Phytolith analysis is a well-established archaeobotanical tool, having provided important insights into pre-Columbian crop cultivation and domestication across Amazonia through the Holocene. Yet, its use as a palaeoecological tool is in its infancy in Amazonia and its effectiveness for reconstructing pre-Columbian land-use beyond archaeological sites (i.e., ‘off-site’) has so far received little critical attention. This paper examines both new and previously published soil phytolith data from SW Amazonia to assess the robustness of this proxy for reconstructing pre-Columbian land-use. We conducted the study via off-site soil pits radiating 7.5 km beyond a geoglyph in Acre state, Brazil, and 50 km beyond a ring-ditch in northern Bolivia, spanning the expected gradients in historical land-use intensity. We found that the spatio-temporal patterns in palm phytolith data across our soil-pit transects support the hypothesis that pre-Columbian peoples enriched their forests with palms over several millennia, although phytoliths are limited in their ability to capture small-scale crop cultivation and deforestation. Despite these drawbacks, we conclude that off-site soil phytolith analysis can provide novel insights into pre-Columbian land use, provided it is effectively integrated with other land-use (e.g., charcoal) and archaeological data.

Hunting impacts tropical vertebrate populations, causing declines of species that function as seed dispersers and predators, or that browse seedlings and saplings. Whether and how the resulting reductions in seed dispersal, seed predation, and browsing translate to changes in the tree composition is poorly understood. Here, we assess the effect of defaunation on the functional composition of communities of tree recruits in tropical rainforests in French Guiana. We selected eight sites along a gradient of defaunation, caused by differences in hunting pressure, in otherwise intact old-growth forests in French Guiana. We measured shifts in functional composition by comparing leaf and fruit traits and wood density between tree recruits (up to 5 cm diameter at breast height) and adults, and tested whether and how these compositional shifts related to defaunation. We found a positive relationship with defaunation for shifts in specific leaf area, a negative relationship for shifts of leaf toughness and wood density, and a weak relationship for shifts in fruit traits. Our results suggest that the loss of vertebrates affects ecological processes such as seed dispersal and browsing, of which browsing remains understudied. Even though these changes sometimes seem minor, together they result in major shifts in forest composition. These changes have long-term ramifications that may alter forest dynamics for generations.

Aim Water availability is the major driver of tropical forest structure and dynamics. Most research has focused on the impacts of climatic water availability, whereas remarkably little is known about the influence of water table depth and excess soil water on forest processes. Nevertheless, given that plants take up water from the soil, the impacts of climatic water supply on plants are likely to be modulated by soil water conditions. Location Lowland Amazonian forests. Time period 1971-2019. Methods We used 344 long-term inventory plots distributed across Amazonia to analyse the effects of long-term climatic and edaphic water supply on forest functioning. We modelled forest structure and dynamics as a function of climatic, soil-water and edaphic properties. Results Water supplied by both precipitation and groundwater affects forest structure and dynamics, but in different ways. Forests with a shallow water table (depth <5 m) had 18% less above-ground woody productivity and 23% less biomass stock than forests with a deep water table. Forests in drier climates (maximum cumulative water deficit < -160 mm) had 21% less productivity and 24% less biomass than those in wetter climates. Productivity was affected by the interaction between climatic water deficit and water table depth. On average, in drier climates the forests with a shallow water table had lower productivity than those with a deep water table, with this difference decreasing within wet climates, where lower productivity was confined to a very shallow water table. Main conclusions We show that the two extremes of water availability (excess and deficit) both reduce productivity in Amazon upland (terra-firme) forests. Biomass and productivity across Amazonia respond not simply to regional climate, but rather to its interaction with water table conditions, exhibiting high local differentiation. Our study disentangles the relative contribution of those factors, helping to improve understanding of the functioning of tropical ecosystems and how they are likely to respond to climate change.

The formalization of community forest tenure rights is expected to promote sustainable community forest management, and is seen as a way to combine objectives related to environmental conservation, livelihood improvement, and local self-determination. However, the formalization of forest tenure rights by itself, does not automatically result in the intended impacts. There is a need to better understand the conditions under which communities are able to use these rights to achieve positive outcomes across multiple dimensions. We formulated a simple theory of change that underlies the formalization of community forest tenure rights, and used it to assess the outcomes, bottlenecks and enabling conditions of community forest tenure models across the forested tropics. Based on this analysis, we identified ten conditions that need to be in place for community forest tenure rights formalization to achieve the intended impacts. The theory of change and associated conditions form a generic conceptual framework that can be used to inform policy and practice of actors supporting community forest tenure rights, including civil society organizations and government agencies.

