement of material. However, as Rosgen's study suggests, important questions remain, especially involving local conditions along park streams. As already explained, grazing increases percentage of bare ground exposed to erosive processes, and in other ways may dispose soils to higher rates of erosion than would occur without grazing; ungulates unquestionably contribute to erosion. As mentioned earlier, documented changes in willows and other riparian vegetation may affect stream processes, which in turn can have a variety of effects, including increased movement of sediment and erosion of stream banks and beds. Riparian areas occupy only a small percentage of the northern range, but ecologists have long recognized that riparian areas are disproportionately significant in the processes of large ecosystems because so much energy and activity is focused in or near them. There is a need for more information on the localized riparian areas associ-
ated with ungulate winter ranges. Though the amount of material potentially involved in erosion in these areas may be much smaller than that SOIL, EROSION, SEDIMENTS, AND WATERSHEDS 65 involved in the steep headwaters and other geologically unstable areas, winter range riparian erosion is an important topic for research emphasis.
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YELLOW"STONE'S NORTHERN RANGE COMPL
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Suggested citation: Yellowstone Nat
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c=J Northern Winter Range _ Boundar
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Aspen, willows, and biodiversity ..
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vii
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THE NORTHERN RANGE xii range criter
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THE NORTHERN RANGE 2 Figure 1.1. Ph
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THE NORTHERN RANGE tion. There was
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THE NORTHERN RANGE 6 Figure 1.6. Gr
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THE NORTHERN RANGE 8 Figure 1.8. El
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THE NORTHERN RANGE 10 unpopular or
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THE NORTHERN RANGE 12 earlier Yello
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Page 32 and 33: THE NORTHERN RANGE 16 Northern rang
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 48 and 49: THE NORTHERN RANGE 32 systems-range
Page 50 and 51: THE NORTHERN RANGE 34 indicates the
Page 52 and 53: THE NORTHERN RANGE 36 Data were gat
Page 54 and 55: THE NORTHERN RANGE 38 grazed and un
Page 56 and 57: THE NORTHERN RANGE showed that graz
Page 58 and 59: , ~ , • V , '. ~ ;' t ~ " ~ .' .~
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
Page 72 and 73: THE NORTHERN RANGE 56 to confirm an
Page 74: THE NORTHERN RANGE 58 RESEARCH RECO
Page 77 and 78: SOIL, EROSION, SEDIMENTS, AND WATER
Page 79: SOIL, EROSION, SEDIMENTS, AND WATER
Page 83 and 84: ELK POPULATION ISSUES IS YELLOWSTON
Page 85 and 86: ange grazing issue, Yellowstone man
Page 87 and 88: ELK POPULATION ISSUES 71 ... Other
Page 89 and 90: ELK POPULATION ISSUES 73 1996d), so
Page 91 and 92: ELK POPULATION ISSUES 75 the northe
Page 93 and 94: ELK POPULATION ISSUES 77 It has evo
Page 96 and 97: 4 , ~ 1 v " 'It , \ J~ ~""~ .:,~ ",
Page 98 and 99: THE NORTHERN RANGE 82 Competition t
Page 100 and 101: Figure 7.3. Bison winter range. Sin
Page 102 and 103: THE NORTHERN RANGE Figure 7.7. Envi
Page 104 and 105: THE NORTHERN RANGE 88 not aware of
Page 106 and 107: THE NORTHERN RANGE 90 tion size, an
Page 108 and 109: THE NORTHERN RANGE 92 activity (95
Page 110 and 111: THE NORTHERN RANGE 94 pursue the su
Page 112 and 113: THE NORTHERN RANGE 96 factors were
Page 114 and 115: THE NORTHERN RANGE Figure 7.13. Num
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Page 118 and 119: THE NORTHERN RANGE 102 complex set
Page 120 and 121: THE NORTHERN RANGE 104 practically
Page 122 and 123: THE NORTHERN RANGE 106 appear suppr
Page 124 and 125: AppendixA. Conferences, Meetings, a
Page 126 and 127: lJO Year Estimate Comment Source 19
Page 128 and 129: 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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