Episodic herbivory, plant density dependence, and stimulation of aboveground plant production
| Autor: | Jacob F. Penner, Mark E. Ritchie |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Range (biology) Stimulation Serengeti Biology 010603 evolutionary biology 01 natural sciences 03 medical and health sciences relative growth rate lcsh:QH540-549.5 herbivory event Grazing Relative growth rate aboveground primary production grazing Ecosystem Ecology Evolution Behavior and Systematics Original Research 030304 developmental biology Nature and Landscape Conservation 0303 health sciences Biomass (ecology) Herbivore Ecology plants herbivory grasslands episodic herbivory Density dependence density dependence lcsh:Ecology |
| Zdroj: | Ecology and Evolution, Vol 10, Iss 12, Pp 5302-5314 (2020) Ecology and Evolution |
| ISSN: | 2045-7758 |
| DOI: | 10.1002/ece3.6274 |
| Popis: | Herbivory is a major energy transfer within ecosystems; an open question is under what circumstances it can stimulate aboveground seasonal primary production. Despite multiple field demonstrations, past theory considered herbivory as a continuous process and found stimulation of seasonal production to be unlikely. Here, we report a new theoretical model that explores the consequences of discrete herbivory events, or episodes, separated in time. We discovered that negative density (biomass) dependence of plant growth, such as might be expected from resource limitation of plant growth, favors stimulation of seasonal production by infrequent herbivory events under a wide range of herbivory intensities and maximum plant relative growth rates. Results converge to those of previous models under repeated, short‐interval herbivory, which generally reduces seasonal production. Model parameters were estimated with new and previous data from the Serengeti ecosystem. Patterns of observed frequent and large magnitude stimulated production in these data agreed generally with those predicted by the episodic herbivory model. The model thus may provide a new framework for evaluating the sustainability and impact of herbivory. The issue of whether herbivores can stimulate plant production remains controversial. Here we develop a theoretical framework for understanding how discrete or episodic herbivory events can stimulate plant production under a wide variety of conditions without increasing nutrient availability. The model predictions, based on new data for relative growth rates of grassland plants, agree reasonably well with previously published data for grazing impacts on above‐ground production in the Serengeti. |
| Databáze: | OpenAIRE |
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