The future of hyperdiverse tropical ecosystems

Immunohematological features of free-living Alouatta belzebul (Linnaeus, 1766) red-handed howler monkeys in the Eastern Amazon

The red-handed howler monkey (Alouatta belzebul) is one of the 35 threatened Brazilian primate species found in two highly endangered Brazilian biomes. Their Amazonian native populations have been declining due to exponential deforestation associated with human activities, especially the construction of dams. The studied population (n = 27) was located in the Belo Monte dam Area of Influence. For the first time, we presented hematological parameters and the basic profile of T (CD3) and B (BSAP PAX5) cells by immunocytochemistry. The results supported the hypothesis that the immuno-hematological profile is influenced by sex, age, and season. Eosinophils were significantly higher in females (p = 0.03), monocytes statistically greater in juveniles (p = 0.04), and total plasma protein increased significantly (p > 0.001) during the dry season. Furthermore, adults showed a statistically higher average absolute number of B lymphocytes than young individuals (p = 0.03), in contrast to T lymphocytes. Even without knowing the full history of antigenic exposure, these results not only contribute to elucidating the boundaries between health and disease but may help lay the groundwork for future research into the effects of anthropogenic stress on immune activation.

Recurrent droughts increase risk of cascading tipping events by outpacing adaptive capacities in the Amazon rainforest

Tipping elements are nonlinear subsystems of the Earth system that have the potential to abruptly shift to another state if environmental change occurs close to a critical threshold with large consequences for human societies and ecosystems. Among these tipping elements may be the Amazon rainforest, which has been undergoing intensive anthropogenic activities and increasingly frequent droughts. Here, we assess how extreme deviations from climatological rainfall regimes may cause local forest collapse that cascades through the coupled forest-climate system. We develop a conceptual dynamic network model to isolate and uncover the role of atmospheric moisture recycling in such tipping cascades. We account for heterogeneity in critical thresholds of the forest caused by adaptation to local climatic conditions. Our results reveal that, despite this adaptation, a future climate characterized by permanent drought conditions could trigger a transition to an open canopy state particularly in the southern Amazon. The loss of atmospheric moisture recycling contributes to one-third of the tipping events. Thus, by exceeding local thresholds in forest adaptive capacity, local climate change impacts may propagate to other regions of the Amazon basin, causing a risk of forest shifts even in regions where critical thresholds have not been crossed locally.

Biodiversity Research in Central America: A Regional Comparison in Scientific Production Using Bibliometrics and Democracy Indicators

Central America science production on biodiversity topics is important in planning future adaptive and conservation policies in a climate-related risk region that is considered a biodiversity hotspot but has the lowest Human Development Index of Latin America. Science production on biodiversity is related to geo-referenced species occurrence records, but the accessibility depends on political frameworks and science funding. This paper aims at foregrounding how the democratic shifts throughout the years have had an impact on science production on biodiversity research, and species records. For this exploration we developed a novel systematic scientometric analysis of science production on biodiversity topics, we used Bio-Dem (open-source software of biodiversity records and socio-political variables) and briefly analyzed the history—from 1980 to 2020—of Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, and Panama. With a data set of 16,304 documents, our analysis shows the significant discrepancies between the low science production of Central American Northern countries (Guatemala, El Salvador, Honduras, and Nicaragua), the prolific production from the Southern (Costa Rica and Panama), and how this relates to democratic stability. Scientific production tends to be more abundant when democratic conditions are guaranteed. The state capture phenomenon and colonial-rooted interactions worldwide have an effect on the conditions under which science is being produced in Central America. Democracy, science production, funding, and conservation are core elements that go hand in hand, and that need to be nourished in a region that struggles with the protection of life and extractive activities in a climate change scenario.

Linking land-use and land-cover transitions to their ecological impact in the Amazon

Human activities pose a major threat to tropical forest biodiversity and ecosystem services. Although the impacts of deforestation are well studied, multiple land-use and land-cover transitions (LULCTs) occur in tropical landscapes, and we do not know how LULCTs differ in their rates or impacts on key ecosystem components. Here, we quantified the impacts of 18 LULCTs on three ecosystem components (biodiversity, carbon, and soil), based on 18 variables collected from 310 sites in the Brazilian Amazon. Across all LULCTs, biodiversity was the most affected ecosystem component, followed by carbon stocks, but the magnitude of change differed widely among LULCTs and individual variables. Forest clearance for pasture was the most prevalent and high-impact transition, but we also identified other LULCTs with high impact but lower prevalence (e.g., forest to agriculture). Our study demonstrates the importance of considering multiple ecosystem components and LULCTs to understand the consequences of human activities in tropical landscapes.

A Standardized Morpho-Functional Classification of the Planet’s Humipedons

It was time to take stock. We modified the humipedon classification key published in 2018 to make it easier and more practical. This morpho-functional taxonomy of the topsoil (humipedon) was only available in English; we also translated it into French and Italian. A standardized morpho-functional classification of humipedons (roughly the top 30–40 cm of soil: organic and organomineral surface horizons) would allow for a better understanding of the functioning of the soil ecosystem. This paper provides the founding principles of the classification of humipedon into humus systems and forms. With the recognition of a few diagnostic horizons, all humus systems can be determined. The humus forms that make up these humus systems are revealed by measuring the thicknesses of the diagnostic horizons. In the final part of the article, several figures represent the screenshots of a mobile phone or tablet application that allows for a fast recall of the diagnostic elements of the classification in the field. The article attempts to promote a standardized classification of humipedons for a global and shared management of soil at planet level.