Tropical forests are the most diverse and productive ecosystems on Earth. While better understanding of these forests is critical for our collective future, until quite recently efforts to measure and monitor them have been largely disconnected. Networking is essential to discover the answers to questions that transcend borders and the horizons of funding agencies. Here we show how a global community is responding to the challenges of tropical ecosystem research with diverse teams measuring forests tree-by-tree in thousands of long-term plots. We review the major scientific discoveries of this work and show how this process is changing tropical forest science. Our core approach involves linking long-term grassroots initiatives with standardized protocols and data management to generate robust scaled-up results. By connecting tropical researchers and elevating their status, our Social Research Network model recognises the key role of the data originator in scientific discovery. Conceived in 1999 with RAINFOR (South America), our permanent plot networks have been adapted to Africa (AfriTRON) and Southeast Asia (T-FORCES) and widely emulated worldwide. Now these multiple initiatives are integrated via ForestPlots.net cyber-infrastructure, linking colleagues from 54 countries across 24 plot networks. Collectively these are transforming understanding of tropical forests and their biospheric role. Together we have discovered how, where and why forest carbon and biodiversity are responding to climate change, and how they feedback on it. This long-term pan-tropical collaboration has revealed a large long-term carbon sink and its trends, as well as making clear which drivers are most important, which forest processes are affected, where they are changing, what the lags are, and the likely future responses of tropical forests as the climate continues to change. By leveraging a remarkably old technology, plot networks are sparking a very modern revolution in tropical forest science. In the future, humanity can benefit greatly by nurturing the grassroots communities now collectively capable of generating unique, long-term understanding of Earth's most precious forests.

A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-20537-x

Equity is an essential element in the implementation of policies related to ecosystem services. With the rapid expansion of commercial land use into tropical forest regions, the urgency and importance to integrate equity issues in space and time in decisions and actions stand without doubt. However, data scarcity in these regions limits the understanding of factors that affect spatial and temporal aspects of equity. This again emphasizes the need of rapid and robust ways to address spatio-temporal patterns of equity that are especially suited for data-scarce regions. This study addresses this gap. We assess the factors that have an influence on spatial equity through an empirical study that compares two sub-regions in the Upper Suriname River Basin. In the first sub-region, some logging and road building occur; the other, however, is more remote and such interventions are not yet developed but merely planned. We collected spatial data for 1995 and 2015 using a participatory GIS survey (n = 493), registering provisioning service hotspots. We then explored spatial equity, according to clan and authority position, by analyzing variation over time and across regions in relation to access capabilities of these users. In the region with roads and logging, spatial equity concerns emerged over time regarding the provision of timber and fish. In the remote region, spatial inequity in access to fish provisioning hotspots of ecosystem services increased while it showed a decreasing trend for timber. In outlining spatial equity concerns, we argue that spatial equity analysis unveils an essential social dimension in the use of the space that is integral in spatial planning processes in data scarce forest regions under external pressures.

Smallholder farmers might adopt different farming practices to cope with multiple stressors depending on their livelihood assets, and with varying environmental and economic outcomes. Ongoing global change is triggering stronger and different stressors that threaten conventional farming practices; however, this could be resolved if livelihood assets that drive decision making are actionable and thus can be modified. This study assessed the influence of farmers' livelihood assets, risk perception, and shocks on the choice of non-conventional farming practices for smallholder coffee farmers in San Martín, Peru. Using household survey data, we collected data on 162 coffee plantations along an elevation gradient. We operationalized the sustainable livelihoods framework for the adoption of shade and input coffee farming strategies and explored farmers' motives to change them. Despite associated high risks with pest and disease pressure, coffee price volatility and climate change, these risks did not explain the current shade and input farming strategies. While in the past five years, farmers adapted shade and input management in response to pest and disease and climate change pressures, these occurred in diverging directions: we found higher human and social assets associated with higher shade levels, and a trend for higher physical and financial assets associated with higher input use. These findings illustrate that two main factors affect decisions on farming practices related to shade and input management and they relate to different livelihood capitals. This suggests a potential for conflicting decision-making, push-and-pulling decisions in different directions. Further the disconnect between livelihood assets and perceptions suggests that perception of risk and shocks might not be sufficient to motivate decision making under changing conditions. Such insights in decision-making typologies and drivers can inform the development of farming practices that enhance resilience and sustainability of smallholder coffee production in Peru and elsewhere in the tropics.

