Growing aridity and seasonality can drive catastrophic changes in the Amazon forest

Campus de Parauapebas, Universidade Federal Rural da Amazônia, Parauapebas, Pará, Brasil
Programa de Pós-Graduação em Ciências Ambientais, Universidade Federal do Pará, Belém, Pará, Brasil
Centro de Ciência do Sistema Terrestre - CCST, Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brasil
DOI
10.7287/peerj.preprints.26646v1
Subject Areas
Ecology, Ecosystem Science, Climate Change Biology
Keywords
Tipping point, Resilience, Bistability, Forest-savanna transitions
Copyright
© 2018 Anjos et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Anjos LJS, de Toledo PM. 2018. Growing aridity and seasonality can drive catastrophic changes in the Amazon forest. PeerJ Preprints 6:e26646v1

Abstract

The consolidation of a non-analogous climate shortly will likely affect the structure and functioning of Amazon, the most biodiverse terrestrial ecosystem on the planet. However, the ecological mechanisms underlying these potential events are still poorly understood. Here, we investigate the mechanism responsible for controlling the forest-savanna transition regime through an objective measure of resilience, based on the multidimensional climatic niche of ecosystems. Our results suggest that there is an alternating dominance, where forest and savanna have their respective basins of attraction. However, we note that the two stable states can coexist only in a narrow ecotonal zone of bistability. In this particular region, there is an equivalence between forest and savanna in quantitative terms and its presence indicates, in addition to a low hysteresis, a propensity for a catastrophic transition regime between forest and savanna. In this sense, we determine the critical levels of resilience that intermediate the dynamics of transition between forest and savanna through such bistable ecotonal zone. Also, we found that bistable region is strongly associated with critical climatic thresholds, mainly on the axis of the moisture availability and climatic seasonality, but with the lower effect of the average annual temperature. Thus, we can expect that if such climatic thresholds are reached, due to ongoing climate change, and forest resilience limits are exceeded; large-scale catastrophic events will suddenly be triggered. The expected effects are the erosion of Amazonian biodiversity, with the massive extinction of species, culminating in the consolidation of a stable state with simplified ecosystems, with a lower density of tree cover.

Author Comment

This is a submission to PeerJ for review.

Supplemental Information

The observational data from forest and savanna ecosystems calculated along resilience gradient

DOI: 10.7287/peerj.preprints.26646v1/supp-1

Observational data for climatic variables calculated along of a trend transitions gradient

DOI: 10.7287/peerj.preprints.26646v1/supp-2