The dazzling variation in plant chemistry is a primary mediator of trophic interactions, including herbivory, predation, parasitism, and disease. At the same time, such interactions feed back to influence spatial and temporal variation in the chemistry of plants. In The Phytochemical Landscape, Mark Hunter provides a novel approach to linking the trophic interactions of organisms with the cycling of nutrients in ecosystems.
Hunter introduces the concept of the "phytochemical landscape" – the shifting spatial and temporal mosaic of plant chemistry that serves as the nexus between trophic interactions and nutrient dynamics. He shows how plant chemistry is both a cause and consequence of trophic interactions, and how it also mediates ecosystem processes such as nutrient cycling. Nutrients and organic molecules in plant tissues affect decomposition rates and the fluxes of elements such as carbon, nitrogen, and phosphorus. The availability of these same nutrients influences the chemistry of cells and tissues that plants produce. In combination, these feedback routes generate pathways by which trophic interactions influence nutrient dynamics and vice versa, mediated through plant chemistry.
Hunter provides evidence from terrestrial and aquatic systems for each of these pathways, and describes how a focus on the phytochemical landscape enables us to better understand and manage the ecosystems in which we live. Essential reading for students and researchers alike, The Phytochemical Landscape offers an integrated approach to population-, community-, and ecosystem-level ecological processes.
1. Introduction 1
1.1 A Matter of Perspective 3
1.2 The Nature of Feedback 4
1.3 Which Autotrophs and Which Traits? 6
1.4 Trait Variation and Trait Diversity 7
1.5 Which Trophic Interactions? 9
1.6 Which Ecosystem Processes? 10
1.7 Webs of Green and Brown 11
2. The Phytochemical Landscape 13
2.1 Defining the Phytochemical Landscape 13
2.2 Variation on the Phytochemical Landscape 17
3. The Variable Chemistry of Primary Production 24
3.1 The Challenging Chemistry of Autotrophs 24
3.2 Origins of Variation in Autotroph Chemistry on the Phytochemical Landscape 25
3.3 Microbial Symbionts and Variation in Autotroph Chemistry: Whose Phenotype Is It Anyway? 30
3.4 Summary and Conclusions 38
4. Effects of Primary Producer Chemistry on Trophic Interactions 39
4.1 Herbivores and Herbivory: The Interactive Effects of Autotroph Chemistry and Natural Enemies 39
4.2 Effects of the Phytochemical Landscape on Natural Enemies 91
5. Effects of Trophic Interactions on the Chemistry of Primary Producers 109
5.1 Background 109
5.2 Effects of Herbivores and Predators on Autotroph Community Structure 111
5.3 Consumer Effects on Succession—Temporal Change on the Phytochemical Landscape 121
5.4 Phytochemical Induction—A Multiplier of Variation in Autotroph Chemistry on the Phytochemical Landscape 124
6. Effects of Autotroph Chemistry on Nutrient Dynamics 138
6.1 The Elements of Life 138
6.2 Recalcitrant Organic Chemistry 142
6.3 Nutrients, Stoichiometry, and the Decomposition of Autotroph Residues 148
6.4 Effects of Autotroph Identity and Diversity on Nutrient Dynamics 153
6.5 Effects of Phytoplankton Residue Chemistry on Nutrient Dynamics in Aquatic Ecosystems 160
6.6 Effects of Phytoplankton Stoichiometry on Nutrient Dynamics in Aquatic Ecosystems 168
7. Effects of Nutrient Availability on the Chemistry of Primary Producers 173
7.1 Introduction 173
7.2 Effects of Nutrient Dynamics on the Chemical Phenotype of Individual Autotrophs 175
7.3 Effects of Nutrient Availability on Primary Producer Diversity 185
7.4 Evolutionary Effects of Nutrient Availability on Autotroph Chemistry 192
7.5 Conclusions 195
8. Linking Trophic Interactions with Ecosystem Nutrient Dynamics on the Phytochemical Landscape 198
8.1 Putting It All Together: Linking Cycles and Generating Feedback 198
8.2 From Trophic Interactions to Ecosystem Processes 199
8.3 Effects of Herbivory on Nutrient Dynamics 200
8.4 Effects of Predators on Nutrient Dynamics 227
8.5 Effects of Nutrient Dynamics on Trophic Interactions 236
8.6 Final Thoughts on Feedback Loops 247
9. Synthesis and Prospects for Future Work 252
9.1 Introduction 252
9.2 Priority 1: Let’s Make Some Maps 253
9.3 Priority 2: Assess the Frequency and Strength of Spatial Correlation 254
9.4 Priority 3: Understanding Time Lags and the Temporal Scale of Spatial Correlation on the Phytochemical Landscape 255
9.5 Priority 4: Exploring Variation in the Strength of Feedback between Trophic Interactions and Nutrient Dynamics on the Phytochemical Landscape 262
9.6 Priority 5: Comparing the Role of the Phytochemical Landscape in Terrestrial and Aquatic Ecosystems 272
9.7 Concluding Remarks 274
References Cited 277
"[...] Eminently readable, supported by nearly 70 pages of references, this is a great source of inspiration and ideas for ecologists and evolutionary biologists at all stages of their career."
– Alan Crowden, BES Bulletin, Volume 48(4), December 2017
"[Phytochemical Landscape] is written well, carefully documented, and adequately illustrated."
"Plant life on Earth is characterized by an enormous variation in its chemistry. In this unique synthesis, Mark Hunter makes a compelling case that explicit recognition of this variation is central to understanding ecological processes, whether at the population, community, or ecosystem levels. It is a must-read for all ecologists interested in interactions and feedbacks, and is destined to become a classic in the general ecological literature."
– David Wardle, Swedish University of Agricultural Sciences
"An organism is basically a bag of interacting chemicals – with an attitude. Gathering, hoarding, and transforming materials from the environment is key for organismal functioning and fitness, and such activities influence ecosystem chemical fluxes and pools. In this masterful book, Hunter synthesizes a heretofore scattered field of research, focusing on how phytochemistry varies across space, and how such variation reflects feedback loops among the physical environment, plants, herbivores, and higher trophic levels. This is essential reading for all ecologists."
– Robert D. Holt, University of Florida
"Hunter has produced a remarkably broad, comprehensivProductse, and intellectually exciting treatment of autotroph chemical traits, their complex interactions with other producer traits and consumers, and how these dynamic interactions affect populations, communities, and ecosystems. This is a conceptually rich resource for students and senior investigators alike."
– Mark Hay, Georgia Institute of Technology
"This timely and authoritative book offers a potentially transformative way of integrating several disparate ecological subfields to foster the pursuit of big-picture ecological science. It could only have been written by someone with Mark Hunter's vision and breadth and depth of knowledge."
– Oswald J. Schmitz, author of Resolving Ecosystem Complexity
"This is an excellent work of scholarship that makes important contributions to our understanding of phytochemistry, herbivory, and their links to ecosystem processes. Hunter's arguments are sound, his organization logical, and his conclusions insightful."
– Jennifer Schweitzer, University of Tennessee