Search

International audience; This paper, developed under the framework of the RECCAP initiative, aims at providing improved estimates of the carbon and GHG (CO 2 , CH 4 and N 2 O) balance of continental Africa. The various components and processes of the African carbon and GHG budget are considered, existing data reviewed, and new data from different methodolo-gies (inventories, ecosystem flux measurements, models, and atmospheric inversions) presented. Uncertainties are quantified and current gaps and weaknesses in knowledge and monitoring systems described in order to guide future requirements. The majority of results agree that Africa is a small sink of carbon on an annual scale, with an average value of Published by Copernicus Publications on behalf of the European Geosciences Union. 382 R. Valentini et al.: A full greenhouse gases budget of Africa −0.61 ± 0.58 Pg C yr −1. Nevertheless, the emissions of CH 4 and N 2 O may turn Africa into a net source of radiative forcing in CO 2 equivalent terms. At sub-regional level, there is significant spatial variability in both sources and sinks, due to the diversity of biomes represented and differences in the degree of anthropic impacts. Southern Africa is the main source region; while central Africa, with its evergreen tropical forests, is the main sink. Emissions from land-use change in Africa are significant (around 0.32 ± 0.05 Pg C yr −1), even higher than the fossil fuel emissions: this is a unique feature among all the continents. There could be significant carbon losses from forest land even without deforestation, resulting from the impact of selective logging. Fires play a significant role in the African carbon cycle, with 1.03 ± 0.22 Pg C yr −1 of carbon emissions, and 90 % originating in savannas and dry woodlands. A large portion of the wild fire emissions are compensated by CO 2 uptake during the growing season, but an uncertain fraction of the emission from wood harvested for domestic use is not. Most of these fluxes have large in-terannual variability, on the order of ±0.5 Pg C yr −1 in standard deviation, accounting for around 25 % of the year-to-year variation in the global carbon budget. Despite the high uncertainty, the estimates provided in this paper show the important role that Africa plays in the global carbon cycle, both in terms of absolute contribution, and as a key source of interannual variability.

It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2. It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2.

Although there are recent claims of a lack of evidence of self-consciousness in many tested species, the ability to recognize oneself in a mirror, which seems an exceedingly rare capacity in the animal kingdom, may not be the only way to check for animal self-awareness (i.e. the capacity to become the object of your own attention). A new testing approach, based on a different sensory modality (such as the sniff-test for self-recognition, STSR), recently proved to be effective with dogs. We applied this sniff test to a group of four captive grey wolves, living in male-female couples in two different enclosures at the Wolf Park in Indiana, USA. In this preliminary study, wolves showed some signs of the ability to recognize themselves through the “olfactory mirror” and exhibited some clues of mark-directed responses, particularly scent-rolling, which may shed more light on this still unclear behavior and represent a sort of olfactory equivalent to passing the original mirror test.

This pandemic situation requests a correct understanding of our impacts on wildlife conservation, which would also provide benefits for our species. In this commentary we revised and discussed some of the repercussions that SARS-CoV-2 pandemic may have to wildlife. We propose four actions that should be taken into account to protect and conserve wildlife in this pandemic era: wildlife "wet" markets must close; human interference with wildlife must be reduced; bats and pangolins must be conserved and not blamed; and Chinese traditional medicine must be more controlled.

The origin of economic niches, conceived as potential markets, has been mostly neglected in economic theory. Ecological niches emerge as new species evolve and fit into a web of interactions, and the more species come into existence, the more (exponentially or power-law distributed) ecological niches emerge. In parallel fashion, economic niches emerge with new goods, and niche formation in economics is also exponentially or power-law distributed. In economics and ecology alike, autocatalytic processes drive the system to greater and greater diversity. Novelty begets novelty in a positive feedback loop. An autocatalytic set of self-enabling transactions feed back upon one another in combinatoric fashion to generate progressive diversity. While these combinatorial dynamics cannot be prestated, the model explains the “hockeystick of economic growth”—a pattern of prolonged stasis followed by a sudden takeoff, such as occurred during the Industrial Revolution or the Cambrian explosion in ecology. Several implications derive from our niche emergence model, including the idea that the evolutionary process of technological change is not something we do; rather, it happens to us.

