Integrated Experimental Ecology

In the first volume of this series (edited by D. E. REICHLE) an international panel of experts treated various aspects of ecosystems research, using deciduous forests of the temperate zone as an example. That collection of articles gave a general view of the extent of our present knowledge and established a conceptual framework for the analysis of an ecosystem. The present volume carries on from there, although it serves a different purpose. It is a report on their methods and their experiences by the members of a research group working as a team. Under the direction of Prof. ELLENBERG, one of the pilot projects of the Inter­ national Biological Program has been begun in the Solling, a forest and grassland area near Gottingen, West Germany. Here scientists representing a variety of disciplines - meteorology, soil science, hydrology, botany, zoology, microbiology, agriculture and forestry - got together to ascertain the practical possibilities of the analysis of ecosystems. The research, which began in 1966, is still going on. Nevertheless, there are good reasons for making a report on experience so far.

Introductory Survey.- I. Ecology and the International Biological Program.- 1. The Biological Basis of Productivity.- 2. Research in Terrestrial Biological Communities.- II. Structure and Functioning of Ecosystems.- 1. General Scope.- 2. Primary Producers.- 3. Secondary Producers: Consumers and Predators.- 4. Decomposers.- 5. Mineral Cycling.- 6. Water Cycling.- 7. Energy Flow.- III. Organization of the Integrated Research.- 1. Cooperative Work.- 2. Synthesis of Results.- IV. The Research Area and the Experimental Plots.- 1. The Solling Region.- 2. The Individual Sample Areas.- a) Beech Forest Plots (B1, B3 and 4).- b) Spruce Forest Plots (F1–3).- c) Grassland Areas (W1 and 2).- d) Arable Fields (A1 and 2).- References.- 1: Primary Production.- A. Measurement of CO2 Gas-Exchange and Transpiration in the Beech (Fagus silvatica L.).- I. Introduction.- II. Measuring Techniques.- 1. Measurement of CO2 Gas-Exchange and Transpiration.- a) Plant Chamber and Transpiration Measurement.- b) CO2 Gas-Exchange.- c) Discussion of the Gas-Exchange Measurements.- 2. Measurement of Leaf Temperature and Meteorological Data.- a) Air Temperature.- b) Air Humidity.- c) Absolute Light Intensity.- d) Leaf Temperature.- e) Water Vapour Gradient and Total Diffusion Resistance.- III. Analysis of the Measurements.- References.- B. Estimation of Photosynthetically Active Leaf Area in Forests.- I. Methods for Beech Leaves.- II. Preliminary Results.- III. Methods for Spruce Needles.- References.- C. Phenological Observations on Beech and Spruce as a Function of Climate.- I. Methods.- II. Phenological Phases Observed in 1967.- III. Phenological Behaviour as a Function of Temperature and Rainfall.- D. Structure and Timber Production of the Forest Stands. ― Report on the Methods Used and Some Results.- I. Introduction.- II. Standing Crop and Yield.- 1. Selection of Sample Plots.- 2. Stand Inventory.- 3. Computation of the Results.- 4. Comparison of Yield Values with Yield Table.- 5. Results of the First Forest Inventory in Spring 1967.- III. Structure and Quality of the Stands.- 1. Method.- 2. Result of the Survey of the Beech Stand B 1.- 3. Stem and Crown Distribution.- a) Special Method.- b) Stem and Crown Distribution of Plot B 1.- IV. Timber Increment.- 1. Method of Increment Research.- 2. Stand Increment of the Larger Experimental Plots.- References.- E. Estimation of Biomass of Forests.- I. Introduction.- II. Leaves etc.- III. Stem and Branches.- IV. Roots.- References.- F. Distribution of Root Tips and Tender Roots of Beech.- I. Methods.- II. Results and Discussion.- 1. Number of Root Tips per 100 ml of Soil.- 2. Biomass of Finest, Fine and Small Roots.- References.- G. The Primary Production of the Ground Vegetation of the Luzulo-Fagetum.- I. Introduction.- II. Method.- III. Some Results.- Reference.- H. Chemical Composition of Plants of the Field Layer. ― Preliminary Report.- I. Introduction.- II. Plant Composition.- 1. Methods.- 2. Some Results and Discussion.- III. Biomass and Chemical Compounds per Area.- 1. Methods.- 2. Some Results and Discussion.- References.- I. Primary Production of a Meadow (Trisetetum flavescentis hercynicum) with Different Fertilizer Treatments. ― Preliminary Report.- I. Introduction.- II. Methods.- 1. Determination of the Changes in the Composition of Species Caused by Fertilizing.- 2. Measurement of the Agriculturally Utilisable Production.- 3. Investigation of the Dynamics of Increment and Losses.- 4. Above-Ground Matter.- 5. Underground Matter.- 6. Determination of the Constituent Substances.- 7. Investigation of the Root Activity.- 8. Observation of the Root Systems.