Temperature acclimation of net photosynthesis and its underlying component processes in four tropical tree species

The effect of temperature change on leaf physiology has been extensively studied in temperate trees and to some extent in boreal and tropical tree species. While increased temperature typically stimulates leaf CO2 assimilation and tree growth in high-altitude ecosystems, tropical species are often negatively affected. These trees may operate close to their temperature optima and have a limited thermal acclimation capacity due to low seasonal and historical variation in temperature. To test this hypothesis, we studied the extent to which the temperature sensitivities of leaf photosynthesis and respiration acclimate to growth temperature in four common African tropical tree species. Tree seedlings native to different altitudes and therefore adapted to different growth temperatures were cultivated at three different temperatures in climate-controlled chambers. We estimated the acclimation capacity of the temperature sensitivities of light-saturated net photosynthesis, the maximum rates of Rubisco carboxylation (Vcmax) and thylakoid electron transport (J), and dark respiration. Leaf thylakoid membrane lipid composition, nitrogen content and leaf mass per area were also analyzed. Our results showed that photosynthesis in tropical tree species acclimated to higher growth temperatures, but that this was weakest in the species originating from the coolest climate. The temperature optimum of J acclimated significantly in three species and variation in J was linked to changes in the thylakoid membrane lipid composition. For Vcmax, there was only evidence of significant acclimation of optimal temperature in the lowest elevation species. Respiration acclimated to maintain homeostasis at growth temperature in all four species. Our results suggest that the lowest elevation species is better physiologically adapted to acclimate to high growth temperatures than the highest elevation species, indicating a potential shift in competitive balance and tree community composition to the disadvantage of montane tree species in a warmer world.

The response of ants to climate change

Ants (Hymenoptera: Formicidae) are one of the most dominant terrestrial organisms worldwide. They are hugely abundant, both in terms of sheer numbers and biomass, on every continent except Antarctica and are deeply embedded within a diversity of ecological networks and processes. Ants are also eusocial and colonial organisms-their lifecycle is built on the labor of sterile worker ants who support a small number of reproductive individuals. Given the climatic changes that our planet faces, we need to understand how various important taxonomic groups will respond; this includes the ants. In this review, we synthesize the available literature to tackle this question. The answer is complicated. The ant literature has focused on temperature, and we broadly understand the ways in which thermal changes may affect ant colonies, populations, and communities. In general, we expect that species living in the Tropics, and in thermally variable microhabitats, such as the canopy and leaf litter environments, will be negatively impacted by rising temperatures. Species living in the temperate zones and those able to thermally buffer their nests in the soil or behaviorally avoid higher temperatures, however, are likely to be unaffected or may even benefit from a changed climate. How ants will respond to changes to other abiotic drivers associated with climate change is largely unknown, as is the detail on how altered ant populations and communities will ramify through their wider ecological networks. We discuss how eusociality may allow ants to adapt to, or tolerate, climate change in ways that solitary organisms cannot and we identify key geographic and phylogenetic hotspots of climate vulnerability and resistance. We finish by emphasizing the key research questions that we need to address moving forward so that we may fully appreciate how this critical insect group will respond to the ongoing climate crisis.

Latitudinal Diversity Gradient in the Changing World: Retrospectives and Perspectives

The latitudinal diversity gradient (LDG) is one of the most extensive and important biodiversity patterns on the Earth. Various studies have established that species diversity increases with higher taxa numbers from the polar to the tropics. Studies of multicellular biotas have supported the LDG patterns from land (e.g., plants, animals, forests, wetlands, grasslands, fungi, and so forth) to oceans (e.g., marine organisms from freshwater invertebrates, continental shelve, open ocean, even to the deep sea invertebrates). So far, there are several hypotheses proposed to explore the diversity patterns and mechanisms of LDG, however, there has been no consensus on the underlying causes of LDG over the past few decades. Thus, we reviewed the progress of LDG studies in recent years. Although several explanations for the LDG have been proposed, these hypotheses are only based on species richness, evolution and the ecosystems. In this review, we summarize the effects of evolution and ecology on the LDG patterns to synthesize the formation mechanisms of the general biodiversity distribution patterns. These intertwined factors from ecology and evolution in the LDG are generally due to the wider distribution of tropical areas, which hinders efforts to distinguish their relative contributions. However, the mechanisms of LDG always engaged controversies, especially in such a context that the human activity and climate change has affected the biodiversity. With the development of molecular biology, more genetic/genomic data are available to facilitate the estimation of global biodiversity patterns with regard to climate, latitude, and other factors. Given that human activity and climate change have inevitably impacted on biodiversity loss, biodiversity conservation should focus on the change in LDG pattern. Using large-scale genetic/genomic data to disentangle the diversity mechanisms and patterns of LDG, will provide insights into biodiversity conservation and management measures. Future perspectives of LDG with integrative genetic/genomic, species, evolution, and ecosystem diversity patterns, as well as the mechanisms that apply to biodiversity conservation, are discussed. It is imperative to explore integrated approaches for recognizing the causes of LDG in the context of rapid loss of diversity in a changing world.

Loss of soil microbial residue carbon by converting a tropical forest to tea plantation

Land-use change can lead to profound changes in the storage of soil organic carbon (SOC) in the tropics. Soil microbial residues make up the majority of persistent SOC pools, yet the impact of land-use change on microbial residue C accumulation in the tropics is not well understood. Here, we investigated how the conversion of tropical primary montane rainforest to secondary forest and the conversions of secondary forest to Prunus salicina plantation and tea plantation, influence the accumulation of soil microbial residue C (indicated by amino sugars). Our results showed that the secondary forest had a higher SOC than that of the primary forest (+63%), while they had no difference in microbial residue C concentration, indicating a relatively slow microbial-derived C accrual during secondary succession. Moreover, the P. salicina plantation and tea plantation had lower SOC than the secondary forest (-53% and -57%, respectively). A decrease in fungal biomass (-51%) resulted in less fungal and total residue C concentrations in the tea plantation than in the secondary forest (-38% and -35%, respectively), indicating microbial-derived C loss following the forest conversion. The change in microbial residue C depended on litter standing crop rather than soil nutrient and root biomass. Litter standing crop affected microbial residue C concentration by regulating fungal biomass and hydrolytic enzyme activities. Taken together, our results highlight that litter-microbe interactions drive microbial residue C accumulation following forest conversions in the tropics.

