Value to Herbivores of Plant Physical and Chemical Diversity in Time and Space

• Published in: Crop science Vol. 47; no. 1; pp. 382 - 398
• Main Authors: Provenza, F.D, Villalba, J.J, Haskell, J, MacAdam, J.W, Griggs, T.C, Wiedmeier, R.D
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Madison, WI Crop Science Society of America 01.01.2007; American Society of Agronomy
• Subjects: Agricultural ecosystems; agroecosystems; animal morphology; animal physiology; Animal productions; Behavior; Biological and medical sciences; botanical composition; chemical constituents of plants; Chemicals; Complex systems; feed intake; Food; Forage; Fundamental and applied biological sciences. Psychology; Gene expression; grazing; Herbivores; literature reviews; Monoculture; Nutrients; Pasture; pastures; Pest control; plant communities; Plant diversity; Plant species; range management; Rangelands; secondary metabolites; spatial variation; species diversity; temporal variation; Terrestrial animal productions; Toxins; Vertebrates; Fodder crop; Chemical properties; Herbivorous; Animal plant relation; Physical properties
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2006.02.0083

Whether foraging on pastures or rangelands, herbivores encounter plant species that differ in their concentrations of nutrients. They also all contain various secondary compounds that at too high doses can be toxic, but at the appropriate dose many of these toxins may have medicinal benefits. The quantity of forage an animal consumes depends on the other forages it selects because nutrients and toxins interact. Food intake also depends on an individual's morphology and physiology, and marked variation is common, even among closely related animals, in needs for nutrients and abilities to cope with toxins. Thus, individuals can better meet their needs when offered a variety of foods that differ in nutrients and toxins than when constrained to a single food. Nonetheless, we have focused on a few species, often grown in monoculture, and we have reduced concentrations of secondary compounds with little appreciation for their roles in protecting plants against herbivores, pathogens, and competitors. In nature, where diversity of plants is the rule and not the exception, eating a variety of foods is how animals cope with, and may benefit from, secondary compounds. The potential benefits of creating mixtures of plant species whose nutrient and secondary compound profiles complement one another are obvious, though much remains to be learned about how to reconstruct agro-ecosystems with plants that complement and enhance one another structurally, functionally, and biochemically.