Research Methods in Ecology

Chapter I. the Foundation of Ecology

THE NEED OF A SYSTEM PAGE 1. The scope of ecology 1 2. Ecology and physiology 1 Historical Development 3. Geographical distribution 2 4. The plant formation 2 5. Plant succession 3 6. Ecological phytogeography 4 7. Experimental ecology 4 8. Ecology of the habitat 5 9. The evidence from historical development 6 Present Status of Ecology 10. The lack of special training 6 11. Descriptive ecology 7 12. The value of floristic 8 13. Reconnaissance and investigation 8 14. Resident investigation 9 15. The dangers of a restricted field 9 Applications of Ecology 16. The subjects touched by ecology 10 17. Physiology and pathology 11 18. Experimental evolution 11 19. Taxonomy 12 20. Forestry 14 21. Physiography 15 22. Soil physics 15 23. Zoogeography 15 24. Sociology 16

THE ESSENTIALS OF A SYSTEM

25. Cause and effect: habitat and plant 16 26. The place of function 17

Chapter Ii. the Habitat

CONCEPT AND ANALYSIS

27. Definition of the habitat 18 28. Factors 18 Classification of Factors 29. The nature of factors 19 30. The influence of factors 19 Determination of Factors 31. The need of exact measurement 20 32. The value of meteorological methods 20 33. Habitat determination 21 34. Determinable and efficient differences 21 Instrumentation 35. Methods 22 36. Method of simple instruments 22 37. Method of automatic instruments 23 38. Combined methods 23

CONSTRUCTION AND USE OF INSTRUMENTS

39. The selection of instruments 24 Water-content 40. Value of different instruments 25 Geotome methods 41. The geotome 25 42. Soil borers 26 43. Taking samples of soil 26 44. Weighing 27 45. Computation 28 46. Time and location of readings 28 47. Location of readings 29 48. Depth of samples 30 49. Check and control instruments 30 Physical and Physiological Water 50. The availability of soil water 30 51. Terms 31 52. Chresard determination under control 32 53. Chresard readings in the field 33 54. Chresard values of different soils 34 Records and Results 55. The field record 35 56. The permanent record 36 57. Sums and means 36 58. Curves 37 Humidity 59. Instruments 37 Psychrometers 60. Kinds 37 61. The sling psychrometer 38 62. Readings 39 63. Cog psychrometer 39 64. Construction and use 40 65. Hygrometers 40 Psychrographs 66. The Draper psychrograph 41 67. Placing the instrument 42 68. Regulating and operating the instrument 43 69. The weekly visit 44 Humidity Readings and Records 70. The time of readings 44 71. Place and height 45 72. Check instruments 45 73. Humidity tables 46 74. Sums, means, and curves 47 Conversion scale for temperatures 75. Records 48 Light 76. Methods 48 The Photometer 77. Construction 49 78. Filling the photometer 50 79. Making readings 50 80. The Dawson-Lander sun recorder 51 81. The selagraph 52 Standards 82. Use 53 83. Making a standard 53 84. Kinds of standards 54 Readings 85. Time 55 Chart for determining sun’s altitude 57 86. Table for determining apparent noon 58 87. Place 59 Table of intensity at various angles 60 Reflected and Absorbed Light 88. The fate of incident light 60 89. Methods of determination 61 90. Leaf and epidermis prints 62 Expression of Results 91. Light records 63 92. Light sums, means and curves 63 Temperature 93. 64 Thermometers 94. Air thermometers 64 95. Soil thermometers 64 96. Maximum-minimum thermometers 65 97. Radiation thermometers 67 98. Thermographs 67 Readings 99. Time 69 100. Place and height 70 Expression of Results 101. Temperature records 70 102. Temperature sums and means 70 103. Temperature curves 71 104. Plant temperatures 71 Precipitation 105. General relations 72 106. The rain gauge 73 107. Precipitation records 74 Wind 108. Value of readings 74 109. The anemometer 75 110. Records 76 Soil 111. Soil as a factor 76 112. The value of soil surveys 77 113. The origin of soils 77 114. The structure of soils 78 115. Mechanical analysis 79 116. Kinds of soils 79 117. The chemical nature of soils 80 Physiography 118. Factors 80 Altitude 119. Analysis into factors 81 120. The barometer 82 Slope 121. Concept 83 122. The clinometer 83 123. The trechometer 84 Exposure 124. Exposure 85 125. Surface 85 126. Record of physiographic factors 86 127. Topography 86 Biotic Factors 128. Influence and importance 86 129. Animals 87 130. Plants 87

