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Soil organic matter contributes to productivity in terrestrial ecosystems and contains more carbon than is found in the atmosphere. Yet, there is little understanding of soil organic carbon (SOC) sequestration processes during tropical forest succession, particularly after land abandonment from agriculture practices.Here, we used vegetation and environmental data from two large‐scale surveys covering a total landscape area of 20,000 ha in Southeast Asia to investigate the effects of plant species diversity, functional trait diversity, phylogenetic diversity, above‐ground biomass and environmental factors on SOC sequestration during forest succession.We found that functional trait diversity plays an important role in determining SOC sequestration across successional trajectories. Increases in SOC carbon storage were associated with indirect positive effects of species diversity and succession age via functional trait diversity, but phylogenetic diversity and above‐ground biomass showed no significant relationship with SOC stock. Furthermore, the effects of soil properties and functional trait diversity on SOC carbon storage shift across elevation.Synthesis. Our results suggest that reforestation and restoration management practices that implement a trait‐based approach by combining long‐lived and short‐lived species (conservative and acquisitive traits) to increase plant functional diversity could enhance SOC sequestration for climate change mitigation and adaptation efforts, as well as accelerate recovery of healthy soils. [ABSTRACT FROM AUTHOR]

Population declines and range contractions due to habitat loss are pervasive among nonhuman primates, with 60% of species threatened with extinction. However, the extensive vocal activity displayed by many primates makes them excellent candidates for passive acoustic surveys. Passive acoustic survey data is increasingly being used to support occupancy models, which have proven to be an efficient means of estimating both population trends and distributions. Passive acoustic surveys can be conducted relatively quickly and at broad scales, but efficient audio data processing has long proven elusive. The machine learning algorithm BirdNET was originally developed for birds but was recently expanded to include nonavian taxa. We demonstrate that BirdNET can accurately and efficiently identify an endangered primate, the Yucatán black howler monkey (Alouatta pigra), by sound in passive acoustic survey data (collected in southeastern Chiapas, Mexico), enabling us to use a single‐season occupancy model to inform further survey efforts. Importantly, we also generated data on up to 286 co‐occurring bird species, demonstrating the value of integrated animal sound classification tools for biodiversity surveys. BirdNET is freely available, requires no computer science expertise to use, and can readily be expanded to include more species (e.g., its species list recently tripled to >3000), suggesting that passive acoustic surveys, and thus occupancy modeling, for primate conservation could rapidly become much more accessible. Importantly, the long history of bioacoustics in primate research has yielded a wealth of information about their vocal behavior, which can facilitate appropriate survey design and data interpretation. Highlights: The BirdNET algorithm was developed to identify birds by sound but was recently expanded to include non‐avian taxa; we demonstrate that it can identify an endangered primate, the Yucatán black howler monkey (Alouatta pigra).BirdNET‐based howler monkey detections enabled us to use an occupancy model to inform further survey efforts—and to generate data on up to 286 co‐occurring bird species, illustrating the value of multispecies classifiers for biodiversity surveys.Combining free and easy‐to‐use tools like BirdNET, passive acoustic surveys, and occupancy modeling can facilitate rapid, broad‐scale assessments of primate population trends and distributions. [ABSTRACT FROM AUTHOR]

Severe droughts can lead to fires that cause massive tree mortality in even the wettest and most isolated Amazonian forests. After repeated fires, blackwater floodplain forests can remain in an open vegetation state of arrested succession that facilitates a transition towards a white‐sand 'savanna‐like' vegetation. These vegetation shifts, from closed‐canopy floodplain forests to open fire scars and eventually white‐sand savannas, may have profound implications for fish communities that depend on floodplain forests for food and recruitment. In turn, changes in fish communities may contribute to the arrested forest recovery after fires as fish are important seed dispersal agents for many floodplain tree species.To explore the impacts of floodplain forest fires on fish communities, we sampled fish in unburnt forests, fire scars, and white‐sand savannas in the middle Rio Negro basin (Brazil) during two consecutive flooding seasons. We compared the abundance, species richness, and the taxonomic and trophic composition of fish assemblages across the three habitat types.We found significant shifts in fish assemblages in fire scars compared to unburnt floodplain forests. Also, as fire scars increased in size, total fish biomass decreased strongly. Fish communities in unburnt floodplain forests seem to be characterized by a higher proportion of smaller and omnivorous fish species than fish communities in burned floodplain forests and white sand savannas. Fish assemblages in fire scars and white‐sand savanna were not significantly different.Synthesis and Applications. Amazonian fish communities change after floodplain forest fires. Unburnt forests have diverse fish communities, with a large proportion of unique and small omnivorous species. In contrast, carnivores and detritivores become more common in fire scars and white‐sand savannas formed after forest fires. Less omnivore fish after forest fires can reduce tree seed dispersal and forest regeneration, affecting ecosystem functioning and the services provided by Amazonian forests. Fish are also a primary source of food and income for people living in Amazonian floodplains. Preventing forest fires is therefore of fundamental importance for the conservation of Amazonian aquatic and terrestrial ecological communities as well as for the livelihood of people. [ABSTRACT FROM AUTHOR]

Nitrogen (N) deposition is a pervasive anthropogenic change that can alter the dynamics and storage of carbon (C) in tropical soils by altering the transformation of plant litter C to soil organic C (SOC). The response of fungi may be particularly important for explaining how N deposition affects SOC storage in tropical forests because they are the primary decomposers of plant litter. Fungi can be grouped into different ecological guilds, or functional groups, which often have contrasting responses to the same environmental change. However, little is known if shifts in fungal guilds and their functions explain increased tropical forest SOC storage under N deposition.We addressed this knowledge gap by assessing the effects of long‐term (6 years) experimental N addition (+N) on fungal guilds, their functions and SOC fractions in a tropical forest.Total SOC, dissolved organic C (DOC), particulate organic C and fungal necromass C were all higher in +N soils. The fungal community in +N soils was dominated by generalist saprotrophs, and leaf saprotroph abundance increased nearly 93‐fold compared to controls. These changes were accompanied by an increase in lignocellulolytic enzymes, indicating accelerated decomposition of recalcitrant litter C compounds. Chitosanase, which catalyses synthesis of glucosamine, was 1.37× higher in +N soils than controls; correspondingly, fungal necromass C contributed 1.42× more to SOC. Greater abundance of saprotrophic enzymes involved in organic acid synthesis in +N soils was associated with higher concentration of Ca2+ and DOC.We propose that N deposition increases SOC storage by enhancing saprotroph abundance and activity, whereby increased organic acid production supports fungal growth both directly and indirectly via the release of nutrients and DOC, resulting in greater inputs of necromass to the soil. Our findings highlight the importance of considering shifts in guild‐level fungal abundance and function to investigate changes in SOC dynamics and storage. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Climate change impacts on tropical forests and tree species have been documented as changes in distribution, growing period, phenology, habitat, productivity, species composition, and migration. This study attempts to assess the current and future habitat suitability distribution of two dominant species of Central India, teak (Tectona grandis Linn. f.) and sal (Shorea robusta Gaertn. f.) using a maximum entropy (MaxEnt) model to predict species occurrences by finding the distribution that has the most spread. The future suitable habitat ranges of the species were modeled for two time periods (2050 and 2070) and two representative concentration pathways (RCP 2.6 and 8.5). Representative concentration pathways are scenarios that describe alternative trajectories for carbon dioxide emissions and the resulting atmospheric concentration from 2000 to 2100. We collected and modeled the spatially well-dispersed species occurrence points of teak and sal. The results suggested an increase in suitable habitat range for teak and a decrease for sal for both time periods and RCPs. Furthermore, the jackknife analysis identified temperature and precipitation seasonality as the major variables that influence the distribution of teak. In the case of sal, minimum temperature makes the maximum contribution to distribution changes. The suitable silvicultural strategies for forest management are proposed based on the future distribution of species in relation to the climate variables responsible for the change in their distribution range. These findings and strategies will help forest departments build future management plans for teak and sal forest with a focus on minimizing the impact of climate change. Study Implications: Our study used maximum entropy (MaxEnt) modeling to understand the impact of changing climate on the distribution of teak and sal forests of central India and to propose future silvicultural strategies. The study used MaxEnt model for two time periods and two climate change scenarios at highest resolution. An increase in future suitable habitat for teak and a decrease for sal is predicted by the model. Temperature for teak and precipitation for sal were identified as the major influencing climatic variables. We recommend forest and other related government departments to commission focused research to understand the changing patterns of species with climate change and design appropriate silviculture strategies for effective management. [ABSTRACT FROM AUTHOR]

