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Gold mining is a major driver of Amazonian forest loss and degradation. As mining activity encroaches on primary forest in remote and inaccessible areas, satellite imagery provides crucial data for monitoring mining-related deforestation. High-resolution imagery, in particular, has shown promise for detecting artisanal gold mining at the forest frontier. An important next step will be to establish relationships between satellite-derived land cover change and biodiversity impacts of gold mining. In this study, we set out to detect artisanal gold mining using high-resolution imagery and relate mining land cover to insects, a taxonomic group that accounts for the majority of faunal biodiversity in tropical forests. We applied an object-based image analysis (OBIA) to classify mined areas in an Indigenous territory in Guyana, using PlanetScope imagery with ~3.7 m resolution. We complemented our OBIA with field surveys of insect family presence or absence in field plots (n = 105) that captured a wide range of mining disturbances. Our OBIA was able to identify mined objects with high accuracy (90% balanced accuracy). Field plots with a higher proportion of OBIA-derived mine cover had significantly lower insect family richness. The effects of mine cover on individual insect taxa were highly variable. Insect groups that respond strongly to mining disturbance could potentially serve as bioindicators for monitoring ecosystem health during and after gold mining. With the advent of global partnerships that provide universal access to PlanetScope imagery for tropical forest monitoring, our approach represents a low-cost and rapid way to assess the biodiversity impacts of gold mining in remote landscapes.

Biodiversity science encompasses multiple disciplines and biological scales from molecules to landscapes. Nevertheless, biodiversity data are often analyzed separately with discipline‐specific methodologies, constraining resulting inferences to a single scale. To overcome this, we present a topic modeling framework to analyze community composition in cross‐disciplinary datasets, including those generated from metagenomics, metabolomics, field ecology and remote sensing. Using topic models, we demonstrate how community detection in different datasets can inform the conservation of interacting plants and herbivores. We show how topic models can identify members of molecular, organismal and landscape‐level communities that relate to wildlife health, from gut microbes to forage quality. We conclude with a future vision for how topic modeling can be used to design cross‐scale studies that promote a holistic approach to detect, monitor and manage biodiversity.

Huge areas of tropical forests are degraded, reducing their biodiversity, carbon, and timber value. The recovery of these degraded forests can be significantly inhibited by climbing plants such as lianas. Removal of super-abundant climbers thus represents a restoration action with huge potential for application across the tropics. While experimental studies largely report positive impacts of climber removal on tree growth and biomass accumulation, the efficacy of climber removal varies widely, with high uncertainty as to where and how to apply the technique. Using meta-analytic techniques, we synthesize results from 26 studies to quantify the efficacy of climber removal for promoting tree growth and biomass accumulation. We find that climber removal increases tree growth by 156% and biomass accumulation by 209% compared to untreated forest, and that efficacy remains for at least 19 years. Extrapolating from these results, climber removal could sequester an additional 32 Gigatons of CO

Reducing emissions from deforestation and forest degradation (REDD+) is a climate change mitigation policy in which rich countries provide payments to developing countries for protecting their forests. In 2009, the countries of Norway and Guyana entered into one of the first bilateral REDD+ programs, with Norway offering to pay US$250 million to Guyana if annual deforestation rates remained below 0.056% from 2010 to 2015. To quantify the impact of this national REDD+ program, we construct a counterfactual times-series trajectory of annual tree cover loss using synthetic matching. This analytical approach allows us to quantify tree cover loss that would have occurred in the absence of the Norway-Guyana REDD+ program. We found that the Norway-Guyana REDD+ program reduced tree cover loss by 35% during the implementation period (2010 to 2015), equivalent to 12.8 million tons of avoided CO 2 emissions. Our analysis indicates that national REDD+ payments attenuated the effect of increases in gold prices, an internationally traded commodity that is the primary deforestation driver in Guyana. Overall, we found strong evidence that the program met the additionality criteria of REDD+. However, we found that tree cover loss increased after the payments ended, and therefore, our results suggest that without continued payments, forest protection is not guaranteed. On the issue of leakage, which is complex and difficult to quantify, a multinational REDD+ program for a region could address leakage that results from differences in forest policies between neighboring countries.

