Valuing the functionality of tropical ecosystems beyond carbon

Land-based carbon sequestration projects, such as tree planting, are a prominent strategy to offset carbon emissions. However, we risk reducing natural ecosystems to one metric – carbon. Emphasis on restoring ecosystems to balance ecosystem services, biodiversity conservation, and carbon sequestration is a more appropriate strategy to protect their functioning

Developing cost-effective field assessments of carbon stocks in human-modified tropical forests

Across the tropics, there is a growing financial investment in activities that aim to reduce emissions from deforestation and forest degradation, such as REDD+. However, most tropical countries lack on-the-ground capacity to conduct reliable and replicable assessments of forest carbon stocks, undermining their ability to secure long-term carbon finance for forest conservation programs. Clear guidance on how to reduce the monetary and time costs of field assessments of forest carbon can help tropical countries to overcome this capacity gap. Here we provide such guidance for cost-effective one-off field assessments of forest carbon stocks. We sampled a total of eight components from four different carbon pools (i.e. aboveground, dead wood, litter and soil) in 224 study plots distributed across two regions of eastern Amazon. For each component we estimated survey costs, contribution to total forest carbon stocks and sensitivity to disturbance. Sampling costs varied thirty-one-fold between the most expensive component, soil, and the least, leaf litter. Large live stems (≥10 cm DBH), which represented only 15% of the overall sampling costs, was by far the most important component to be assessed, as it stores the largest amount of carbon and is highly sensitive to disturbance. If large stems are not taxonomically identified, costs can be reduced by a further 51%, while incurring an error in aboveground carbon estimates of only 5% in primary forests, but 31% in secondary forests. For rapid assessments, necessary to help prioritize locations for carbon- conservation activities, sampling of stems ≥20cm DBH without taxonomic identification can predict with confidence (R2 = 0.85) whether an area is relatively carbon-rich or carbon-poor—an approach that is 74% cheaper than sampling and identifying all the stems ≥10cm DBH. We use these results to evaluate the reliability of forest carbon stock estimates provided by the IPCC and FAO when applied to human-modified forests, and to highlight areas where cost savings in carbon stock assessments could be most easily made

Tropical forests in the Americas are changing too slowly to track climate change

Understanding the capacity of forests to adapt to climate change is of pivotal importance for conservation science, yet this is still widely unknown. This knowledge gap is particularly acute in high-biodiversity tropical forests. Here, we examined how tropical forests of the Americas have shifted community trait composition in recent decades as a response to changes in climate. Based on historical trait-climate relationships, we found that, overall, the studied functional traits show shifts of less than 8% of what would be expected given the observed changes in climate. However, the recruit assemblage shows shifts of 21% relative to climate change expectation. The most diverse forests on Earth are changing in functional trait composition but at a rate that is fundamentally insufficient to track climate change

Week 96 efficacy and safety results of the phase 3, randomized EMERALD trial to evaluate switching from boosted-protease inhibitors plus emtricitabine/tenofovir disoproxil fumarate regimens to the once daily, single-tablet regimen of darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) in treatment-experienced, virologically-suppressed adults living with HIV-1

Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg was investigated through 96 weeks in EMERALD (NCT02269917). Virologically-suppressed, HIV-1-positive treatment-experienced adults (previous non-darunavir virologic failure [VF] allowed) were randomized (2:1) to D/C/F/TAF or boosted protease inhibitor (PI) plus emtricitabine/tenofovir-disoproxil-fumarate (F/TDF) over 48 weeks. At week 52 participants in the boosted PI arm were offered switch to D/C/F/TAF (late-switch, 44 weeks D/C/F/TAF exposure). All participants were followed on D/C/F/TAF until week 96. Efficacy endpoints were percentage cumulative protocol-defined virologic rebound (PDVR; confirmed viral load [VL] >= 50 copies/mL) and VL = 50 copies/mL (VF) (FDA-snapshot analysis). Of 1141 randomized patients, 1080 continued in the extension phase. Few patients had PDVR (D/C/F/TAF: 3.1%, 24/763 cumulative through week 96; late-switch: 2.3%, 8/352 week 52-96). Week 96 virologic suppression was 90.7% (692/763) (D/C/F/TAF) and 93.8% (330/352) (late-switch). VF was 1.2% and 1.7%, respectively. No darunavir, primary PI, tenofovir or emtricitabine resistance-associated mutations were observed post-baseline. No patients discontinued for efficacy-related reasons. Few discontinued due to adverse events (2% D/C/F/TAF arm). Improved renal and bone parameters were maintained in the D/C/F/TAF arm and observed in the late-switch arm, with small increases in total cholesterol/high-density-lipoprotein-cholesterol ratio. A study limitation was the lack of a control arm in the week 96 analysis. Through 96 weeks, D/C/F/TAF resulted in low PDVR rates, high virologic suppression rates, very few VFs, and no resistance development. Late-switch results were consistent with D/C/F/TAF week 48 results. EMERALD week 96 results confirm the efficacy, high genetic barrier to resistance and safety benefits of D/C/F/TAF