ABSTRACT Tropical forests are three-dimensional with the presence of numerous micro-environments formed by horizontal and vertical gradients. Such micro-environments can affect the nesting preference of organisms, including the trap-nesting Hymenoptera. Bees and wasps are key elements in ecosystems and are considered as sensitive to environmental changes, and trap-nests sampling methodology is widely used in their ecological and conservation studies. However, many uncertainties remain about nesting site preferences. From this perspective, our aim is to assess the diversity descriptors of trap-nesting Hymenoptera in different micro-environments. The sampling was conducted on three micro-environments (canopy, understory and treefall gaps) replicated on ten permanent plots within a Brazilian Atlantic forest hotspot. In each micro-environment, we installed trap-nest stations made by a set of twenty bamboo artificial nests. We found 762 brood cells from ten wasp and five bee species. The rarefaction curves indicate the lower species richness in understory stations, while treefall gaps and canopy stations were not significantly different. We analyzed abundance, mortality and parasitism rates using generalized linear models, but only abundance varies significantly among micro-environments. Our data indicates that trap-nesting Hymenoptera prefer to nest in micro-environments with higher exposure of sunlight. Canopy and treefall gap assemblages are consistently more abundant and diverse than understory probably due the higher temperature and lower humidity. On the other hand, mortality, parasitism rates, and the species composition were similar among environments. Our hypothesis is that the species composition was not affected as these species have a foraging range that encompasses nearby micro-environments.

It is widely accepted that phosphorus (P) limits microbial metabolic processes and thus soil organic carbon (SOC) decomposition in tropical forests. Global change factors like elevated atmospheric nitrogen (N) deposition can enhance P limitation, raising concerns about the fate of SOC. However, how elevated N deposition affects the soil priming effect (PE) (i.e., fresh C inputs induced changes in SOC decomposition) in tropical forests remains unclear. We incubated soils exposed to 9 years of experimental N deposition in a subtropical evergreen broadleaved forest with two types of 13C‐labeled substrates of contrasting bioavailability (glucose and cellulose) with and without P amendments. We found that N deposition decreased soil total P and microbial biomass P, suggesting enhanced P limitation. In P unamended soils, N deposition significantly inhibited the PE. In contrast, adding P significantly increased the PE under N deposition and by a larger extent for the PE of cellulose (PEcellu) than the PE of glucose (PEglu). Relative to adding glucose or cellulose solely, adding P with glucose alleviated the suppression of soil microbial biomass and C‐acquiring enzymes induced by N deposition, whereas adding P with cellulose attenuated the stimulation of acid phosphatase (AP) induced by N deposition. Across treatments, the PEglu increased as C‐acquiring enzyme activity increased, whereas the PEcellu increased as AP activity decreased. This suggests that P limitation, enhanced by N deposition, inhibits the soil PE through varying mechanisms depending on substrate bioavailability; that is, P limitation regulates the PEglu by affecting soil microbial growth and investment in C acquisition, whereas regulates the PEcellu by affecting microbial investment in P acquisition. These findings provide new insights for tropical forests impacted by N loading, suggesting that expected changes in C quality and P limitation can affect the long‐term regulation of the soil PE. [ABSTRACT FROM AUTHOR]

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Forests serve as a sink and source of carbon and play a substantial role in regional and global carbon cycling. The Himalayan forests act as climate regulators of the Hindukush region, which is experiencing climate change at a high pace, and a proper understanding of these systems is necessary to mitigate this problem. We hypothesize that the variance of abiotic factors and vegetation will influence the carbon sink and source function of the different forest types of the Himalayas. Carbon sequestration was computed from the increment of carbon stocks estimated allometrically using Forest Survey of India equations, and soil CO2 flux was determined by the alkali absorption method. The carbon sequestration rate and CO2 flux by the different forests exhibited a negative relation. The carbon sequestration rate was highest with minimum emission in the temperate forest, while the tropical forest recorded the least sequestration and maximum carbon flux rate. The Pearson correlation test between carbon sequestration and tree species richness and diversity revealed a positive-significant influence but negative relation with climatic factors. An analysis of variance indicated significant seasonal differences between the rate of soil carbon emissions due to variations in the forest. A multivariate regression analysis of the monthly soil CO2 emission rate shows high variability (85%) due to fluctuations of climatic variables in the Eastern Himalayan forests. Results of the present study revealed that the carbon sink and source function of forests respond to changes in forest types, climatic variables, and edaphic factors. Tree species and soil nutrient content influenced carbon sequestration, while shifts in climatic factors influenced soil CO2 emission rate. Increased temperature and rainfall may further change the soil quality by enhancing soil CO2 emission and reducing soil organic carbon, thereby impacting this region's carbon sink and source function. Enhancing tree diversity in the forests of this region may be beneficial for retarding this impact. [ABSTRACT FROM AUTHOR]

Collaboration between ecologists and learning scientists can give rise to powerful models for scientific outreach within ecology. This paper presents a process by which learning scientists and ecologists codesigned a science curriculum that invites students to join an ecological community of practice. In the Journey to El Yunque middle school science curriculum, students engage with simulation models generated from data gathered by Luquillo Long Term Ecological Research (LUQ LTER) scientists. Journey to El Yunque students can explore post‐hurricane population changes in yagrumo (Cecropia schreberiana), tabonuco (Dacryodes excelsa), coquís (Eleutherodactylus coquí), snails (Caracolus caracola), anoles (Anolis stratulus and A. gundlachi), veiled stinkhorn mushrooms (Dictyophora indusiata), and caterpillars (Historis odius). Ecology‐based revisions to Journey to El Yunque have included adding models of the effects of repeated hurricanes on limiting factors, based in part on findings from a canopy trimming experiment. Revisions based on classroom testing include simplifying student‐facing model controls to allow students to focus on the essential model components. The ongoing collaboration that keeps the Journey to El Yunque curriculum on the cutting edge of ecological and educational advances has been sustained for over two decades. We attribute the longevity of this work to (1) the long‐term nature of LUQ LTER, (2) a sustained interdisciplinary collaboration, and (3) our long‐term relationships with schools. [ABSTRACT FROM AUTHOR]

