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Tropical forests are changing in composition and productivity, probably in response to changes in climate and disturbances. The responses to these multiple environmental drivers, and the mechanisms underlying the changes, remain largely unknown. Here, we use a functional trait approach on timescales of 10,000?years to assess how climate and disturbances influence the community-mean adult height, leaf area, seed mass, and wood density for eight lowland and highland forest landscapes. To do so, we combine data of eight fossil pollen records with functional traits and proxies for climate (temperature, precipitation, and El Niño frequency) and disturbances (fire and general disturbances). We found that temperature and disturbances were the most important drivers of changes in functional composition. Increased water availability (high precipitation and low El Niño frequency) generally led to more acquisitive trait composition (large leaves and soft wood). In lowland forests, warmer climates decreased community-mean height probably because of increased water stress, whereas in highland forests warmer climates increased height probably because of upslope migration of taller species. Disturbance increased the abundance of acquisitive, disturbance-adapted taxa with small seeds for quick colonization of disturbed sites, large leaves for light capture, and soft wood to attain fast height growth. Fire had weak effects on lowland forests but led to more stress-adapted taxa that are tall with fast life cycles and small seeds that can quickly colonize burned sites. Site-specific analyses were largely in line with cross-site analyses, except for varying site-level effects of El Niño frequency and fire activity, possibly because regional patterns in El Niño are not a good predictor of local changes, and charcoal abundances do not reflect fire intensity or severity. With future global changes, tropical Amazonian and Andean forests may transition toward shorter, drought- and disturbance-adapted forests in the lowlands but taller forests in the highlands. 1 Introduction 2 Materials and methods 2.1 Sites 2.2 Fossil pollen records 2.3 Functional traits 2.4 Community-mean traits 2.5 Climate 2.6 Fire activity 2.7 General disturbance 2.8 Analyses 3 Results 3.1 Adult tree height 3.2 Leaf area 3.3 Seed mass 3.4 Wood density 4 Discussion 4.1 More favorable climatic growing conditions lead to more acquisitive trait values 4.2 Fires lead to more stress-adapted species, while general disturbances lead to more acquisitive species 4.3 Adult height and LA are most responsive to climate and disturbances 4.4 Local disturbance histories determine local responses to climate and disturbances 5 Conclusions

Advancements in satellite-based forest monitoring increasingly enable the near real-time detection of small-scale tropical forest disturbances. However, there is an urgent need to enhance such monitoring methods with automated direct driver attributions to detected disturbances. This would provide important additional information to make forest disturbance alerts more actionable and useful for uptake by different stakeholders. In this study, we demonstrate spatially explicit and near real-time methods to monitor direct drivers of small-scale tropical forest disturbance across a range of tropical forest conditions in Suriname, the Republic of the Congo and the Democratic Republic of the Congo. We trained a convolutional neural network with Sentinel-1 and Sentinel-2 data to continuously classify newly detected RAdar for Detecting Deforestation (RADD) alerts as smallholder agriculture, road development, selective logging, mining or other. Different monitoring scenarios were evaluated based on varying sensor combinations, post-disturbance time periods and confidence levels. In general, the use of Sentinel-2 data was found to be most accurate for driver classifications, especially with data composited over a period of 4 to 6 months after the disturbance detection. Sentinel-1 data showed to be valuable for more rapid classifications of specific drivers, especially in areas with persistent cloud cover. Throughout all monitoring scenarios, smallholder agriculture was classified most accurately, while road development, selective logging and mining were more challenging to distinguish. An accuracy assessment throughout the full extent of our study regions revealed a Macro-F1 score of 0.861 and an Overall Accuracy of 0.897 for the best performing model, based on the use of 6-month post-disturbance Sentinel-2 composites. Finally, we addressed three specific monitoring use cases that relate to rapid law enforcement against illegal activities, ecological impact assessments and timely carbon emission reporting, by optimizing the trade-off in classification timeliness and confidence to reach required accuracies. Our findings demonstrate the strong capacities of high spatiotemporal resolution satellite data for monitoring direct drivers of small-scale forest disturbance, considering different user interests. The produced forest disturbance driver maps can be accessed via: https://bartslagter94.users.earthengine.app/view/forest-disturbance-drivers.

