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Recent reports warned that planting leguminous trees under monocultures elevates nitrous oxide (N2O) emissions through N-rich litter inputs. We hypothesized that planting trees on sandy soil can avoid the legume-derived boost of N2O emissions through limiting water availability for N2O production. Effects of planting legumes on methane (CH4) uptakes were also examined. N2O emissions and CH4 uptakes were compared among five tropical tree plantation stands including three leguminous stands (Acacia auriculiformis, Acacia mangium, and Xylia xylocarpa) and two non-leguminous stands (Eucalyptus camaldulensis, and Hopea odorata). Due to lower water contents of the soil, the N2O fluxes in our study site were at the lower end of the tropical rain forests. As we hypothesized, no clear differences in N2O emissions were observed between leguminous and non-leguminous stands. CH4 uptake rates in the present study were lower than those of other tropical forests. CH4 uptakes in leguminous stands did not differ from those in non-leguminous stands. Overall, we demonstrated that planting leguminous trees on sandy soils has a potential to enable us to manage leguminous monoculture tree plantations without boosting N2O emissions or reducing CH4 uptakes. [ABSTRACT FROM AUTHOR]

Understory fires represent an accelerating threat to Amazonian tropical forests and can, during drought, affect larger areas than deforestation itself. These fires kill trees at rates varying from

Understanding how plant carbon metabolism responds to environmental variables such as light is central to understanding ecosystem carbon cycling and the production of food, biofuels, and biomaterials. Here, we couple a portable leaf photosynthesis system to an autosampler for volatile organic compounds (VOCs) to enable field observations of net photosynthesis simultaneously with emissions of VOCs as a function of light. Following sample collection, VOCs are analyzed using automated thermal desorption-gas chromatograph-mass spectrometry (TD-GC-MS). An example is presented from a banana plant in the central Amazon with a focus on the response of photosynthesis and the emissions of eight individual monoterpenes to light intensity. Our observations reveal that banana leaf emissions represent a 1.1 +/- 0.1% loss of photosynthesis by carbon. Monoterpene emissions from banana are dominated by trans-β-ocimene, which accounts for up to 57% of total monoterpene emissions at high light. We conclude that the developed system is ideal for the identification and quantification of VOC emissions from leaves in parallel with CO2 and water fluxes.The system therefore permits the analysis of biological and environmental sensitivities of carbon metabolism in leaves in remote field locations, resulting in the emission of hydrocarbons to the atmosphere.•A field-portable system is developed for the identification and quantification of VOCs from leaves in parallel with leaf physiological measurements including photosynthesis and transpiration.•The system will enable the characterization of carbon and energy allocation to the biosynthesis and emission of VOCs linked with photosynthesis (e.g. isoprene and monoterpenes) and their biological and environmental sensitivities (e.g. light, temperature, CO2).•Allow the development of more accurate mechanistic global VOC emission models linked with photosynthesis, improving our ability to predict how forests will respond to climate change. It is our hope that the presented system will contribute with critical data towards these goals across Earth's diverse tropical forests.

The data set contains images of leaf venation networks obtained from tree species in Malaysian Borneo. The data set contains 726 leaves from 295 species comprising 50 families, sampled from eight forest plots in Sabah. Image extents are approximately 1 × 1 cm, or 50 megapixels. All images contain a region of interest in which all veins have been hand traced. The complete data set includes over 30 billion pixels, of which more than 600 million have been validated by hand tracing. These images are suitable for morphological characterization of these species, as well as for training of machine-learning algorithms that segment biological networks from images. Data are made available under the Open Data Commons Attribution License. You are free to copy, distribute, and use the database; to produce works from the database; and to modify, transform, and build upon the database. You must attribute any public use of the database, or works produced from the database, in the manner specified in the license. For any use or redistribution of the database, or works produced from it, you must make clear to others the license of the database and keep intact any notices on the original database.

There is mounting empirical evidence that lianas affect the carbon cycle of tropical forests. However, no single vegetation model takes into account this growth form, although such efforts could greatly improve the predictions of carbon dynamics in tropical forests. In this study, we incorporated a novel mechanistic representation of lianas in a dynamic global vegetation model (the Ecosystem Demography Model). We developed a liana-specific plant functional type and mechanisms representing liana-tree interactions (such as light competition, liana-specific allometries, and attachment to host trees) and parameterized them according to a comprehensive literature meta-analysis. We tested the model for an old-growth forest (Paracou, French Guiana) and a secondary forest (Gigante Peninsula, Panama). The resulting model simulations captured many features of the two forests characterized by different levels of liana infestation as revealed by a systematic comparison of the model outputs with empirical data, including local census data from forest inventories, eddy flux tower data, and terrestrial laser scanner-derived forest vertical structure. The inclusion of lianas in the simulations reduced the secondary forest net productivity by up to 0.46 tC  ha-1  year-1 , which corresponds to a limited relative reduction of 2.6% in comparison with a reference simulation without lianas. However, this resulted in significantly reduced accumulated above-ground biomass after 70 years of regrowth by up to 20 tC /ha (19% of the reference simulation). Ultimately, the simulated negative impact of lianas on the total biomass was almost completely cancelled out when the forest reached an old-growth successional stage. Our findings suggest that lianas negatively influence the forest potential carbon sink strength, especially for young, disturbed, liana-rich sites. In light of the critical role that lianas play in the profound changes currently experienced by tropical forests, this new model provides a robust numerical tool to forecast the impact of lianas on tropical forest carbon sinks.