The Policy Implications of the Dasgupta Review: Land Use Change and Biodiversity: Invited Paper for the Special Issue on "The Economics of Biodiversity: Building on the Dasgupta Review" in Environmental and Resource Economics

The "Dasgupta Review" of the economics of biodiversity (Dasgupta 2021) identifies many factors that threaten the ecological sustainability of our economies. This article examines how two policy failures - the underpricing and underfunding of nature - influence global land use change and terrestrial biodiversity loss. If natural areas are priced too cheaply, then converting them to agriculture, forestry and other land uses is less costly than protecting or preserving habitats. Underfunding nature further reduces the incentives for conservation and restoration. The current global funding gap for biodiversity is just under $900 billion annually, and especially impacts developing countries. Ending the underpricing of natural landscape requires removing environmentally harmful subsidies and adopting policies that place an additional cost on the use of land and natural resources or on pollution. Overcoming the funding gap means expanding public and private sources of financing nature, particularly for poorer countries, such as biodiversity offsets, payments for ecosystem services, debt-for-nature swaps, green bonds, sustainable supply chains and international environmental agreements. Using the example of peatlands, the article shows how such a comprehensive global strategy can be built.

Long-term monitoring reveals widespread and severe declines of understory birds in a protected Neotropical forest

Long-term studies on the population dynamics of tropical resident birds are few, and it remains poorly understood how their populations have fared in recent decades. Here, we analyzed a 44-y population study of a Neotropical understory bird assemblage from a protected forest reserve in central Panama to determine if and how populations have changed from 1977 to 2020. Using the number of birds captured in mist nets as an index of local abundance, we estimated trends over time for a diverse suite of 57 resident species that comprised a broad range of ecological and behavioral traits. Estimated abundances of 40 (∼70%) species declined over the sampling period, whereas only 2 increased. Furthermore, declines were severe: 35 of the 40 declining species exhibited large proportional losses in estimated abundance, amounting to ≥50% of their initial estimated abundances. Declines were largely independent of ecology (i.e., body mass, foraging guild, or initial abundance) or phylogenetic affiliation. These widespread, severe declines are particularly alarming, given that they occurred in a relatively large (∼22,000-ha) forested area in the absence of local fragmentation or recent land-use change. Our findings provide robust evidence of tropical bird declines in intact forests and bolster a large body of literature from temperate regions suggesting that bird populations may be declining at a global scale. Identifying the ecological mechanisms underlying these declines should be an urgent conservation priority.

Relationships between species richness and ecosystem services in Amazonian forests strongly influenced by biogeographical strata and forest types

Despite increasing attention for relationships between species richness and ecosystem services, for tropical forests such relationships are still under discussion. Contradicting relationships have been reported concerning carbon stock, while little is known about relationships concerning timber stock and the abundance of non-timber forest product producing plant species (NTFP abundance). Using 151 1-ha plots, we related tree and arborescent palm species richness to carbon stock, timber stock and NTFP abundance across the Guiana Shield, and using 283 1-ha plots, to carbon stock across all of Amazonia. We analysed how environmental heterogeneity influenced these relationships, assessing differences across and within multiple forest types, biogeographic regions and subregions. Species richness showed significant relationships with all three ecosystem services, but relationships differed between forest types and among biogeographical strata. We found that species richness was positively associated to carbon stock in all biogeographical strata. This association became obscured by variation across biogeographical regions at the scale of Amazonia, resembling a Simpson’s paradox. By contrast, species richness was weakly or not significantly related to timber stock and NTFP abundance, suggesting that species richness is not a good predictor for these ecosystem services. Our findings illustrate the importance of environmental stratification in analysing biodiversity-ecosystem services relationships.

Potential plants for inflammatory dysfunction in the SARS-CoV-2 infection

The inflammatory process is a biological response of the organism to remove injurious stimuli and initiate homeostasis. It has been recognized as a key player in the most severe forms of SARS-CoV-2, characterized by significantly increased pro-inflammatory cytokine levels, the so-called "cytokine storm" that appears to play a pivotal role in this disease. Therefore, the aim of this systematic review was to select clinical trials with anti-inflammatory plants and relate the activity of these plants to inflammatory markers of SARS-CoV-2 infection. PRISMA guidelines are followed, and studies of interest are indexed in PubMed and ClinicalTrials.gov databases. As a result, 32 clinical trials encompassing 22 plants were selected. The main anti-inflammatory mechanisms described in the studies are the inhibition of inflammatory cytokines, such as IL-6, TNF-a, IFN-γ, and IL-1; decreased CRP and oxidative marker levels; increased endogenous antioxidant levels; modulation of cardiovascular risk markers. The data found are not directly related to SARS-CoV-2 infection. However, they provide possibilities for new studies as plants have a wide array of phytochemicals, and detecting which ones are responsible for anti-inflammatory effects can provide invaluable contribution to studies aiming to evaluate efficacy in scenarios of SARS-CoV-2 infection.

