Wolf, elk, and aspen food web relationships: Context and complexity

Forest Ecology and Management

Volumn 299, Issue , 2013, Pages 70-80

  Eisenberg, Cristina ^a   Seager, S Trent ^a   Hibbs, David E ^a  

^a OREGON STATE UNIVERSITY   (United States)

Author keywords

Fire; Trophic cascades; Ungulates

Indexed keywords

CONTRIBUTING FACTOR; ECOLOGICAL IMPACTS; ECOLOGICAL RELATIONSHIPS; INTEGRATED APPROACH; POPULUS TREMULOIDES; SCIENTIFIC FINDINGS; TROPHIC CASCADES; UNGULATES;

DROUGHT; FIRES; FORESTRY;

ECOSYSTEMS;

CANID; COMMUNITY STRUCTURE; DECIDUOUS TREE; FOOD WEB; HERBIVORY; LANDSCAPE; MAMMAL; OVERSTORY; PLANT-HERBIVORE INTERACTION; POPULATION DECLINE; PREDATOR-PREY INTERACTION; TROPHIC CONTROL; TROPHIC LEVEL;

DISEASES; DROUGHT; ECOLOGY; FOOD; FOREST FIRES; FORESTS; POPULUS TREMULOIDES;

CANIDAE; CANIS FAMILIARIS; CANIS LUPUS; CERVUS ELAPHUS; POPULUS; POPULUS TREMULOIDES; UNGULATA;

EID: 84878152181     PISSN: 03781127     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.foreco.2013.01.014     Document Type: Article

References (154)