Urban forests associated with green infrastructure for sustainable outcomes are particularly critical in the Global South, where some of the world’s fastest-growing cities are located. However, compared to temperate cities, the drivers of urban tree species distribution in tropical cities remain understudied. In this study, we quantify the spatial distribution and abundance of urban forests in the tropical city of Georgetown, Guyana. British colonialism has shaped this city, including forced movement of peoples under slavery from Africa and indentured servants from the Indian Subcontinent. We studied how this multicultural context has influenced tree species distributions in the capital city of the only Anglophone country in South America. We quantified the abundance of tree species using a stratified sampling design to distribute transects across fifteen neighborhoods that vary in distance to the colonial center of the city and ethnic composition. We recorded a total of 57 unique species, the majority of which (73%) were cultivated for their edible fruits. We identify tree species that likely represent Guyana’s unique multicultural heritage by comparing our species list to flora in nine cities in neighboring countries (Venezuela and Brazil) with different colonial histories. This international comparison identified a set of tree species that occurred only in Guyana. Relationships between ethnic composition and colonial history and tree species distribution were weak at the neighborhood scale, where proportion of East Indian residents had little explanatory power and distance to colonial center was correlated with abundance of only some species groups. This apparent discrepancy between neighborhood and national scales may relate to the establishment of Guyanese food as a unifying national identifier across ethnicities. The prominence of edible fruit trees in our study suggests a set of species that could be incorporated into urban planning to strengthen biocultural linkages, foster cultural integration, and promote food security.

Selective logging causes at least half of the emissions from tropical forest degradation. Reduced-impact logging for climate (RIL-C) is proposed as a way to maintain timber production while minimizing forest damage. Here we synthesize data from 61 coordinated field-based surveys of logging impacts in seven countries across the tropics. We estimate that tropical selective logging emitted 834 Tg CO2 in 2015, 6% of total tropical greenhouse gas emissions. Felling, hauling, and skidding caused 59%, 31%, and 10% of these emissions, respectively. We suggest that RIL-C incentive programs consider a feasible target carbon impact factor of 2.3 Mg emitted per Mg of timber extracted. Operational modifications are needed to achieve this target, such as reduced wood waste, narrower haul roads, and lower impact skidding equipment. Full implementation would reduce logging emissions by 44% (366 Tg CO2 year−1) and deliver 4% of the nationally determined contributions to the Paris Climate Agreement from tropical countries, while maintaining timber supplies.

Areas allocated for industrial logging and community-owned forests account for over 50% of all remaining tropical forests. Landscape-scale conservation strategies that include these forests are expected to have substantial benefits for biodiversity, especially for large mammals and birds that require extensive habitat but that are susceptible to extirpation due to synergies between logging and hunting. In addition, their responses to logging alone are poorly understood due to their cryptic behavior and low densities. In this study, we assessed the effects of logging and hunting on detection and occupancy rates of large vertebrates in a multiple-use forest on the Guiana Shield. Our study site was certified as being responsibly managed for timber production and indigenous communities are legally guaranteed use-rights to the forest. We coupled camera-trap data for wildlife detection with a spatially explicit dataset on indigenous hunting. A multi-species occupancy model found a weak positive effect of logging on occupancy and detection rates, while hunting had a weak negative effect. Model predictions of species richness were also higher in logged forest sites compared to unlogged forest sites. Density estimates for jaguars and ocelots in our multiple-use area were similar to estimates reported for fully protected areas. Involvement of local communities in forest management, control of forest access, and nesting production forests in a landscape that includes protected areas seemed important for these positive biodiversity outcomes. The maintenance of vertebrate species bodes well for both biodiversity and the humans that depend on multiple-use forests.