Coral reef benthic community changes in the Anthropocene: Biogeographic heterogeneity, overlooked configurations, and methodology

Non-random community changes are becoming more frequent in many ecosystems. In coral reefs, changes towards communities dominated by other than hard corals are increasing in frequency, with severe impacts on ecosystem functioning and provision of ecosystem services. Although new research suggests that a variety of alternative communities (i.e. not dominated by hard corals) exist, knowledge on the global diversity and functioning of alternative coral reef benthic communities, especially those not dominated by algae, remains scattered. In this systematic review and meta-analysis of 523 articles, we analyse the different coral reef benthic community changes reported to date and discuss the advantages and limitations of the methods used to study these changes. Furthermore, we used field cover data (1116 reefs from the ReefCheck database) to explore the biogeographic and latitudinal patterns in dominant benthic organisms. We found a mismatch between literature focus on coral-algal changes (over half of the studies analysed) and observed global natural patterns. We identified strong biogeographic patterns, with the largest and most biodiverse biogeographic regions (Western and Central Indo-Pacific) presenting previously overlooked soft-coral-dominated communities as the most abundant alternative community. Finally, we discuss the potential biases associated with methods that overlook ecologically important cryptobenthic communities and the potential of new technological advances in improving monitoring efforts. As coral reef communities inevitably and swiftly change under changing ocean conditions, there is an urgent need to better understand the distribution, dynamics as well as the ecological and societal impacts of these new communities.

Tropical forests are home to over half of the world's vertebrate species

Tropical forests are renowned for their astonishing diversity of life, but the fundamental question of how many species occur in tropical forests remains unanswered. Using geographic range maps and data on species habitat associations, we determined that tropical forests harbor 62% of global terrestrial vertebrate species, more than twice the number found in any other terrestrial biome on Earth. Up to 29% of global vertebrate species are endemic to tropical forests, with more than 20% of these species at risk of extinction. Humid tropical forests (also known as tropical rainforests) and the Neotropics dominate as centers of species diversity, harboring more than 90% and nearly half of all tropical forest vertebrates, respectively. To maintain the biodiversity that underpins the ecosystem functions and services essential for human well-being, we emphasize the critical importance of environmental policies aimed at reducing tropical deforestation and mitigating deleterious anthropogenic pressures on these imperiled ecosystems.

How much do we know about trade-offs in ecosystem services? A systematic review of empirical research observations

As an important domain of sustainability science, trade-offs in ecosystem services (ES) is crucial for spatial planning to sustainably manage natural resources while satisfying the needs of local and non-local beneficiaries. However, there is still a growing debate in understanding, characterization, and visualization of the trade-off relationships. This paper systematically reviews a total of 473 articles, published in the last 16 years (2005-2020) through 135 academic journals, based on empirical studies conducted in over 80 countries, and led by the researcher from over 50 countries. Trade-off relationships are often visualized as spatial associations of ES, but very few articles have characterized trade-offs as the causal interaction among ES. More than two-thirds of the studies were carried out in temperate and sub-tropical regions, but we depicted an under-representation of the critical ecosystems in tropics. About 90% of the articles were based on funded research but the involvement of government institutions was very low (<10%). Trade-off analysis was based only on biophysical constraints of the ecosystem, as observed in more than 80% of the selected articles, without due regards of the divergence in utility functions of different stakeholders and ecosystem beneficiaries. This study identifies a total of 198 pairs of conflicting ES, of which the trade-off between crop production and carbon/climate services has the highest records of observation (i.e., as identified by 20% of the total studies). Further, this study identifies the major drivers (i.e., ecological and social) and stakeholders (i.e., land users and government agencies) of trade-off in ES, and major gaps in the analytical approach to understand the trade-off relationships. Based on our findings, we have discussed and recommended a number of research trajectories, including trans-disciplinary research considering both biophysical constraints and utility functions, in order to guide the future direction of sustainability science through the creation of win-win scenarios.

Strahler Ordering Analyses on Branching Coral Canopies: Stylophora pistillata as a Case Study

The three-dimensional structural complexities generated by living sessile organisms, such as trees and branching corals, embrace distinct communities of dwelling organisms, many of which are adapted to specific niches within the structure. Thus, characterizing the build-up rules and the canopy compartments may clarify small-scale biodiversity patterns and rules for canopy constituents. While biodiversity within tree canopies is usually typified by the vertical axis that is delineated by its main compartments (understory, trunk, crown), traditional studies of coral canopy dwelling species are evaluated only by viewing the whole coral head as a single homogeneous geometric structure. Here, we employ the Strahler number of a mathematical tree for the numerical measurements of the coral’s canopy complexity. We use the branching Indo-Pacific coral species Stylophora pistillata as a model case, revealing five compartments in the whole coral canopy volume (Understory, Base, Middle, Up, and Bifurcation nods). Then, the coral’s dwellers’ diel distribution patterns were quantified and analyzed. We observed 114 natal colonies, containing 32 dwelling species (11 sessile), totaling 1019 individuals during day observations, and 1359 at night (1–41 individuals/colony). Biodiversity and abundance associated with Strahler numbers, diel richness, abundance, and patterns for compartmental distributions differed significantly between day/night. These results demonstrate that the coral-canopy Strahler number is an applicable new tool for assessing canopy landscapes and canopy associated species biodiversity, including the canopy-compartmental utilization by mobile organisms during day/night and young/adult behaviors.

Integrated index-based assessment reveals long-term conservation progress in implementation of Convention on Biological Diversity

The Convention on Biological Diversity (CBD) has launched two long-term, target-based conservation Strategic Plans in the past two decades. We compiled an index-based assessment framework to evaluate target achievements of the CBD using long-term indicators. The CBD Index is steadily increasing, with the Goal Indices for biodiversity mainstreaming, protection, and supporting mechanisms all improving over time. While the State and Pressure Indices continue to deteriorate coupled with human population and economic development, their changing rates have slowed down, most likely because of the constantly growing conservation efforts as revealed by the Response Index. The first quantitative assessment of the CBD’s long-term performance may provide critical science-based evidence for continuing commitments to developing and implementing a new Post-2020 Global Biodiversity Framework. We also call for enhanced efforts to address the emerging challenges in achieving the 2050 Vision for Biodiversity and the adoption of a rapid assessment framework to track future progress.