Launched in 2015, the large-scale initiative Indonesian Biodiversity Discovery and Information System (IndoBioSys) is a multidisciplinary German-Indonesian collaboration with the main goal of establishing a standardised framework for species discovery and all associated steps. One aspect of the project includes the application of DNA barcoding for species identification and biodiversity assessments. In this framework, we conducted a large-scale assessment of the insect fauna of the Mount Halimun-Salak National Park which is one of the largest tropical rain-forest ecosystems left in West Java. In this study, we present the results of processing 5,034 specimens of Phoridae (scuttle flies) via DNA barcoding. Despite limited sequencing success, we obtained more than 500 clusters using different algorithms (RESL, ASAP, SpeciesIdentifier). Moreover, Chao statistics indicated that we drastically undersampled all trap sites, implying that the true diversity of Phoridae is, in fact, much higher. With this data release, we hope to shed some light on the hidden diversity of this megadiverse group of flies. [ABSTRACT FROM AUTHOR]

Water deficit in the atmosphere and soil are two key interactive factors that constrain transpiration and vegetation productivity. It is not clear which of these two factors is more important for the water and carbon flux response to drought stress in ecosystems. In this study, field data and numerical modeling were used to isolate their impact on evapotranspiration (ET) and gross primary productivity (GPP) at a tropical forest site in Barro Colorado Island (BCI), Panama, focusing on their response to the drought induced by the El Niño event of 2015–2016. Numerical simulations were performed using a plant hydrodynamic scheme (HYDRO) and a heuristic approach that ignores stomatal sensitivity to leaf water potential in the Energy Exascale Earth System Model (E3SM) Land Model (ELM). The sensitivity of canopy conductance (Gs) to vapor pressure deficit (VPD) obtained from eddy-covariance fluxes and measured sap flux shows that, at both ecosystem and plant scale, soil water stress is more important in limiting Gs than VPD at BCI during the El Niño event. The model simulations confirmed the importance of water stress limitation on Gs, but overestimated the VPD impact on Gs compared to that estimated from the observations. We also found that the predicted soil moisture is less sensitive to the diversity of plant hydraulic traits than ET and GPP. During the dry season at BCI, seasonal ET, especially soil evaporation at VPD > 0.42 kPa, simulated using HYDRO and ELM, were too strong and will require alternative parameterizations.

Leaf respiration in the dark (Rdark) and light (Rday) is poorly characterized in diverse tropical ecosystems, and little to no information exists on the degree of light suppression in common tree species within the Amazon basin, and their dependences upon plant functional traits and position within the canopy. We quantified Rdark and apparent Rday using the Kok method and measured key leaf traits in 26 tree individuals of different species distributed in three different canopy positions: canopy, lower canopy, and understory. To explore the relationships between the leaf traits we used the standardized major axis (SMA). We found that canopy trees had significantly higher rates of Rdark and Rday than trees in the understory. The difference between Rdark and Rday (the light suppression of respiration) was greatest in the understory (68 ± 9%, 95% CI) and lower canopy (49 ± 9%, 95% CI) when compared to the canopy (37 ± 10%, 95% CI). We also found that Rday was significantly and strongly correlated with Rdark (p < 0.001) for all the canopy positions. Also, leaf mass per area (LMA) and leaf Phosphorus concentration (P) had a significant relationship with Rdark (p < 0.001; p = 0.003), respectively. In addition, a significant relationship was found for LMA in the canopy and lower canopy positions (p = 0.009; p = 0.048) while P was only significant in the canopy (p = 0.044). Finally, no significant relationship was found between Rdark and nitrogen, sugars, and starch. Our results highlight the importance of including representation of the light suppression of leaf respiration in terrestrial biosphere models and also of accounting for vertical gradients within forest canopies and connections with functional traits.

Amazonian droughts are increasing in frequency and severity. However, little is known about how this may influence species-specific vulnerability to drought across different ecosystem types. We measured 16 functional traits for 16 congeneric species from six families and eight genera restricted to floodplain, swamp, white-sand or plateau forests of Central Amazonia. We investigated whether habitat distributions can be explained by species hydraulic strategies, and if habitat specialists differ in their vulnerability to embolism that would make water transport difficult during drought periods. We found strong functional differences among species. Nonflooded species had higher wood specific gravity and lower stomatal density, whereas flooded species had wider vessels, and higher leaf and xylem hydraulic conductivity. The P50 values (water potential at 50% loss of hydraulic conductivity) of nonflooded species were significantly more negative than flooded species. However, we found no differences in hydraulic safety margin among species, suggesting that all trees may be equally likely to experience hydraulic failure during severe droughts. Water availability imposes a strong selection leading to differentiation of plant hydraulic strategies among species and may underlie patterns of adaptive radiation in many tropical tree genera. Our results have important implications for modeling species distribution and resilience under future climate scenarios.

Capturing birds of tropical rainforest canopies is important for answering many questions in ecology, evolution, and conservation, but canopy birds are often out of reach when using conventional mist-netting methods. Some methods exist to mist-net canopy birds, but modifications needed for target-capturing large frugivores are not well documented. Here, we describe a canopy netting method for capturing large, fruit-eating birds in rainforests. The methods presented here emphasize a large net area, maneuverability of netting, and collapsibility for safely preventing the escape of captured birds. During three different projects in the rainforests of Cameroon, this technique has resulted in the successful capture of hornbills (Bucerotidae), turacos (Musophagidae), and fruit pigeons (Columbidae). We recommend this technique for canopy bird research and encourage documentation of any modifications.

Due to increasing anthropogenic pressure, over half of the world’s tropical forests are reforested or afforested secondary forests or plantations. The recovery pace and potential of these forests depend largely on soil microbially-mediated biogeochemical cycling. Here we measured soil extracellular enzyme activities and quantified microbial metabolic limitations using a vector analysis in a bare land (BL, representing the original state before restoration), two afforested sites [i.e. a restored secondary forest (MF) and a managed Eucalyptus exserta plantation (EP)] and a nearby undisturbed forest (UF) in south China. Results showed that soil microbial metabolisms were co-limited by carbon (C) and phosphorus (P) across the four forests. Both microbial C and P limitations were higher in BL than UF. Microbial C limitation significantly reduced after restoration only in MF when compared to BL, but it was still higher than that in UF. Interestingly, microbial P limitation significantly enhanced after restoration in both EP and MF when compared to BL, and it did not differ between the two restored forests. Structural equation modeling (SEM) showed that microbial C limitation was primarily attributed to microbial C use efficiency, while microbial P limitation was co-driven by plant biomass, microbial C use efficiency and soil P availability. These findings suggest microbial C limitation could be gradually recovered after forest restoration in southern China, which would facilitate soil organic carbon accumulation. However, the enhanced microbial P limitation after forest restoration underlines the necessity to develop optimal P management in these restored forests.

