Herbivores limit the population size of big-leaf mahogany trees in an Amazonian forest

Norghauer, Julian Martin; Free, Christopher M.; Landis, R. Matthew; Grogan, James; Malcolm, Jay R.; Thomas, Sean C. (2016). Herbivores limit the population size of big-leaf mahogany trees in an Amazonian forest. Oikos, 125(1), pp. 137-148. Wiley 10.1111/oik.02324

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The Janzen–Connell hypothesis proposes that specialized herbivores maintain high numbers of tree species in tropical forests by restricting adult recruitment so that host populations remain at low densities. We tested this prediction for the large timber tree species, Swietenia macrophylla, whose seeds and seedlings are preyed upon by small mammals and a host-specific moth caterpillar Steniscadia poliophaea, respectively. At a primary forest site, experimental seed additions to gaps – canopy-disturbed areas that enhance seedling growth into saplings – over three years revealed lower survival and seedling recruitment closer to conspecific trees and in higher basal area neighborhoods, as well as reduced subsequent seedling survival and height growth. When we included these Janzen–Connell effects in a spatially explicit individual-based population model, the caterpillar's impact was critical to limiting Swietenia's adult tree density, with a > 10-fold reduction estimated at 300 years. Our research demonstrates the crucial but oft-ignored linkage between Janzen–Connell effects on offspring and population-level consequences for a long-lived, potentially dominant tree species.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Library Plant Sciences
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)

UniBE Contributor:

Norghauer, Julian Martin

Subjects:

500 Science > 580 Plants (Botany)

ISSN:

0030-1299

Publisher:

Wiley

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

04 Apr 2016 14:52

Last Modified:

04 Apr 2016 14:52

Publisher DOI:

10.1111/oik.02324

BORIS DOI:

10.7892/boris.79203

URI:

https://boris.unibe.ch/id/eprint/79203

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