How the loss of forest fauna undermines the achievement of the SDGs

The human-driven loss of biodiversity has numerous ecological, social, and economic impacts at the local and global levels, threatening important ecological functions and jeopardizing human well-being. In this perspective, we present an overview of how tropical defaunation-defined as the disappearance of fauna as a result of anthropogenic drivers such as hunting and habitat alteration in tropical forest ecosystems-is interlinked with four selected Sustainable Development Goals (SDGs). We discuss tropical defaunation related to nutrition and zero hunger (SDG 2), good health and well-being (SDG 3), climate action (SDG 13), and life on land (SDG 15). We propose a range of options on how to study defaunation in future research and how to address the ongoing tropical defaunation crisis, including but not limited to recent insights from policy, conservation management, and development practice.

Measuring biodiversity from DNA in the air

The crisis of declining biodiversity¹ exceeds our current ability to monitor changes in ecosystems. Rapid terrestrial biomonitoring approaches are essential to quantify the causes and consequences of global change. Environmental DNA² has revolutionized aquatic ecology,³ permitting population monitoring⁴ and remote diversity assessments matching or outperforming conventional methods of community sampling.^3-5 Despite this model, similar methods have not been widely adopted in terrestrial ecosystems. Here, we demonstrate that DNA from terrestrial animals can be filtered, amplified, and then sequenced from air samples collected in natural settings representing a powerful tool for terrestrial ecology. We collected air samples at a zoological park, where spatially confined non-native species allowed us to track DNA sources. We show that DNA can be collected from air and used to identify species and their ecological interactions. Air samples contained DNA from 25 species of mammals and birds, including 17 known terrestrial resident zoo species. We also identified food items from air sampled in enclosures and detected taxa native to the local area, including the Eurasian hedgehog, endangered in the United Kingdom. Our data demonstrate that airborne eDNA concentrates around recently inhabited areas but disperses away from sources, suggesting an ecology to airborne eDNA and the potential for sampling at a distance. Our findings demonstrate the profound potential of air as a source of DNA for global terrestrial biomonitoring.

A Stepwise-Clustered Simulation Approach for Projecting Future Heat Wave Over Guangdong Province

A heat wave is an important meteorological extreme event related to global warming, but little is known about the characteristics of future heat waves in Guangdong. Therefore, a stepwise-clustered simulation approach driven by multiple global climate models (i.e., GCMs) is developed for projecting future heat waves over Guangdong under two representative concentration pathways (RCPs). The temporal-spatial variations of four indicators (i.e., intensity, total intensity, frequency, and the longest duration) of projected heat waves, as well as the potential changes in daily maximum temperature (i.e., Tmax) for future (i.e., 2006–2095) and historical (i.e., 1976–2005) periods, were analyzed over Guangdong. The results indicated that Guangdong would endure a notable increasing annual trend in the projected Tmax (i.e., 0.016–0.03°C per year under RCP4.5 and 0.027–0.057°C per year under RCP8.5). Evaluations of the multiple GCMs and their ensemble suggested that the developed approach performed well, and the model ensemble was superior to any single GCM in capturing the features of heat waves. The spatial patterns and interannual trends displayed that Guangdong would undergo serious heat waves in the future. The variations of intensity, total intensity, frequency, and the longest duration of heat wave are likely to exceed 5.4°C per event, 24°C, 25 days, and 4 days in the 2080s under RCP8.5, respectively. Higher variation of those would concentrate in eastern and southwestern Guangdong. It also presented that severe heat waves with stronger intensity, higher frequency, and longer duration would have significant increasing tendencies over all Guangdong, which are expected to increase at a rate of 0.14, 0.83, and 0.21% per year under RCP8.5, respectively. Over 60% of Guangdong would suffer the moderate variation of heat waves to the end of this century under RCP8.5. The findings can provide decision makers with useful information to help mitigate the potential impacts of heat waves on pivotal regions as well as ecosystems that are sensitive to extreme temperature.

Serum biochemistry panel of free-living red-handed howler monkeys (Alouatta belzebul) in the Eastern Amazon

BACKGROUND

The red-handed howler monkey (Alouatta belzebul) is one of 116 imperiled Brazilian primate species. We aimed to determine the serum biochemical profile of free-ranging red-handed howler monkeys in a highly disturbed area of the eastern Amazon.

METHODS

We obtained serum samples from 26 monkeys, in which we analyzed 20 biochemical variables.

RESULTS AND CONCLUSIONS

Calcium concentration was significantly lower in adult males (1.82 ± 0.25 mmol/L) than in adult females (2.10 ± 0.50 mmol/L). Both adults (males = 89 ± 85 UI/L, females = 62 ± 23 UI/L) had lower alkaline phosphatase serum activity than juvenile females (178 ± 120 UI/L). Adult male had higher levels of the direct bilirubin (13.9 ± 8.2 µmol/L) and creatinine (74.3 ± 19.4 µmol/L) than juvenile females (5.1 ± 1.4 µmol/L and 38.9 ± 15.0 µmol/L, respectively). This detailed biochemical profile may be useful for the management of red-handed howler monkeys in the wild and to support further studies at ex situ facilities.