This study utilized a remotely sensed dataset with a high spatial resolution of 3 m to predict species diversity in the Bobiri Forest Reserve (BFR), a moist semi-deciduous tropical forest in Ghana. We conducted a field campaign of tree species measurements to achieve this objective for species diversity estimation. Thirty-five field plots of 50 m × 20 m were established, and the most dominant tree species within the forest were identified. Other measurements, such as diameter at breast height (DBH ≥ 5 cm), tree height, and each plot’s GPS coordinates, were recorded. The following species diversity indices were estimated from the field measurements: Shannon–Wiener (H′), Simpson diversity index (D2), species richness (S), and species evenness (J′). The PlanetScope surface reflectance data at 3 m spatial resolution was acquired and preprocessed for species diversity prediction. The spectral/pixel information of all bands, except the coastal band, was extracted for further processing. Vegetation indices (VIs) (NDVI—normalized difference vegetation index, EVI—enhanced vegetation index, SRI—simple ratio index, SAVI—soil adjusted vegetation index, and NDRE—normalized difference red edge index) were also calculated from the spectral bands and their pixel value extracted. A correlation analysis was then performed between the spectral bands and VIs with the species diversity index. The results showed that spectral bands 6 (red) and 2 (blue) significantly correlated with the two main species diversity indices (S and H′) due to their influence on vegetation properties, such as canopy biomass and leaf chlorophyll content. Furthermore, we conducted a stepwise regression analysis to investigate the most important spectral bands to consider when estimating species diversity from the PlanetScope satellite data. Like the correlation results, bands 6 (red) and 2 (blue) were the most important bands to be considered for predicting species diversity. The model equations from the stepwise regression were used to predict tree species diversity. Overall, the study’s findings emphasize the relevance of remotely sensed data in assessing the ecological condition of protected areas, a tool for decision-making in biodiversity conservation.

The tropical forests in the Amazon store large amounts of carbon and are still considered a carbon sink. There is evidence that deforestation can turn a forest landscape into a carbon source due to land use and forest degradation. Deforestation causes fragmented forest landscapes. It is known from field experiments that forest dynamics at the edge of forest fragments are altered by changes in the microclimate and increased tree mortality (“edge effects”). However, it is unclear how this will affect large fragmented forest landscapes, and thus the entire Amazon region. The aim of this study is to investigate different forest attributes in edge and core forest areas at high resolution, and thus to identify the large-scale impacts of small-scale edge effects. Therefore, a well-established framework combining forest modelling and lidar-generated forest structure information was combined with radar-based forest cover data. Furthermore, forests were also analyzed at the landscape level to investigate changes between highly fragmented and less-fragmented landscapes. This study found that the aboveground biomass in forest edge areas is 27% lower than in forest core areas. In contrast, the net primary productivity is 13% higher in forest edge areas than in forest core areas. In the second step, whole fragmented landscapes were analyzed. Nearly 30% of all forest landscapes are highly fragmented, particularly in the regions of the Arc of Deforestation, on the edge of the Andes and on the Amazon river banks. Less-fragmented landscapes are mainly located in the central Amazon rainforest. The aboveground biomass is 28% lower in highly fragmented forest landscapes than in less-fragmented landscapes. The net primary productivity is 13% higher in highly fragmented forest landscapes than in less-fragmented forest landscapes. In summary, fragmentation of the Amazon rainforest has an impact on forest attributes such as biomass and productivity, with mostly negative effects on forest dynamics. If deforestation continues and the proportion of highly fragmented forest landscapes increase, the effect may be even more intense. By combining lidar, radar and forest modelling, this study shows that it is possible to map forest structure, and thus the degree of forest degradation, over a large area and derive more detailed information about the carbon dynamics of the Amazon region.

Tropical forest and savanna biomes are pivotal in the functioning of the Earth system. Both are biodiverse and under increasing threat due to land clearing and anthropogenic climate change, and play important roles in the global carbon cycle, through maintenance of a large carbon pool in tropical forests, and exchange in savannas through extensive landscape fires. Reliable mapping of tropical forest and savanna is essential to understand how the current distribution of these vegetation types is controlled by climate land clearing and fire. Using Google Maps satellite imagery, we manually classified 24 239 random points as forest, savanna, or anthropogenic landscapes within the tropics and applied this novel dataset to defining the climatic zone where forest and savanna exist as alternative states. Because fire and climate are correlated, we developed separate geospatial models to rank the importance of climate, topography, and human influence on vegetation present. This modeling confirmed that those areas with more fires had lower probabilities of tropical forest, that forest was most likely in areas with high mean annual rainfall with little seasonal variation in precipitation, and that anthropogenic factors disrupt this environmental predictability. We also identified areas where tropical forest and savanna both co-occur, but these were relatively uncommon. These relationships suggest that future drier climates projected under anthropogenic climate change, combined with clearing and burning that have reduced tropical forest extent to a subset of its theoretical distribution, will lead to irreversible loss of tropical forests. Our modeling provides global mapping that can be used track further changes to distribution of tropical forests.

Forests play a crucial role in quantifying global carbon storage and detecting climate change in the form of aboveground biomass (AGB), which introduces an approach to study carbon cycle, ecology, and biodiversity. The monitoring and estimation of forest AGB are considered very important and of practical value. As we know, forest AGB relates with height, density and diameter at breast height, and how to relate the ecophysical parameters with remote sensing images is vital for forest AGB estimation. In this paper, we aim to explore structure parameters about forest density and height, extracted by tomographic SAR (TomoSAR) techniques, for further improving the precision of AGB estimation models. Firstly, vertical structure profiles are constructed via TomoSAR, and the structure features are extracted. Secondly, the correlation between these features and the in-situ forest maximum height, tree density, and average AGB in plot scale is analyzed. Thirdly, the 8-fold cross-validation and step-wise regression methods were utilized to construct the tropical forest AGB models. Finally, the results of these models have been presented and analyzed. Based on the analysis, it indicates that “Model 7” is the most effective model, and its performance at both plot and pixel scales indicates a high level of accuracy for predicting forest AGB. These findings suggest that the proposed method can be effectively applied to tropical forested areas and has good scalability.

