Model of Transient Changes in Arctic and Boreal Vegetation in Response to Climate and Land Use Change

One of the greatest challenges in global-change research is to predict the future distribution of vegetation. Most models of vegetation change predict either the response of a patch of present vegetation to climatic change or the future equilibrium distribution of vegetation based on the present relationship between climate and vegetation. Here we present a model that is, to our knowledge, the first model of ecosystem change in response to transient changes in climate, disturbance regime, and recruitment over the next 50-500 yr. The frame-based model uses quantitative and qualitative variables to de- velop scenarios of vegetation change from arctic tundra to boreal forest in response to global changes in climate (as predicted by general circulation models (GCMs)), fire, and land use. Seed availability, tree growth rate, and probability of fire were the model param- eters that most strongly influenced the balance between tundra and boreal forest in tran- sitional climates. The rate of climatic warming strongly affected the time lag between the onset of climate change and the simulated ecosystem response but had relatively little effect on the rate or pattern of ecosystem change. The model calculated that, with a gradual ramped change of 3?C in the next century (corresponding to average rate of warming predicted by GCMs), any change from tundra to forest would take 150 yr, consistent with pollen records. The model suggested that tundra would first be invaded by conifer forests, but that the proportion of broad-leaved deciduous forest would increase, reflecting increased fire frequency, as climatic warming continued. The change in fire frequency was determined more strongly by climatically driven changes in vegetation than by direct climatic effects on fire probability. The pattern of climatic warming was more important than the rate of warming or change in precipitation in determining the rate of conversion from tundra to forest. Increased climatic variability promoted ecosystem change, particularly when oscil- lations were long relative to the time required for tree maturation. Management policies related to logging and moose-predator control affected vegetation as much or more than did changes in climate and must be included in future scenarios of global changes in ecosystem distribution. We suggest that frame-based models provide a critical link between patch and equilibrium models in predicting ecosystem change in response to transient changes in climate over the coming decades to centuries.

[1]  Luc Sirois,et al.  A Systems Analysis of the Global Boreal Forest: The transition between boreal forest and tundra , 1992 .

[2]  C. E. Van Wagner,et al.  Age-class distribution and the forest fire cycle , 1978 .

[3]  C. S. Holling Resilience of ecosystems: local surprise and global change. , 1985 .

[4]  Linda Selkregg Alaska regional profiles , 1974 .

[5]  Gordon B. Bonan,et al.  Carbon and nitrogen cycling in North American boreal forests. II. Biogeographic patterns , 1990 .

[6]  R. Wein Frequency and Characteristics of Arctic Tundra Fires , 1976 .

[7]  J. Kutzbach,et al.  Feedbacks between climate and boreal forests during the Holocene epoch , 1994, Nature.

[8]  M. B. Davis,et al.  Quaternary history and the stability of forest communities , 1981 .

[9]  Jeremy S. Fried,et al.  Predicting the impacts of global warming on wildland fire , 1992 .

[10]  Thomas M. Smith,et al.  The potential for application of individual-based simulation models for assessing the effects of global change , 1992 .

[11]  C. W. Thornthwaite,et al.  Instructions and tables for computing potential evapotranspiration and the water balance , 1955 .

[12]  G. Bonan Comparison of atmospheric carbon dioxide concentration and metabolic activity in Boreal Forest ecosystems , 1992 .

[13]  C. T. Dyrness,et al.  Fire in Taiga Communities of Interior Alaska , 1986 .

[14]  R. Wein,et al.  Changes in Arctic Eriophorum Tussock Communities Following Fire , 1973 .

[15]  C. Krebs,et al.  Can the Solar Cycle and Climate Synchronize the Snowshoe Hare Cycle in Canada? Evidence from Tree Rings and Ice Cores , 1993, The American Naturalist.

[16]  Barrie Maxwell,et al.  2 – Arctic Climate: Potential for Change under Global Warming , 1992 .

[17]  M. Rosenzweig Net Primary Productivity of Terrestrial Communities: Prediction from Climatological Data , 1968, The American Naturalist.

[18]  W. Cramer,et al.  A global biome model based on plant physiology and dominance, soil properties and climate , 1992 .

[19]  Daniel B. Botkin,et al.  Sensitivity of Cool-Temperate Forests and their Fossil Pollen Record to Rapid Temperature Change , 1985, Quaternary Research.

[20]  M. Edwards,et al.  A TUNDRA-STEPPE TRANSITION ON KATHUL MOUNTAIN, ALASKA, U.S.A. , 1989 .

[21]  Sakari Tuhkanen,et al.  Climatic parameters and indices in plant geography , 1980 .

[22]  R. L. Crocker,et al.  SOIL DEVELOPMENT IN RELATION TO VEGETATION AND SURFACE AGE AT GLACIER BAY, ALASKA* , 1955 .

[23]  F. Stuart Chapin,et al.  Carbon/nutrient balance of boreal plants in relation to vertebrate herbivory , 1983 .

[24]  S. Payette,et al.  Reconstruction of tree-line vegetation response to long-term climate change , 1989, Nature.

[25]  Gordon B. Bonan,et al.  Carbon and nitrogen cycling in North American boreal forests , 1990 .

[26]  B. Walker Is Succession a Viable Concept in African Savanna Ecosystems , 1981 .

