On the Ecology of Mountainous Forests in a Changing Climate: A ...

More documents

Recommendations

Info

158 Chapter 6 Finally, most climate scenarios give us an indication about what the change in a given weather variable will be by a certain point in the future. However, in most scenarios it is not known how this change will be realized. Most impact studies so far have assumed that climate changes linearly (Solomon 1986, Pastor & Post 1988, Kienast 1991); other authors have studied the response of forest models to an instantaneous climatic change, i.e. its step response (Fischlin et al. 1994, Bugmann & Fischlin 1994). Thus, there arises the question how sensitive the behaviour of forest gap models is to the assumptions on the nature of transient climatic change. 6.2.1 Material & methods Forest models Five forest gap models are used in this study: The first model, FORECE (Kienast 1987), is a conventional gap model that was analyzed in detail in chapter 2. The second model, FORCLIM 1.1 (Bugmann & Fischlin 1994), is a simplified descendant of FORECE and comprises only the most fundamental ecological processes (cf. section 2.3.1); the formulation of climatic factors in FORCLIM 1.1 is done in the same way as in FORECE. The third model, FORCLIM 1.3 (Bugmann & Fischlin 1994), was developed from FORCLIM 1.1 by altering the mathematical formulations of the climatic factors (cf. section 2.3.2 and Fischlin et al. 1994). The fourth model, FORCLIM-E/P, is one variant of the model developed in chapter 3; it differs from FORCLIM 1.3 concerning the formulation of ecological factors and of climatic influences. The last model is FORCLIM-E/P/S, which incorporates also belowground carbon and nitrogen turnover (chapter 3). Study sites and steady state climate scenarios Six sites were selected along a climatological and at the same time altitudinal gradient, ranging from above the current alpine timberline to central alpine valleys close to the dry timberline. In a previous study of possible impacts of climatic change on forests, Kienast (1991) presented simulation results from the sites St. Gotthard, Airolo, and Sion along with results from 15 other sites. To allow for a comparison of the results from the Kienast (1991) study with the ones obtained here, these three sites will be used as well. Gyalistras et al. (1994) developed a methodology to relate large-scale temperature and pressure anomalies to local weather anomalies by means of principal component analysis and canonical correlation analysis (“Downscaling”). Based on the results obtained by this technique for the sites Bever, Davos, and Bern, Bugmann & Fischlin (1994) performed
Model applications 159 simulation studies with the FORECE, FORCLIM 1.1, and FORCLIM 1.3 models. Thus, these three sites are included in the present study as well. Moreover, a slight modification was applied to the climatic data from the site St. Gotthard: Under current climatic conditions (SMA 1901-1970), FORCLIM simulates the existence of forests at an elevation of 2090 m, which appears to be realistic (e.g. Renner 1982). To obtain a site above timberline, i.e. at an elevation about 100 m higher than the climate station St. Gotthard, its temperature was lowered by 0.7 °C throughout the year, resulting in the site Gotthard II, where FORCLIM simulates no forest under current climate. Tab. 6.2: Scenarios of climatic change for the year 2100 according to various sources. All changes are relative to current climate. The “IPCC” scenario is based on the “Business–As–Usual” scenario A of fossil fuel emissions. The “Kienast” scenario is based on steady-state 2xCO 2 GCM runs. The “Regionalized” scenarios are based on the downscaled trends from an uncorrected 100-year (1986-2085) transient run of the ECHAM GCM for the IPCC “Business–As–Usual” scenario A (Cubasch et al. 1992). Bold face denotes the scenarios used in the present study. Precipitation changes are given as percentages or as centimeters per month (cm/mo). The standard deviations of T and P were assumed not to change. Scenario T Summer P Summer T Winter P Winter Ref. IPCC, 2030 (global) +1.5 °C + a few % +1.5 °C + a few % 1 IPCC, 2030 (C. Europe) +2.5 °C -15% +1.5 °C – 1 IPCC, 2100 (global) +3.7 °C – +3.7 °C – 1 IPCC, 2100 (C. Europe) +4.7 °C – +3.7 °C – 1 Kienast +3.0 °C +10% +3.5 °C +10% 2 Regionalized, Bern +2.64 °C +3.98 cm/mo +3.76 °C +3.13 cm/mo 3 Regionalized, Davos +3.28 °C +0.91 cm/mo +3.00 °C +2.14 cm/mo 3 Regionalized, Bever +4.16 °C +3.82 cm/mo +1.48 °C +2.54 cm/mo 3 1 Houghton et al. (1990), Fischlin et al. (1994) 2 Mitchell (1983), Mitchell & Lupton (1984), Wigley & Jones (1988), Kienast (1991) 3 Gyalistras et al. (1994), Bugmann & Fischlin (1994) The scenarios of future climatic change stem from three sources (Tab. 6.2). First, a scenario was developed based on the report of the Intergovernmental Panel on Climate Change (IPCC, Houghton et al. 1990). This scenario was extrapolated from the difference between the regional scenario for central and southern Europe and the global average scenario for the year 2030 (Tab. 6.2). Second, a scenario similar to the one used by Kienast (1991) was adapted; the only difference is that Kienast (1991) applied the changes projected for the winter months to the climatic parameters of December through February, whereas in the present study these changes are used to modify the climatic parameters of the six “winter” months October through March in accordance with IPCC
Page 1:
Diss. ETH No. 10638 On the Ecology
Page 4 and 5:
ii Table of contents A BSTRACT.....
Page 6 and 7:
iv APPENDIX .......................
Page 8 and 9:
vi Harald BUGMANN, 1994: On the eco
Page 10 and 11:
viii Harald BUGMANN, 1994: Aspekte
Page 13 and 14:
1 1 . Introduction 1.1 Climatic cha
Page 15 and 16:
Introduction 3 1.2 Methods for the
Page 17 and 18:
Introduction 5 in a changing climat
Page 19 and 20:
Introduction 7 Their integrative ca
Page 21 and 22:
Introduction 9 (1984) provides a mo
Page 23 and 24:
Introduction 11 The main advantage
Page 25 and 26:
13 2 . Analysis of existing forest
Page 27 and 28:
Analysis of existing forest gap mod
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
The forest model FORCLIM 45 carbon
Page 41 and 42:
The forest model FORCLIM 47 TREE GR
Page 43 and 44:
The forest model FORCLIM 49 gBFlag
Page 45 and 46:
The forest model FORCLIM 51 Disturb
Page 47 and 48:
The forest model FORCLIM 53 decay o
Page 49 and 50:
The forest model FORCLIM 55 the est
Page 51 and 52:
The forest model FORCLIM 57 3.3 Mod
Page 53 and 54:
The forest model FORCLIM 59 Light a
Page 55 and 56:
The forest model FORCLIM 61 Overall
Page 57 and 58:
The forest model FORCLIM 63 D (cm)
Page 59 and 60:
The forest model FORCLIM 65 a) b) c
Page 61 and 62:
The forest model FORCLIM 67 Growth
Page 63 and 64:
The forest model FORCLIM 69 Stress-
Page 65 and 66:
The forest model FORCLIM 71 Tab. 3.
Page 67 and 68:
The forest model FORCLIM 73 3.3.2 F
Page 69 and 70:
The forest model FORCLIM 75 where k
Page 71 and 72:
The forest model FORCLIM 77 NITROGE