METHODS OF HABITAT INVESTIGATION

131. 88 Method of Simple Instruments 132. Choice of stations 88 133. Time of readings 89 134. Details of the method 89 135. Records 91 Method of Ecograph Batteries 136. 92 Expression of Physical Factor Results 137. The form of results 94 Factor Records 138. 94 Factor Curves 139. Plotting 95 140. Kinds of curves 96 141. Combinations of curves 96 142. The amplitude of curves 98 Factor Means and Sums 143. 98

Chapter Iii. the Plant

STIMULUS AND RESPONSE

General Relations 144. The nature of stimuli 100 145. The kinds of stimuli 100 146. The nature of response 101 147. Adjustment and adaptation 102 148. The measurement of response 103 149. Plasticity and fixity 104 150. The law of extremes 105 151. The method of working hypotheses 106 Hydroharmose Adjustment 152. Water as a stimulus 107 153. The influence of other factors upon water 107 154. Response 108 155. The measurement of absorption 109 156. The quantitative relation of absorption and transpiration 111 157. Measurement of transpiration 113 158. Field methods 114 159. Expression of results 116 160. Coefficient of transpiration 117 Adaptation 161. Modifications due to water stimuli 118 162. Modifications due to a small water supply 118 163. The decrease of water loss 118 164. The increase of water supply 121 165. Modifications due to an excessive water supply 121 166. Plant types 122 167. Xerophytic types 122 168. Types of leaf xerophytes 123 169. Types of stem xerophytes 125 170. Bog plants 126 171. Hydrophytic types 127 Photoharmose Adjustment 172. Light as a stimulus 129 173. The reception of light stimuli 131 174. The response of the chloroplast 132 175. Aeration and translocation 134 176. The measurement of responses to light 135 Adaptation 177. Influence of chloroplasts upon form and structure 138 178. Form of leaves and stems 139 179. Modification of the epidermis 140 180. The differentiation of the chlorenchym 142 181. Types of leaves 144 182. Heliophytes and sciophytes 144

EXPERIMENTAL EVOLUTION

183. Scope 145 184. Fundamental lines of inquiry 146 185. Ancestral form and structure 146 186. Variation and mutation 147 187. Methods 149 Method of Natural Experiment 188. Selection of species 149 189. Determination of factors 151 190. Method of record 152 Method of Habitat Cultures 191. Scope and advantages 153 192. Methods 153 193. Transfer 154 194. Modification of the habitat 156 Method of Control Cultures 195. Scope and procedure 157 196. Water-content series 158 197. Light series 160