Nitrogen (N) deposition is a component of global change that has considerable impact on belowground carbon (C) dynamics. Plant growth stimulation and alterations of fungal community composition and functions are the main mechanisms driving soil C gains following N deposition in N-limited temperate forests. In N-rich tropical forests, however, N deposition generally has minor effects on plant growth; consequently, C storage in soil may strongly depend on the microbial processes that drive litter and soil organic matter decomposition. Here, we investigated how microbial functions in old-growth tropical forest soil responded to 13 years of N addition at four rates: 0 (Control), 50 (Low-N), 100 (Medium-N), and 150 (High-N) kg N ha-1  year-1 . Soil organic carbon (SOC) content increased under High-N, corresponding to a 33% decrease in CO2 efflux, and reductions in relative abundances of bacteria as well as genes responsible for cellulose and chitin degradation. A 113% increase in N2 O emission was positively correlated with soil acidification and an increase in the relative abundances of denitrification genes (narG and norB). Soil acidification induced by N addition decreased available P concentrations, and was associated with reductions in the relative abundance of phytase. The decreased relative abundance of bacteria and key functional gene groups for C degradation were related to slower SOC decomposition, indicating the key mechanisms driving SOC accumulation in the tropical forest soil subjected to High-N addition. However, changes in microbial functional groups associated with N and P cycling led to coincidentally large increases in N2 O emissions, and exacerbated soil P deficiency. These two factors partially offset the perceived beneficial effects of N addition on SOC storage in tropical forest soils. These findings suggest a potential to incorporate microbial community and functions into Earth system models considering their effects on greenhouse gas emission, biogeochemical processes, and biodiversity of tropical ecosystems.

Nitrogen (N) deposition is a component of global change that has considerable impact on belowground carbon (C) dynamics. Plant growth stimulation and alterations of fungal community composition and functions are the main mechanisms driving soil C gains following N deposition in N-limited temperate forests. In N-rich tropical forests, however, N deposition generally has minor effects on plant growth; consequently, C storage in soil may strongly depend on the microbial processes that drive litter and soil organic matter decomposition. Here, we investigated how microbial functions in old-growth tropical forest soil responded to 13 years of N addition at four rates: 0 (Control), 50 (Low-N), 100 (Medium-N), and 150 (High-N) kg N ha-1  year-1 . Soil organic carbon (SOC) content increased under High-N, corresponding to a 33% decrease in CO2 efflux, and reductions in relative abundances of bacteria as well as genes responsible for cellulose and chitin degradation. A 113% increase in N2 O emission was positively correlated with soil acidification and an increase in the relative abundances of denitrification genes (narG and norB). Soil acidification induced by N addition decreased available P concentrations, and was associated with reductions in the relative abundance of phytase. The decreased relative abundance of bacteria and key functional gene groups for C degradation were related to slower SOC decomposition, indicating the key mechanisms driving SOC accumulation in the tropical forest soil subjected to High-N addition. However, changes in microbial functional groups associated with N and P cycling led to coincidentally large increases in N2 O emissions, and exacerbated soil P deficiency. These two factors partially offset the perceived beneficial effects of N addition on SOC storage in tropical forest soils. These findings suggest a potential to incorporate microbial community and functions into Earth system models considering their effects on greenhouse gas emission, biogeochemical processes, and biodiversity of tropical ecosystems.

Mapping of deforestation, forest degradation, and recovery is essential to characterize country-level forest change and formulate mitigation actions. Previous studies have mainly used a simple forest/non-forest classification after forest disturbance to identify deforestation and forest degradation. However, a more flexible approach that is applicable to different forest conditions is desirable. In this study, we examined an approach for mapping deforestation, forest degradation, and recovery using disturbance types and tree canopy cover estimates from annual Landsat time-series data from 1988 to 2020 across Cambodia. We developed models to estimate both disturbance types and tree canopy cover based on a random forest algorithm using predictor variables derived from a trajectory-based temporal segmentation approach. The estimated disturbance types and canopy cover in each year were then used in a rule-based classification of deforestation, forest degradation, and recovery. The producer’s and user’s accuracies ranged from 59.1% to 72.9% and 60.8% to 91.6%, respectively, for the forest change classes of mapping deforestation, forest degradation, and recovery. The approach developed here can be adjusted for different definitions of deforestation, forest degradation, and recovery according to research objectives and thus has the potential to be applied to other study areas.

Mapping the spatial distribution of soil organic carbon (SOC) in lands covered by tropical forests is important to understand the relationship and dynamics of SOC in this type of ecosystem. In this study, the Random Forest (RF) algorithm was used to map SOC stocks of topsoil (0–15 cm) in forest lands of the Dominican Republic. The methodology was developed using geospatial datasets available in the Google Earth Engine (GEE) platform combined with a set of 268 soil samples. Twenty environmental covariates were analyzed, including climate, topography, and vegetation. The results indicate that Model A (combining all 20 covariates) was only marginally better than Model B (combining topographic and climatic covariates), and Model C (only combining multispectral remote sensing data derived from Landsat 8 OLI images). Model A and Model B yielded SOC mean values of 110.35 and 110.87 Mg C ha−1, respectively. Model A reported the lowest prediction error and uncertainty with an R2 of 0.83, an RMSE of 35.02 Mg C ha−1. There was a strong dependence of SOC stocks on multispectral remote sensing data. Therefore, multispectral remote sensing proved accurate to map SOC stocks in forest ecosystems in the region.

The present study was accomplished to assess and compare tree diversity, carbon stock, and to find the relationship between carbon stock and tree diversity in scientifically and conventionally managed community forests (CFs) of Kanchanpur District, Nepal. A total of 94 sample plots were overlaid with a systematic random sampling method (51 plots in scientifically managed Singhapur CF and 43 plots were established in conventionally managed Kalika CF). The height and DBH of each tree were measured to calculate biomass and carbon stock. Shannon-Wiener and Simpson’s indexes were calculated for tree diversity. The data were pooled and analyzed using MS Excel and SPSS software. The values were statistically compared using a t-test. The total carbon stock and tree diversity were higher in scientifically managed CF (207.58 tons/ha and H= 0.97) than conventionally managed CF (183.72 tons/ha and H=0.85). Shorea robusta has a major contribution on total carbon stock in both CFs (Kalika: 66.34% and Singhapur: 70.43%) followed by Terminalia tomentosa (Kalika: 24.65% and Singhapur: 13.36%). The t-test did not show any significant difference for the mean values of carbon stocks and tree diversity between the CFs at a 5% level of significance. However, carbon stock showed a weak but positive relationship with species richness and negative with evenness. The result of the study recommends managing forests scientifically for increased tree diversity leading to enhanced carbon deposition.