- III. Some Results.- 1. Changes in the Species Composition Caused by Fertilizing.- 2. The Utilizable Production.- 3. The Dynamics of Increment and Losses.- a) Above-Ground Matter.- b) Organic Matter Below Ground.- 4. The Constituent Substances.- 5. Root Activity.- IV. Further Investigations Proposed.- References.- J. Green Area Indices of Grassland Communities and Agricultural Crops under Different Fertilizing Conditions.- I. Introduction.- II. Methods.- III. Some Results.- 1. Grassland Communities.- 2. Agricultural Crops.- IV. Weight/Surface Ratio.- V. Comparison and Discussion of the Reported Data.- Reference.- K. Methodological Studies to Distinguish Functional from Non-functional Roots of Grassland Plants.- I. Introduction.- II. Material and Methods.- 1. Partial Chemical Characterisation of Cell-Wall Substances.- 2. Quantitative Determination of the Dehydrogenase Activity of Roots at Different Stages of Growth.- 3. Labelling with Carbon-14.- III. Some Results and Discussion.- References.- L. Determination of Energy Values.- I. Introduction.- II. Methods.- 1. Preparation of the Samples.- 2. Determination of Energy Value.- III. Some Results.- 1. Energy Values of Different Plants.- 2. Seasonal Variations.- 3. Influence of Different Fertilizer Treatment.- IV. Discussion.- References.- 2: Secondary Production.- M. Food and Energy Turnover of Leaf-eating Insects and their Influence on Primary Production.- I. Introduction.- II. Food and Energy Turnover.- III. Species Used for Productivity Studies.- IV. Methods of Measuring Population Density.- 1. Evaluation of Number of Viable Eggs Laid.- 2. Sampling from a Unit of Soil.- 3. Sampling Animals during Emergence.- a) Photo-Eclector of the Usual Shape and Function.- b) The Extraordinary Significance of Photo-Eclectors.- c) Photo-Eclectors for Larger Areas.- d) The Significance of Arboreal Photo-Eclectors in Population and Community Studies.- 4. Sampling in the Canopy Area in Respect of Fluctuations between Canopy and Ground Levels.- a) Census of Animals on Foliage Samples.- b) Census of Animals in Shaking Samples.- c) Calculation of Population Density in Old Beech Stands.- V. Preliminary Results in the Study of Production and Energy Turnover.- 1. Production of Imagines.- 2. Cost of Maintenance in Imagines.- VI. The Influence of Leaf-eating Insects on Primary Production.- References.- N. Studies in the Productivity of Lepidoptera Populations.- I. Introduction.- II. Methods.- 1. Population Dynamics.- a) Abundance of Eggs.- b) Abundance of Caterpillars.- c) Abundance of Pupae.- d) Abundance of Imagines.- 2. Food and Energy Turnover.- a) Determination of Production.- b) Determination of Respiration.- c) Determination of Assimilation.- III. Some Results.- References.- O. Food and Energy Turnover of Phytophagous and Predatory Arthropods ― Methods Used to Study Energy Flow.- I. Introduction.- II. Production.- III. Respiration.- 1. Phytophagous Insects (Funke).- a) Animals Used for Measurements.- b) Respiratory Flasks.- c) Experimental Conditions.- d) Duration of Measurements.- e) Repetition of Measurements.- f) Determination of Respiratory Loss in Leaf Miners.- 2. Zoophagous Arthropods on the Ground Layer (Weidemann).- a) Animals Used for the Measurements.- b) Experimental Temperature and Humidity.- c) Duration of Measurements.- d) Repetition of Measurements.- 3. Calculation of Population Oxygen Consumption.- 4. Computation of Population Energy Loss Due to Respiration.- IV. Assimilation.- 1. Phytophagous Insects (Funke).- 2. Predatory Arthropods of the Ground Layer (Weidemann).- a) Food.- b) Determination of Assimilated Food.- c) Determination of Food Quantity.- d) Evaluation of Assimilation (also for Phytophagous Insects).- References.- P. Food and Energy Turnover of Predatory Arthropods of the Soil Surface. ― Methods Used to Study Population Dynamics Standing Crop and Production.- I. Introduction.- II. Determination of Important Species in Relation to Productivity and Energy Flow.- III. Life Cycle and Population Dynamics.- 1. Phenology.- 2. Life Cycle.- 3. Population Dynamics.- a) Abundance of Eggs.- b) Abundance of Developmental Stages (Larvae) and Adults.- c) Abundance of Large Carabidae.- 4. Life Tables.- IV. Standing Crop.- V. Production.- 1. Total Production.- a) Production from Reproduction.- b) Production from Individual Growth.- 2. Minimum Production.- VI. Preliminary Results.- References.- Q. On the Abundance of Bacteria and Other Microorganisms.- I. Introduction.- II. Methods and Material.- 1. Sampling of the Soil.- 2. Preparing the Soil Suspensions for the Plate Counts.- 3. Solid Media Used for the Plate Counts.- a) Soil Extract Glucose Agar.- b) Malt Extract Agar.- c) Rose Bengal Malt Extract Agar.- 4. Liquid Media Used for Tube Counts.