[27]  W. Cramer,et al.  Assessing Impacts of Climate Change on Vegetation Using Climate Classification Systems , 1993 .

[28]  I. Noble,et al.  The Use of Vital Attributes to Predict Successional Changes in Plant Communities Subject to Recurrent Disturbances , 1980 .

[29]  S. Payette,et al.  Secular climate change in old-growth tree-line vegetation of northern Quebec , 1985, Nature.

[30]  R. F. Griggs The Edge of the Forest in Alaska and the Reasons for Its Position , 1934 .

[31]  R. Neilson Transient Ecotone Response to Climatic Change: Some Conceptual and Modelling Approaches. , 1993, Ecological applications : a publication of the Ecological Society of America.

[32]  R. Bryson Air Masses, Streamlines and the Boreal Forest , 1966 .

[33]  W. Mattson,et al.  The Role of Drought in Outbreaks of Plant-eating Insects , 1987 .

[34]  H. Shugart,et al.  The transient response of terrestrial carbon storage to a perturbed climate , 1993, Nature.

[35]  I. Fung,et al.  The sensitivity of terrestrial carbon storage to climate change , 1990, Nature.

[36]  James S. Clark,et al.  Effect of climate change on fire regimes in northwestern Minnesota , 1988, Nature.

[37]  J. A. Larsen The Vegetation of the Ennadai Lake Area, N.W.T.: Studies in Subarctic and Arctic Bioclimatology , 1965 .

[38]  W. Oechel,et al.  Effects of soil temperature on the carbon exchange of taiga seedlings. II. Photosynthesis, respiration, and conductance , 1983 .

[39]  W. Post,et al.  Linear regressions do not predict the transient responses of eastern north american forests to CO2-induced climate change , 1993 .

[40]  F. Woodward Climate and plant distribution , 1987 .

[41]  Elgene O. Box,et al.  Tasks for Vegetation Science I: Macroclimate and Plant Forms: An Introduction to Predictive Modeling in Phytogeography , 2011 .

[42]  Leslie A. Viereck,et al.  ELEMENT CYCLING IN TAIGA FORESTS : STATE-FACTOR CONTROL , 1991 .

[43]  J. Houghton,et al.  Climate change : the IPCC scientific assessment , 1990 .

[44]  C. Fastie,et al.  Causes and Ecosystem Consequences of Multiple Pathways of Primary Succession at Glacier Bay, Alaska , 1995 .

[45]  M. Flannigan,et al.  CLIMATE CHANGE AND WILDFIRE IN CANADA , 1991 .

[46]  S. Payette,et al.  White spruce expansion at the tree line and recent climatic change , 1985 .

[47]  F. Hu,et al.  Arctic Tundra Biodiversity: A Temporal Perspective from Late Quaternary Pollen Records , 1995 .

[48]  D. Cooper White Spruce above and Beyond Treeline in the Arrigetch Peaks Region, Brooks Range, Alaska , 1986 .

[49]  D. Hopkins,et al.  Paleoecology of Beringia. , 1984 .

[50]  G. Bonan,et al.  Effects of boreal forest vegetation on global climate , 1992, Nature.

[51]  N. Matveyeva,et al.  4 – Circumpolar Arctic Vegetation , 1992 .

[52]  R. Haugen Climate of Remote Areas in North-Central Alaska: 1975-1979 Summary, , 1982 .

[53]  Yosef Cohen,et al.  MOOSE BROWSING AND SOIL FERTILITY IN THE BOREAL FORESTS OF ISLE ROYALE NATIONAL PARK , 1993 .

[54]  I. Noble,et al.  A Model of the Responses of Ecotones to Climate Change. , 1993, Ecological applications : a publication of the Ecological Society of America.

[55]  V. Furyaev,et al.  A Systems Analysis of the Global Boreal Forest: A spatial model of long-term forest fire dynamics and its applications to forests in western Siberia , 1989 .

[56]  David A. MacLean,et al.  The Role of fire in northern circumpolar ecosystems , 1983 .

[57]  W. Cooper,et al.  The Recent Ecological History of Glacier Bay, Alaska: The Present Vegetation Cycle , 1923 .

[58]  J. Fox,et al.  Forest fires and the snowshoe hare-Canada lynx cycle , 2004, Oecologia.

[59]  Leslie A. Viereck,et al.  Forest Succession and Soil Development Adjacent to the Chena River in Interior Alaska , 1970, Arctic and Alpine Research.

[60]  L. C. Bliss,et al.  Reproductive Ecology of Picea Mariana (Mill.) BSP., at Tree Line Near Inuvik, Northwest Territories, Canada , 1980 .

[61]  D. C. West,et al.  Forest Succession Models , 1980 .

[62]  J. Smol,et al.  Rapid response of treeline vegetation and lakes to past climate warming , 1993, Nature.

[63]  Anthony M. Starfield,et al.  Qualitative, rule-based modeling , 1990 .

[64]  P. Vitousek,et al.  Biological invasions by exotic grasses, the grass/fire cycle, and global change , 1992 .

[65]  T. Sharik,et al.  A Systems Analysis of the Global Boreal Forest: The reproductive process in boreal forest trees , 1992 .

[66]  W. Post,et al.  Influence of climate, soil moisture, and succession on forest carbon and nitrogen cycles , 1986 .

[67]  J. Yarie,et al.  Forest fire cycles and life tables: a case study from interior Alaska , 1981 .