1. Alverson W.S., Waller D.M., Solheim S.L. Forests too deer: edge effects in northern Wisconsin. Cons. Biol. 2003, 2:348-358.
2. Bailey J., Witham T.G. Interactions among fire, aspen, and elk affect insect diversity: reversal of a community response. Ecology 2002, 83:1701-1712.
3. Baker W.L., Munroe J.A., Hessl A.E. The effects of elk on aspen in the winter range in Rocky Mountain National Park. Ecography 1997, 20:155-165.
4. Baker B.W., ducharme H.C., Mitchell D.C.S., Stanley T.R., Peinetti H.R. Interaction of beaver and elk herbivory reduces standing crop of willow. Ecol. Appl. 2005, 15:110-118.
5. Barmore W.J. Ecology of Ungulates and their Winter Range in Northern Yellowstone National Park: Research and Synthesis 1962-1970 2003, National Park Service, Mammoth Hot Springs, WY, 524pp.
6. Barnett D.T., Stohlgren T.J. Aspen persistence near the national elk refuge and gros ventre valley elk feedgrounds of Wyoming, USA. Landsc. Ecol. 2001, 16:569-580.
7. Bartos D.J., Mueggler W.J. Early succession in aspen communities following fire in western Wyoming. J. Range Manage. 1981, 34:315-318.
8. Bass, R. 2005. Wolf Palette. Orion Magazine July/August.
9. Bassett J.R. Tree growth as affected by soil moisture availability. Soil Sci. Soc. Am. J. 1963, 28:436-438.
10. Belleau A., Brais S., pare D. Soil treatment dynamics after harvesting and slash treatments in boreal aspen stands. Soil. Sc. Soc. Am. J. 2006, 70:1189-1199.
11. Berger J., Stacey P.B., Bellis L., Johnson M.P. A mammalian predator-prey imbalance: grizzly bear and wolf extinction affect avian neotropical migrants. Ecol. Appl. 2001, 11:947-960.
12. Beschta R.L., Ripple W.J. Wolves, elk, and aspen in the winter range of Jasper National Park. Canada. Can. J. For. Res. 2007, 37:1-13.
13. Beschta R.L., Ripple W.J. Large predators and trophic cascades in terrestrial ecosystems of the western United States. Biol. Cons. 2009, 142:2401-2414.
14. Beyer, H., 2006. Wolves, elk, and willow on Yellowstone National Park's Northern Range. M.S. Thesis. University of Alberta, Edmonton.
15. Bilyeu D.M., Cooper D.J., Hobbs N.T. Water tables constrain height recovery of willows on Yellowstone's Northern Range. Ecol. Appl. 2008, 18:80-92.
16. Binkley D., Moore M.M., Binkley D., Moore M.M., Romme W.H., Brown P.M. Was Aldo Leopold right about the Kaibab deer herd?. Ecosystems 2006, 9:227-241.
17. Borer E.T., Seabloom E.W., Shurin J.B., Anderson K., Blanchette C.A., Broitman B., Cooper S.D., Halpern B. What determines the strength of a trophic cascade?. Ecology 2005, 86:528-537.
18. Brodie J., Post E., Watson F., Berger J. Climate change intensification of herbivore impacts on tree recruitment. Proc. R. Soc. B 2012, 279:1366-1370.
19. Brown J.S. Vigilance, patch use, and habitat selection: foraging under predation risk. Evol. Ecol. Res. 1999, 1:49-71.
20. Brown J.S., Kotler B.P. Hazardous duty pay and the foraging cost of predation. Ecol. Lett. 2004, 7:999-1014.
21. Brown J.S., Laundré W., Gurung M. The ecology of fear: optimal foraging game theory and trophic interactions. J. Mammal. 1999, 80:385-399.
22. Brown K., Hansen A.J., Keane R.E., Graumlich L.J. Complex interactions shaping aspen dynamics in the greater Yellowstone ecosystem. Landscape Ecol. 2006, 21:933-951.
23. Canon S.K., Urness P.J., DeByle N.V. Habitat selection, foraging behavior, and dietary nutrition of elk in burned aspen forest. J. Range Manage. 1987, 40:433-438.
24. Carpenter S.R., Kitchell J.F., Hodgson J.R. Cascading trophic interactions and lake productivity. Bioscience 1985, 35:634-639.