International audience; Forests that regrow naturally on abandoned fields are important for restoring biodiversity and ecosystem services, but can they also preserve the distinct regional tree floras? Using the floristic composition of 1215 early successional forests (≤20 years) in 75 human-modified landscapes across the Neotropic realm, we identified 14 distinct floristic groups, with a between-group dissimilarity of 0.97. Floristic groups were associated with location, bioregions, soil pH, temperature seasonality, and water availability. Hence, there is large continental-scale variation in the species composition of early successional forests, which is mainly associated with biogeographic and environmental factors but not with human disturbance indicators. This floristic distinctiveness is partially driven by regionally restricted species belonging to widespread genera. Early secondary forests contribute therefore to restoring and conserving the distinctiveness of bioregions across the Neotropical realm, and forest restoration initiatives should use local species to assure that these distinct floras are maintained.

International audience; Tropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation.

The original version of this Article contained an error in Table 2, where the number of individuals in the “All Amazonia” row was reported as 11,6431 instead of 116,431. Also, the original version of this Article contained an error in the Methods, where the R2 for the proportion of broken/uprooted dead trees increase per year was reported as 0.12, the correct value being 0.06. The original version of this Article contained errors in the author affiliations. The affiliation of Gerardo A. Aymard C. with UNELLEZGuanare, Herbario Universitario (PORT), Portuguesa, Venezuela Compensation International Progress S.A. Ciprogress–Greenlife.

Tropical forests are globally important, but it is not clear whether biodiversity enhances carbon storage and sequestration in them. We tested this relationship focusing on components of functional trait biodiversity as predictors. Data are presented for three rain forests in Bolivia, Brazil and Costa Rica. Initial above-ground biomass and biomass increments of survivors, recruits and survivors + recruits (total) were estimated for trees ≥10 cm d.b.h. in 62 and 21 1.0-ha plots, respectively. We determined relationships of biomass increments to initial standing biomass (AGBi), biomass-weighted community mean values (CWM) of eight functional traits and four functional trait variety indices (functional richness, functional evenness, functional diversity and functional dispersion). The forest continuum sampled ranged from ‘slow’ stands dominated by trees with tough tissues and high AGBi, to ‘fast’ stands dominated by trees with soft, nutrient-rich leaves, lighter woods and lower AGBi. We tested whether AGBi and biomass increments were related to the CWM trait values of the dominant species in the system (the biomass ratio hypothesis), to the variety of functional trait values (the niche complementarity hypothesis), or in the case of biomass increments, simply to initial standing biomass (the green soup hypothesis). CWMs were reasonable bivariate predictors of AGBi and biomass increments, with CWM specific leaf area SLA, CWM leaf nitrogen content, CWM force to tear the leaf, CWM maximum adult height Hmax and CWM wood specific gravity the most important. AGBi was also a reasonable predictor of the three measures of biomass increment. In best-fit multiple regression models, CWMHmax was the most important predictor of initial standing biomass AGBi. Only leaf traits were selected in the best models for biomass increment; CWM SLA was the most important predictor, with the expected positive relationship. There were no relationships of functional variety indices to biomass increments, and AGBi was the only predictor for biomass increments from recruits. Synthesis. We found no support for the niche complementarity hypothesis and support for the green soup hypothesis only for biomass increments of recruits. We have strong support for the biomass ratio hypothesis. CWMHmax is a strong driver of ecosystem biomass and carbon storage and CWM SLA, and other CWM leaf traits are especially important for biomass increments and carbon sequestration. Fil: Finegan, B.. Production and Conservation in Forests Programme; Costa Rica Fil: Peña Claros, Marielos. Facultad de Ciencias Agrícolas. Instituto Boliviano de Investigación Forestal; Bolivia. Wageningen University. Forest Ecology and Forest Management Group; Países Bajos Fil: de Oliveira, Alexandre. Universidade de São Paulo. Departamento de Ecologia; Brasil Fil: Ascarrunz, Nataly. Facultad de Ciencias Agrícolas. Instituto Boliviano de Investigación Forestal; Bolivia Fil: Bret Harte, M. Syndonia. University of Alaska. Institute of Arctic Biology; Estados Unidos Fil: Carreno Rocabado, Geovana. Facultad de Ciencias Agrícolas. Instituto Boliviano de Investigación Forestal; Bolivia. Wageningen University. Forest Ecology and Forest Management Group; Países Bajos Fil: Casanoves, Fernando. Biostatistics Unit; Costa Rica Fil: Diaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Eguiguren Velepucha, Paul. Production and Conservation in Forests Programme; Costa Rica Fil: Fernandez, Fernando. Production and Conservation in Forests Programme; Costa Rica Fil: Licona, Juan Carlos. Facultad de Ciencias Agrícolas. Instituto Boliviano de Investigación Forestal; Bolivia Fil: Lorenzo, Leda. Universidade de São Paulo. Departamento de Ecologia; Brasil Fil: Salgado Negret, Beatriz. Production and Conservation in Forests Programme; Costa Rica. Instituto Alexander von Humboldt; Colombia Fil: Vaz, Marcel. Universidade de São Paulo. Departamento de Ecologia; Brasil Fil: Poorter, Lourens. Facultad de Ciencias Agrícolas. Instituto Boliviano de Investigación Forestal; Bolivia. Wageningen University. Forest Ecology and Forest Management Group; Países Bajos