The inclusion of managed tropical forests in climate change mitigation has made it important to find the sustainable sweet-spot for timber production, carbon retention, and the quick recovery of both. Here we focus on recovery of aboveground carbon and timber stocks over the first 32 years after selective logging with the CELOS Harvest System in Suriname. Our data are from twelve 1-ha permanent sample plots in which growth, survival, and recruitment of trees ≥15 cm diameter were monitored between 1978 and 2012. We evaluate plot-level changes in basal area, stem density, aboveground carbon, and timber stock in response to average timber harvests of 15, 23, and 46 m3 ha−1. We use a linear mixed-effects model in a Bayesian framework to quantify recovery time for aboveground carbon and timber stock, as well as annualized increments for both. Our statistical models accounted for the uncertainty associated with the height and biomass allometries used to estimate aboveground carbon and increased precision of annualized aboveground carbon increments by including data from forty-one plots located elsewhere on the Guiana Shield. The probabilities of aboveground carbon recovery to pre-logging levels 32 years after harvests of 15, 23 and 46 m3 ha−1 were 45%, 40%, and 24%, respectively. Net aboveground carbon increment for logged forests across all harvest intensities was 0.64 Mg C ha−1 yr−1, more than twice the rate observed in unlogged forests (0.26 Mg C ha−1 yr−1). The probabilities of timber stock recovery at the end of the 32-year period were highest after harvest intensities of 15 and 23 m3 ha−1 (with 80% probability) and lowest after the harvest of 46 m3 ha−1 (with 70% probability). Timber stock recovery across all harvest intensities was driven primarily by residual tree growth. Application of the legal cutting limit of 25 m3 ha−1 will require more than 70 and 40 years to recover aboveground carbon and timber stocks, respectively, with 90% probability. Based on the low recruitment rates of the twelve species harvested, the 25 year cutting cycle currently implemented in Suriname is too short for long-term timber stock sustainability. We highlight the value of propagating uncertainty from individual tree measurements to statistical predictions of carbon stock recovery. Ultimately, our study reveals the trade-offs that must be made between timber and carbon services as well as the opportunity to use carbon payments to enable longer cutting rotations to capture carbon from forest regrowth.

The selective logging that characterizes most timber extraction operations in the tropics leaves large patches of logging blocks (i.e., areas allocated for harvesting) intact, without evidence of direct impacts. For example, in ~10,000 ha sampled in 48 forest management enterprises in Africa (Gabon, Republic of Congo, and the Democratic Republic of Congo), Indonesia, Suriname, and Mexico, an average of 69% (range 20–97%) of the area in logging blocks was not directly affected by timber harvests. The proportion of intact forest within logging blocks decreased very slightly with increases in harvest intensity in the accessed portion of the logging blocks (9–86 m3 ha−1) but decreased strongly with harvest intensity in entire logging blocks (0.3–48.2 m3 ha−1). More forest was left intact in areas farther from roads, on slopes >40%, and within 25 m of perennial streams, but the effect sizes of each of these variables was small (~8%). It is less clear how much of the intact forest left after one harvest will remain intact through the next. Conservation benefits without reductions in timber yields will derive from better management planning so that sensitive and ecologically critical areas, such as steep slopes and riparian buffers, constitute large and permanent proportions of the intact forest in selectively logged landscapes in the tropics.

To assess the impacts of a low-intensity selective timber harvest on a palm community in Belize, we mapped logging infrastructure (i.e., roads, log landings, skid trails, and stumps) and measured palm regeneration 1 year after a timber harvest carried out using reduced-impact logging (RIL) practices. We sampled palms across a gradient of increasing harvest impact severity from areas not directly affected by logging, in felling gaps, on secondary and primary skid trails, and on log landings. We used generalised linear mixed-effect models fitted in a Bayesian framework and applied a non-metric multi-dimensional scaling of the ecological distances between sites to evaluate differences in palm seedling regeneration density and species composition, respectively. The harvest of an average of 2.5 trees ha−1 caused 0.4% of the forest to be converted to log landings, 0.7% and 3.6% to roads and skid trails, and 2.3% to felling gaps, which left 93.0% of the 350 ha harvest block with no direct impacts of logging. The difference in abundance and species composition of palm regeneration in unlogged areas compared to felling gaps and skid trails was small, but log landings had markedly lower densities. These results highlight that the impacts of selective logging are minor at least where harvest intensities are low and RIL practices are employed. If further reductions in canopy opening and soil disturbance are desired, we recommend that logs be cable-yarded (i.e., winched) the final 20 m to skid trails instead of driving to the tree stumps. We estimate that implementation of this practice would reduce total skid trail coverage from 3.6% to 2.9% and overall forest disturbance from 7.0% to 6.3%. However, further reductions in disturbance might be inimical to the maintenance of palms and will certainly not favour regeneration of light-demanding commercial timber species (e.g., Swietenia macrophylla).