Higher levels of taxonomic and evolutionary diversity are expected to maximize ecosystem function, yet their relative importance in driving variation in ecosystem function at large scales in diverse forests is unknown. Using 90 inventory plots across intact, lowland, terra firme, Amazonian forests and a new phylogeny including 526 angiosperm genera, we investigated the association between taxonomic and evolutionary metrics of diversity and two key measures of ecosystem function: aboveground wood productivity and biomass storage. While taxonomic and phylogenetic diversity were not important predictors of variation in biomass, both emerged as independent predictors of wood productivity. Amazon forests that contain greater evolutionary diversity and a higher proportion of rare species have higher productivity. While climatic and edaphic variables are together the strongest predictors of productivity, our results show that the evolutionary diversity of tree species in diverse forest stands also influences productivity. As our models accounted for wood density and tree size, they also suggest that additional, unstudied, evolutionarily correlated traits have significant effects on ecosystem function in tropical forests. Overall, our pan-Amazonian analysis shows that greater phylogenetic diversity translates into higher levels of ecosystem function: tropical forest communities with more distantly related taxa have greater wood productivity.

Crop production often comes at the expense of losses in ecosystem services and biodiversity; however, this might not always be the case. Here we test the effects of shade gradients and agricultural inputs on trade-offs or synergies between coffee yield and ecosystem services and biodiversity data for smallholder coffee plantations of Arabica coffee in Peru. We collected data using surveys (n = 162 farmers) and field sampling (n = 62 farms) and modelled the relationship between coffee yield, butterfly species richness and carbon storage, accounting for soil fertility and yield losses to pests and diseases. We found that both carbon and forest butterfly species richness were higher in plantations with more shade, and with no reduction in coffee yields with increasing shade. There were no significant correlations between coffee yield, forest butterfly species richness and carbon storage. Use of agricultural inputs, especially fertilizers, was highest in sites with low coffee yield, but was not related with either forest butterfly species richness or carbon. The lack of trade-offs between yield, forest butterfly species richness and carbon, and their relationships with shade and agricultural inputs suggest that it is possible to manage coffee agroforests to simultaneously provide multiple ecosystem services without reducing coffee yields.

Most of the planet's diversity is concentrated in the tropics, which includes many regions undergoing rapid climate change. Yet, while climate‐induced biodiversity changes are widely documented elsewhere, few studies have addressed this issue for lowland tropical ecosystems. Here we investigate whether the floristic and functional composition of intact lowland Amazonian forests have been changing by evaluating records from 106 long‐term inventory plots spanning 30 years. We analyse three traits that have been hypothesized to respond to different environmental drivers (increase in moisture stress and atmospheric CO2 concentrations): maximum tree size, biogeographic water‐deficit affiliation and wood density. Tree communities have become increasingly dominated by large‐statured taxa, but to date there has been no detectable change in mean wood density or water deficit affiliation at the community level, despite most forest plots having experienced an intensification of the dry season. However, among newly recruited trees, dry‐affiliated genera have become more abundant, while the mortality of wet‐affiliated genera has increased in those plots where the dry season has intensified most. Thus, a slow shift to a more dry‐affiliated Amazonia is underway, with changes in compositional dynamics (recruits and mortality) consistent with climate‐change drivers, but yet to significantly impact whole‐community composition. The Amazon observational record suggests that the increase in atmospheric CO2 is driving a shift within tree communities to large‐statured species and that climate changes to date will impact forest composition, but long generation times of tropical trees mean that biodiversity change is lagging behind climate change.

