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Facilitation; Lotka–Volterra; Plant–herbivore interaction; Predator–prey model; Shifting mosaic; Vegetation dynamics
Abstract:
Body size of vertebrate herbivores is strongly linked to other life
history traits, most notably (1) tolerance of low quality forage and (2)
vulnerability to predation, which both impact the composition and
dynamics of natural communities. However, no study has thus far explored
how the combination of these two body-size related traits affects the
long-term composition and dynamics of the herbivore and plant
communities. We made a simple model of ordinary differential equations
and simulated a grassland system with three herbivore species (small,
medium, large) and two predator species (small, large) to investigate
how the combination of low-quality tolerance and predation-vulnerability
structure the herbivore and plant community. We found that facilitation
and competition between different-sized herbivores and predation by
especially small predators stimulate coexistence among herbivore
species. Furthermore, the interaction between different-sized herbivores
and predators generated cyclical succession in the plant community, i.e.
alternating periods of short vegetation dominated by high-quality
plants, with periods of tall vegetation dominated by low-quality plants.
Our results suggest that cyclical succession in plant communities is
more likely to occur when a predator predominantly preys on small
herbivore species. Large predators also play an important role, as their
addition relaxed the set of conditions under which cyclical succession
occurred. Consequently, our model predictions suggest that a diverse
predator community plays an important role in the long-term dynamics and
maintenance of diversity in both the herbivore and plant community. (C)
2015 Elsevier Inc. All rights reserved.
