Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Contents

 Summary 1

I. What is FACE? 2
II. Materials and methods 2
III. Photosynthetic carbon uptake 3
IV. Acclimation of photosynthesis 6
V. Growth, above-ground production and yield 8
VI. So, what have we learned? 10

 Acknowledgements 11


 References 11


Appendix 1. References included in the database for meta-analyses  14


 Appendix 2. Results of the meta-analysis of FACE effects 18



Summary
Free-air CO2 enrichment (FACE) experiments allow study of the effects of elevated [CO2] on plants and ecosystems grown under natural conditions without enclosure. Data from 120 primary, peer-reviewed articles describing physiology and production in the 12 large-scale FACE experiments (475–600 ppm) were collected and summarized using meta-analytic techniques. The results confirm some results from previous chamber experiments: light-saturated carbon uptake, diurnal C assimilation, growth and above-ground production increased, while specific leaf area and stomatal conductance decreased in elevated [CO2]. There were differences in FACE. Trees were more responsive than herbaceous species to elevated [CO2]. Grain crop yields increased far less than anticipated from prior enclosure studies. The broad direction of change in photosynthesis and production in elevated [CO2] may be similar in FACE and enclosure studies, but there are major quantitative differences: trees were more responsive than other functional types; C4 species showed little response; and the reduction in plant nitrogen was small and largely accounted for by decreased Rubisco. The results from this review may provide the most plausible estimates of how plants in their native environments and field-grown crops will respond to rising atmospheric [CO2]; but even with FACE there are limitations, which are also discussed.

What have we learned from 15 years of free-air CO2 enrichment (FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2.

I. CONTEXT * The Ecosystem Concept * Earth's Climate System * Geology and Soils * II. MECHANISMS * Terrestrial Water and Energy Balance * Carbon Input to Terrestrial Ecosystems * Terrestrial Production Processes * Terrestrial Decomposition * Terrestrial Plant Nutrient Use * Terrestrial Nutrient Cycling * Aquatic Carbon and Nutrient Cycling * Trophic Dynamics * Community Effects on Ecosystem Processes * III. PATTERNS * Temporal Dynamics * Landscape Heterogeneity and Ecosystem Dynamics * IV. INTEGRATION * Global Biogeochemical Cycles * Managing and Sustaining Ecosystem * Abbreviations * Glossary * References

Principles of Terrestrial Ecosystem Ecology

Human production of food and energy is the dominant continental process that breaks the triple bond in molecular nitrogen (N2) and creates reactive nitrogen (Nr) species. Circulation of anthropogenic Nr in Earth’s atmosphere, hydrosphere, and biosphere has a wide variety of consequences, which are magnified with time as Nr moves along its biogeochemical pathway. The same atom of Nr can cause multiple effects in the atmosphere, in terrestrial ecosystems, in freshwater and marine systems, and on human health. We call this sequence of effects the nitrogen cascade. As the cascade progresses, the origin of Nr becomes unimportant. Reactive nitrogen does not cascade at the same rate through all environmental systems; some systems have the ability to accumulate Nr, which leads to lag times in the continuation of the cascade. These lags slow the cascade and result in Nr accumulation in certain reservoirs, which in turn can enhance the effects of Nr on that environment. The only way to eliminate Nr accumul...

http://bioeeos660-f12-bowen.wikispaces.umb.edu/file/view/Galloway+et+al.+2003.pdf

The Nitrogen Cascade

Publisher Summary In this chapter, the advances that have been made in understanding the ecology of the mineral nutrition of wild plants from terrestrial ecosystems have been reviewed. This chapter is organized along three lines. First, the issues of nutrient-limited plant growth and nutrient uptake, with special emphasis on the importance of the uptake of nutrients in organic form—both by mycorrhizal and by non-mycorrhizal plants—and the importance of symbiotic nitrogen fixation is treated. In addition, the influence of allocation patterns on mineral nutrient uptake is described. Next, a few of the nutritional aspects of leaf functioning and how nutrients are used for biomass production by the plant are explored. That is done by studying the nutrient use efficiency (NUE) of plants and the various components of NUE. Finally, the feedback of plant species to soil nutrient availability by reviewing patterns in litter decomposition and nutrient mineralization is investigated. The chapter concludes with a synthesis of the various aspects of the mineral nutrition of wild plants. The chapter ends with a conceptual description of plant strategies with respect to mineral nutrition.

The Mineral Nutrition of Wild Plants Revisited: A Re-evaluation of Processes and Patterns

Due to the limitations in methodology it has been a difficult task to measure rhizosphere respiration and original soil carbon decomposition under the influence of living roots. 14C-labeling has been widely used for this purpose in spite of numerous problems associated with the labeling method. In this paper, a natural 13C method was used to measure rhizosphere respiration and original soil carbon decomposition in a short-term growth chamber experiment. The main objective of the experiment was to validate a key assumption of this method: the δ13C value of the roots represents the δ13C value of the rhizosphere respired CO2. Results from plants grown in inoculated carbon-free medium indicated that this assumption was valid. This natural 13C method was demonstrated to be advantageous for studying rhizosphere respiration and the effects of living roots on original soil carbon decomposition.