In many cases, government institutions lack to consider community areas as a part of their traditional land use in spatial planning policy. The results of numerous investigations into participatory mapping have been insufficiently adopted by Spatial Planning Regulation (SPR). In Indonesia, Spatial Planning Regulation (Rencana Tata Ruang Wilayah / RTRW) is an instrument to guide sectors related to land uses both development and protection. Using a case study for the Merauke district of Papua province in Indonesia, we demonstrate how participatory mapping results can be integrated into SPR. To our knowledge, this is the first successful attempt to integrate important community areas into the regulation of district spatial planning. Participatory GIS (PGIS) was used to map important community areas. There are three phases to the process of combining PGIS with Spatial Planning Regulation. The first phase was to develop a shared vision between the communities and district government and commitment from both parties to accept the final mapping results for use in the further planning process. The second was to facilitate the community to conduct the participatory GIS process and the final phase was to integrate the important community areas into the spatial planning regulation at a scale of 1:50.000 by the RTRW of Merauke district. The total area adopted by the RTRW was about 69% of cultural preservation areas under protected areas. The rest of the important community areas merged into land use allocations within both categories of protected areas (22%) and development areas (9%). In this case, 91% of the community areas were secured from other land use purposes for agriculture, mining, forestry and infrastructure. The PGIS approach can be applied to other districts across Indonesia for mapping the community land use practices in Spatial Planning Regulation.

Tropical agroforestry systems provide a number of ecosystem services that might help sustain the production of multiple crops, improve farmers' livelihoods and conserve biodiversity. A major drawback of agroforestry coffee systems is the perceived lower economic performance compared to high-input monoculture coffee systems, which is driving worldwide intensification practices of coffee systems. However, comprehensive cost-benefit analyses of small-scale coffee plantations are scarce. Consequently, there is a need to improve our understanding of the economic performance of coffee systems under different shade and input management practices. We provide a comprehensive economic analysis of Arabica coffee farming practices where we compare productivity, costs, net income and benefit-cost ratio (BCR) of 162 small-scale, Peruvian coffee plantations under different shade and input management practices along an elevation gradient. By using a cluster analysis, three shade and three input classes (low, medium and high) were defined. We found similar economic performance for all shade classes, but reduced net income and BCR in the High-Input class. More specifically, there was no difference in net income or BCR between low, medium and high shade classes. The High-Input class had significantly lower net income and BCR, mainly due to increased costs of (hired) labour, land, and fertilizer and fungicides; costs which were not fully compensated for by higher coffee yields. Coffee yield decreased with elevation, whereas gate coffee price and quality, as well as shade levels, increased with elevation. Additional revenues from timber could increase farmers' income and overall economic performance of shaded plantations in the future. Our analysis provides evidence that for small-scale coffee production, agroforestry systems perform equally well or better than unshaded plantations with high input levels, reinforcing the theory that good economic performance can coincide with conservation of biodiversity and associated ecosystem services. Additional comprehensive and transparent economic analyses for other geographic regions are needed to be able to draw generalizable conclusions for smallholder coffee farming worldwide. We advise that future economic performance studies simultaneously address the effects of shade and input management on economic performance indicators and take biophysical variation into account.

Quantifying the relationship between tree diameter and height is a key component of efforts to estimate biomass and carbon stocks in tropical forests. Although substantial site‐to‐site variation in height–diameter allometries has been documented, the time consuming nature of measuring all tree heights in an inventory plot means that most studies do not include height, or else use generic pan‐tropical or regional allometric equations to estimate height. Using a pan‐tropical dataset of 73 plots where at least 150 trees had in‐field ground‐based height measurements, we examined how the number of trees sampled affects the performance of locally derived height–diameter allometries, and evaluated the performance of different methods for sampling trees for height measurement. Using cross‐validation, we found that allometries constructed with just 20 locally measured values could often predict tree height with lower error than regional or climate‐based allometries (mean reduction in prediction error = 0.46 m). The predictive performance of locally derived allometries improved with sample size, but with diminishing returns in performance gains when more than 40 trees were sampled. Estimates of stand‐level biomass produced using local allometries to estimate tree height show no over‐ or under‐estimation bias when compared with biomass estimates using field measured heights. We evaluated five strategies to sample trees for height measurement, and found that sampling strategies that included measuring the heights of the ten largest diameter trees in a plot outperformed (in terms of resulting in local height–diameter models with low height prediction error) entirely random or diameter size‐class stratified approaches. Our results indicate that even limited sampling of heights can be used to refine height–diameter allometries. We recommend aiming for a conservative threshold of sampling 50 trees per location for height measurement, and including the ten trees with the largest diameter in this sample.

the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

There is a growing disconnect between the international conferences where grand solutions for tropical conservation are designed and the complex local realities in tropical landscapes where plans need to be implemented. Every tropical landscape is different and no “one size will fit all.” There is a tendency for global processes to prescribe simple generalized solutions that provide good sound bites that can be communicated with political actors and the media. Sustainable outcomes in tropical landscapes require locally adapted, unique approaches supported by long-term processes of learning and adaptation. Tropical biologists and conservationists can play a key role by establishing effective local–global links and by directly engaging in local policy discourses while remaining connected to evolving political imperatives.