25. Caughley G. Eruption of ungulate populations, with emphasis on the Himalayan thar in New Zealand. Ecology 1970, 51:53-72.
26. Chen H.Y.H., Krestov P.V., Klinka A. Trembling aspen site index in relation to environmental measures of site quality at two spatial scales. Can. J. For. Res. 2002, 32:112-119.
27. Cook J.G. Nutrition and food. North American Elk: Ecology and Management 2002, 344-345. Smithsonian Institution Press, Washington, DC. D. Toweill, J.W. Thomas (Eds.).
28. Creel S., Christianson D. Wolf presence and increased willow consumption by Yellowstone elk: implications for trophic cascades. Ecology 2009, 90:2454-2466.
29. Creel S., Winnie J.A., Christianson D., Liley S. Time and space in general models of antipredator response: tests with wolves and elk. Anim. Behav. 2008, 76:1139-1146.
30. Crooks K.R., Soulé M.E. Mesopredator release and avifaunal extinctions in a fragmented system. Nature 1999, 400:563-566.
31. Darwin C. The Origin of Species 1859, The Modern Library, New York.
32. Dawes-Gromadski T.Z. Trophic trickles rather than cascades: conditional top-down and bottom-up dynamics in a chenopod Austral shrubland. Austral Ecol. 2002, 27:490-508.
33. DeByle, N.V., 1985. Wildlife. In: Debyle, N.F., Winokur, R.P. (Eds.). Aspen: Ecology and Management in the Western United States. RM-119. US Department of Agriculture, Forest Service, Ft. Collins, CO, pp. 125-155.
34. DeByle, N.V., Winokur, R.P., 1985. Aspen: ecology and management in the Western United States. General Technical Report RM-119. US Department of Agriculture, Forest Service, Ft. Collins, CO.
35. Eisenberg C. The Wolf's Tooth: Keystone Predators, Trophic Cascades, and Biodiversity 2010, Island Press, Washington, DC.
36. Eisenberg, C. 2012. Complexity of food webs in a large mammal system. Dissertation. Oregon State University, Corvallis, OR, 239pp.
37. Elton C.S. Animal Ecology 1926, University of Chicago Press, Chicago, IL.
38. Estes J.A., Tinker M.T., Bodkin J.L. Using ecological function to develop recovery criteria for depleted species: sea otters and kelp forests in the Aleutian archipelago. Conserv. Biol. 2010, 24:852-860.
39. Estes J.A., Terborgh J.A., Brashares J.S., Power M.E., Berger J., Bond W.J., Carpenter S.R., Essington T.E., Holt R.D., Jackson J.B.C., Marquis R.J., Oksanen L., Oksanen T., Paine R.T., Pikitich E.K., Ripple W.J., Sandin S.A., Scheffer M. Trophic downgrading of planet Earth. Science 2011, 33:301-306.
40. Ferrari M.C.O., Elvidge C.K., Jackson C.D., Chivers D.P., Brown G.E. The responses of prey fish to temporal variation in predation risk: sensory habituation or risk assessment?. Behav. Ecol 2010, 10.1093/beheco/arq023.
41. Fortin D., Beyer H., Boyce M.S., Smith D.W., Duchesne T., Mao J.S. Wolves influence elk movements: behavior shapes a trophic cascade in Yellowstone National Park. Ecology 2005, 86:1320-1330.
42. Franklin J.F., Spies T.A., Carey A.B., Thomburgh D.A., Berg D.R., Lindenmayer D.B., Harmon M.E., Keetone M.S., Shaw D.C., Bible K., Chen J. Disturbances and structural development of natural forest ecosystems with silvicultural implications, using Douglas-fir forests as an example. For. Ecol. Manage. 2002, 155:399-423.
43. Geist V. Adaptive behavioral strategies. North American elk: Ecology and Management 2002, 389-433. Smithsonian Institute Press, Washington, DC. D.E. Toweill, J.W. Thomas (Eds.).
44. Grace J.B. Structural Equation Modeling and Natural Systems 2006, Cambridge University Press, Cambridge, UK.
45. Hairston N.G., Smith F.E., Slobodkin L.B. Community structure, population control, and competition. Am. Nat. 1960, 94:421-425.