The tropical forest carbon (C) balance threatened by extensive socio‐economic development in the Greater Mekong Subregion (GMS) in Asia is a notable data gap and remains contentious. Here we generated a long‐term spatially quantified assessment of changes in forests and C stocks from 1999 to 2019 at a spatial resolution of 30 m, based on multiple streams of state‐of‐the‐art high‐resolution satellite imagery and in situ observations. Our results show that (i) about 0.54 million square kilometers (21.0% of the region) experienced forest cover transitions with a net increase in forest cover by 4.3% (0.11 million square kilometers, equivalent to 0.31 petagram of C [Pg C] stocks); (ii) forest losses mainly in Cambodia, Thailand, and in the south of Vietnam, were also counteracted by forest gains in China due mainly to afforestation; and (iii) at the national level during the study period an increase in both C stocks and C sequestration (net C gain of 0.087 Pg C) in China from new plantation, offset anthropogenetic emissions (net C loss of 0.074 Pg C) mainly in Cambodia and Thailand from deforestation. Political, social, and economic factors significantly influenced forest cover change and C sequestration in the GMS, positively in China while negatively in other countries, especially in Cambodia and Thailand. These findings have implications on national strategies for climate change mitigation and adaptation in other hotspots of tropical forests. [ABSTRACT FROM AUTHOR]

Intrinsic soil properties have been shown to mediate the effects of ectomycorrhizal (ECM) fungi and their associated trees on soil organic matter (SOM) and nitrogen (N) cycling, but variation in the contribution of fungal communities to ECM effects across different forests remains uncertain. To investigate the potential role of fungal communities in driving observed variation in ECM effects, we characterized fungal community composition and function using DNA sequence variability of the ITS2 region of the fungal rRNA operon and measured chemical properties of forest floor leaf litter, soil organic horizon, and soil mineral horizons (0–5cm, 15–20 cm depth) beneath ECM-associated Oreomunnea mexicana focal trees. We sampled beneath focal trees in arbuscular mycorrhizal (AM)- and ECM-dominated stands within four adjacent watersheds that differed in underlying soil pH and fertility. We found that overall fungal community composition and the ratio of ECM to saprotrophic fungi differed between AM- and ECM-dominated stands in the lowest pH and fertility watershed but were similar between stand mycorrhizal types in the highest pH and fertility watershed. Patterns in fungal community composition and function aligned with patterns in N isotopic composition of forest floor leaf litter and mineral soil, which could reflect greater ECM transfer of N to the trees and greater contribution of hyphal biomass to SOM in the lowest pH and fertility watershed. Overall, our results suggest the potential for watershed-scale variation in soil pH and fertility to mediate fungal community contributions to variation in ECM effects on biogeochemical syndromes. [ABSTRACT FROM AUTHOR]

Lightning strikes are a significant cause of tree mortality and damage in some regions of the tropics. Formation of lightning scars on tropical trees, however, is considered rare and therefore of little relevance in identifying trees struck by lightning. Here, we suggest, based on observations made in the Bwindi Impenetrable National Park (Uganda), that lightning scars can be frequent and may be a useful diagnostic feature to aid in identifying trees struck by lightning. [ABSTRACT FROM AUTHOR]

The underrepresentation of many important rainforest species in pollen records still hinders accurate paleovegetation reconstructions in tropical Southeast Asia. In this study, we conducted a modern phytolith study of 141 plant and 15 surface soil samples around the forests of Jerai Hill in western Peninsular Malaysia to evaluate the potential of phytolith assemblages as a proxy for indicating tropical vegetation types. In the plant samples, including many Dipterocarpaceae species, tracheary annulate/helical phytoliths occur most commonly, followed by silicified epidermis, silicified stomata, elongate entire, sclereid, trichomes, irregular. A few diagnostic phytoliths with unique morphological features are found in dicotyledonous trees, palms, and ferns, such as spheroid ornate (sph_orn) and spheroid echinate (sph_ech). In contrast, the phytolith assemblage of surface sediment is dominated by sph_orn, sph_ech, and spheroid psilate. This suggests that similar to pollen, the contribution from dominating forest vegetation rich in Dipterocarpaceae species is obscure in phytolith deposits. However, phytolith analysis highlights the representation of monocotyledons and a few dicotyledonous trees. The more sensitive indication of Poaceae short-cell phytoliths than pollen for parent plants implies that their ratio to forest indicator phytoliths might be a valuable proxy of landscape openness. Additionally, the statistical analysis confirms that phytolith assemblages in the heath forest are slightly different from those in the lowland dipterocarp forest, exhibiting their potential to indicate various vegetation types. [ABSTRACT FROM AUTHOR]

Selective logging is one of the largest drivers of tropical forest degradation. While logged forests often retain high alpha‐diversity of tropical trees at local spatial scales, understanding how selective logging impacts tree beta‐diversity and community composition across far larger spatial scales remains a key unresolved question.We leverage large datasets of more than 155,000 adult trees over 35 cm DBH covering 3100 ha of Amazonian rainforest to inform simulations of selective logging harvests across a gradient of logging intensity (0–40 m3 ha−1). These simulations incorporate real world price data, account for all forest damage throughout the harvest process and assume preferential harvest of the most valuable stems. We use the simulations to assess how selective logging affects canopy tree beta‐diversity and composition across large spatial scales, whether nestedness or turnover of species best explains variation in communities across space, and how the spatial scale of sampling influences observed beta‐diversity effects.Selective logging had minimal impacts on beta‐diversity across the canopy tree community, but caused substantial subtractive heterogenization in community composition for larger trees, in particular very large trees over 110 cm DBH. Turnover is the dominant component of tree beta‐diversity in unlogged and logged forests. Increasing the spatial grain of sampling reduced the observed importance of logging in explaining patterns of beta‐diversity in very large tree communities.Synthesis and applications. Minimal impacts on tree beta‐diversity across large spatial scales points towards the retention of substantial conservation value in logged tropical forests. Strong subtractive heterogenization in very large trees indicates the breakdown of broad scale patterns of composition with potential negative consequences for recruitment processes, fauna reliant upon emergent trees, and other ecosystem functions and services. Avoiding large‐scale erosion of very large tree community composition in the Amazon requires stronger conservation policies, including enforced retention or maximum cutting diameters. [ABSTRACT FROM AUTHOR]

Aim: Central Africa shelters diverse and iconic megafauna, which is threatened by climate and land‐use changes and increased hunting‐induced defaunation. Though crucial for coordinating regional conservation actions, how species assemblages are spatially structured remains poorly understood. This study aims to fill this knowledge gap for mammals across central African forests. Location: Tropical moist forests from Nigeria to the Albertine Rift. Methods: An extensive compilation of forest‐dwelling mammal species lists was made from wildlife and bushmeat‐related surveys across central Africa. A beta‐diversity approach enabling the clustering of surveys composed of similar species was implemented to identify and delimit zoogeographic districts, separately for three well‐documented mammal orders: carnivores, primates and artiodactyls. Random forest classification models were then used to identify the environmental determinants of the district's distribution and to produce a continuous zoogeographic map (and associated uncertainties) critical to assess the conservation status of each district and their ongoing threats. Results: While carnivores do not present a clear spatial structure within central African forests, our findings highlight the structuring role of rivers on both primate and artiodactyl assemblages' distributions. We retained eight and six spatially congruent districts for primates and artiodactyls, respectively. These districts were shaped by the Ubangi‐Congo River system, and the Cross and Sanaga Rivers, with a secondary role of insularity and precipitation identified for primates. Highly threatened districts were highlighted, especially in Nigeria and in the Democratic Republic of Congo, the latter including vast areas that are understudied and poorly represented in the protected area network. Main Conclusions: Beyond refining our understanding of the diversity and uniqueness of mammalian assemblages across central African forests, our map of zoogeographic districts has far‐reaching implications for the conservation of highly threatened taxa, allowing to target species and areas of interest for further sampling, conservation and rewilding efforts. [ABSTRACT FROM AUTHOR]