Measurement of rhizosphere respiration and organic matter decomposition using natural 13C

The temperature sensitivity of soil organic matter (SOM) decomposition has been a crucial topic in global change research, yet remains highly uncertain. One of the contributing factors to this uncertainty is the lack of understanding about the role of rhizosphere priming effect (RPE) in shaping the temperature sensitivity. Using a novel continuous 13C-labeling method, we investigated the temperature sensitivity of RPE and its impact on the temperature sensitivity of SOM decomposition. We observed an overall positive RPE. The SOM decomposition rates in the planted treatments increased 17–163% above the unplanted treatments in three growth chamber experiments including two plant species, two growth stages, and two warming methods. More importantly, warming by 5 °C increased RPE up to threefold, hence, the overall temperature sensitivity of SOM decomposition was consistently enhanced (Q10 values increased 0.3–0.9) by the presence of active rhizosphere. In addition, the proportional contribution of SOM decomposition to total soil respiration was increased by soil warming, implying a higher temperature sensitivity of SOM decomposition than that of autotrophic respiration. Our results, for the first time, clearly demonstrated that root–soil interactions play a crucial role in shaping the temperature sensitivity of SOM decomposition. Caution is required for interpretation of any previously determined temperature sensitivity of SOM decomposition that omitted rhizosphere effects using either soil incubation or field root-exclusion. More attention should be paid to RPE in future experimental and modeling studies of SOM decomposition.

Rhizosphere priming effect increases the temperature sensitivity of soil organic matter decomposition

The rhizosphere is one of the key fine-scale components of C cycles This study was undertaken to improve understanding of the potential effects of atmospheric CO2 increase on rhizosphere processes Using C isotope techniques, we found that elevated atmospheric CO2 significantly increased wheat plant growth, dry mass accumulation, rhizosphere respiration, and soluble C concentrations in the rhizosphere When plants were grown under elevated CO2 concentration, soluble C concentration in the rhizosphere increased by approximately 60% The degree of elevated CO2 enhancement on rhizosphere respiration was much higher than on root biomass Averaged between the two nitrogen treatments and compared with the ambient CO2 treatment, wheat rhizosphere respiration rate increased 60% and root biomass only increased 26% under the elevated CO2 treatment These results indicated that elevated atmospheric CO2 in a wheat-soil system significantly increased substrate input to the rhizosphere due to both increased root growth and increased root activities per unit of roots Nitrogen treatments changed the effect of elevated CO2 on soil organic matter decomposition Elevated CO2 increased soil organic matter decomposition (22%) in the nitrogen-added treatment but decreased soil organic matter decomposition (18%) without nitrogen addition Soil nitrogen status was therefore found to be important in determining the directions of the effect of elevated CO2 on soil organic matter decomposition

Elevated CO2, rhizosphere processes, and soil organic matter decomposition

Microbial-faunal interactions in the rhizosphere and effects on plant growth

Nitrogen (N) immobilization in sterilized (abiotic) and non-sterilized (biotic) O and A horizons was studied to determine the relative importance of biotic and abiotic processes in N retention in forest ecosystems. We collected samples from a variety of forest locations in Washington, Nevada, California, Tennessee, and North Carolina with differing soil types, vegetation, N status, and soil acidity. Included among these sites were adjacent stands of N 2 -fixing and non-N 2 -fixing species and sites of differing N status due to slope position at a given location. We treated O and A horizon samples from each site with ( 15 NH 4 ) 2 SO 4 : sterilization was achieved by adding HgCl 2 , which proved to he highly effective. We found significant levels of both abiotic and biotic N immobilization in all soils. Biotic N immobilization was much greater in the N-poor sites in California and Nevada than in the other sites and was inversely related to N concentration overall. Biotic immobilization was directly related to pH and base saturation among all sites, but we hypothesize that these correlations resulted from a correlation between those parameters and N concentration. Abiotic N immobilization varied less than biotic N immobilization across sites and was unrelated to N concentration or pH. The percentage of total N immobilization as abiotic N immobilization varied considerably (from 6-90%), and was positively correlated with N concentration. These results suggest that abiotic N immobilization can be a significant process in a variety of soil types. Across soil types with increasing N saturation, biotic N immobilization decreases and abiotic N immobilization accounts for a greater proportion of total N immobilization.

Weixin Cheng

Papers

Measurement of rhizosphere respiration and organic matter decomposition using natural 13C

Rhizosphere priming effect increases the temperature sensitivity of soil organic matter decomposition

Elevated CO2, rhizosphere processes, and soil organic matter decomposition

Microbial-faunal interactions in the rhizosphere and effects on plant growth

Biotic and Abiotic Nitrogen Retention in a Variety of Forest Soils