Predicted trajectories of tree community change in Amazonian rainforest fragments
File(s)Ewers et al-neural network 160909.docx (325.27 KB)
Accepted version
Author(s)
Ewers, RM
Andrade, A
Laurance, SG
Camargo, JL
Lovejoy, TE
Type
Journal Article
Abstract
A great challenge for ecologists is predicting how communities in fragmented tropical landscapes will change in the future. Available evidence suggests that fragmented tropical tree communities are progressing along a trajectory of ‘retrogressive succession’, in which the community shifts towards an early or mid-successional state that will persist indefinitely. Here, we investigate the potential endpoint of retrogressive succession, examining whether it will eventually lead to the highly depauperate communities that characterise recently abandoned agricultural lands. We tested this hypothesis by using neural networks to construct an empirical model of Amazonian rainforest-tree-community responses to experimental habitat fragmentation. The strongest predictor of tree-community composition in the future was its composition in the present, modified by variables like the composition of the surrounding habitat matrix and distance to forest edge. We extrapolated network predictions over a 100 yr period and quantified trajectories of forest communities in multidimensional ordination space. We found no evidence that forest communities, including those near forest edges, were converging strongly towards a composition dominated by just one or two early successional genera. Retrogressive succession may well be stronger in fragmented landscapes altered by chronic disturbances, such as edge-related fires, selective logging, or intense windstorms, but in this experimental landscape in which other human disturbances are very limited, it is unlikely that forest edge communities will fully revert to the species poor assemblages observed in very early successional landscapes.
Date Issued
2016-11-11
Date Acceptance
2016-09-29
Citation
Ecography, 2016, 40 (1), pp.26-35
ISSN
1600-0587
Publisher
Wiley
Start Page
26
End Page
35
Journal / Book Title
Ecography
Volume
40
Issue
1
Copyright Statement
© 2016 The Authors. Ecography © 2016 Nordic Society Oikos
Sponsor
Commission of the European Communities
Grant Number
281986
Subjects
Ecology
0501 Ecological Applications
0502 Environmental Science And Management
0602 Ecology
Publication Status
Published