Tropical forest ecosystems are hotspots for biodiversity and represent one of the largest terrestrial carbon stocks, making their role in climate change mitigation (CCM) programmes increasingly important (e.g. REDD+). In Latin America these ecosystems suffer from high land use pressures that have resulted in a dramatic biodiversity loss. Little is known about how CCM options may impact on biodiversity and how this in turn may affect ecosystem carbon storage. Within this context, the FP7 ROBIN (Role Of Biodiversity In climate change mitigatioN) project developed a framework for multi-scale integrated analysis of the impacts that land use change may have on the ecological and social-economic processes of these ecosystems. The framework represents a continuous feedback loop in which changes in CCM options modify land use, that results in biodiversity change, affecting ecosystem functions, leading to changes in ecosystem services that affect human outcomes and societal behaviour, and which then affect the main drivers and pressures on biodiversity and ecosystems, and so on. We have constructed an indicator framework that allows to quantify, link and assess these interactions at three spatial scales: regional (Central and South America), national (Bolivia, Brazil, Guyana and Mexico) and sub-national (study sites representing multifunctional landscapes). Indicators are selected through a demand-driven approach, by directing modelling and assessment efforts towards end-user relevant issues using stakeholder participatory processes. Indicator values are grounded on field data, statistics and model outputs. The framework provides a basis for understanding potential tipping points and unexpected consequences that may arise from the implementation of climate change mitigation policies, or management options (e.g. reducing deforestation and burning, or expansion of areas of biofuel crops in illegal areas). An illustrative example, showing how the framework helps to identify the appropriate indicators to synthesise the impacts of afforestation (one of the CCM options) across the ecological and socio-ecological processes and regions is presented