Jagua (Genipa americana L.) is widely distributed throughout the Americas. It has been used since ancient times due to the pigments extracted from its fruit. This study aimed to evaluate the vegetative growth of five Jagua accessions by adjusting non-linear models to dasometric growth variables. The accessions (Porce, Chigorodó, San Carlos, San Luis, and Vigía del Fuerte in Antioquia) were collected in the central-western region of Colombia. The growth, determined through plant height and stem diameter (at 0.10 and 1.30 m), was evaluated for 262 weeks in the municipality of Amalfi. A descriptive analysis of the growth behavior of each accession was performed, and the fit of four nonlinear functional models was evaluated. An influence of the accession factor on growth was found due the different growth rates. The Weibull model was the one with the best fit and predictive capacity, which confirmed the differences between accessions.

Publicly available EO datasets offer new possibilities to generate biodiversity information at the community composition level, an essential biodiversity variable, beyond forest type. We demonstrated the potential of Sentinel-2, GEDI LiDAR canopy height and ALOS-DEM in discriminating and classifying tropical tree communities in the Western Himalayas, India. For this, tree communities were first identified based on the ordination of field data and subsequently classified using satellite data applying machine learning, i.e. random forest (RF). From the three forest types in the study area, eight distinct tree communities were identified for which classification accuracy increased from single date (75.17%) to multi-date images (85.33%) and further by applying feature selection (88.17%). Whereas the best classification accuracy of 94.66% was achieved when canopy height and topographic variables were also considered. The findings suggest that RF is suitable for mapping tree communities by combining Sentinel-2 with GEDI and DEM parameters. [ABSTRACT FROM AUTHOR]

Summary: Spatial redistribution of nutrients by atmospheric transport and deposition could theoretically act as a continental‐scale mechanism which counteracts declines in soil fertility caused by nutrient lock‐up in accumulating biomass in tropical forests in Central Africa. However, to what extent it affects carbon sinks in forests remains elusive.Here we use a terrestrial biosphere model to quantify the impact of changes in atmospheric nitrogen and phosphorus deposition on plant nutrition and biomass carbon sink at a typical lowland forest site in Central Africa.We find that the increase in nutrient deposition since the 1980s could have contributed to the carbon sink over the past four decades up to an extent which is similar to that from the combined effects of increasing atmospheric carbon dioxide and climate change. Furthermore, we find that the modelled carbon sink responds to changes in phosphorus deposition, but less so to nitrogen deposition.The pronounced response of ecosystem productivity to changes in nutrient deposition illustrates a potential mechanism that could control carbon sinks in Central Africa. Monitoring the quantity and quality of nutrient deposition is needed in this region, given the changes in nutrient deposition due to human land use. [ABSTRACT FROM AUTHOR]

Climate change globally affects soil microbial community assembly across ecosystems. However, little is known about the impact of warming on the structure of soil microbial communities or underlying mechanisms that shape microbial community composition in subtropical forest ecosystems. To address this gap, we utilized natural variation in temperature via an altitudinal gradient to simulate ecosystem warming. After 6 years, microbial co‐occurrence network complexity increased with warming, and changes in their taxonomic composition were asynchronous, likely due to contrasting community assembly processes. We found that while stochastic processes were drivers of bacterial community composition, warming led to a shift from stochastic to deterministic drivers in dry season. Structural equation modelling highlighted that soil temperature and water content positively influenced soil microbial communities during dry season and negatively during wet season. These results facilitate our understanding of the response of soil microbial communities to climate warming and may improve predictions of ecosystem function of soil microbes in subtropical forests. [ABSTRACT FROM AUTHOR]

Tropical forests are biologically diverse and structurally complex ecosystems that can store a large quantity of carbon and support a great variety of plant and animal species. However, tropical forest structure can vary dramatically within seemingly homogeneous landscapes due to subtle changes in topography, soil fertility, species composition and past disturbances. Although numerous studies have reported the effects of field-based stand structure attributes on aboveground biomass (AGB) in tropical forests, the relative effects and contributions of UAV LiDAR-based canopy structure and ground-based stand structural attributes in shaping AGB remain unclear. Here, we hypothesize that mean top-of-canopy height (TCH) enhances AGB directly and indirectly via species richness and horizontal stand structural attributes, but these positive relationships are stronger at a larger spatial scale. We used a combined approach of field inventory and LiDAR-based remote sensing to explore how stand structural attributes (stem abundance, size variation and TCH) and tree species richness affect AGB along an elevational gradient in tropical forests at two spatial scales, i.e., 20 m × 20 m (small scale), and 50 m × 50 m (large scale) in southwest China. Specifically, we used structural equation models to test the proposed hypothesis. We found that TCH, stem size variation and abundance were strongly positively associated with AGB at both spatial scales, in addition to which increasing TCH led to greater AGB indirectly through increased stem size variation. Species richness had negative to negligible influences on AGB, but species richness increased with increasing stem abundance at both spatial scales. Our results suggest that light capture and use, modulated by stand structure, are key to promoting high AGB stocks in tropical forests. Thus, we argue that both horizontal and vertical stand structures are important for shaping AGB, but the relative contributions vary across spatial scales in tropical forests. Importantly, our results highlight the importance of including vertical forest stand attributes for predicting AGB and carbon sequestration that underpins human wellbeing. [ABSTRACT FROM AUTHOR]

