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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Does extreme environmental severity promote plant facilitation? An experimental field test in a subtropical coastal dune

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Author(s):
Castanho, Camila T. [1] ; Oliveira, Alexandre A. [1] ; Prado, Paulo Inacio K. L. [1]
Total Authors: 3
Affiliation:
[1] Univ Sao Paulo, Grad Program Ecol, BR-05508900 Sao Paulo, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Oecologia; v. 178, n. 3, p. 855-866, JUL 2015.
Web of Science Citations: 6
Abstract

The stress gradient hypothesis (SGH) postulates how the balance between plant competition and facilitation shifts along environmental gradients. Early formulations of the SGH predicted that facilitation should increase monotonically with stress. However, a recent theoretical refinement of the SGH postulates stronger facilitation under moderate stress, followed by a decreasing role of facilitation in the most severe environments. We conducted field experiments along the most severe part of a coastal dune gradient in southeast Brazil to test the effect of stress on the intensity and importance of the net interactions between two tree species. First, we compared the performance of distinct life stages of Ternstroemia brasiliensis in the presence and absence of Guapira opposita adults along a beach-to-inland gradient, a gradient of environmental severity. To test the effect of one stress factor in particular, we also manipulated water availability, a limiting resource due to the sandy soils. At the most severe part of the coastal gradient (i.e. closest to the seashore), both intensity and importance of the interaction between G. opposita and T. brasiliensis were negatively related to stress, with a pattern consistent across distinct life stages of the target species. However, the sign of the net interaction depended on the life stage of the target species. Our results provide empirical evidence that the role of facilitation tends to wane, leading to neutral or even negative net interactions between species as stress reaches its maximum, as predicted by the recent refinements of the SGH. (AU)

FAPESP's process: 12/09794-7 - Facilitation or competition? A meta-analysis of the factors determining plant interactions in coastal sand dunes
Grantee:Camila de Toledo Castanho
Support Opportunities: Scholarships in Brazil - Post-Doctoral