46. Halaj J., Wise D.H. Terrestrial trophic cascades: how much do they trickle?. Am. Nat. 2001, 57:262-281.
47. Halofsky J., Ripple W.J. Recoupling fire and aspen recruitment after wolf reintroduction in Yellowstone National Park, USA. For. Ecol. Manage. 2008, 256:1004-1008.
48. Hanna P., Kulakowski D. The influences of climate on aspen dieback. For. Ecol. Manage. 2012, 274:91-98.
49. Hebblewhite M., Pletscher D.H., Paquet P.C. Elk population dynamics in areas with and without predation by recolonizing wolves in Banff national Park. Can. J. Zool. 2002, 80:789-799.
50. Hebblewhite M., White C.A., Nietvelt C.G., McKenzie J.A., Hurd T.E., Fryxell J.M., Bayley S.E., Paquet P.C. Human activity mediates a trophic cascade caused by wolves. Ecology 2005, 86:2135-2144.
51. Hebblewhite M., Merrill E.H., McDonald T.L. Spatial decomposition of predation risk using resource selection functions: an example in a wolf-elk predator-prey system. Oikos 2005, 111:101-111.
52. Hessl A., Graumlich L. Interactive effects of human activities, herbivory and fire on quaking aspen (Populus tremuloides) age structures in western Wyoming. J. Biogeogr. 2002, 29:889-902.
53. Hobbs N.T., Baker D.L., Ellis J.E., Swift D.M. Composition and quality of elk winter diets in Colorado. J. Wildlife Manage. 1981, 45:156-171.
54. Hogg E.H., Brandt J.P., Michaelean M.E. Impacts of a regional drought on the productivity, dieback, and biomass of Western Canadian forests. Can. J. For. Res. 2008, 38:1373-1384.
55. Hollenbeck J., Ripple W.J. Aspen patch and migratory bird relationships in the Northern Yellowstone Ecosystem. Landsc. Ecol. 2008, 22:1411-1425.
56. Horsley S.B., Stout S.L., deCalesta D.S. White-tailed deer impact on the vegetation dynamics of a northern hardwood forest. Ecol. Appl. 2003, 13:98-118.
57. Houston D. The Northern Yellowstone Elk: Ecology and Management 1982, Macmillan Publishing, New York.
58. Hunter M.D., Price P.W. Playing chutes and ladders: heterogeneity and the relative roles of bottom-up and top-down forces in natural communities. Ecology 1992, 73:724-732.
59. Jacobi, W.R., Kelly, E.F., Troendle, C.A. Anqwin, P.A., Wettstein, C.A., 1998. Environmental conditions and aspen regeneration failure. USDA Forest Service. Tech. Rept. R1-60, 25pp.
60. Johnston, B.C., 2001. Multiple factors affect aspen regeneration on the Uncomphagre Plateau, West-Central Colorado. USDA Forest Service Proceedings RMRS-P18.
61. Johnston D.B., Cooper D.J., Hobbs N.T. Elk browsing decreases above-ground growth of water-stressed willows by modifying plant architecture. Oecologia 2007, 154:467-478.
62. Jones B.E., Rickman T.H., Vazquez A., Sado Y., Tate K.W. Removal of encroaching conifers to regenerate degraded aspen stands in the Sierra Nevada. Restor. Ecol. 2005, 13:372-379.
63. Kashian D.M., Romme W.H., Regan C.M. Recponciling diversgent interpretations of quaking aspen decline on the Northern Colorado Front range. Ecol. Appl. 2007, 17:1296-1311.
64. Kauffman M.J., Varley N., Smith D.W., Stahler D.R., MacNulty D.R., Boyce M.S. Landscape heterogeneity shapes predation in a newly restored predator-prey system. Ecol. Lett. 2007, 10:690-700.
65. Kauffman M., Brodie J.F., Jules E.S. Are wolves saving Yellowstone's aspen? A landscape-level test of a behaviorally mediated trophic cascade. Ecology 2010, 91:2742-2755.
66. Kay, C.E. 2001. Evaluation of burned aspen communities in Jackson Hole, Wyoming. USDA Forest Service Proceedings RMRS-P-18.