Tropical forests have long been thought to be in stable state, but recent insights indicate that global change is leading to shifts in forest dynamics and species composition. These shifts may be driven by environmental changes such as increased resource availability, increased drought stress, and/or recovery from past disturbances. The relative importance of these drivers can be inferred from analyzing changes in trait values of tree communities. Here, we evaluate a decade of change in species and trait composition across five old-growth Neotropical forests in Bolivia, Brazil, Guyana, and Costa Rica that cover large gradients in rainfall and soil fertility. To identify the drivers of compositional change, we used data from 29 permanent sample plots and measurements of 15 leaf, stem, and whole-plant traits that are important for plant performance and should respond to global change drivers. We found that forests differ strongly in their community-mean trait values, resulting from differences in soil fertility and annual rainfall seasonality. The abundance of deciduous species with high specific leaf area increases from wet to dry forests. The community-mean wood density is high in the driest forests to protect xylem vessels against drought cavitation, and is high in nutrient-poor forests to increase wood longevity and enhance nutrient residence time in the plant. Interestingly, the species composition changed over time in three of the forests, and the community-mean wood density increased and the specific leaf area decreased in all forests, indicating that these forests are changing toward later successional stages dominated by slow-growing, shade-tolerant species. We did not see changes in other traits that could reflect responses to increased drought stress, such as increased drought deciduousness or decreased maximum adult size, or that could reflect increased resource availability (CO2, rainfall, or nitrogen). Changes in species and trait composition in these forests are therefore most likely caused by recovery from past disturbances. These compositional changes may also lead to shifts in ecosystem processes, such as a lower carbon sequestration and “slower” forest dynamics.