Old-growth forest loss and secondary forest recovery across Amazonian countries

There is growing recognition of the potential of large-scale forest restoration in the Amazon as a 'nature-based solution' to climate change. However, our knowledge of forest loss and recovery beyond Brazil is limited, and carbon emissions and accumulation have not been estimated for the whole biome. Combining a 33 year land cover dataset with estimates of above-ground biomass and carbon sequestration rates, we evaluate forest loss and recovery across nine Amazonian countries and at a local scale. We also estimate the role of secondary forests in offsetting old-growth deforestation emissions and explore the temporal trends in forest loss and recovery. We find secondary forests across the biome to have offset just 9.7% of carbon emissions from old-growth deforestation, despite occupying 28.8% of deforested land. However, these numbers varied between countries ranging from 9.0% in Brazil to 23.8% in Guyana for carbon offsetting, and 24.8% in Brazil to 56.9% in Ecuador for forest area recovery. We reveal a strong, negative spatial relationship between old-growth forest loss and recovery by secondary forests, showing that regions with the greatest potential for large-scale restoration are also those that currently have the lowest recovery (e.g. Brazil dominates deforestation and emissions but has the lowest recovery). In addition, a temporal analysis of the regions that were >80% deforested in 1997 shows a continued decline in overall forest cover. Our findings identify three important challenges: (a) incentivising large-scale restoration in highly deforested regions, (b) protecting secondary forests without disadvantaging landowners who depend on farm-fallow systems, and (c) preventing further deforestation. Combatting all these successfully is essential to ensuring that the Amazon biome achieves its potential in mitigating anthropogenic climate change

Detecting and reducing heterogeneity of error in acoustic classification

Passive acoustic monitoring can be an effective method for monitoring species, allowing the assembly of large audio datasets, removing logistical constraints in data collection and reducing anthropogenic monitoring disturbances. However, the analysis of large acoustic datasets is challenging and fully automated machine learning processes are rarely developed or implemented in ecological field studies. One of the greatest uncertainties hindering the development of these methods is spatial generalisability—can an algorithm trained on data from one place be used elsewhere? We demonstrate that heterogeneity of error across space is a problem that could go undetected using common classification accuracy metrics. Second, we develop a method to assess the extent of heterogeneity of error in a random forest classification model for six Amazonian bird species. Finally, we propose two complementary ways to reduce heterogeneity of error, by (i) accounting for it in the thresholding process and (ii) using a secondary classifier that uses contextual data. We found that using a thresholding approach that accounted for heterogeneity of precision error reduced the coefficient of variation of the precision score from a mean of 0.61 ± 0.17 (SD) to 0.41 ± 0.25 in comparison to the initial classification with threshold selection based on F-score. The use of a secondary, contextual classification with thresholding selection accounting for heterogeneity of precision reduced it further still, to 0.16 ± 0.13, and was significantly lower than the initial classification in all but one species. Mean average precision scores increased, from 0.66 ± 0.4 for the initial classification, to 0.95 ± 0.19, a significant improvement for all species. We recommend assessing—and if necessary correcting for—heterogeneity of precision error when using automated classification on acoustic data to quantify species presence as a function of an environmental, spatial or temporal predictor variable