Vertebrates play key roles as seed dispersers, herbivores, and top predators in tropical ecosystems. Therefore, obtaining population estimates for these species and understanding the factors that affect them are essential for wildlife management since changes in their populations have consequences for entire ecosystems. Vertebrate abundances in tropical forest may be related to habitat characteristics, resource seasonality, and human pressure. However, how ecological variables and human pressure concurrently influence animal abundances is not well understood. We investigated the associations between the number of records of vertebrates (ground-dwelling birds and medium- and large-sized mammals) and habitat features, food availability, and human pressure in a sustainable protected area in the Brazilian Amazon of western Pará, Brazil. Our study design included the recording of animals at 38 camera trap stations, sampling of environmental variables (canopy cover, leaf area index, tree height, and local altitude) and food resources (fruit or prey biomass), and measurement of a hunting pressure proxy (distance from human settlements). Our results indicated that groups responded in different ways: omnivorous mammals were affected positively by local altitude, canopy openness, and leaf area index; game birds were affected positively by local altitude and leaf area index; ungulates were affected negatively by local altitude and positively by food resources; and large rodents were affected only by food resources (positively). In contrast, insectivorous mammals and mesopredators were not affected by any variable we tested. Surprisingly, no groups responded to distance from human access, although the low number of records of large species, such Tapirus terrestris and Dicotyles tajacu, suggests that the sampled area may suffer from significant hunting pressure. [ABSTRACT FROM AUTHOR]

Soil microorganisms in tropical forests can adapt to phosphorus (P)-poor conditions by changing the activity ratios of different types of phosphatases. We tested whether microorganisms in P-poor tropical forest soils increased the phosphomonoesterase (PME) to phosphodiesterase (PDE) activity ratio, because a one-step enzymatic reaction of monoester P degradation might be more adaptive for microbial P acquisition than a two-step reaction of diester P degradation. A continuous 10-year P addition experiment was performed in three tropical forests. The activities of PME and PDE, and their ratio in soil, were determined under the hypothesis that the P-fertilized plots where P shortage is relieved would have lower PME:PDE ratios than the unfertilized controls. We demonstrated that long-term P addition in tropical forest soil did not alter the PME:PDE ratio in primary and secondary forests, whereas P fertilization elevated the PME:PDE ratio in planted forest. These results were in contrast to previous results. The long-term, large-scale P fertilization in our study may have reduced litter- and/or throughfall-derived PDE, which negated the lowered PME:PDE ratio via exogenous P inputs. [ABSTRACT FROM AUTHOR]

The niche theory is always central in explaining the structure of communities, helping to understand the distributions, interactions and coexistence of species fully. This study analysed niches and interspecific associations of dominant species in the evergreen broadleaved forest type. In 2022, we established a 3‑ha study plot within the strictly protected zone of Nui Ong Nature Reserve, southern Vietnam. All trees with a diameter at breast height (DBH) 5 cm in the study plot were determined, including their names and DBH. The results showed that five out of thirteen dominant species of the stand were ecologically significant. The similarity, breadth and overlap of niches of dominant tree species indicated that most were specialist species. The overall interspecific association among dominant species showed that the stand structure was relatively stable with a variance ratio = 1.34. Among seventy-nine pairs of thirteen dominant species, five pairs surpassed all tests of Chi-square, association coefficient and Pearson's correlation, in which two positive association pairs and three negative association pairs. The differences in niches and interspecific associations of dominant species in this study must be attentive in planning forest management and developing strategies for vegetation restoration in southern Vietnam. [ABSTRACT FROM AUTHOR]

Although silicon (Si) is one of soil abundant constituents and one of the key elements enhancing plant disease resistance, banana uptake of Si is limited by soil Si availability. It remains unclear what factors regulates soil Si availability and whether banana Si uptake increases with increasing soil Si availability in home garden soils. To test whether soil Si availability and banana leaf SiO2 contents are affected by soil types or fertility management practices, we measured (1) banana leaf SiO2 contents along the gradient of livestock inputs in Andisols of Tanzania and (2) water extractable Si, phosphate-buffer extractable Si, and banana leaf SiO2 in the home garden soils with different degree of volcanic ash admixing and with/without leguminous trees in Indonesia (East Java and East Kalimantan). Livestock dung application increased banana leaf SiO2 contents in the Tanzanian home gardens. Water extractable Si increased with increasing soil pH, but soil phosphate-buffer extractable Si and banana leaf SiO2 contents were strongly regulated by oxalate-extractable Si and andic properties in the Indonesian home gardens. Effects of companion trees (agroforestry) increased banana leaf SiO2 only in two of three Andisols (Java). These results suggest that banana leaf SiO2 contents could be primarily regulated by admixing degree of volcanic parent materials rich in weatherable minerals, but that banana leaf SiO2 contents could also be increased by inputs of livestock dung rich in Si (Tanzania) and agroforestry (Indoensia). [ABSTRACT FROM AUTHOR]

Although natural regeneration is often an efficient process for recovering degraded areas, the emergence of invasive species can complicate this process and lead the ecosystem to an alternative stable state (ASS) that disrupts ecosystem functioning. Identifying this condition is a key step in the design of restoration strategies. In this sense, we used a spatially explicit approach using the landscape metric area and the analysis of land-use and land-cover change to identify the dynamics of areas dominated by P. aquilinum, an invasive species well known for producing ASS. In our study site, a Mexican semi-evergreen tropical forest and seasonal lowland flooded forest, P. aquilinum has been in ASS for decades. We analyzed P. aquilinum dynamics in a period of 28 years (1989–2017) using a supervised classification of Landsat imagery. We found that, at the landscape scale, agriculture and livestock increased 224%, while semi-evergreen tropical forest and P. aquilinum cover showed losses of 13% and 72%, respectively. At the patch scale, we also found a statistically significant decrease in P. aquilinum patch area between 1989 and 1997 and 2017, but not between 1997 and 2017. Our results show that the areas dominated by P. aquilinum only change in time mainly through management toward productive activities, while patches not managed retain their area. Our study highlights the importance of spatial scale analysis for the understanding of landscape ecosystem dynamics for guiding decision-making and further research. [ABSTRACT FROM AUTHOR]

Copyright of Economic Botany is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Oil palm plantations have dramatically expanded in tropical Asia over the past decades. Although their establishment has been projected to increase nitrous oxide (N2O) emissions, earlier reports have shown inconsistent results. This study analyzed these previously published data to compare N2O emissions in oil palm plantations to reference forests. A linear mixed-effects model was used to examine the significance of the effect of establishing oil palm plantations on N2O emissions, rather than to calculate mean effect sizes because of limitations in the data structure. The results indicated that N2O emissions were significantly greater from oil palm plantations than from reference forests, as expected. This is the first study to report the effect of oil palm plantations on N2O emissions by synthesizing previously published data. To quantify the size of this effect, additional studies with frequent and long-term monitoring data are needed. [ABSTRACT FROM AUTHOR]