67. Kaye M. Medoscale synchrony in quaking aspen establishment across the interior western US. For. Ecol. Manage. 2011, 262:389-397.
68. Keigley, R.B., Frisina, M.R., 1998. Browse Evaluation by Analysis of Growth Form. Montana Fish Wildlife & Parks, Helena, MT.
69. Kimble D.S., Tyers D.B., Robison-Cox J., Sowell B.F. Aspen recovery since wolf reintroduction on the Northern Yellowstone Winter Range. Range. Ecol. and Manage. 2011, 64:119-130.
70. Kreibel D., tickner J., Epstein P., Lemons J., Levins R., Loechler E.L., Quinn M., Rudel R., Stoto M. The precautionary principle in environmental science. Environ. Health Perspect. 2001, 109:971-976.
71. Kulakowski D., Veblen T.T., Drinkwater S. The persistence of quaking aspen (Populus tremuloides) in the Grand Mesa area. Colorado. Ecol. Appl. 2004, 14:1603-1614.
72. Kulakowski D.T., Veblen T., Kurzel B.P. Influences of infrequent fire, elevation and pre-fire vegetation on the persistence of quaking aspen (Populus tremuloides) in the Flat Tops area, Colorado. J. Biogeogr. 2006, 33:1397-1413.
73. Lamalfa E.M., Ryel R.J. Differential snowpack accumulation and water dynamics in aspen and conifer communities: implications for water yield and ecosystem function. Ecosystems 2008, 11:569-581.
74. Larsen E.J., Ripple W.J. Aspen age structure in the northern Yellowstone ecosystem, USA. For. Ecol. Manage. 2003, 179:469-482.
75. Larsen E.J., Ripple W.J. Aspen stand conditions on elk winter ranges in the Northern Yellowstone Ecosystem, USA. Nat. Areas J. 2005, 25:326-338.
76. Laundré J.W., Hernandez L., Altendorf K.B. Wolves, elk, and bison: re-establishing the " landscape of fear" in Yellowstone National Park. Can. J. Zool. 2001, 79:1401-1409.
77. Lavigne, D.M. 1995. Ecological interactions between marine mammals, commercial fisheries, and their prey: Unraveling the tangled web. In: Proceedings of the Marine Birds and Mammals in Arctic Food Webs Symposium, Newfoundland, 1992. Canadian Wildlife Service, Environment Canada, Ottawa.
78. Leopold A. Deer irruptions. Wisc. Acad. Sci, Arts, Lett. 1943, 351-366.
79. Leopold A., 1949. A Sand County Almanac, and Sketches Here and There, Oxford University Press, Oxford.
80. Leopold A., Sowls L.K., Spencer D.L. A survey of over-populated deer ranges in the United States. J. Wildl. Manage. 1947, 11:162-183.
81. Lima S. Nonlethal effects in the ecology of predator-prey interactions. Bioscience 1998, 48:25-34.
82. Lima S.L., Dill L.M. Behavioral decisions made under the risk of predation: a review and prospectus. Can. J. Zool. 1990, 68:619-640.
83. Lindeman R. The trophic-dy aspect of ecology. Ecology 1942, 23:399-418.
84. Lindroth, R.L., St. Clair, S.B. 2013. Adaptations of quaking aspen (Populus tremuloides Michx.) for defense against herbivores, Forest Ecol. Manage. 299, 14-21.
85. Littell J.S., Peterson D.L., Joelker M.T. Douglas-fir growth in mountain ecosystems: water limits tree growth from stand to region. Ecol. Monogr. 2008, 78:349-368.
86. Lotka A.J. Relation between birth rates and death rates. Science 1907, 26:121-130.
87. Marshall, K.N., 2012. Wolves, elk, and willows: alternate states and transition thresholds on Yellowstone's Northern Range. Dissertation. Colorado State University, Fort Collins, CO.
88. McAnn K.S., Hastings A., Strong D.R. Trophic cascades and trophic trickles in pelagic food webs. Proc. R. Soc. London 1998, 265:205-209.
89. McLaren B.E., Peterson R.O. Wolves, moose, and tree rings on Isle Royale. Science 1994, 266:1555-1558.
90. Mech D. Is science in danger of sanctifying the wolf?. Biol. Conserv. 2012, 150:143-149.