To determine the annual periodicity of growth rings in seven tree species from a tropical moist forest in Santa Cruz, Bolivia, a fire scar was used as a marker point to verify the annual nature of tree rings. The number of tree rings formed between the 1995 fire scar and the collection of the cross sections in 2002 was visually identified. The seven species showed annual growth rings. In most cases, boundaries between rings were marked by the presence of marginal parenchyma and wall-thicked fibers formed at the end of the growing season. Growth lenses and false rings were recorded in some species. Tree rings can be carefully used in Santa Cruz forests to determine rates of growth. This information is crucial for defining forest management practices in tropical regions., Se establece el carácter anual de las bandas de crecimiento presentes en el leño de siete especies forestales de un bosque tropical húmedo. Se usó como indicador para la verificación del carácter anual de los anillos la cicatriz dejada por un incendio ocurrido en el año 1995. Los anillos presentes en el leño de estas especies desde la ocurrencia del incendio en 1995 hasta el año de muestreo en 2002 fueron determinados visualmente. Las siete especies estudiadas poseen bandas anuales de crecimiento cuyos límites están generalmente demarcados por la presencia de parénquima marginal y el engrosamiento de fibras al final del período de crecimiento. En algunas especies se observó la presencia de lentes de crecimiento y falsos anillos. Los anillos de crecimiento en especies tropicales, aunque presenta algunas dificultades para su datación, pueden ser usados para determinar tasas de crecimiento en los bosques de Santa Cruz. Esta información es crucial para definir planes de manejo forestal sostenibles.

Soil characteristics are important drivers of variation in wet tropical forest structure and diversity, but few studies have evaluated these relationships in drier forest types. Using tree and soil data from 48 and 32 1 ha plots, respectively, in a Bolivian moist and dry forest, we asked how soil conditions affect forest structure and diversity within each of the two forest types. After correcting for spatial effects, soil-vegetation relationships differed between the dry and the moist forest, being strongest in the dry forest. Furthermore, we hypothesized that soil nutrients would play a more important role in the moist forest than in the dry forest because vegetation in the moist forest is less constrained by water availability and thus can show its full potential response to soil fertility. However, contrary to our expectations, we found that soil fertility explained a larger number of forest variables in the dry forest (50 percent) than in the moist forest (17 percent). Shannon diversity declined with soil fertility at both sites, probably because the most dominant, shade-tolerant species strongly increased in abundance as soil fertility increased.

1. The analysis of species distribution patterns along environmental gradients is important for understanding the diversity and ecology of plants and species responses to climate change, but detailed data are surprisingly scarce for the tropics. 2. Here, we analyse the distribution of 100 woody species over 220 1-ha forest plots distributed over an area of c. 160 000 km2, across large environmental gradients in lowland Bolivia and evaluate the relative importance of climate and soils in shaping species distribution addressing four multivariate environmental axes (rainfall amount and distribution, temperature, soil fertility and soil texture). 3. Although species abundance was positively related to species frequency (the number of plots in which the species is found), this relationship was rather weak, which challenges the view that most tropical forests are dominated at large scales by a few common species. 4. Species responded clearly to environmental gradients, and for most of the species (65%), climatic and soil conditions could explain most of the variation in occurrence (R2 > 0.50), which challenges the idea that most tropical tree species are habitat generalists. 5. Climate was a stronger driver of species distribution than soils; 91% of the species were affected by rainfall (distribution), 72% by temperature, 47% by soil fertility and 44% by soil texture. In contrast to our expectation, few species showed a typical unimodal response to the environmental gradients.6. Synthesis. Tropical tree species specialize for different parts of the environmental gradients, and climate is a stronger driver of species distribution than soils. Because climate change scenarios predict increases in annual temperature and a stronger dry season for tropical forests, we may expect potentially large shifts in the distribution of tropical trees

