Movement strategies of seed predators as determinants of plant recruitment patterns

Lorenzo Mari*, Renato Casagrandi, Marino Gatto, Tal Avgar, Ran Nathan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Plant recruitment in nature exhibits several distinctive patterns ranging from hump shaped to monotonically decreasing with distance from the seed source. We investigate the role of post-dispersal seed predation in shaping these patterns, introducing a new mechanistic model that explicitly accounts for the movement strategy used by seed eaters. The model consists of two partial differential equations describing the spatiotemporal dynamics of both seed and predator densities. The movement strategy is defined by how predators move in response to the different cues they can use to search for seeds. These cues may be seed density, seed intake, distance from the plant, density of conspecific foragers, or a mixture of these four. The model is able to reproduce all the basic plant recruitment patterns found in the field. We compare the results to those of the ideal free distribution (IFD) theory and show that hump-shaped plant recruitment patterns cannot be generated by IFD predators and, in general, by foragers that respond exclusively to seed density. These foragers can produce only nonincreasing patterns, the shapes of which are determined by the foragers' navigation capacities. In contrast, hump-shaped patterns can be produced by distance-responsive predators or by foragers that use conspecifics as a cue for seed abundance.

Original languageAmerican English
Pages (from-to)694-711
Number of pages18
JournalAmerican Naturalist
Volume172
Issue number5
DOIs
StatePublished - Nov 2008

Keywords

  • Foraging behavior
  • Ideal free distribution
  • Janzen-connell effect
  • Partial differential equations model
  • Postdispersal seed predation

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