91. Menge B.A. Top-down and bottom-up community regulation in marine rocky intertidal habitats. J. Exp. Mar. Biol. Ecol. 2005, 250:257-289.
92. Menge B.A., Sutherland J.P. Species diversity gradients: synthesis of the roles of predation, competition, and temporal heterogeneity. Am. Nat. 1976, 110:351-369.
93. Menge B., Berlow E.L., Blanchette C.A., Navarrete S.A., Yamada S.B. The keystone species concept: variation in interaction strength in a rocky intertidal habitat. Ecol. Mono. 1994, 64:249-296.
94. Mock K.E., Rowe C.A., Hooten M.B., Dewoody J., Hipkins V.D. Clonal dynamics in western North American aspen (Populus tremuloides). Mol. Ecol. 2008, 17:4827-4844.
95. Morelli, T.L., Carr, S.C., 2011. A review of the potential effects of climate change on quaking aspen (Populus tremuloides) in the Western United States and a new tool for surveying sudden aspen decline. Gen. Tech. Rep. PSW-GTR-235. US Department of Agriculture, Forest Service, Pacific Southwest Research Station, Albany, CA, 31p.
96. Mueggler W.F. Age distribution and reproduction of intermountain aspen stands. West. J. Appl. For. 1989, 4:41-45.
97. Murdoch W.W. " Community structure, population control, and competition" , -A critique. Am. Nat. 1966, 100:219-226.
98. Murie, O.J., 1926-1954. Unpublished field notes on elk and wolves. Olaus J. Murie Papers, Teton Science School Archives, Murie Museum, Jackson, WY.
99. Naiman R.J., Rogers K.H. Large animals and system-level characteristics in river corridors. Bioscience 1997, 47:521-529.
100. Navarrete S.A., Menge B. Keystone predation and interaction strength: interactive effects of predators on their main prey. Ecol. Monogr. 1996, 66:409-429.
101. Oaten D.K., Larsen K.W. Stand characteristics of three forest types within the dry interior forests of British Columbia, Canada: implications for biodiversity. For. Ecol. Manage. 2008, 256:114-120.
102. Oksanen L., Oksanen T. The logic and realism of the hypothesis of exploitation ecosystems. Am. Nat. 2000, 155:703-723.
103. Paine R.T. A note on trophic complexity and species diversity. Am. Nat. 1969, 103:91-93.
104. Paine R.T. Food webs: linkage, interaction strength and community infrastructure. J. Anim. Ecol. 1980, 49:667-685.
105. Painter L., Ripple W.J. Effects of bison on willow and cottonwood in northern Yellowstone National Park. For. Ecol. Manage. 2012, 264:150-158.
106. Polis G.A. Food webs, trophic cascades, and community structure. Austral Ecol. 1994, 19:121-136.
107. Polis G.A., Strong D.R. Food web complexity and community dynamics. Am. Nat. 1996, 147:813-846.
108. Power M.E. Effects of fish in river food webs. Science 1990, 250:811-814.
109. Power M.E. Top-down and bottom-up forces in food webs: do plants have primacy?. Ecology 1992, 73:733-746.
110. Reisner, M.D., 2010. Drivers of plant community dynamics in sagebrush steppe ecosystems: cattle grazing, heat and water stress. Doctoral dissertation. Oregon State University, Corvallis, OR.
111. Ripple W.J., Beschta R.L. Wolves and the ecology of fear: can predation risk structure ecosystems?. Bioscience 2004, 54:755-766.
112. Ripple W.J., Beschta R.L. Restoring Yellowstone's aspen with wolves. Biol. Conserv. 2007, 138:514-519.
113. Ripple W.J., Beschta R.L. Trophic Cascades in Yellowstone: the first 15 years after wolf reintroduction. Biol. Conserv. 2011, 145:205-213.
114. Ripple W.J., Larsen E.J. Historic aspen recruitment, elk, and wolves, in northern Yellowstone National Park, USA. Biol. Conserv. 2000, 95:361-370.
