Accelerating loss of resilience in Bornean rainforests

Abstract

Climate change and human activity are eroding tropical rainforest resilience, risking tipping points of mass forest dieback towards savannah-like or treeless states. Here, we extend a close analysis of tipping-point early-warning signals in satellite-sensed vegetation data from the Amazon to Borneo, revealing resilience loss via critical slowing down of recovery from perturbation. Specifically, we examine spatiotemporal patterns in rising lag-1 autocorrelation and variance to assess whether, when and where resilience loss accelerated, and how these patterns relate to climate, human activity and animal biodiversity. We find that Bornean rainforests lost resilience over 1991-2016, with a marked acceleration from a breakpoint in 2004. Resilience loss accelerated earlier in subregions with higher human footprint, and was more severe in drier, more human-impacted subregions before the breakpoint. Post-breakpoint, resilience loss was stronger in wetter and less biodiverse areas. We also uncover the apparent reallocation of post-breakpoint resilience loss to areas that had previously appeared more resistant. Climate and bird and mammal richness appear to be most strongly correlated with this pattern. Our results provide enhanced evidence of Bornean rainforest resilience loss and its potential drivers, underscoring the urgent need for ecological conservation and climate change mitigation in Borneo and worldwide.