Growth ring variations were used to provide the rates in diameter growth for seven tree species in the Bolivian Cerrado biogeographical province. Ten to 50 trees were measured per species. Ring width measurements provided accurate data on the rates of tree growth. Variations in growth rates were determined among species and among sites for the same species over a common period of 100 years. Diametric increases range from 0.43 to 0.56 cm year-1 in Chiquitano biogeographical district. For species in Guarayos district, diametric increments range from 0.51 to 1.06 cm year-1. For Centrolobium microchaete growing in both districts, the annual diametric increments oscillate between 0.35 to 0.40 cm year-1 and 0.55 to 0.65 cm year-1 in Chiquitano and Guarayos districts, respectively. Diametric increases in Chiquitano district were not significantly different among sites, whereas in Guarayos district, annual increases differ among species and from the same species growing in Chiquitano district. Observed diameter growth rates indicate that diametrical increments are generally slower than commonly assumed, with considerable variation among species and between districts. Therefore, the idea of applying similar rules for the management of different species across different sites without considering actual growth rates is not recommended, with long-term consequences for the sustainability of forests at the tropical dry Bolivian Cerrado., La información obtenida a partir de los anillos de crecimiento fue utilizada para proveer los ritmos de crecimiento diamétrico de siete especies forestales de la provincia biogeográfica del Cerrado Boliviano. En este análisis dendrocronológico se emplearon 10 a 50 árboles por especies. La medición del ancho de los anillos de crecimiento brindó datos precisos, con los cuales se determinó la variabilidad del incremento entre especies y entre sitios para un periodo común de 100 años. Los incrementos diamétricos variaron de 0,43 a 0,56 cm año-1 en especies correspondientes al distrito Chiquitano. Para especies del distrito de Guarayos, los valores fueron de 0,51 a 1,06 cm año-1. Para Centrolobium microchaete que crece en ambos distritos, los valores medios de crecimiento por rodal oscilaron entre 0,35 y 0,40 cm año-1 en el distrito Chiquitano y de 0,55 a 0,65 cm año-1 en el de Guarayos. Los incrementos diamétricos en sitios del distrito Chiquitano no presentaron diferencias significativas, en cambio en Guarayos los incrementos fueron diferentes entre especies y, a su vez, diferentes a los del distrito Chiquitano. Las tasas de crecimiento diamétrico indican que el crecimiento diamétrico, en general, es más lento de lo comúnmente asumido, con variaciones importantes entre especies y entre sitios de crecimiento. Por ello, la idea de establecer pautas fijas de manejo similares para todas las especies y sitios, sin considerar las tasas reales de crecimiento, no sería la recomendada, poniendo en algunos casos en riesgo la sostenibilidad de los bosques "manejados" del cerrado boliviano.

1. In a recent paper, we analysed the effects of climate, soil and logging disturbance on tree and forest growth (Toledo et al. 2011a). We took advantage of one of the largest data sets in the Neotropics, consisting of 165 1-ha plots and over 62 000 trees distributed over an area of c. 160 000 km2, across large environmental gradients in lowland Bolivia. The main findings were that climate was the strongest driver of spatial variation in tree growth, whereas soils had only a modest effect on growth and that the effect of logging disappeared after a few years. 2. Ferry (2012) suggest that we underestimated the disturbance effects on growth because of a supposedly wrong coding of Time After Logging (TAL) for unlogged plots. Although we have good biological reasons why we coded TAL like we did, we checked Ferry et al.s suggestions for recoding and found no differences in variables that significantly explained tree and forest growth. We agree, however, that for future research, it is important to go beyond simple descriptors such as time after logging and basal area logged, to better describe the variation in logging impact found in areas under forest management. 3. Ferry et al. claim that we did not define basal area growth properly. We believe this is a semantic issue, as we clearly defined basal area growth as the net change in basal area. This net basal area change in Bolivian forests is indeed relatively high compared to other studies, which may be attributed to the higher soil fertility and biogeographic differences in species composition and their traits. 4. Synthesis. Many apparent discrepancies in the ecological literature arise because tropical forest ecologists tend to see the world from the perspective of their own forest (despite clear biogeographic differences) and try to capture the same ecological processes using different variables and measurement protocols. To advance our understanding and go beyond single-case studies, we need to assemble large databases, quantify forest dynamics and disturbances in similar ways, be aware of differences among forests and analyse environmental doseresponse curves.