Large-scale deforestation in the tropics, triggered by logging and subsequent agricultural monoculture has a significant adverse impact on biodiversity due to habitat degradation. Here, we measured the diversity of butterfly species in three agricultural landscapes, agroforestry orchards, oil palm, and rubber tree plantations. Butterfly species were counted at 127 sampling points over the course of a year using the point count method. We found that agroforestry orchards supported a greater number of butterfly species (74 species) compared to rubber tree (61 species) and oil palm plantations (54 species) which were dominated by generalist (73%) followed by forest specialists (27%). We found no significant difference of butterfly species composition between agroforestry orchards and rubber tree plantation, with both habitats associated with more butterfly species compared to oil palm plantations. This indicates butterflies were able to persist better in certain agricultural landscapes. GLMMs suggested that tree height, undergrowth coverage and height, and elevation determined butterfly diversity. Butterfly species richness was also influenced by season and landscape-level variables such as proximity to forest, mean NDVI, and habitat. Understanding the factors that contributed to butterfly species richness in an agroecosystem, stakeholders should consider management practices to improve biodiversity conservation such as ground vegetation management and retaining adjacent forest areas to enhance butterfly species richness. Furthermore, our findings suggest that agroforestry system should be considered to enhance biodiversity in agricultural landscapes. [ABSTRACT FROM AUTHOR]

Re‐establishing extirpated wildlife—or "rewilding"—is touted as a way to restore biodiversity and ecosystem processes, but we lack real‐world examples of this process, particularly in Southeast Asia. Here, we use a decade of aggregated camera trap data, N‐mixture occupancy models, and input from local wildlife experts to describe the unassisted recolonization of two native large herbivores in Singapore. Sambar deer (Rusa unicolor) escaped from captivity (in private or public zoos) in the 1970s and contemporary camera trap data show they have only colonized nearby forest fragments and their abundance remains low. Wild pigs (Sus scrofa), in contrast, naturally recolonized by swimming from Malaysia in the 1990s and have rapidly expanded their range and abundance across Singapore. While wild pigs have not recolonized all viable green spaces yet, their trajectory indicates they soon will. We also note that a third ungulate, the muntjac deer (Muntiacus muntjak), was captured in camera trapping in 2014 and 2015 but was never recorded afterward despite increased sampling effort, and thus we do not focus on their presumably unsuccessful recolonization. The divergent rewilding trajectories between sambar deer and wild pigs suggest different conservation outcomes and management requirements. Sambar deer may restore lost plant–animal interactions such as herbivory and seed dispersal without requiring significant management. Wild pigs, in contrast, have reached high numbers rapidly and may require active management to avoid hyperabundance and negative ecological impacts in regions, such as Singapore that lack both hunting and large predators. [ABSTRACT FROM AUTHOR]

Pedro Rojas's 1961 excavation of numerous stone vessels at the Huayurco site has led scholars to suspect that the Jaén region of the northeastern Peruvian Andes was an important center of early ceremonial stone bowl production. This discovery not only provided clear evidence of an independent craft technology within the ceja de selva , or eastern Andean tropical montane forest, but the similarity of these stone vessels to examples found at coastal and highland Andean sites also suggested that the Jaén region produced these vessels as a means of participating within early interregional exchange networks. Because empirical evidence of tropical forest exchange items within coastal and highland sites is difficult to obtain because of these items' suspected perishable nature, the stone vessels represented an alternative means for understanding early Andean–Amazonian relations. Despite the importance of this discovery, little follow-up investigation has been conducted. In this article, I define the Jaén stone vessel tradition on the basis of form, design, and technology. I then review the archaeological literature on early Andean stone vessels to show how these vessels help articulate Jaén's participation within Andean interaction spheres between 2500 and 800 BC. [ABSTRACT FROM AUTHOR]

In Africa, most protected forests are in densely human‐dominated landscapes where human–wildlife conflict is intense. We documented farmer perceptions and responses to crop‐raiding wildlife from Kibale National Park, Uganda. Crop raiding was mostly (95%) by baboons (Papio anubis) and elephants (Loxodonta africana). While the financial loss caused by baboons and elephants did not differ, elephants were perceived as more damaging. Guarding and trenches were perceived as the most effective deterrent strategies for baboons and elephants, respectively. Distance from the park boundary and household income were significantly associated with a greater likelihood of crop raiding. Distance from the park, household head age and the species that raided crops, influenced whether a household applied one or more deterrent strategies. Households headed by women or older adults were most vulnerable, experiencing greater losses to raiding. Patterns of human–wildlife conflict around Kibale forest are complex, but the extent of crop damage was mostly determined by distance from the park and farm socio‐economic status and thus their ability to mitigate or deter raiding. Managing crop raiding requires collaboration between the park and affected farmers to ensure that mutually managed deterrent methods, such as trenching (elephants) and guarding (baboons), are effectively shared, applied and maintained. [ABSTRACT FROM AUTHOR]

Endophytic fungi comprise a group of microorganisms of great diversity, which can be modulated by biotic and abiotic factors. The present study aims to understand how environmental factors, blooming and cultivars change the diversity of the endophytic fungal communities in sorghum leaves in two forest areas in Brazil. Our results showed that Sorghum bicolor has a rich and diverse community of endophytic fungi distributed in Ascomycota, Basidiomycota and Mucoromycota, with members of Dothideomycetes and Sordariomycetes as dominant groups. We found 581 endophytic fungi (filamentous and yeasts) identified in 55 species of 37 genera. A greater diversity and richness of endophytic fungi were found in sorghum leaves from the Atlantic Forest (diversity = H′ = 2.68 and richness = 46), differing significantly from the Caatinga forest (diversity = H′ = 2.51 and richness = 25). No difference in richness or diversity was observed between the two crops or between the phenological stages. We detected different species indicator for the two areas, nine taxa were associated with sorghum in the Atlantic Forest (Colletotrichum sp. 2, Epicoccum sorghinum, Curvularia sp., Colletotrichum sp. 1, Fusarium thapsinum, Nigrospora oryzae, Phyllosticta capitalensis, Fusarium oxysporum and Amesia nigricolor) and five taxa were indicators of sorghum in the Caatinga Forest (Meyerozyma sp., Talaromyces pinophilus, Metschnikowia sp., Rhodosporidiobolus sp. and Acremonium pinkertoniae). One species was an indicator of the cultivar IPA 2502 and no species were related to the cultivar IPA SF15. In relation to pre-blooming and post-blooming stages, two species were considered indicators for the former while six were considered for the latter. We observed that the number of filamentous fungi increases with the post-blooming stage and higher rainfall, while the diversity of endophytic yeasts was influenced by smaller rainfall and pre-blooming stage. Our data improves the understanding of factors that may influence the endophytic fungal community in ecologically and economically important grass species. The endophytic fungal diversity associated with sorghum is important to the mycodiversity estimation and may be useful in studies of biocontrol of pathogens and promotion of crops growth. [ABSTRACT FROM AUTHOR]