The trend of wildlife habitat fragmentation worldwide continues as a result of anthropogenic activities on development of a linear infrastructure and land use changes, which is often implemented as part of spatial planning policies. In this paper we expand upon an existing approach to design wildlife corridors through habitat quality assessment. We used models of Habitat Quality of Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) and Corridor Design tools. The habitat quality model of InVEST provides a rapid approach to assess status and change of biodiversity, and can contribute to enhanced corridor design of fragmented wildlife habitat. We conducted an assessment of habitat quality of the RIMBA corridor landscape, which is part of Riau, Jambi and West Sumatra provinces of central Sumatra Island. The result of the habitat quality model was used as the main input to evaluate habitat connectivity and assess the target segment of roads that cross the modelled corridor. We found 20 wildland blocks, the total area of the corridor modelled including wildland blocks was calculated as about 0.77 million hectares. We have obtained accurate quantitative measurement of the length of roads crossing the corridor, with a total of 417.78 km (artery 10.31 km; collector 19.52 km; and local 1987.9 km roads). This method can be replicated as an approach in valuing the quality of habitat as part of the implementation of the presidential decree of Sumatra Island Spatial Planning. This may also be applied to the spatial planning of other major islands in Indonesia and elsewhere.

This paper compares financial and biodiversity performance of small-scale shaded coffee and cocoa plantations versus intensified conventional ones. We conduct a meta-analysis including 23 studies on coffee and cocoa plantations over a 26year period. Our results show that, contrary to common perceptions, profitability and cost-efficiency are higher for small-scale shaded systems. Despite the lower yields for shaded systems, the lower costs per area and higher price per kilogram of coffee or cocoa causes shaded systems to perform better financially. This finding shows that the traditional indicator ‘yield’ is an inaccurate measure of financial performance when studying diversified systems, and that the more detailed indicators as net revenue or benefit-cost ratio should be used instead. Few studies specifically reported on the relationship between biodiversity and financial performance, providing divergent results, yet various papers showed a promising optimum relationship for intermediate levels of shade. Because shaded systems are known to correlate positively with biodiversity, we postulate that they can offer competitive business opportunities for small-scale farmers, while also contributing to biodiversity conservation. Still, there is a pressing need for multidisciplinary studies to quantify financial and biodiversity performance simultaneously, and to identify opportunities for scaling up shaded systems.

Within the tropics, the species richness of tree communities is strongly and positively associated with precipitation. Previous research has suggested that this macroecological pattern is driven by the negative effect of water‐stress on the physiological processes of most tree species. This implies that the range limits of taxa are defined by their ability to occur under dry conditions, and thus in terms of species distributions predicts a nested pattern of taxa distribution from wet to dry areas. However, this ‘dry‐tolerance’ hypothesis has yet to be adequately tested at large spatial and taxonomic scales. Here, using a dataset of 531 inventory plots of closed canopy forest distributed across the western Neotropics we investigated how precipitation, evaluated both as mean annual precipitation and as the maximum climatological water deficit, influences the distribution of tropical tree species, genera and families. We find that the distributions of tree taxa are indeed nested along precipitation gradients in the western Neotropics. Taxa tolerant to seasonal drought are disproportionally widespread across the precipitation gradient, with most reaching even the wettest climates sampled; however, most taxa analysed are restricted to wet areas. Our results suggest that the ‘dry tolerance' hypothesis has broad applicability in the world's most species‐rich forests. In addition, the large number of species restricted to wetter conditions strongly indicates that an increased frequency of drought could severely threaten biodiversity in this region. Overall, this study establishes a baseline for exploring how tropical forest tree composition may change in response to current and future environmental changes in this region.