Floristic variation is high in the Neotropics, but little is known about the factors shaping this variation at the mesoscale. We examined floristic composition and its relationship with environmental factors across 220 1-ha permanent plots in tropical lowland Bolivia. For each plot, abundance of 100 species (93 tree and 7 palm species =10 cm diam) was obtained. Climatic data, related to rainfall seasonality and temperature, were interpolated from all available weather stations in the region, and soil properties, related to texture and fertility, were obtained for each plot. Floristic variation was strongly associated with differences in water availability and temperature, and therefore the climatic gradient shaped floristic variation more strongly than the edaphic gradient. Detrended correspondence analysis ordination divided lowland Bolivia primarily into two major groups (Southern Chiquitano region vs. the Amazon region) and a multiple response permutation procedure distinguished five floristic regions. Overall, the tested environmental variables differed significantly among the five regions. Using indicator species analysis, we distinguished 82 strong indicator species, which had significant environmental preferences for one floristic region. These species can be used as indicators of environmental conditions or to determine which floristic region a certain forest belongs. Given the predicted decreases in rainfall and increases in temperature for tropical lowland forests, our gradient approach suggests that species composition may shift drastically with climate change

Bolivia started to implement the Forestry Law (# 1700) in 1996. Since then the Bolivian forestry sector has changed significantly from an unplanned and exploitative logging regime to an organized system based on reduced impact logging techniques and management plans elaborated by trained forestry technicians and professionals. It has also expanded access to forest harvesting by allowing rural and indigenous communities the right to manage forest resources along with private companies. The law also provided a suite of technical tools to ensure the sustainable use of the forest resource. The 1996 forestry law and its implementation has resulted in a diversification of species being used for timber production, an increase in the amount of finished forest product exports, and improvements towards forest sustainability. This latter aspect is most evident in the approximately two million hectares of tropical forests that have been certified as sustainably managed under the Principles and Criteria defined by the Forest Stewardship Council (FSC) (Certificación Forestal Voluntaria 2008). Despite Bolivia’s status as a sustainable forestry leader, there are political, socioeconomic, and ecological challenges to sustainable forest management. Most of these challenges have their origins outside the forestry sector and are related to the development vision being used in the country. These limitations are of concern to the sustainability of Bolivia’s forestry sector and their recognition is important in order to be able to mitigate their effects in the future. The rest of this chapter will expand upon the successes and challenges to sustainable forest management in Bolivia.

To both celebrate and reflect upon this International Year of Biodiversity, Biotropica has invited opinion articles from a number of scientists across the globe. As lightly edited personal opinions, the commentaries reflect the diversity of passionate and often controversial views expressed across the scientific community. Thus, these commentaries should provide much food for thought, and hopefully some inspiration, on how we perceive biodiversity on our currently human-dominated planet and how we should respond to its loss

The complexity of factors driving tropical deforestation demand integrated approaches from concerned researchers and policy makers. Strict protection is sometimes the most appropriate mode of conservation, but conservation through management is often the better option. In either case, this essay highlights the importance of considering the social/cultural, economic, and political contexts in which these forests are threatened. By attempting to understand the cultural settings, institutional architectures and dynamics, and local expectations, and then by combining the concepts and tools of a range of disciplines, researchers will be more likely to forge lasting partnerships and increase their potential for sustained improvement in resource management and overall forest conservation

Many harvested timber species of tropical forests have not been regenerating sufficiently for future cutting cycles, which can demand the application of post-harvesting silvicultural treatments. This study analyzed the profitability of sawnwood produced through four treatments applied on seedlings and saplings naturally present or planted in logging gaps as follows: (1) the standard procedures of reduced-impact logging or control; (2) the tending of the naturally established regeneration; (3) enrichment planting 1 (EP-1); and (4) enrichment planting 2 (EP-2). In EP-1 commercial species were planted in 2-year-old gaps with no logging residuals removal from the gap while in EP-2 seedlings were planted in 1-year-old gaps with logging residuals removal from the gap. The planted timber species in EP-2 had higher financial value and higher growth rates than the timber species planted in EP-1. The experiment was carried out in a certified managed forest in the Eastern Amazon, Brazil. The growth rates of the treated seedlings and saplings were projected in 30 and 60 years from the treatment establishment to simulate sawnwood production. The simulations indicated that, increases of 25 and 50% in growth rates and increases up to 500% in timber prices under annual interest rates of 4 and 6%, the treatments of tending and enrichment planting can be profitable at year 60. These silvicultural treatments, under technological improvements, tend to become financially more profitable, meaning higher financial returns to forest managers and investors.