Ecotourism is developing rapidly in biodiversity hotspots worldwide, but there is limited and mixed empirical evidence that ecotourism achieves positive biodiversity outcomes. We assessed whether ecotourism influenced forest loss rates and trajectories from 2000 to 2017 in Himalayan temperate forests. We compared forest loss in 15 ecotourism hubs with nonecotourism areas in 4 Himalayan countries. We used matching statistics to control for local-level determinants of forest loss, for example, population density, market access, and topography. None of the ecotourism hubs was free of forest loss, and we found limited evidence that forest-loss trajectories in ecotourism hubs were different from those in nonecotourism areas. In Nepal and Bhutan, differences in forest loss rates between ecotourism hubs and matched nonecotourism areas did not differ significantly, and the magnitude of the estimated effect was small. In India, where overall forest loss rates were the lowest of any country in our analysis, forest loss rates were higher in ecotourism hubs than in matched nonecotourism areas. In contrast, in China, where overall forest loss rates were highest, forest loss rates were lower in ecotourism hubs than where there was no ecotourism. Our results suggest that the success of ecotourism as a forest conservation strategy, as it is currently practiced in the Himalaya, is context dependent. In a region with high deforestation pressures, ecotourism may be a relatively environmentally friendly form of economic development relative to other development strategies. However, ecotourism may stimulate forest loss in regions where deforestation rates are low.Efectos del Ecoturismo sobre la Pérdida de Bosques en el Punto Caliente de Biodiversidad en el Himalaya con base en Análisis Contrafactuales Resumen El ecoturismo está desarrollándose rápidamente en los puntos calientes de biodiversidad en todo el mundo, pero existe evidencia empírica mixta y limitada de los resultados positivos que se logran con el ecoturismo. Valoramos si el ecoturismo influyó sobre las tasas de pérdida forestal y sus trayectorias entre el 2000 y el 2017 en los bosques templados del Himalaya. Comparamos la pérdida forestal en quince focos ecoturísticos con la pérdida forestal en las áreas sin ecoturismo de cuatro países del Himalaya. Utilizamos estadística correspondiente para controlar las determinantes a nivel local de la pérdida del bosque, por ejemplo, la densidad poblacional, el acceso al mercado y la topografía. Ninguno de los focos ecoturísticos estaba libre de pérdida forestal, además de que encontramos evidencia limitada de que las trayectorias de la pérdida forestal en los focos ecoturísticos eran diferentes a las trayectorias en las áreas sin ecoturismo. En Nepal y en Bután, las diferencias en la pérdida forestal entre los focos ecoturísticos y las áreas sin ecoturismo correspondidas no difirieron significativamente y la magnitud del efecto estimado fue menor. En la India, donde las tasas generales de pérdida forestal fueron las más bajas de cualquier país en nuestro análisis, las tasas de pérdida forestal fueron más altas en los focos ecoturísticos que en las áreas sin ecoturismo correspondidas. Como contraste, en China, donde las tasas generales de pérdida forestal fueron más altas, las tasas de pérdida forestal fueron más bajas en los focos ecoturísticos que en donde no existe el ecoturismo. Nuestros resultados sugieren que el éxito del ecoturismo como estrategia de conservación del bosque, a como se práctica actualmente en el Himalaya, depende del contexto. En una región con presiones altas de deforestación, el ecoturismo puede ser una forma de desarrollo económico relativamente amigable con el ambiente comparado con otras estrategias de desarrollo. Sin embargo, el ecoturismo puede estimular la pérdida forestal en regiones en las que las tasas de deforestación son bajas.全球范围内, 生物多样性热点地区的生态旅游正在快速发展, 但缺少明确的实证证据来证明生态旅游对生物多样性保护有积极作用。本研究评估了生态旅游是否对 2000-2017 年间喜马拉雅温带森林的森林丧失率和森林丧失轨迹产生影响。我们比较了喜马拉雅地区四个国家的十五个生态旅游区与非生态旅游区的森林丧失情况。我们用配对的统计数据来控制当地影响森林丧失的其它因素, 如人口密度, 开放市场程度和地形等。我们发现所有生态旅游区都遭受了森林丧失, 且有限的证据表明, 生态旅游区与非生态旅游区森林丧失轨迹并不一致。在尼泊尔和不丹, 生态旅游区与相配对的非生态旅游区的森林丧失率没有显著差异, 我们估计的生态旅游影响程度也很低。在本研究中, 印度的森林总体丧失率最低, 生态旅游区的森林丧失率比相配对的非生态旅游区更高。相比之下, 在森林总体丧失率最高的中国, 生态旅游区的森林丧失率却比非生态旅游区的更低。我们的结果表明, 以目前喜马拉雅地区的实践为例, 生态旅游能否成为一种成功的森林保护策略要依据具体情况。在森林砍伐压力较大的地区, 生态旅游可能是相比于其它发展策略较为坏境友好的经济发展形式, 但在森林砍伐率低的地区, 生态旅游则可能加速森林丧失。【翻译: 胡怡思; 审校: 聂永刚】.

SummaryWhile around 20% of the Amazonian forest has been cleared for pastures and agriculture, one fourth of the remaining forest is dedicated to wood production [1]. Most of these production forests have been or will be selectively harvested for commercial timber, but recent studies show that even soon after logging, harvested stands retain much of their tree-biomass carbon and biodiversity [2,3]. Comparing species richness of various animal taxa among logged and unlogged forests across the tropics, Burivalova et al. [4] found that despite some variability among taxa, biodiversity loss was generally explained by logging intensity (the number of trees extracted). Here, we use a network of 79 permanent sample plots (376 ha total) located at 10 sites across the Amazon Basin [5] to assess the main drivers of time-to-recovery of post-logging tree carbon (Table S1). Recovery time is of direct relevance to policies governing management practices (i.e., allowable volumes cut and cutting cycle lengths), and indirectly to forest-based climate change mitigation interventions.