Atlantic Forest has experienced an expansion of vegetation fragments in abandoned pasture areas. Thus, we aimed to evaluate seed rain over abandoned pasture from two forest patches of the Southeast Atlantic Forest related to distance from the edge and patch size. For eight months, seeds were collected, measured and weighed. Our results showed decreased seed rain (in terms of number, weight and size of seeds) within abandoned pastures with increasing distance from the forest edge and decreasing fragment size. We also found a more diverse and even plant community in the seed rain of small patch and discussed the meaning of these results for pasture regeneration, as the importance of small and large patches as seed sources in a landscape. [ABSTRACT FROM AUTHOR]

While ecologists agree that habitat loss has a substantial negative effect on biodiversity it is still very much a matter of debate whether habitat fragmentation has a lesser effect and whether this effect is positive or negative for biodiversity. Here, we assess the relative influence of tropical forest loss and fragmentation on the prevalence of vector‐borne blood parasites of the genera Plasmodium and Haemoproteus in six forest bird species. We also determine whether habitat loss and fragmentation are associated with a rise or fall in prevalence. We sample more than 4000 individual birds from 58 forest sites in Guadeloupe and Martinique. Considering 34 host–parasite combinations independently and a fine characterization of the amount and spatial configuration of habitat, we use partial least square regressions to disentangle the relative effects of forest loss, forest fragmentation, landscape heterogeneity, and local weather conditions on spatial variability of parasite prevalence. Then we test for the magnitude and the sign of the effect of each environmental descriptor. Strikingly, we show that forest fragmentation explains twice as much of the variance in prevalence as habitat loss or landscape heterogeneity. In addition, habitat fragmentation leads to an overall rise in prevalence in Guadeloupe, but its effect is variable in Martinique. Both habitat loss and landscape heterogeneity exhibit taxon‐specific effects. Our results suggest that habitat loss and fragmentation may have contrasting effects between tropical and temperate regions and that inter‐specific interactions may not respond in the same way as more commonly used biodiversity metrics such as abundance and diversity. [ABSTRACT FROM AUTHOR]

Forest tree communities are largely structured by interactions between phenotypes and their environments. Functional traits have been popularized as providing key insights into plant functional tradeoffs. Similarly, tree crown—stem diameter and tree height—stem diameter allometric relationships are likely to be strongly coordinated with functional trait tradeoff axes. Specifically, species with functional traits indicative of conservative strategies (i.e., dense wood, heavy seeds) should be related to tree architectures that have lower heights and wider crowns for a given stem diameter. For example, shade‐tolerant species in tropical forests are typically characterized as having dense wood, large seeds, and relatively broad crowns at early ontogenetic stages. Here, we focus on 14 dominant dicot tree species in a tropical forest. We utilized hierarchical Bayesian models to characterize species‐specific height and crown size allometric parameters. We sampled from the posterior distributions for these parameters and correlated them with six functional traits. We also characterize the expected height and crown size for a series of reference stem diameters to quantify the relationship between traits and tree architecture across size classes. We find little interspecific variation in allometric slopes, but clear variation in allometric intercepts. Allometeric height intercepts were negatively correlated with wood density and crown size intercepts were positively related to wood density and seed mass and negatively related to leaf percent phosphorus. Thus, interspecific variation in tree architecture is generated by interspecific variation in allometric intercepts and not slopes. These intercepts could be predicted using a handful of functional traits where conservative traits were indicative of trees that are relatively short and have larger crown sizes. This demonstrates a coordination of tropical tree life histories that can be characterized simultaneously with functional traits and tree allometries. [ABSTRACT FROM AUTHOR]

Invasive plant species can modify ecosystem structure and function, potentially leading to the loss of native species, environmental and biotic homogenisation, changes in nutrient cycling, impairment of ecosystem services, and decrease in the rate of regeneration of plant recruits. We assessed the effects of the non-native and invasive vine Tradescantia zebrina on the germination and development of the native tree Hymenaea courbaril in north-eastern Brazil. We hypothesised that the invasive species would negatively impact the germination and development, and, via competition, the growth of the native species. We conducted a germination experiment for six months in seven forest patches. Seeds of H. courbaril were cultivated in four possible combinations of two treatments: under a cover with and without T. zebrina, and on soil that originated from places with and without T. zebrina present. Neither T. zebrina cover or soil affected the germination or biomass of H. courbaril during the experiment. H. courbaril seedlings were taller and had longer roots when cultivated in soil that originated from places with T. zebrina. T. zebrina presence alters soil properties in a way that triggers morphological responses in H. courbaril, which can be associated to a perceived competition context. [ABSTRACT FROM AUTHOR]