The stoichiometry of key elements such as C, N, and P is an important indicator of ecosystem nutrient status and biogeochemical cycling. Nevertheless, the responses of soil and plant C:N:P stoichiometric characteristics to natural vegetation restoration remain poorly understood. In this study, we investigated C, N, and P contents and stoichiometry in soil and fine roots along vegetation restoration stages (grassland, shrubland, secondary forest, and primary forest) in a tropical mountainous area in southern China. We found that soil organic carbon, total N, C:P ratio, and N:P ratio significantly increased with vegetation restoration and significantly decreased with increasing soil depth, whereas there was no significant effect on soil total P and C:N ratio. Furthermore, vegetation restoration significantly increased the fine root N and P content and N:P ratio, whereas soil depth significantly decreased the fine root N content and increased the C:N ratio. The increasing average N:P ratio in fine roots from 17.59 to 21.45 suggested that P limitation increased with vegetation restoration. There were many significant correlations between C, N, and P contents and their ratios in soil and fine roots, indicating a reciprocal control of nutrient stoichiometric characteristics between them. These results contribute to our understanding of changes in soil and plant nutrient status and biogeochemical cycling during vegetation restoration and provide valuable information for restoration and management of tropical ecosystems. [ABSTRACT FROM AUTHOR]

Food production in Amazonian traditional societies often occurs through shifting cultivation that uses few pesticides and relies on ecosystem services provided by natural enemies. However, these sustainable agricultural practices are being threatened by increasing livestock and mechanised agriculture.This study aimed to evaluate the effects of the conversion from Amazon Forest to anthropogenic land uses (shifting cultivation and pasture) on α‐ and β‐diversity, functional groups, and ant‐mediated predation.Three types of habitats were sampled: forest (eight sites), shifting cultivation (five sites) and pasture (seven sites). The ant assembly of each site was sampled using pitfall traps in the epigeic and hypogeic strata. Beetle larvae were used to evaluate the predation function.Negative effects on epigeic ants and functional groups were found to be greater in sites where anthropogenic land use was more intensive (pasture) than in those where it was less intensive (shifting cultivation). Furthermore, this change increased the predation of insects in shifting cultivation and pasture compared to that in forest. This increase in insect predation was due to high activity of Ectatomma brunneum Smith, 1858, an environmental indicator for shifting cultivation and pasture.The increase in the number of predations in shifting cultivation and pasture may be beneficial from the perspective of biological pest control. However, this relationship needs to be better understood because the high presence and predatory activity of Ectatomma brunneum in these environments may be one mechanism by which α‐ and β‐diversity decrease through antagonistic interactions and dominance. [ABSTRACT FROM AUTHOR]

General flowering (GF), irregular synchronous mass flowering of multiple tree species across multiple families, is a unique biological phenomenon of the mixed lowland dipterocarp forest in Southeast Asia. Characterizing the spatial extent and temporal dynamics of GF is essential for an improved understanding of climate–vegetation interactions and the potential climate change impact on this species‐rich rainforest. We investigated the utility of newly available high‐temporal (daily) and high‐spatial (3–4 m) resolution remote sensing by the PlanetScope commercial satellite constellation for detecting flowering trees in a dipterocarp rainforest at Lambir Hills National Park, Sarawak, Malaysia. Our study was focused on the latest GF event known to have occurred in the region in the year 2019. PlanetScope successfully acquired 13 clear‐sky or minimally cloud‐contaminated scenes over the park during a study period of January 1, 2019 to August 31, 2019 encompassing the 2019 GF event. In situ phenology observations verified that the PlanetScope images detected the flowering crowns of tree species that turned into white or orange. This multitemporal image dataset also captured the flowering peak and species differences. The correlation coefficients between the multitemporal image signatures and in situ phenology observations were moderate to very strong (0.52–0.85). The results indicated that the 2019 GF event was a whole‐park phenomenon with the flowering peak in May. This study reports the first successful satellite‐based observations of a GF event and suggests the possibility of regional‐scale characterization of species‐level phenology in the dipterocarp forest, key information for biodiversity conservation in Southeast Asia. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The balance between precipitation and evapotranspiration (ET) has direct effect on vegetation, and any change in its structure and composition can influence it. The aim of this study is to determine experimentally the daily evapotranspiration (ET) of the invasive species, Hedychium coronarium, and to compare with a group of four native species of the riparian forest. The experiment was carried out in a greenhouse with three different treatments: (1) only the invasive species; (2) only native species; and (3) a mixture of invasive and native species. In each lysimeter, pressure transducers recorded the water level at every 15 min along 14 months. Daily ET was calculated by the method of Gribovszki et al. (2008) and varied according to the treatment, indicating that different species (invasive or native) use the water differently. The maximum accumulated daily ET occurred for mixture treatment (2540.16 mm), while the treatment with the invasive plant presented the lowest value (2172.53 mm). H. coronarium, in monodominant stands, can reduce evapotranspiration on invaded areas and increase it when immersed in the riparian forest. [ABSTRACT FROM AUTHOR]

Accounting for intraspecific trait variation (ITV) is crucial to plant ecology for vegetation modeling efforts. ITV can be substantial; however, it remains unclear how ITV influences community-weighted mean (CWM) trait estimates. We use leaf and root trait data from 423 trees of 72 species from 15 Angiosperm families in combination with community data from 164 25 × 25 m plots comprising 580 species to evaluate the contributions of ITV and compositional turnover to CWMs, comparing unlogged primary tropical forest to selectively logged and clear-cut secondary tropical forest. We also examine the effect of imputing missing trait values using phylogenetic generalized linear modeling (PhyloPars) on CWMs. For six of the seven traits, ITV negatively covaried with community compositional turnover to generate larger CWM differences between forest types than observed if ITV was not integrated. For example, plot average-weighted mean specific leaf area was 10.7 and 10.4 m2 kg−1 for primary and secondary forests, not accounting for ITV, but shifted to 9.8 and 11.1 m2 kg−1 after doing so. Our results from 72 species assemblages were largely consistent with results using phylogenetically imputed traits for the entire community. The contribution of ITV to CWMs ranged from 25 to 75%, with ITV, not species turnover, driving CWM trait variation among successional forest types. CWM trait estimates became more conservative with forest age, whereas ITV for many traits showed an opposing acquisitive shift (i.e., increasing in leaf area or root length) and because of negative covariation between ITV and species turnover, weighted mean trait differences between successional forest types increased. [ABSTRACT FROM AUTHOR]