Page 73 and 74:
The forest model FORCLIM 79 peratur
Page 75 and 76:
The forest model FORCLIM 81 of degr
Page 77 and 78:
The forest model FORCLIM 83 microcl
Page 79 and 80:
The forest model FORCLIM 85 Tab. 3.
Page 81 and 82:
The forest model FORCLIM 87 3.4.3 F
Page 83 and 84:
The forest model FORCLIM 89 All the
Page 85 and 86:
The forest model FORCLIM 91 The mas
Page 87 and 88:
The forest model FORCLIM 93 FORCLIM
Page 89 and 90:
Behaviour of FORCLIM along a transe
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102: Behaviour of FORCLIM along a transe
Page 115 and 116: Parameter sensitivity & model valid
Page 147 and 148: 153 6 . Model applications Climatic
Page 149 and 150: Model applications 155 The simulate
Page 151: Model applications 157 6.2 Possible
Page 155 and 156: Model applications 161 Simulation e
Page 157 and 158: Model applications 163 At the site
Page 159 and 160: Model applications 165 Bever Biomas
Page 161 and 162: Model applications 167 tainty inher
Page 163 and 164: Model applications 169 scenario cho
Page 165 and 166: Discussion 171 Finally, the analysi
Page 167 and 168: Discussion 173 bitrarily chosen par
Page 169 and 170: Discussion 175 comparably small imp
Page 171 and 172: Discussion 177 end of the 21st cent
Page 173 and 174: Conclusions 179 Ecological factors
Page 175 and 176: Conclusions 181 species composition
Page 177 and 178: References 183 Begon, M., Harper, J
Page 179 and 180: References 185 Burger, H., 1951. Ho
Page 181 and 182: References 187 Faber, P.J., 1991. A
Page 183 and 184: References 189 Huntley, B. & Birks,
Page 185 and 186: References 191 Leemans, R. & Prenti
Page 187 and 188: References 193 Olson, J.S., 1963. E
Page 189 and 190: References 195 Rudloff, W., 1981. W
Page 191 and 192: References 197 Smith, T.M., Leemans
Page 193 and 194: References 199 Whittaker, R.H., 195
Page 195 and 196: Appendix 201 II. Derivation of para
Page 197 and 198: Appendix 203 Tab. A-4: Tree species
Page 199 and 200: Appendix 205 Tab. A-7: Values for m
Page 201 and 202: Appendix 207 The minimum winter tem
Page 203 and 204:
Appendix 209 Tab. A-11: Shade toler
Page 205 and 206:
Appendix 211 Tab. A-14: Climatic pa
Page 207 and 208:
Appendix 213 IV. Source code of the
Page 209 and 210:
Appendix 215 FROM SimBase IMPORT De
Page 211 and 212:
Appendix 217 END; (* IF *) prevDay
Page 213 and 214:
Appendix 219 PROCEDURE InitializeFW
Page 215 and 216:
Appendix 221 InstallSeparator( fMen
Page 217 and 218:
Appendix 223 FROM FCPFileIO IMPORT
Page 219 and 220:
Appendix 225 modelSp^.p.kHm := sens
Page 221 and 222:
Appendix 227 DeclMV( meanLitt[leafS
Page 223 and 224:
Appendix 229 Swiss Federal Institut
Page 225 and 226:
Appendix 231 (*********************
Page 227 and 228:
Appendix 233 BEGIN WITH sp^ DO d :=
Page 229 and 230:
Appendix 235 Definition module FCPB
Page 231 and 232:
Appendix 237 Purpose Simulation mod
Page 233 and 234:
Appendix 239 END Immobilization; PR
Page 235 and 236:
Appendix 241 CONST lem = 3; VAR ef:
Page 237 and 238:
Appendix 243 Purpose Provides the b
Page 239 and 240:
Appendix 245 Example of a text file
Page 241 and 242:
Appendix 247 Tab. A-15: Lower end o
Page 243 and 244:
Appendix 249 Tab. A-17: Percentage
Page 245 and 246:
Appendix 251 Tab. A-19: Significant
Page 247 and 248:
Appendix 253 VI. Derivation of para
Page 249 and 250:
Appendix 255 Tab. A-21: Species-spe
Page 251 and 252:
Appendix 257 Tab. A-22 (continued)
show all

On the Ecology of Mountainous Forests in a Changing Climate: A ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?