Parental exposures increase the vulnerability of copepod offspring to copper and a simulated marine heatwave

Extreme temperatures from marine heatwaves (MHWs) and pollution are dominant stressors in tropical marine ecosystems. However, we know little about the role of transgenerational effects of metals and MHWs in shaping the offspring's vulnerability to these stressors. We addressed this fundamental knowledge gap by exposing the planktonic copepod Pseudodiaptomus incisus to copper (Cu: control, 15 and 60 μg L^-1) under 2 temperatures (30 and a simulated marine heatwave at 34 °C) in the first generation (F1) and 16 treatments in F2: offspring from each of 4 F1 conditions (control or 15 μg Cu L^-1 × 30 or 34 °C) was reared in 4 F2 conditions (control or 15 μg Cu L^-1 × 30 or 34 °C). We assessed changes in copepod performance, particularly survival, adult size, grazing, and reproduction. In F1, Cu or marine heatwave (MHW) exposures reduced all fitness traits of F1; the effects were particularly strong when both stressors were present. Transgenerational effects of Cu or MHW also strongly reduced F2 performance. Direct Cu and MHW effects on the offspring were further strengthened by transgenerational effects, resulting in more substantial reductions in F2 performance when both generations were exposed to these stressors. As copepods are major food resources for corals, shrimps, or fish larvae and juveniles, strong transgenerational and direct effects of Cu and MHW can have a cascading effect on entire coastal food webs. These results highlight the importance of considering the interaction of transgenerational and direct effects of multiple stressors, particularly relevant for short-lived organisms in tropical marine ecosystems.

Big Bird Plots: Benchmarking Neotropical Bird Communities to Address Questions in Ecology and Conservation in an Era of Rapid Change

Extensive networks of large plots have the potential to transform knowledge of avian community dynamics through time and across geographical space. In the Neotropics, the global hotspot of avian diversity, only six 100-ha plots, all located in lowland forests of Amazonia, the Guianan shield and Panama, have been inventoried sufficiently. We review the most important lessons learned about Neotropical forest bird communities from those big bird plots and explore opportunities for creating a more extensive network of additional plots to address questions in ecology and conservation, following the model of the existing ForestGEO network of tree plots. Scholarly impact of the big bird plot papers has been extensive, with the papers accumulating nearly 1,500 citations, particularly on topics of tropical ecology, avian conservation, and community organization. Comparisons of results from the plot surveys show no single methodological scheme works effectively for surveying abundances of all bird species at all sites; multiple approaches have been utilized and must be employed in the future. On the existing plots, abundance patterns varied substantially between the South American plots and the Central American one, suggesting different community structuring mechanisms are at work and that additional sampling across geographic space is needed. Total bird abundance in Panama, dominated by small insectivores, was double that of Amazonia and the Guianan plateau, which were dominated by large granivores and frugivores. The most common species in Panama were three times more abundant than those in Amazonia, whereas overall richness was 1.5 times greater in Amazonia. Despite these differences in community structure, other basic information, including uncertainty in population density estimates, has yet to be quantified. Results from existing plots may inform drivers of differences in community structure and create baselines for detection of long-term regional changes in bird abundances, but supplementation of the small number of plots is needed to increase generalizability of results and reveal the texture of geographic variation. We propose fruitful avenues of future research based on our current synthesis of the big bird plots. Collaborating with the large network of ForestGEO tree plots could be one approach to improve understanding of linkages between plant and bird diversity. Careful quantification of bird survey effort, recording of exact locations of survey routes or stations, and archiving detailed metadata will greatly enhance the value of benchmark data for future repeat surveys of the existing plots and initial surveys of newly established plots.

Congruent trophic pathways underpin global coral reef food webs

Ecological interactions uphold ecosystem structure and functioning. However, as species richness increases, the number of possible interactions rises exponentially. More than 6,000 species of coral reef fishes exist across the world's tropical oceans, resulting in an almost innumerable array of possible trophic interactions. Distilling general patterns in these interactions across different bioregions stands to improve our understanding of the processes that govern coral reef functioning. Here, we show that across bioregions, tropical coral reef food webs exhibit a remarkable congruence in their trophic interactions. Specifically, by compiling and investigating the structure of six coral reef food webs across distinct bioregions, we show that when accounting for consumer size and resource availability, these food webs share more trophic interactions than expected by chance. In addition, coral reef food webs are dominated by dietary specialists, which makes trophic pathways vulnerable to biodiversity loss. Prey partitioning among these specialists is geographically consistent, and this pattern intensifies when weak interactions are disregarded. Our results suggest that energy flows through coral reef communities along broadly comparable trophic pathways. Yet, these critical pathways are maintained by species with narrow, specialized diets, which threatens the existence of coral reef functioning in the face of biodiversity loss.

Mangroves are an overlooked hotspot of insect diversity despite low plant diversity

BACKGROUND

The world's fast disappearing mangrove forests have low plant diversity and are often assumed to also have a species-poor insect fauna. We here compare the tropical arthropod fauna across a freshwater swamp and six different forest types (rain-, swamp, dry-coastal, urban, freshwater swamp, mangroves) based on 140,000 barcoded specimens belonging to ca. 8500 species.

RESULTS

We find that the globally imperiled habitat "mangroves" is an overlooked hotspot for insect diversity. Our study reveals a species-rich mangrove insect fauna (>3000 species in Singapore alone) that is distinct (>50% of species are mangrove-specific) and has high species turnover across Southeast and East Asia. For most habitats, plant diversity is a good predictor of insect diversity, but mangroves are an exception and compensate for a comparatively low number of phytophagous and fungivorous insect species by supporting an unusually rich community of predators whose larvae feed in the productive mudflats. For the remaining tropical habitats, the insect communities have diversity patterns that are largely congruent across guilds.

CONCLUSIONS

The discovery of such a sizeable and distinct insect fauna in a globally threatened habitat underlines how little is known about global insect biodiversity. We here show how such knowledge gaps can be closed quickly with new cost-effective NGS barcoding techniques.

