Abstract
Hunting impacts tropical vertebrate populations, causing declines of species that function as seed dispersers and predators, or that browse seedlings and saplings. Whether and how the resulting reductions in seed dispersal, seed predation, and browsing translate to changes in the tree composition is poorly understood. Here, we assess the effect of defaunation on the functional composition of communities of tree recruits in tropical rainforests in French Guiana. We selected eight sites along a gradient of defaunation, caused by differences in hunting pressure, in otherwise intact old-growth forests in French Guiana. We measured shifts in functional composition by comparing leaf and fruit traits and wood density between tree recruits (up to 5 cm diameter at breast height) and adults, and tested whether and how these compositional shifts related to defaunation. We found a positive relationship with defaunation for shifts in specific leaf area, a negative relationship for shifts of leaf toughness and wood density, and a weak relationship for shifts in fruit traits. Our results suggest that the loss of vertebrates affects ecological processes such as seed dispersal and browsing, of which browsing remains understudied. Even though these changes sometimes seem minor, together they result in major shifts in forest composition. These changes have long-term ramifications that may alter forest dynamics for generations.
| Original language | English |
|---|---|
| Article number | e3872 |
| Pages (from-to) | 1-11 |
| Number of pages | 11 |
| Journal | Ecology |
| Volume | 104 |
| Issue number | 1 |
| Early online date | 19 Sept 2022 |
| DOIs | |
| Publication status | Published - Jan 2023 |
Bibliographical note
Funding Information:We thank the Parc amazonien de Guyane (PAG) and the Réserve naturelle des Nouragues for sharing their line transect data, and for logistical support. We thank Stephane Guitet and Olivier Brunaux, our main partners in the HABITAT program. We thank the Nouragues research field station (managed by CNRS) which benefits from “Investissement d'Avenir” grants managed by Agence Nationale de la Recherche (AnaEE France ANR-11-INBS-0001; Labex CEBA ANR-10-LABX-25-01). Funding for line transects was provided by ONCFS/OFB, EU funds HABITAT and CHASSE programs, French ministries of Environment (ECOTROP program), and of Overseas territories, CNRS Nouragues, PAG and ONF. We are very grateful to Christophe Bhagooa, all students and others who participated in the fieldwork efforts for vegetation sampling. Funding for vegetation sampling was provided by the Trésor foundation, the Nouragues travel grants program, Tropenbos International, the Prince Bernhard Chair for International Nature Conservation, the Van Eeden foundation, the Alberta Mennega foundation and the Miquel foundation.
Funding Information:
the Miquel foundation; the Alberta Mennega foundation; the Van Eeden foundation; the Prince Bernhard Chair for International Nature Conservation; Tropenbos International; the Nouragues travel grants program; Trésor foundation; ONF; PAG; CNRS Nouragues; Overseas territories; French ministries of Environment (ECOTROP program); EU funds HABITAT and CHASSE programs; ONCFS/OFB; Agence Nationale de la Recherche, Grant/Award Numbers: Labex CEBA ANR‐10‐LABX‐25‐01, AnaEE France ANR‐11‐INBS‐0001 Funding information
Funding Information:
We thank the Parc amazonien de Guyane (PAG) and the Réserve naturelle des Nouragues for sharing their line transect data, and for logistical support. We thank Stephane Guitet and Olivier Brunaux, our main partners in the HABITAT program. We thank the Nouragues research field station (managed by CNRS) which benefits from “Investissement d'Avenir” grants managed by Agence Nationale de la Recherche (AnaEE France ANR‐11‐INBS‐0001; Labex CEBA ANR‐10‐LABX‐25‐01). Funding for line transects was provided by ONCFS/OFB, EU funds HABITAT and CHASSE programs, French ministries of Environment (ECOTROP program), and of Overseas territories, CNRS Nouragues, PAG and ONF. We are very grateful to Christophe Bhagooa, all students and others who participated in the fieldwork efforts for vegetation sampling. Funding for vegetation sampling was provided by the Trésor foundation, the Nouragues travel grants program, Tropenbos International, the Prince Bernhard Chair for International Nature Conservation, the Van Eeden foundation, the Alberta Mennega foundation and the Miquel foundation.
Publisher Copyright:
© 2022 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America.
Keywords
- functional composition
- functional trait
- hunting
- leaf toughness
- specific leaf area
- wood density