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Data and code from: The functional form of specialized predation affects whether Janzen-Connell effects can prevent competitive exclusion

Citation

Smith, Daniel (2022), Data and code from: The functional form of specialized predation affects whether Janzen-Connell effects can prevent competitive exclusion, Dryad, Dataset, https://doi.org/10.5061/dryad.vhhmgqnw7

Abstract

Janzen-Connell Effects (JCEs), specialized predation of seeds and seedlings near conspecific trees, are hypothesized to maintain species richness. While previous studies show JCEs can maintain high richness relative to neutral communities, recent theoretical work indicates JCEs may weakly inhibit competitive exclusion when species exhibit inter-specific fitness variation. However, recent models make somewhat restrictive assumptions about the functional form of specialized predation -- that JCEs occur at a fixed rate when offspring are within a fixed distance of a conspecific tree. Using a theoretical model, I show that the functional form of JCEs largely impacts their ability to maintain coexistence. If predation pressure increases additively with adult tree density and decays exponentially with distance, JCEs maintain considerably higher species richness than predicted by recent models. Loosely parameterizing the model with data from a Panamanian tree community, I elucidate the conditions under which JCEs are capable of maintaining high species richness.

Usage Notes

This file contains the simulation outputs that are necessary to recreate the figures (figures from the Appendices, mainly). For R code that recreates all the figures, see: https://doi.org/10.5281/zenodo.6462743

Funding

National Science Foundation, Award: NSF OCE 1851489

National Science Foundation, Award: NSF DGE 1735359