115. Ripple W.J., Larsen E.J., Renkin R.A., Smith D. Trophic cascades among wolves, elk, and aspen on Yellowstone National Park's Northern Range. Biol. Conserv. 2001, 102:227-234.
116. Ripple W.J., Rooney T.P., Beschta R.L. Large predators, deer, and trophic cascades in boreal and temperate ecosystems. Trophic Cascades: Predators, Prey, and the Changing Dynamics of Nature 2010, 141-161. Island Press, Washington, DC. J. Terborgh, J. Estes (Eds.).
117. Robbins J. Lessons from the wolf. Sci. Am. 2004, 29:84-91.
118. Rogers P. Using forest health monitoring to assess aspen forest cover change in the southern Rockies ecoregion. For. Ecol. Manage. 2002, 155:223-236.
119. Rogers, P.C., Landhäuser, S.M, Pino, B., Ryel, R.J., 2013. A functional framework for improved management of western North American aspen (Populus tremuloides Michx). For. Sci. (in press).
120. Romme W.H., Turner M.G., Wallace L.L., Walker J.S. Aspen, elk, and fire in the northern range of Yellowstone National Park. Ecology 1995, 76:2097-2106.
121. Romme, W.H., Floyd-Hanna, L, Hanna, D.D., Bartlett, E., 2001. Aspen's ecological role in the west. In: Shepperd, W.D., Binkley, D., Bartos, D.L., Stohlgren, T.J., Eskew, L.G. (Eds.), Sustaining Aspen in Western Landscapes: Symposium Proceedings; 13-15 June 2000, Grand Junction, CO. USDA Forest Service Proceedings RMRS-P-18, pp. 242-259.
122. Schmitz O.J., Beckerman A.P., O'Brien K.M. Behaviorally mediated trophic cascades: effects of predation risk on food web interactions. Ecology 1997, 78:1388-1399.
123. Schmitz O.J., Hamback P.A., Beckerman A.P. Trophic cascades in terrestrial systems: a review of the effects of carnivore removals on plants. Am. Nat. 2000, 155:141-153.
124. Schmitz O.J., Post E., Burns C.E., Johnston K.M. Ecosystem response to global climate change: moving beyond color mapping. Bioscience 2003, 53:1199-1205.
125. Schmitz O.J., Kalies E.L., Booth M.G. Alternative dynamic regimes and trophic control of plant succession. Ecosystems 2006, 9:659-672.
126. Seager, S.T., 2010. Quaking Aspen Persistence in Three Oregon Landscapes. M.S. Thesis. Oregon State University, Corvallis, OR.
127. Seager, S.T., Eisenberg, C., St. Clair, S., 2013. Patterns and consequences of ungulate herbivory on aspen in western North America. For. Ecol. Manage. 299, 81-90.
128. Shepperd, W.D., Binkley, D., Bartos, D.L., Stohlgren, T.J., Eskew, L.G. (Eds.), 2001a. Sustaining Aspen in Western Landscapes: Symposium Proceedings; 13-15 June 2000, Grand Junction, CO. USDA Forest Service Proceedings RMRS-P-18. Rocky Mountain Research Station, Grand Junction, CO.
129. Shepperd W.D., Bartos D.L., Mata S.A. Above- and below-ground effects of aspen clonal regeneration and succession to conifers. Can. J. For. Res. 2001, 31:739-745.
130. Sinclair A.R.E. Mammal population regulation, keystone processes, and ecosystem dynamics. Phil. Trans. R. Soc. London. 2003, 358:1729-1740.
131. Singer F.J. Habitat partitioning and wildfire relationships of cervids in Glacier National Park, Montana. J. Wildl. Manage. 1979, 43:437-444.
132. Singer, F.J. (Ed.), 1996. Effects of Grazing by Wild Ungulates in Yellowstone National Park. Technical Report NPS/NRYELL/NRTR/96-01. USDI NPS Natural Resource Program Center. Denver, CO, USA.
133. Smith A., Smith F.W. Twenty-year change in aspen dominance in pure aspen and mixed aspen/conifer stands on the Uncompahgre Plateau, Colorado, USA. For. Ecol. Manage. 2005, 213:338-348.
134. Smith D.W., Peterson R.O., Houston D.B. Yellowstone after wolves. Bioscience 2003, 53:330-340.