The Montreal Protocol protects the terrestrial carbon sink

The control of the production of ozone-depleting substances through the Montreal Protocol means that the stratospheric ozone layer is recovering¹ and that consequent increases in harmful surface ultraviolet radiation are being avoided^2,3. The Montreal Protocol has co-benefits for climate change mitigation, because ozone-depleting substances are potent greenhouse gases^4-7. The avoided ultraviolet radiation and climate change also have co-benefits for plants and their capacity to store carbon through photosynthesis⁸, but this has not previously been investigated. Here, using a modelling framework that couples ozone depletion, climate change, damage to plants by ultraviolet radiation and the carbon cycle, we explore the benefits of avoided increases in ultraviolet radiation and changes in climate on the terrestrial biosphere and its capacity as a carbon sink. Considering a range of strengths for the effect of ultraviolet radiation on plant growth^8-12, we estimate that there could have been 325-690 billion tonnes less carbon held in plants and soils by the end of this century (2080-2099) without the Montreal Protocol (as compared to climate projections with controls on ozone-depleting substances). This change could have resulted in an additional 115-235 parts per million of atmospheric carbon dioxide, which might have led to additional warming of global-mean surface temperature by 0.50-1.0 degrees. Our findings suggest that the Montreal Protocol may also be helping to mitigate climate change through avoided decreases in the land carbon sink.

The Montreal Protocol protects the terrestrial carbon sink

The control of the production of ozone-depleting substances through the Montreal Protocol means that the stratospheric ozone layer is recovering¹ and that consequent increases in harmful surface ultraviolet radiation are being avoided^2,3. The Montreal Protocol has co-benefits for climate change mitigation, because ozone-depleting substances are potent greenhouse gases^4-7. The avoided ultraviolet radiation and climate change also have co-benefits for plants and their capacity to store carbon through photosynthesis⁸, but this has not previously been investigated. Here, using a modelling framework that couples ozone depletion, climate change, damage to plants by ultraviolet radiation and the carbon cycle, we explore the benefits of avoided increases in ultraviolet radiation and changes in climate on the terrestrial biosphere and its capacity as a carbon sink. Considering a range of strengths for the effect of ultraviolet radiation on plant growth^8-12, we estimate that there could have been 325-690 billion tonnes less carbon held in plants and soils by the end of this century (2080-2099) without the Montreal Protocol (as compared to climate projections with controls on ozone-depleting substances). This change could have resulted in an additional 115-235 parts per million of atmospheric carbon dioxide, which might have led to additional warming of global-mean surface temperature by 0.50-1.0 degrees. Our findings suggest that the Montreal Protocol may also be helping to mitigate climate change through avoided decreases in the land carbon sink.

Speaking across boundaries to explore the potential for interdisciplinarity in ecosystem services knowledge production

Conservation is likely to be most successful if it draws on knowledge from across the natural and social sciences. The ecosystem services concept has been called a boundary object in that it facilitates development of such interdisciplinary knowledge because it offers a common platform for researchers, policy makers, and practitioners. However, a question that remains is to what extent the interdisciplinary knowledge needed is provided by disciplinary diversity within the field. We asked where is knowledge on ecosystem services produced, how interdisciplinary is this knowledge, and which disciplines facilitate the greatest disciplinary integration? We defined interdisciplinarity as the extent to which published research draws on knowledge that crosses disciplinary borders and used citations as a quantitative indicator of communication among disciplines, based on journal classification. We used disciplinary diversity, richness, and heterocitation as measures of interdisciplinarity and betweenness centrality as a measure of disciplinary integration. Our data set contained 22,153 publications on ecosystem services, published from 1983 to 2018. We found that ecosystem services research matured; average yearly output growth was 33.8%, more than the 8-9% growth in scientific output across all fields. Over time, the network clustering coefficient, measuring connectedness of individual disciplines, rose from 0.388 to 0.727, suggesting increased density in the network of citations. Researchers in the field published more articles (3566 in 2018 alone) across more disciplines (77 unique disciplines in 2018). However, this growth was not mirrored by an increase in the diversity (stable at 0.7-0.9) or richness (averaging 0.35 unique disciplines per citation) of citation patterns. Heterocitation scores, or out-of-group citations, for arts, humanities, social sciences, and law ranged from 56% to 64%, which was lower than we expected, although this may serve to protect the integrity of social science disciplines and attract broader engagement from within. Ultimately, a small number of productive disciplines are central to supporting disciplinary integration. However, opportunities exist for conservation practice to draw on a broader field of research, to realize the potential that the diverse body of knowledge of interdisciplinary work offers.

Tracking the impacts of El Niño drought and fire in human-modified Amazonian forests

With humanity facing an unprecedented climate crisis, the conservation of tropical forests has never been so important - their vast terrestrial carbon stocks can be turned into emissions by climatic and human disturbances. However, the duration of these effects is poorly understood, and it is unclear whether impacts are amplified in forests with a history of previous human disturbance. Here, we focus on the Amazonian epicenter of the 2015-16 El Niño, a region that encompasses 1.2% of the Brazilian Amazon. We quantify, at high temporal resolution, the impacts of an extreme El Niño (EN) drought and extensive forest fires on plant mortality and carbon loss in undisturbed and human-modified forests. Mortality remained higher than pre-El Niño levels for 36 mo in EN-drought-affected forests and for 30 mo in EN-fire-affected forests. In EN-fire-affected forests, human disturbance significantly increased plant mortality. Our investigation of the ecological and physiological predictors of tree mortality showed that trees with lower wood density, bark thickness and leaf nitrogen content, as well as those that experienced greater fire intensity, were more vulnerable. Across the region, the 2015-16 El Niño led to the death of an estimated 2.5 ± 0.3 billion stems, resulting in emissions of 495 ± 94 Tg CO2 Three years after the El Niño, plant growth and recruitment had offset only 37% of emissions. Our results show that limiting forest disturbance will not only help maintain carbon stocks, but will also maximize the resistance of Amazonian forests if fires do occur.

