Patterns of Herbivory Along a Prouductivity Gradient: An Empirical and Theoretical Investigation
| Autor: | Jef Huisman, René van der Wal, Han Olff, Johan van de Koppel |
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| Přispěvatelé: | IBED Other Research (FNWI), Conservation Ecology Group |
| Rok vydání: | 1996 |
| Předmět: |
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Salt marsh Foraging efficiency Foraging Rabbit Biology Grazing pressure Functional response Geese Grazing Terrestrial Ecology and Nature Conservation Terrestrische ecologie en natuurbeheer Herbivory Predator-prey theory LESSER SNOW GEESE TROPICAL PASTURES Ecology Evolution Behavior and Systematics Hare Herbivore geography WIMEK geography.geographical_feature_category Ecology Plant-herbivore model Vegetation Standing crop Productivity (ecology) TROPHIC LEVELS Multiple stable states Primary productivity EXPLOITATION ECOSYSTEMS PLANT STRUCTURE COMMUNITIES PREDATOR-PREY SYSTEMS ARCTIC SALT-MARSH |
| Zdroj: | Ecology, 77, 736-745 Ecology, 77, 736-745. Wiley-Blackwell Ecology 77 (1996) Ecology, 77(3), 736-745. Wiley-Blackwell |
| ISSN: | 0012-9658 |
| DOI: | 10.2307/2265498 |
| Popis: | According to classical exploitation theory, an increase of primary productivity should result in increased herbivore grazing pressure, thus maintaining a low plant standing crop, However, field data obtained from a salt marsh revealed a maximal grazing pressure by hares, rabbits, and geese at intermediate levels of plant standing crop. Grazing pressure was relatively low in the more productive parts. We argue that this pattern is due to a low foraging efficiency of these herbivores in dense vegetation. In order to investigate this hypothesis, we examine a plant-herbivore model where grazing becomes less efficient in dense vegetation, and analyze the behavior of this model along a gradient of primary productivity. In systems of intermediate productivity, the model predicts that a plant-herbivore system may have two stable states. In one state, the herbivore maintains a low standing crop. The other state is dominated by a dense vegetation unsuitable for herbivore grazing. In systems of high productivity, the herbivore is unable to keep plant growth in check and a dense vegetation develops. Thus, in line with our field data but in contrast to classical exploitation theory, our model does not predict ''top-down'' control in productive environments. |
| Databáze: | OpenAIRE |
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