Spatial correlation increase in single-sensor satellite data reveals loss of Amazon rainforest resilience

TL;DR

This study demonstrates that spatial correlation in single-sensor satellite data is a more reliable indicator of Amazon rainforest resilience loss than local measures, revealing significant resilience decline especially in the southwest and north from 2002 to 2019.

Contribution

It introduces the use of spatial correlation as a robust resilience indicator in satellite data, avoiding biases from multi-sensor and land-use changes.

Findings

Resilience of the Amazon rainforest has declined until 2019.

Resilience loss is especially pronounced in southwestern and northern Amazon.

Spatial correlation provides a more reliable resilience measure than local indicators.

Abstract

The Amazon rainforest (ARF) is threatened by deforestation and climate change, which could trigger a regime shift to a savanna-like state. Previous work suggesting declining resilience in recent decades was based only on local resilience indicators. Moreover, previous results are potentially biased by the employed multi-sensor and optical satellite data and undetected anthropogenic land-use change. Here, we show that the spatial correlation provides a more robust resilience indicator than local estimators and employ it to measure resilience changes in the ARF, based on single-sensor Vegetation Optical Depth data under conservative exclusion of human activity. Our results show an overall loss of resilience until around 2019, which is especially pronounced in the southwestern and northern Amazon for the time period from 2002 to 2011. The demonstrated reliability of spatial correlation in coupled systems suggests that in particular the southwest of the ARF has experienced pronounced resilience loss over the last two decades.