Temporal patterns of Amazonian insect acoustic activity

Insects are one of the most diverse taxa and are fundamental to the delivery of many ecosystem services. Despite their global ubiquity and ecological importance, there is little research on temporal variation in insect activity, especially in the tropics where the group is most diverse. Gaps in our knowledge of insects are compounded by a lack of robust methods to monitor their activity at fine timescales. Ecoacoustic techniques have emerged as an effective means to monitor a range of taxa over long periods. Here, we assess insect acoustic activity in the eastern Brazilian Amazon across daily and seasonal cycles over 2 years. We relate acoustic indices to two subsets of manually assessed activity—sonotype diversity and spectrogram coverage. We find evidence for daily and seasonal periodicity, with both the spectrogram coverage and number of insect sonotypes higher nocturnally. Insect acoustic activity peaks during the dry season. Of the five acoustic indices used, the Bioacoustic Index best predicted acoustic insect activity across both metrics. Our results indicate that passive acoustic monitoring can be an effective tool for assessing broad trends in insect phenology. This article is part of the theme issue ‘Acoustic monitoring for tropical ecology and conservation’

Anthropogenic disturbances simplify frugivory interactions in Amazonia

Frugivory interactions are essential ecological processes for the regeneration of tropical forests, ensuring ecosystem resilience following disturbances. However, little is known about how frugivory interactions are shaped by anthropogenic disturbances, especially in Amazonia – one of the most biodiverse ecosystems on Earth. We investigate how selective logging and forest fires impact both arboreal and terrestrial frugivory interactions in Amazonian forests. We focus on four forest classes: Undisturbed, Logged, Logged‐and‐17y‐burned (burned 17 years before sampling) and Logged‐and‐3y‐burned (burned three years before sampling). We recorded 4670 frugivory interactions at the community level, in a sampling effort of 31 484 h. Undisturbed forests sustained a significantly higher number of species and interactions when compared to Logged‐and‐17y‐burned forests, and similar numbers to Logged and Logged‐and‐3y‐burned. Selective logging and forest fires did not alter significantly the structural properties of the frugivory networks, which were highly modular, moderately specialised, poorly connected and non‐nested. Regarding community composition, we detected high β‐diversity of plant species, frugivore species, and their interactions between all study areas, as well as within and between forest classes, mainly driven by species turnover. Logged‐and‐17y‐burned forests hosted the most unique interaction composition compared to Undisturbed forests. Our study provides novel evidence that anthropogenic disturbances, particularly selective logging and forest fires, negatively affect frugivory interactions in Amazonian forests. These effects may persist for years after the initial disturbance events and could be exacerbated due to the predicted increase in forest fires driven by climate change

Reducing socio-environmental impacts of wildfire in sustainable-use reserves in Central Amazon: experiences of the No-Flames Project ("Projeto Sem-Flama")

Sustainable Use Reserves cover 728,270 km2 of the Brazilian Amazon and sustain smallholder communities living in tandem with forest protection. These traditional peoples have used fire for centuries as a central component of their agricultural practices. Today, in the context of a changing climate, agricultural fires are more likely to escape from cultivation areas and promote large socioenvironmental impacts. This happened during the 2015-16 El-Niño, when large wildfires burned 1 Million ha of forests in the Tapajós region, including the Tapajós National Forest Reserve (Flona, 12% burned) and the Tapajós-Arapiuns Extractive Reserve (Resex, 23%). Addressing forest fires is key to mitigate climate change, control biodiversity loss and safeguard local livelihoods. However, interventions to reduce wildfires are implemented by top-down approaches neglecting both local knowledge and management preferences, which could explain performance failures. It is vital to co-develop innovative fire management policies with local communities to enhance the effectiveness of strategies. This presentation will summarize the transdisciplinary workshops held by the No-Flames Project in March 2019. Our main objectives are to engage with local communities, deepen our understanding of their realities, the problems they are facing with increasing fire and envisage possible interventions that can be co-created. We applied two participatory methods - World Cafe and Social Cartography - with representative community members in the Flona (n=8 communities) and the Resex (n=9). Initial results reveal a strong awareness of the increasing flammability of their forests and the multiple burdens arising in this context, from reduced food security to local transportation difficulties. Changes in the social structure (e.g. from collective to individual practices within communities and families) were among the recurrent factors associated to increasing wildfires in the region. Potential solutions perceived by communities were developing programs for environmental education for children and young adults, re-valuing traditional knowledge, especially that of seniors, and integrating it into daily practices, and access to technical support for ecological restoration. Our experience confirms that smallholder forest communities are suffering from wildfires and suggests that engagement with diverse perceptions of the problem can identify novel solutions that move beyond fire prohibition in the search for more equitable alternatives. Â