Variation in decay rates across woody species is a key uncertainty in predicting the fate of carbon stored in deadwood, especially in the tropics. Quantifying the relative contributions of biotic decay agents, particularly microbes and termites, under different climates and across species with diverse wood traits could help explain this variation.To fill this knowledge gap, we deployed woody stems from 16 plant species native to either rainforest (n = 10) or savanna (n = 6) in northeast Australia, with and without termite access. For comparison, we also deployed standardized, non‐native pine blocks at both sites. We hypothesized that termites would increase rates of deadwood decay under conditions that limit microbial activity. Specifically, termite contributions to wood decay should be greater under dry conditions and in wood species with traits that constrain microbial decomposers.Termite discovery of stems was surprisingly low with only 17.6% and 22.6% of accessible native stems discovered in the rainforest and savanna respectively. Contrary to our hypothesis, stems discovered by termites decomposed faster only in the rainforest. Termites discovered and decayed pine blocks at higher rates than native stems in both the rainforest and savanna.We found significant variation in termite discovery and microbial decay rates across native wood species within the same site. Although wood traits explained 85% of the variation in microbial decay, they did not explain termite‐driven decay. For stems undiscovered by termites, decay rates were greater in species with higher wood nutrient concentrations and syringyl:guiacyl lignin ratios but lower carbon concentrations and wood densities.Synthesis. Ecosystem‐scale predictions of deadwood turnover and carbon storage should account for the impact of wood traits on decomposer communities. In tropical Australia, termite‐driven decay was lower than expected for native wood on the ground. Even if termites are present, they may not always increase decomposition rates of fallen native wood in tropical forests. Our study shows how the drivers of wood decay differ between Australian tropical rainforest and savanna; further research should test whether such differences apply world‐wide. [ABSTRACT FROM AUTHOR]

As a tropical nation with ~40% forested land area and 290 protected areas in the Indo-Burma Biodiversity Hotspot, Vietnam holds an important part of global forests. Despite a complex history of multiple colonial rules, war, rapid economic development and societal growth, Vietnam was one of a few Southeast Asian countries to reverse deforestation trends and sustain net forest cover gain since the 1990s. However, a considerable amount of Vietnam's forest gain has been from plantation forestry, as Vietnam's policies have promoted economic development. In the Central Highlands region of Vietnam, widespread forest degradation and deforestation has occurred recently in some areas due to plantation forestry and other factors, including fire-linked deforestation, but protected areas here have been largely effective in their conservation goals. We studied deforestation, wildfires, and the contribution of fire-linked deforestation from 2001 to 2020 in an area near the Da Lat Plateau of the Central Highlands of Vietnam. We stratified our study area to distinguish legally protected areas and those in the surrounding landscape matrix without formal protection. Using satellite-derived data, we investigated four questions: (1) Have regional deforestation trends continued in parts of the Central Highlands from 2001 to 2020? (2) Based on remotely sensed fire detections, how has fire affected the Central Highlands and what proportion of deforestation is spatiotemporally linked to fire? (3) Were annual deforestation and burned area lower in protected areas relative to the surrounding land matrix? (4) Was the proportion of fire-linked deforestation lower in protected areas than in the matrix? To answer these questions, we integrated the Global Forest Change and FIRED VIETNAM datasets. We found that 3794 fires burned 8.7% of the total study area and 13.6% of the area became deforested between 2001 and 2020. While nearly half of fires were linked to deforestation, fire-linked deforestation accounted for only a small part of forest loss. Across the entire study area, 54% of fire-linked deforestation occurred in natural forests and 46% was in plantation forests. Fire ignitions in the study area were strongly linked to the regional dry season, November to March, and instrumental climate data from 1971 to 2020 showed statistically significant increasing trends in minimum, mean, and maximum temperatures. However, the total area burned did not have a significant increasing trend. Regional trends in deforestation continued in Vietnam's Central Highlands from 2001 to 2020, and nearly half of all detected fires can be spatially and temporally linked to forest loss. However, protected areas in the region effectively conserved forests relative to the surrounding landscape. [ABSTRACT FROM AUTHOR]

Understanding the factors that make a site susceptible to invasion is essential to mitigate the impacts of invasive alien plant species (IAPS) on biodiversity. Miconia crenata is one of the few IAPS that can colonize undisturbed tropical rainforests. In this study, we investigate the abundance of Miconia crenata in disturbed and undisturbed lowland mixed dipterocarp forest and Kerangas forests in Sabah, Malaysia. Three 400 m long transects were established within each of the four sites. The transects ran from the forest edge into the interior, and eight 25 m2 plots were established at fixed distances along each transect. A further twenty 100 m2 plots were established in each of the undisturbed sites of Kabili-Sepilok Forest Reserve. We found that the density of Miconia crenata was significantly lower along the transects in the Kerangas forest, compared to mixed dipterocarp forest. Miconia crenata densities were also significantly lower along transects in the undisturbed forest compared to the disturbed forest. Within the undisturbed sites, Miconia crenata was 13 times more abundant in the mixed dipterocarp forest compared to the Kerangas forest. This difference in Miconia crenata abundance between the two forest types is probably due to soil fertility, with fertile sites more susceptible to invasion by Miconia crenata. [ABSTRACT FROM AUTHOR]

Indonesia, particularly the island of Java, is dominated by a number of Shorea tree species (Dipterocarpaceae). Trees of the genus have been utilized for various practices, and they play a fundamental role in managing the stability of tropical forests. This study was carried out to understand the relationships between biomass and microfibril angle in Shorea spp. growing in West Java, where Shorea spp., are abundant. A total of 35 young trees belonging to 5 species were studied. The average age of these trees was 9 years, but in general there was a wide variation in tree diameter and total height. On average, biomass was the highest in S. leprosura and the lowest in S. palembanica. The lowest average microfibril angles (MFAs) were found in S. leprosura and S. mecistopteryx. The regression relationship between biomass and diameter was strong with an R2 value of 0.85, while the strength of the relationship between MFA and diameter was weaker (R2 = 0.195). In general, the MFA degree decreased with increased biomass accumulation Shorea species, which affects tree resistance to environmental variables and competitiveness in Indonesian tropical forests. [ABSTRACT FROM AUTHOR]

Females are predicted to adjust their reproductive investment to optimize the trade-off between current and future reproduction. In many cooperatively breeding birds, females have been shown to reduce their investment both pre- and posthatching in response to the presence of food-provisioning helpers. However, in species where not all group members help during the posthatching stage, it is currently unclear to which social cues (i.e. group size versus number of helpers) females should tune their investment. Here, we used the cooperatively breeding placid greenbul, Phyllastrephus placidus , as a model species to examine whether and how group size and number of helpers affect female investment in eggs and food provisioning. We found that females used a contrasting strategy pre- and posthatching in response to different social cues: they laid larger eggs in larger groups while reducing their feeding rate when assisted by more helpers. We also found that fledging success increased with group size and that nestlings raised in groups with helpers fledged with longer wings but found no relation between condition of the young and number of helpers. Since the perceived contrasting investment strategies may have several underlying causes, we conclude that predicting the influence of social conditions on maternal investment may be more challenging than previously believed. • Maternal pre- and posthatching investment is associated with different social cues. • Maternal egg investment (egg size) increased with group size. • Maternal feeding rates decreased with number of helpers. • Fledging success increased with group size. • Wing length, but not condition, of fledglings increased with number of helpers. [ABSTRACT FROM AUTHOR]