- a) Nitrite-and Nitrate-forming Bacteria.- b) N2-fixing Anaerobic Spore-forming Bacteria (Clostridia).- III. Preliminary Results.- References.- R. Microbial Transformation of Organic Material in the Soil.- I. Introduction.- II. Methods and Some Results.- 1. Cellulose.- 2. Lignin.- 3. Amino Acids.- 4. Enzymes.- 5. Tannins.- 6. Chlorophyll Content.- References.- 3: Environmental Conditions.- S. The Measurement of Climatic Elements which Determine Production in Various Plant Stands. ― Methods and Preliminary Results.- I. The Task.- II. The Measuring Stations.- 1. The Measuring Field on W 1.- 2. The Measuring Field on B 1.- 3. Other Measuring Fields.- III. Recording the Data.- IV. Type of Sensors.- V. Disposition of the Sensors.- VI. Methods of Determining the Components of the Heat Balance.- 1. The Sverdrup (Bowen) Method.- 2. Determination of Evapotranspiration by Brogmus’ Formula.- VII. Preliminary Results.- References.- T. The Characterization of the Woodland Light Climate.- I. Introduction.- II. Light Measurements.- 1. Integrating Measurements.- 2. Instantaneous Measurements.- 3. Mapping the Spatial Distribution of Diffuse Light.- III. Some Results.- 1. Instantaneous Measurements.- 2. Integrating Measurements.- 3. Maps of the Distribution of Diffuse Light.- IV. Discussion and Conclusions.- References.- U. Aspects of Soil Water Behavior as Related to Beech and Spruce Stands. ― Some Results of the Water Balance Investigations.- I. Introduction.- II. Climate, Geology and Soil.- III. Experimental Layout.- IV. Soil Water Tension.- 1. Changes in Tension with Time.- 2. Comment on Statistical Methods Used.- 3. Typical Tension Profiles.- V. Flow Rates ― a First Approximation.- References.- Va. Methods of Investigating Micromorphology of Humus.- I. Introduction.- II. Description in the Field.- III. Investigations by Stereomicroscope.- IV. Technique of Investigating Ground Thin Sections.- 1. Sampling and Preparation.- 2. Microscopic Techniques.- a) Morphometry.- b) Chemical Techniques.- c) Optical Techniques.- V. Cut Thin Section Study and Debris Preparation.- 1. Sampling and Preparation.- 2. Microscopic Techniques.- VI. Particle and Fabric Analysis.- 1. Particle Analysis.- 2. Fabric Analysis.- VII. Application of Humus Micromorphology.- References.- Vb. Methods Used in Micromorphological and Micromorphometric Soil Studies.- I. Introduction.- II. Freeze-Drying Methods.- References.- W. Soil Chemical Differences between Beech and Spruce Sites ― an Example of the Methods Used.- I. Introduction.- 1. General Framework.- 2. Research Area.- II. Soil Chemical Methods Used.- 1. Bioelement Stores.- a) Carbon and Nitrogen.- b) Phosphorus.- c) Cations.- d) Total Cation Exchange Capacity.- 2. Equilibrium Soil Solution and Schofield’s Potentials.- 3. Exchange and Solubility Equilibria.- III. Sampling Procedures and Statistical Treatment of Data.- IV. Analytical Errors and Sampling Effects for Bioelement Content in Mineral Soil.- V. Carbon and Nitrogen Stores and pH.- VI. Phosphate Stores.- VII. Mobilizable Cation Stores.- VIII. Equivalent Fractions of Exchangeable Cations.- IX. Cation Equivalent Fractions in Equilibrium Soil Solution.- X. Schofield’s Potentials in Equilibrium Soil Solution.- XL Gapon Coefficients.- XII. Discussion.- References.- X. Investigations of the Content and the Production of Mineral Nitrogen in Soils.- I. Introduction.- II. Methods.- 1. Determination of Net Mineralization.- 2. Treatment of Samples.- 3. Analysis.- 4. Determination of Water Content and Volume-Weight, or “Area-Weight”.- 5. Calculation of Nmin Content.- III. Some Results.- 1. Nmin Content of the Soil under Field Conditions.- a) Horizontal Distribution.- b) Vertical Distribution.- 2. Net Mineralization.- a) Significance of Differences between the Nmin Contents before and after 6 Weeks of Storage.- b) Vertical Distribution.- IV. Discussion.- 1. Methodological Consequences.- 2. Field Nmin Content.- 3. Net Mineralization.- V. Review of Further Results.- 1. Meadow Soils.- 2. Forest Soils.- References.- 4: Range of Validity of the Results.- Y. Phenological Comparisons of the Forest Research Area in the Soiling with Similar Forests in Other Mountain Ranges.- I. Introduction.- II. Methods.- 1. Interpretation of the Vegetative Phases in Spring and Early Summer.- a) General.- b) The Development Phases of Deciduous Trees.- c) Conifers.- d) Herbs and Grasses.- 2. Interpretation of the Generative Phases for All Categories of Plants.- 3. Observation of the Autumn Aspect.- III. Phenological Comparison of Solling with Other Regions.- IV. Comparison of Phenological Development with Photosynthetic Activity 207 References.- Z. Results of a Grassland Mapping in the High Soiling.- I. Grassland Communities Mapped.- II. Applicability Range of the Production Studies.- References.