Controversy surrounds the reported dry season greening of the Central Amazon forests based on the Enhanced Vegetation Index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS). As the solar zenith angle decreases during the dry season, it affects the sub-pixel shade content and artificially increases Near-infrared (NIR) reflectance and EVI. MODIS' coarse resolution also creates a challenge for cloud and terrain filtering. To reduce these artifacts and then validate MODIS seasonal spectral patterns we use 16 years of 1 km resolution MODIS-MAIAC (Multi-Angle Implementation of Atmospheric Correction) images, corrected to a nadir view and 45° solar zenith angle, together with an improved cloud filter. Then we show that the 30 m Landsat-8 Operational Land Imager (OLI) surface reflectance over two Landsat scenes provides independent evidence supporting the MODIS-MAIAC seasonality for EVI, NIR, and GCC (an additional important vegetation index, green chromatic coordinate). Our empirical method for controlling for sun-sensor geometry effects in Landsat scenes encompasses the use of seasonally distinct images that have similar solar zenith angles and cloud-free pixels on flat uplands having the same phase angle. We extended this validation to nine Amazon sub-basins comprising ∼546 Landsat-8 images. Our study shows that the dry-season green-up pattern observed by MODIS is corroborated by Landsat-8, and is independent of satellite data artifacts. To investigate the mechanisms driving these seasonal changes we further used Central Amazon tower-mounted RGB cameras providing a 4-year record at the Amazon Tall Tower (ATTO, 2°8′36″S, 59°0′2″W) and a 7-year record at the Manaus k34 tower (2°36′33″ S, 60°12′33″W) to obtain monthly upper canopy green leaf cover (a proxy for Leaf Area Index - LAI) and monthly leaf age class abundances (based on the age since leaf flushing, by crown). These were compared to seasonal patterns of GCC and EVI in small MODIS-MAIAC windows centered on each tower. MODIS-MAIAC GCC was positively correlated with newly flushed leaves (R2 = 0.76 and 0.44 at ATTO and k34, respectively). EVI correlated strongly with the abundance of mature leaves (R2 = 0.82 and 0.80) but was poorly correlated with LAI (R2 = 0.20 and 0.41, respectively). Therefore, seasonal spectral patterns in the Central Amazon are likely controlled by leaf age variation, not quantity of leaf area. [ABSTRACT FROM AUTHOR]

Passive restoration offer better preservation for the diverse legacy of forest ecosystems, but many interactions on the restoration process remain poorly understood. In this study, the seasonality of accumulated litter layer, nutrient content, potential return, and soil quality were evaluated under the initial (subjected to 11-year) and advanced (subjected to 46-year) passive restoration conditions in Cerrado, Brazil. Measurements were carried out for a period of one year. Accumulated litter layer, nutrient content, potential return, and nutrient use efficiency were 50%, 43%, 13%, and 42% higher in the advanced passive restoration site compared to the initial restoration site. For both sites, the annual litter content followed the order: N > Ca > K > Mg > P > Fe > Mn > B > Zn > Cu. Significant increases in soil organic matter and cation exchange capacity were found in the advanced passive restoration. The annual average had shown a higher macronutrient concentration in the soil for the initial restoration, while a higher micronutrient concentration was found for the advanced restoration. The seasonality affected the accumulated litter layer, litter nutrients, potential return and soil quality. Some litter and soil nutrients were significantly correlated, evidencing the nutrient associations between litter and soil. Hence, both the passive restoration stages and rain were factors that regulated the temporal patterns of accumulated litter layer as well as the nutrient cycling in Cerrado passive restoration models. [ABSTRACT FROM AUTHOR]

There are few scientific studies evaluating the impact of the loss of wetlands on the banks of tropical rivers on assemblages of small non‐flying mammals. To understand the possible deleterious effects of hydroelectric construction in tropical forests on this group of mammals, we used data from 2 years of monitoring carried out during the period before the filling of a hydroelectric plant reservoir in the Brazilian Amazon, and related them to vegetation, soil and topography. We captured 659 individuals of 20 small‐mammal species. The species assemblage composition in the flooded areas was a subset of species that occurred in both floodable and non‐floodable areas, and only one species was captured exclusively in the flooded area. Species composition was influenced by the proportion of sand, by soil nutrient concentration and distance from water bodies. We conclude that there is no evidence that the flooding of low‐lying areas along the Madeira River would negatively affect the assemblage of non‐flying small mammals in the short term because the remaining areas have similar assemblages of small mammals as those destined for flooding. Whether the area lost will be important for population dynamics will depend on the conservation of the remaining areas. [ABSTRACT FROM AUTHOR]

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Tropical forests are critical for ecosystem functioning and are the major provider of global ecosystem services. The combined effects of climate change and anthropogenic disturbances in the tropics, however, have caused a mass decline in major ecosystem services in recent decades. Nevertheless, most previous studies focused entirely on these disturbances' effects on forest ecosystem services without taking into consideration the combined effects of climate change and disturbances on key ecosystem services' indicators. This is more pronounced in Bangladesh, which is one of the countries most adversely affected by global climate change. We investigated anthropogenic disturbances' effects on regulating ecosystem services under different rainfall regimes in Khadimnagar National Park (KNP) and Satchari National Park (SNP), two major forested, protected areas in Northeast Bangladesh. We considered twelve indicators for five aboveground ecosystem services (i.e., primary production, carbon storage, biodiversity, wildlife habitat, and timber production) and four indicators for four belowground ecosystem services (i.e., organic carbon storage, soil aggregate stability, soil physical support, and soil water regulation) in our study. The effects of disturbances on the indicators of four aboveground ecosystem services (i.e., primary production, tree carbon storage, biodiversity conservation, and timber production) and one belowground ecosystem service (soil physical support) differed in terms of rainfall regimes. Disturbances negatively influenced indicators of primary production (p = 0.03, r = −0.28), tree carbon storage (p = 0.02, r = −0.29), and timber production (p = 0.002, r = −0.39), and positively impacted soil organic carbon storage (p = 0.04, r = 0.27) only under a medium-rainfall regime. Interestingly, a significant positive impact of disturbances on soil physical support (p = 0.001, r = 0.39) was observed under heavy rainfall in our study. In addition, disturbances were significantly associated with biodiversity conservation (p < 0.05) and wildlife habitat quality (p < 0.05) under both rainfall classes. Our findings provide critical insights into the synergistic role of anthropogenic perturbations in regulating ecosystem services with rainfall pattern as a key climatic parameter, which can be useful in restoring large tracts of degraded tropical forests in the United Nations (UN) Decade on Ecosystem Restoration. [ABSTRACT FROM AUTHOR]