Chapter Iv. the Formation

METHODS OF INVESTIGATION AND RECORD

198. The need of exact methods 161 Quadrats 199. Uses 161 200. Possible objections 163 Kinds of Quadrats and Their Use 201. Size and kinds 164 202. Tapes and stakes 164 203. Locating quadrats 165 The List Quadrat 204. Description 165 205. Manner of use 166 206. Table of abundance 166 The Chart Quadrat 207. Description and use 167 208. The chart 168 209. Mapping 168 210. Factors and photographs 170 The Permanent Quadrat 211. Description and uses 170 212. Manner of use 172 The Denuded Quadrat 213. Description 173 214. Methods of denuding and recording 174 215. Physical factors 175 Aquatic Quadrats 216. Scope 175 Transects 217. The transect 176 The Line Transect 218. Description and method 176 219. The location and size 177 The Belt Transect 220. Details 178 The Permanent Transect 221. Advantages 179 222. Details 179 The Denuded Transect 223. 180 The Layer Transect 224. 180 Ecotone Charts 225. 181 The Migration Circle 226. Purpose 182 227. Location and method 182 228. The denuded circle 183 229. Photographs 183 Cartography 230. Value of cartographic methods 183 231. Standard scale 184 232. Color scheme 184 233. Formation and vegetation maps 185 234. Continental maps 187 Photography 235. 188 236. The camera and its accessories 188 237. The choice of a camera 190 238. The use of the camera 191 239. The sequence of details 192 240. The time of exposure 193 241. Developing 194 242. Finishing 195 Formation and Succession Herbaria 243. Concept and purpose 196 244. Details of collecting 197 245. Arrangement 197 246. Succession herbaria 198

DEVELOPMENT AND STRUCTURE

247. Vegetation an organism 199 248. Vegetation essentially dynamic 199 249. Functions and structures 199 Association 250. Concept 200 251. Causes 201 252. Aggregation 203 Kinds of Association 253. Categories 204 254. Stratum association 204 255. Ground association 205 256. Species guild association 206 257. Light association 206 258. Water-content association 208

THE DEVELOPMENT OF THE FORMATION

259. 210 Invasion 260. 210 Migration 261. 210 262. Mobility 211 263. Organs for dissemination 211 264. Contrivances for dissemination 212 265. Position of disseminules 214 266. Seed production 215 267. Agents of migration 216 268. The direction of migration 219 Ecesis 269. Concept 220 270. Germination of the seed 221 271. Adjustment to the habitat 223 Barriers 272. Concept 224 273. Physical barriers 225 274. Biological barriers 225 275. Influence of barriers 226 Endemism 276. Concept 227 277. Causes 228 278. Significance 228 Polyphylesis and Polygenesis 279. Concept 230 280. Proofs of polygenesis 231 281. Origin by polyphylesis 232 Kinds of Invasion 282. Continuous and intermittent invasion 234 283. Complete and partial invasion 235 284. Permanent and temporary invasion 235 Manner of Invasion 285. Entrance into the habitat 236 286. Influence of levels 238 Investigation of Invasion 287. 239 Succession 288. Concept 239 289. Kinds of succession 240 Primary Successions 290. 241 291. Succession through elevation 241 292. Succession through volcanic action 242 293. Weathering 243 294. Succession in residuary soils 243 295. Succession in colluvial soils 244 296. Succession in alluvial soils 245 297. Succession in aeolian soils 246 298. Succession in glacial soils 247 Secondary Successions 299. 247 300. Succession in eroded soils 247 301. Succession in flooded soils 248 302. Succession by subsidence 249 303. Succession in land slips 249 304. Succession in drained or dried soils 249 305. Succession by animal agency 250 306. Succession by human agency 250 307. Succession in burned areas 251 308. Succession in lumbered areas 252 309. Succession by cultivation 253 310. Succession by drainage 253 311. Succession by irrigation 253 312. Anomalous successions 254 313. Perfect and imperfect successions 254 314. Stabilization 255 Causes and Reactions 315. 256 316. Succession by preventing weathering 257 317. Succession by binding aeolian soils 258 318. Succession by reducing run-off and erosion 259 319. Succession by filling with silt and plant remains 260 320. Succession by enriching the soil 261 321. Succession by exhausting the soil 262 322. Succession by the accumulation of humus 263 323. Succession by modifying atmospheric factors 264 Laws of Succession 324. 264 Classification and Nomenclature 325. Basis 267 326. Nomenclature 267 327. Illustrations 270 Investigation of Succession 328. General rules 270 329. Method of alternating stages 271 330. The relict method 272

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