Weak Competition Among Tropical Tree Seedlings: Implications for Species Coexistence

Authors

C.E. Timothy Paine, Louisiana State University
Kyle E. Harms, Smithsonian Tropical Research InstituteFollow
Stefan A. Schnitzer, Marquette UniversityFollow
Walter P. Carson, University of PittsburghFollow

Document Type

Article

Language

eng

Publication Date

7-2008

Publisher

Wiley

Source Publication

Biotropica

Source ISSN

0006-3606

Abstract

The intensity of competition among forest tree seedlings is poorly understood, but has important ramifications for their recruitment and for the maintenance of species diversity. Intense competition among seedlings could allow competitively dominant species to exclude subordinate species. Alternatively, the low density and small stature of forest tree seedlings could preclude intense interseedling competition. In this case, other processes, such as size‐asymmetric competition with adults, interactions with consumers, or neutral dynamics would prevail as those structuring the forest understory. We tested the intensity of, and potential for, intraspecific competition among tree seedlings of three species (Brosimum alicastrum, Matisia cordata, and Pouteria reticulata) in two Neotropical rain forests. We reduced stem densities by up to 90 percent and monitored individual growth and survival rates for up to 24 mo. Individual growth and survival rates were generally unrelated to stem density. Contrary to the predicted behavior of intensely competing plant populations, the distribution of individual heights did not become more left‐skewed with time for any species, regardless of plot density; i.e., excesses of short, suppressed individuals did not accumulate in high‐density plots. We further measured the overlap of zones of influence (ZOIs) to assess the potential for resource competition. Seedling ZOIs overlapped only slightly in extremely dense monodominant plots, and even less in ambient‐density plots of mixed composition. Our results thus suggest that interseedling competition was weak. Given the low density of tree seedlings in Neotropical forests, we infer that resource competition among seedlings may be irrelevant to their recruitment.

Comments

Accepted version. Biotropica, Vol. 40, No. 4 (July 2008): 432-440. DOI. © 2008 Wiley. Used with permission.

Recommended Citation

Paine, C.E. Timothy; Harms, Kyle E.; Schnitzer, Stefan A.; and Carson, Walter P., "Weak Competition Among Tropical Tree Seedlings: Implications for Species Coexistence" (2008). Biological Sciences Faculty Research and Publications. 793.
https://epublications.marquette.edu/bio_fac/793