The effects of hurricanes Irma and Maria and a severe drought on the temperature, precipitation, and soil moisture (under canopy and in the open) were calculated at 22 sites from 0–1045 m in northeastern Puerto Rico from 2001–2021, against the background short-term trend. Median and minimum air temperatures increased uniformly across the elevational gradient, 1.6 times as fast in the air under the canopy (+0.08 °C/yr) and 2.2 times as fast in the soil under the canopy (+0.11 °C/yr) as for air temperature in the open. There were no substantial moisture trends (average decrease <0.01 mm/yr). The peak effect of the hurricanes on under-canopy air temperature was the same as under-canopy soil temperature at 1000 m (+3, 0.7, 0.4 °C for maximum, median, minimum) but air maximum and minimum temperature peak effects were twice as high at 0 m (and soil temperatures stayed constant). Soil temperature hurricane recovery took longer at higher elevations. The peak effect of the hurricanes and the drought on the soil moisture was the same (but in opposite directions, ±0%), except for the wettest months where drought peak effect was larger and increasing with elevation. Differing patterns with elevation indicate different ecosystem stresses. [ABSTRACT FROM AUTHOR]

This study was conducted between 2001 and 2016 and aimed to evaluate the effect of interactions between meteorological variables, pasture burning, and pasture degradation on milk production in dairy cattle in the micro-region of Itapetinga, located in the Brazilian Atlantic Forest. The results showed that in 2015, with the occurrence of a strong El Niño event, above-average indices of air temperature, evapotranspiration, and heat foci, and below-average levels of rain and air humidity were observed, which impacted 38.97% of the micro-region's extremely degraded pastures. The Mann–Kendall test showed decreasing trends in milk production (DPL), temperature and humidity index (UTI), food consumption (RCA), and design rate (TC). These decreases were significant in 11 of the 14 municipalities that make up the micro-region. In correlation analysis, UTI, DPL, RCA, and TC presented very strong correlations among themselves for all the municipalities, with the average air temperature being the variable with the best correlation among these indexes. These results indicate that the development of this activity is still dependent on climatic conditions, thereby directly influencing milk production in the micro-region. Evaluating the interactions between climatic conditions and productivity is of great importance for the sustainability of livestock production as the degradation of pastureland necessitates the search for new production areas, thereby directly impacting biodiversity through the suppression of forest remnants, such as those of the Atlantic Forest. [ABSTRACT FROM AUTHOR]

We identify two nocturnal turbulence regimes at different heights above the Amazon Forest and their variation in relation to the proximity of the forest canopy. We analyzed fast response data measured at the Uatumã Sustainable Development Reserve in central Amazonia, Brazil, during September 2021 to January 2022. Our results show that the threshold wind speed that separate the weak turbulence regime from strong turbulence regime increased as a function of the distance above the canopy (43 m, 50 m, 75 m, 100 m, 127 m, 151 m e 172 m). However, at 196 m, 223 m, 247 m, 274 m e 298 m height the change of the turbulence regime occurred at the same threshold wind speed. In contrast, at 316 m we evidenced only situations where the turbulence was weak. This pattern indicated that the structure and roughness of dense forest affect the turbulence structure. [ABSTRACT FROM AUTHOR]

Mining contributes importantly to tropical deforestation and land degradation. To mitigate these effects, mining companies are increasingly obliged to restore abandoned mine lands, but factors driving restoration success are hardly evaluated. Here, we investigate the influence of ecological factors (restoration age, soil properties and surrounding forest area) and management factors (diversity and density of planted species, mine zone) on the recovery rate of forest structure and tree diversity on 40 post-mining restoration areas in Southern Amazonia, Brazil, using a 9-year annual monitoring dataset consisting of over 25 000 trees.We found that recovery of forest structure was closely associated with interactions between soil quality and the planted tree communities, and that tree diversity recovery was positively associated with the amount of surrounding forests. We also observed that forest structure and diversity recover more slowly in mine tailings compared to pit surroundings. Our study confirms the complexity of mine land restoration but also reveals that planting design and soil improvement can increase restoration success. For resource-efficient mine restoration, we recommend the focusing of efforts on tailings, which are hardest to restore, and reducing efforts in pit surroundings and areas close to surrounding forest because of their potential for restoration by natural regeneration. [ABSTRACT FROM AUTHOR]

Land management and deforestation in tropical regions cause wildfires and forest degradation, leading to a loss of ecosystem services and global climate regulation. The objective of the study was to provide a comprehensive assessment of the spatial extent and patterns of burned areas in a new deforestation frontier in the Amazonas state. The methodology applied cross-referenced burned area data from 2003 to 2019 with climate, land cover, private properties and Protected Areas information and performed a series of statistical tests. The influence of the Multivariate ENSO Index (MEI) contributed to a decreasing rainfall anomalies trend and increasing temperature anomalies trend. This process intensified the dry season and increased the extent of annual natural vegetation affected by fires, reaching a peak of 681 km2 in 2019. The results showed that the increased deforestation trend occurred mostly in public lands, mainly after the new forest code, leading to an increase in fires from 66 to 84% in 2019. The methods developed here could identify fire extent, trends, and relationship with land cover change and climate, thus pointing to priority areas for preservation. The conclusion presented that policy decisions affecting the Amazon Forest must include estimates of fire risk and impact under current and projected future climates. [ABSTRACT FROM AUTHOR]

Question: Individual plants of some highly diverse angiosperm families occur in aggregated spatial patterns in tropical plant communities, which have been defined as species swarms. Although this spatial aggregation seems paradoxical, because related species should segregate in space owing to expected ecological similarities, it has yet to be tested. We assessed whether species of the family Rubiaceae segregate in space in the understorey of a tropical plant community. Location: An Atlantic Forest fragment in southeast Brazil. Methods: We surveyed all local aggregates of Rubiaceae species within an 18.75‐ha plot across a topographic gradient. Based on the species abundance distribution, we used the 10 most abundant species to model their spatial patterns using univariate and bivariate spline spatial correlations. Bubble graphs were used to show how these species were distributed across the gradient. Results: A total of 12,258 individuals of 47 species were found distributed in 543 local aggregates. The 10 studied species corresponded to 86% of the total abundance and were aggregated in space, at distances from 0 to 10–300 m. Pairwise comparisons revealed a segregation pattern at scales ranging from 0 to 10–230 m. Local aggregates were strongly dominated by a single species, whereas many other species occurred at very low abundances. Conclusion: The studied species of Rubiaceae shared the understorey environment by occupying different portions of available space. Habitat preferences, negative interactions, dispersal limitation and priority effects may explain the observed spatial patterns. Swarms are not paradoxical because species of Rubiaceae use different microhabitats within the forest understorey. [ABSTRACT FROM AUTHOR]