135. Smith E.A., O'Loughlin D., Buck J.R., St.Clair S.B. The influence of conifer succession, physiographic conditions, and herbivory on quaking aspen regeneration after fire. For. Ecol. Manage. 2011, 262:325-330.
136. Smith, D., Leader, YNP Wolf Project, 2012. Personal Communication in Mammoth, Wyoming, on September 19, 2012.
137. Soulé M.E., Estes J.A., Berger J., Martinez Del Rio C. Ecological effectiveness: conservation goals for interactive species. Conserv. Biol. 2003, 17:1238-1250.
138. Soulé M.E., Estes J.A., Miller B., Honnold D.L. Strongly interaction species: conservation policy, management, and ethics. Bioscience 2005, 55:168-176.
139. St.Clair S.B., Guyon J., Donadlson J. Quaking aspen's current and future status in Western North America: the role of succession, climate, biotic agents, and its clonal nature. Prog. Bot. 2010, 71:374-400.
140. Strong D. Are trophic cascades all wet? Differentiation and donor control in speciose systems. Ecology 1992, 73:745-754.
141. Swanson M.E., Franklin J.F., Beschta R.L., Crisafulli C.M., DellaSala D.A., Hutto R.L., Lindenmayer D.B., Swanson F.J. The forgotten stage of forest succession: early successional ecosystems on forest sites. Front. Ecol 2010, 10.1890/090157.
142. Taylor R.J. Predation 1984, Chapman and Hall, New York.
143. Terborgh J., Holt R.D., Estes J.A. Trophic cascades: what they are, how they work, and why they matter. Trophic Cascades: Predators, Prey, and the Changing Dynamics of Nature 2010, 1-18. Island Press, Washington, DC. J. Terborgh, J.A. Estes (Eds.).
144. Tortenson W.L.F., Mosley J.C., Brewer T.K., Tess M.W., Knights J.E. Elk, mule deer, and cattle foraging relationships in foothill and mountain rangeland. Rangeland Ecol. Manage. 2006, 59:80-87.
145. Van der Valk A.G. Forest Ecology: Recent Advances in Plant Ecology 2009, Springer, Netherlands.
146. Vavra, M., Wisdom, M.J., Kie, J.G., Cook, J.G., Riggs, R.A., 2005. The role of ungulate herbivory management on ecosystem patterns and processes: future directions of the Starkey Project. In: Wisdom, M.J., technical editor, The Starkey Project: A Synthesis of Long-Term Studies of Elk and Mule Deer. Reprinted from the 2004 Transactions of the North American Wildlife and natural Resources Conference, Alliance Communications group, Lawrence, KS, pp. 233-239.
147. Vucetich J.A., Smith D.W., Stahler D.R. Influence of climate, harvest, and wolf predation on Yellowstone elk, 1961-2004. Oikos 2005, 111:259-270.
148. White P.J., Garrott R.A. Yellowstone's ungulates after wolves; expectation, realizations, and predictions. Biol. Conserv. 2005, 125:141-152.
149. White C.A., Olmsted C.E., Kay C.E. Aspen, elk, and fire in the Rocky Mountain national parks of North America. Wildl. Soc. Bull. 1998, 26:449-462.
150. White C.A., Feller M.C., Bayley S. Predation risk and the functional response of elk-aspen herbivory. For. Ecol. Manage. 2003, 181:77-97.
151. White P.J., Proffit K.M., Lemke T.O. Changes in elk distribution and group sizes after wolf restoration. Am. Midl. Nat. 2012, 167:174-187.
152. Worrall J.J., Egeland L., Eager T., Mask R.A., Johnson E.W., Kemp P.A., Shepperd W.D. Rapid mortality of Populus tremuloides in southwestern Colorado, USA. For. Ecol. Manage. 2008, 255:686-696.
153. Worrall J.L., Marchetti S.B., Egeland L., Mask R.A., Eager T., Howell B. Effects and etiology of sudden aspen decline in southwestern Colorado, USA. For. Ecol. Manage. 2010, 260:638-648.
154. Worrall, J.J., Rehfeldt, G.E., Hamann, A., Hogg, E.H., Marchetti, S.B., Michaelian, M., Gray, L.K. 2013. Recent declines of Populus tremuloides in North America linked to climate. For. Ecol. Manage. 299, 35-51.