Chromosome-level reference genome of the soursop (Annona muricata): A new resource for Magnoliid research and tropical pomology

The flowering plant family Annonaceae includes important commercially grown tropical crops, but development of promising species is hindered by a lack of genomic resources to build breeding programs. Annonaceae are part of the magnoliids, an ancient lineage of angiosperms for which evolutionary relationships with other major clades remain unclear. To provide resources to breeders and evolutionary researchers, we report a chromosome-level genome assembly of the soursop (Annona muricata). We assembled the genome using 444.32 Gb of DNA sequences (676× sequencing depth) from PacBio and Illumina short-reads, in combination with 10× Genomics and Bionano data (v1). A total of 949 scaffolds were assembled to a final size of 656.77 Mb, with a scaffold N50 of 3.43 Mb (v1), and then further improved to seven pseudo-chromosomes using Hi-C sequencing data (v2; scaffold N50: 93.2 Mb, total size in chromosomes: 639.6 Mb). Heterozygosity was very low (0.06%), while repeat sequences accounted for 54.87% of the genome, and 23,375 protein-coding genes with an average of 4.79 exons per gene were annotated using de novo, RNA-seq and homology-based approaches. Reconstruction of the historical population size showed a slow continuous contraction, probably related to Cenozoic climate changes. The soursop is the first genome assembled in Annonaceae, supporting further studies of floral evolution in magnoliids, providing an essential resource for delineating relationships of ancient angiosperm lineages. Both genome-assisted improvement and conservation efforts will be strengthened by the availability of the soursop genome. As a community resource, this assembly will further strengthen the role of Annonaceae as model species for research on the ecology, evolution and domestication potential of tropical species in pomology and agroforestry.

Collapsing ecosystem functions on an inshore coral reef

Ecosystem functions underpin productivity and key services to humans, such as food provision. However, as the severity of environmental stressors intensifies, it is becoming increasingly unclear if, and to what extent, critical functions and services can be sustained. This issue is epitomised on coral reefs, an ecosystem at the forefront of environmental transitions. We provide a functional profile of a coral reef ecosystem, linking time-series data to quantified processes. The data reveal a prolonged collapse of ecosystem functions in this previously resilient system. The results suggest that sediment accumulation in algal turfs has led to a decline in resource yields to herbivorous fishes and a decrease in fish-based ecosystem functions, including a collapse of both fish biomass and productivity. Unfortunately, at present, algal turf sediment accumulation is rarely monitored nor managed in coral reef systems. Our examination of functions through time highlights the value of directly assessing functions, their potential vulnerability, and the capacity of algal turf sediments to overwhelm productive high-diversity coral reef ecosystems.

Managing fires in a changing world: Fuel and weather determine fire behavior and safety in the neotropical savannas

Fire is an important ecological disturbance, but anthropogenic wildfires increasingly threaten native ecosystems and human lives. In fire-prone ecosystems, zero-fire policies have been replaced by active fire management to reduce the risk of wildfires and improve ecological outcomes. The environmental drivers of fire behavior are widely known, but climate change and deforestation are changing their roles, making fires less predictable. Thus, reassessing the main determinants of fire behavior is preeminent to allow for safe and adaptive uses of fire in protected areas (PA). We did this research in collaboration with PA managers during the initial implementation of a pilot Integrated Fire Management (IFM) program in the Brazilian savanna. The program mainly aimed to prevent large wildfires in the late-dry season and included prescribed burns during the rainy, early- and mid-dry seasons to create vegetation patch mosaics with different fire histories. We assessed fire behavior and its environmental drivers during prescribed fires in the mid-dry season (MF) and experimental late-dry season fires (LF) (emulating wildfires). We applied Linear Models to test for differences in fire intensity, heat released, combustion factor and flame height between fire seasons and to check the influence of meteorological and fuel conditions in these parameters. LF had a significantly higher fire intensity (3508 vs. 895 kW m^-1), heat released (5537 vs. 3329 kW m^-2), combustion factor (90 vs. 51%) and flame height (2.5 vs. 1.9 m) than MF. Relative humidity, air temperature, wind speed and fuel load were the best predictors of fire behavior, corroborating previous research. Air temperature and relative humidity pushed the seasonal differences in fire behavior while wind speed and fuel load showed similar effects across seasons. Our results emphasize the importance of considering primarily environmental variables during fire management planning, especially in the current climate changing world where extreme events and seasonal weather fluctuations are constantly defying our knowledge about fire behavior.

Traditional plants with antioxidant properties in clinical trials-A systematic review

There is a trend toward the use of natural substances present in plants and vegetables. In general, foods rich in antioxidants are complex matrices; therefore, understanding its absorption effects is extremely relevant to know its bioactive potential. Thus, this systematic review focused on clinical trials involving plants (or compounds) registered on the National List of Medicinal Plants of Interest to the Unified Health System (RENISUS) with antioxidant properties. Following the reporting guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyzes studies of interest indexed in the PubMed and ClinicalTrials.gov databases were analyzed. Of the 59 clinical trials found, Allium sativum and Curcuma longa are the plant species with the highest percentage of clinical research. Prevention/attenuation of oxidative stress was one of the main antioxidant mechanisms indicated in the studies. The most tested compounds of the RENISUS plants in clinical trials were curcumin and soy isoflavone. In this review, we selected studies in advanced stages that highlight plants' value in optimizing antioxidant status; however, even with high-quality studies, it is not prudent to overstate the clinical efficacy of these plants.