Treefall gaps are hypothesized to maintain diversity by creating resource‐rich, heterogeneous habitats necessary for species coexistence. This hypothesis, however, is not supported empirically for shade‐tolerant trees, the dominant plant group in tropical forests. The failure of gaps to maintain shade‐tolerant trees remains puzzling, and the hypothesis implicated to date is dispersal limitation. In central Panama, we tested an alternative ‘biotic interference’ hypothesis: that competition between growth forms (lianas vs. trees) constrains shade‐tolerant tree recruitment, survival and diversity in gaps. We experimentally removed lianas from eight gaps and monitored them for 8 years, while also monitoring nine un‐manipulated control gaps. Removing lianas increased tree growth, recruitment and richness by 55, 46 and 65%, respectively. Lianas were particularly harmful to shade‐tolerant species, but not pioneers. Our findings demonstrate that competition between plant growth forms constrains diversity in a species‐rich tropical forest. Because lianas are abundant in many tropical systems, our findings may apply broadly.
Schnitzer, Stefan A. and Carson, Walter P., "Lianas suppress tree regeneration and diversity in treefall gaps" (2010). Biological Sciences Faculty Research and Publications. 731.
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