The type of mycorrhizal associations (i.e. ectomycorrhizal [EM] or arbuscular mycorrhizal [AM]) formed by trees is of fundamental importance for a range of soil properties and processes in forests, yet their importance for the distribution of other important soil biota such as bacteria is largely unknown.We used an experimental common garden and amplicon sequencing to assess how abiotic and biotic variation differentially influenced bacterial communities associated with 13 climax tree species (8 EM members of the Dipterocarpaceae and 5 AM species from different families) planted into a secondary tropical forest in Borneo.Rhizosphere bacterial (RB) communities differed significantly between EM and AM trees but not among EM species and only marginally among AM species.RB communities were related to the density and size of neighbouring EM but not AM trees. Diversity of RB on AM trees responded positively to AM neighbours and negatively to EM neighbours but RB diversity associated with EM trees was unaffected by neighbourhood. Plant‐growth‐promoting taxa of RB assorted similarly to total RB but more strongly.Synthesis. Our results suggest that the distribution of RB communities is associated with plant mycorrhizal type and plant neighbourhood. Because rhizosphere bacteria alter nutrient cycling and influence plant species composition, their distributions are likely important for understanding ecosystem processes and plant demographics in forest ecosystems. [ABSTRACT FROM AUTHOR]

Hymenophyllum subg. Mecodium is subcosmopolitan and comprises ca. 35 species. Its neotropical species are poorly known taxonomically. The high degree of morphological similarity among the species and the absence of clear characters to distinguish them has confounded taxonomic treatments, resulting in the lumping of many putative segregate taxa into a broadly circumscribed Hymenophyllum polyanthos species complex. The goal of the present study was to analyze morphologically and phylogenetically the species of Hymenophyllum subg. Mecodium in the Atlantic Forest domain. Morphological studies were conducted utilizing traditional stereomicroscopy and scanning electron microscopy (SEM). Additionally, Bayesian inference and maximum likelihood phylogenetic analyses were performed using plastid data for seven markers: atpB, atpB-rbcL, matK, rbcL, rbcL-accD, rps4, and rps4-trnS. Seven independent lineages were identified in this study, while morphological analysis supported the delimitation of five taxa within the Atlantic Forest domain: Hymenophyllum apiculatum, H. polyanthos, H. schomburkii, H. undulatum, and H. viridissimum. One taxon, Hymenophyllum sturmii, is recognized as a cryptic species, formed by two independent evolutionary lineages, and treated here provisionally as the H. sturmii complex. A taxonomic revision for the six taxa occurring in the Atlantic Forest domain is presented, including seven new lectotypifications, along with an identification key, descriptions, and illustrations for the species. We also provide data regarding the geographical distribution and conservation status of these six species. [ABSTRACT FROM AUTHOR]

Bamboos are abundant and versatile, hence their growing interest throughout the world in a variety of uses, however, there is little technical information on the anatomy and physical properties that are important to further expand and diversify its uses. For them, the objective was to characterize the anatomy and variation in the axial direction of the physical properties of the three bamboo species in the Madre de Dios region. For this, the bamboo species were collected: Bambusa vulgaris, Gigantochloa apus, and Guadua weberbaueri were through destructive methods, collecting three culms from different bushes and obtaining samples at different heights of the culm (base, intermediate and apex). The anatomy was performed at the base of the culm and the physical properties at the three axial positions. The results show that at the anatomical level, there is a difference between the three species mainly due to the vascular bundles, on the physical properties there was also a difference between species and the variation in the axial direction there was variation in the three positions, in addition, the grouping analysis showed that the species Bambusa vulgaris and Gigantochloa apu form a group due to their anatomical characteristics and physical properties, while Guadua weberbaueri was not grouped with either. Finally, the appropriate uses of the three bamboo species are directly related to their anatomy and physical properties, being key to their sustainable use in tropical forests. [ABSTRACT FROM AUTHOR]

Introduction: Tropical forests provide important ecosystem services, including disease control. However, few studies have focused on how deforestation affects species more suitable to be zoonotic vectors. Objective: To evaluate how deforestation affects the abundance and species richness of rodents and their associated ectoparasites in a tropical ecosystem. Methods: We captured rodents in 6 landscape units, 1 km² each, with 0.7; 5; 40; 46; 78 and 95 % tree cover, in Marques de Comillas, Chiapas, Southern Mexico. In each unit we set 90 Sherman traps that were active 24 hours for 7 days during two sampling seasons (October 2019, and September 2020). We manually extracted ectoparasites from all captured rodents. Results: We captured 70 rodents of five species: Sigmodon toltecus, Heteromys desmarestianus, Ototylomys phyllotis, Peromyscus mexicanus, and Oryzomys couesi. Rodent abundance increased with forest loss (R²= 0.706, P= 0.022). The greatest richness of rodent species occurred in sites with intermediate forest cover (40 and 78 %). The most abundant species were: S. toltecus (N= 45) followed by O. couesi (N= 9), these species dominated in sites with less forest cover. We recorded a total of 23 ectoparasite species, three of them known to be zoonotic vectors: Amblyomma sp., Ornithonyssus bacoti, and Androlaelaps fahrenholzi. Conclusions: The ongoing loss of forests promotes the proliferation of zoonotic disease vectors in this tropical ecosystem, which can potentially increase the frequency of affectation among the local population. [ABSTRACT FROM AUTHOR]