bioRxiv Science⌕ Search

Biology subjects

Le Penru, N. P.

Publications and source records attributed to Le Penru, N. P..

2 recordsLinked to original sources

Accelerating loss of resilience in Bornean rainforests

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.

ecology↗

MAARU: Multichannel Acoustic Autonomous Recording Unit for spatial ecosystem monitoring.

1.1 - Acoustic localisation, which relies on simultaneous multi-microphone recording, adds spatial information to recorded audio and has been used in ecosystem monitoring to count individuals to improve abundance estimates, locate illegal activities such as logging/poaching, and monitor behaviour such as habitat use or species interactions. Studies have shown many advantages of acoustic localisation, but uptake remains limited as the equipment is often expensive, inaccessible, or only suitable for short-term deployments. 2 -Here, we present a low-cost, open-source, 6-channel recorder built entirely from commercially available components which can be integrated into a solar-powered, networked system. The MAARU (Multichannel Acoustic Autonomous Recording Unit) works in long-term autonomous, passive, and ad-hoc deployments. We introduce MAARUs hardware and software and present the results of lab and field tests investigating the devices durability, localisation accuracy, and other applications. 3 -MAARU provides multichannel data with similar costs and power demands to equivalent omnidirectional recorders. MAARU devices have been deployed in the UK and Brazil, where we have shown MAARUs can accurately localise pure tones up to 6kHz and 65dB bird calls as far as 8m away ({+/-}10{degrees} range, 100% and >60% of signals respectively), louder calls may have even further detection radii. We also show how beamforming can be used on MAARU devices to improve species ID confidence scores by 20%+ and recall by 10%+ when using the BirdNET automated bird identification algorithms. 4 -MAARU is an accessible, low-cost option for those looking to explore spatial soundscape ecology accurately and easily. Ultimately, the added directional element of the multichannel recording provided by MAARU allows for a new type of exploration into sonic environments. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/576628v1_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@1078827org.highwire.dtl.DTLVardef@17bd5b1org.highwire.dtl.DTLVardef@10a6696org.highwire.dtl.DTLVardef@1d518f4_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