Funding: We acknowledge funding from the following organizations: Norwegian Agency for Development Cooperation (Norad); Norwegian International Climate and Forest Initiative (NICFI); International Climate Initiative (IKI) of the German; Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB); CGIAR Research Program on Forests, Trees and Agroforestry (CRP‐FTA) with financial support from the CGIAR Fund Donors; EU Horizon 2020 project VERIFY (776810); European Space Agency GlobBiomass project (ESRIN Contract No. 4000113100/14/I-NB); European Research Council (ERC) Advanced Grants T-FORCES (291585) and PANTROP (834775); JAXA (RA-6, EO-RA2); UK Natural Environment Research Council (NERC; including NE/F005806/, NE/D005590/1, NE/T01279X/1, NE/P008755/1 and NE/N012542/1); agreement PR140015 between NERC and the National Centre for Earth Observation; Gordon and Betty Moore Foundation; CNPq (National Council of Science and Technology, Brazil), Grants #401279/2014‐4 (PVE) and #441244/2016‐5 (PELD); Doris Duke Charitable Foundation; the Children's Investment 309 Fund Foundation; COmON Foundation and Good Energies Foundation. For monitoring and reporting forest carbon stocks and fluxes, many countries in the tropics and subtropics rely on default values of forest aboveground biomass (AGB) from the Intergovernmental Panel on Climate Change (IPCC) guidelines for National Greenhouse Gas (GHG) Inventories. Default IPCC forest AGB values originated from 2006, and are relatively crude estimates of average values per continent and ecological zone. The 2006 default values were based on limited plot data available at the time, methods for their derivation were not fully clear, and no distinction between successional stages was made. As part of the 2019 Refinement to the 2006 IPCC Guidelines for GHG Inventories, we updated the default AGB values for tropical and subtropical forests based on AGB data from >25 000 plots in natural forests and a global AGB map where no plot data were available. We calculated refined AGB default values per continent, ecological zone, and successional stage, and provided a measure of uncertainty. AGB in tropical and subtropical forests varies by an order of magnitude across continents, ecological zones, and successional stage. Our refined default values generally reflect the climatic gradients in the tropics, with more AGB in wetter areas. AGB is generally higher in old-growth than in secondary forests, and higher in older secondary (regrowth >20 years old and degraded/logged forests) than in young secondary forests (20 years old). While refined default values for tropical old-growth forest are largely similar to the previous 2006 default values, the new default values are 4.0-7.7-fold lower for young secondary forests. Thus, the refined values will strongly alter estimated carbon stocks and fluxes, and emphasize the critical importance of old-growth forest conservation. We provide a reproducible approach to facilitate future refinements and encourage targeted efforts to establish permanent plots in areas with data gaps. Publisher PDF

Este artículo contiene 18 páginas, 5 tablas, 4 figuras., Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its temporal dynamics are of significant importance, since their effects might change over the course of the decomposition process. Within the TeaComposition initiative, we incubated Green and Rooibos teas at 524 sites across nine biomes. We assessed how macroclimate and atmospheric inorganic N deposition under current and predicted scenarios (RCP 2.6, RCP 8.5) might affect litter mass loss measured after 3 and 12 months. Our study shows that the early to mid-term mass loss at the global scale was affected predominantly by litter quality (explaining 73% and 62% of the total variance after 3 and 12 months, respectively) followed by climate and N deposition. The effects of climate were not litter-specific and became increasingly significant as decomposition progressed, with MAP explaining 2% and MAT 4% of the variation after 12 months of incubation. The effect of N deposition was litter-specific, and significant only for 12-month decomposition of Rooibos tea at the global scale. However, in the temperate biome where atmospheric N deposition rates are relatively high, the 12- month mass loss of Green and Rooibos teas decreased significantly with increasing N deposition, explaining 9.5% and 1.1% of the variance, respectively. The expected changes in macroclimate and N deposition at the global scale by the end of this century are estimated to increase the 12-month mass loss of easily decomposable litter by 1.1– 3.5% and of the more stable substrates by 3.8–10.6%, relative to current mass loss.In contrast, expected changes in atmospheric N deposition will decrease the mid-term mass loss of high-quality litter by 1.4–2.2% and that of low-quality litter by 0.9–1.5% in the temperate biome. Our results suggest that projected increases in N deposition may have the capacity to dampen the climate-driven increases in litter decomposition depending on the biome and decomposition stage of substrate., This work was performed within the TeaComposition initiative, carried out by 190 institutions worldwide. We thank for funding support for the workshop and data analysis from the ILTER. We acknowledge support by the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, funded by the German Research Foundation (FZT 118), Scientific Grant Agency VEGA (Grant No. 2/0101/18), as well as by the European Research Council under the European Union’s Horizon 2020 Research and Innovation Program (Grant Agreement No. 677232). Thanks are due to FCT/MCTES for the financial support to CESAM (UIDB/50017/2020 + UIDP/50017/2020) and to the project PORBIOTA (POCI-01-0145-FEDER-022127). AI Sousa was funded by national funds through the FCTFoundation for Science and Technology, I.P., under the project CEECIND/00962/2017. HS and CB acknowledge FCT support to cE3c through UID/BIA/00329/2013, UID/BIA/00329/2019, and UIDB/00329/2020, and the project PORBIOTA - POCI-01- 0145-FEDER-022127. We are also thankful to UNILEVER for sponsoring the Lipton tea.

The biodiversity–productivity relationship (BPR) constitutes one of the most fundamental yet challenging topics in ecology. Most described BPRs so far are based on relatively small grain sizes (typically smaller than 1ha), and understanding how the BPRs scale up from individual trees to communities of different sizes, a mission critical for biodiversity conservation and forest management, still remains elusive. Based on a unique 54.12-ha large-scale forest observational site in Northeastern China, where we georeferenced and measured approx. 90,000 trees in two consecutive inventories, we studied BPRs across a cascade of spatial scales using geostatistical analysis and bootstrapping. To explore the underlying mechanisms of the scale dependency of BPR, we further investigated the scale gradient in biodiversity and productivity, respectively, and assessed neighbourhood influences on individual trees. Across all the spatial scales, we found a consistent positive concave-down effect of tree species richness on forest productivity. The elasticity of substitution (θ) represented the degree to which species can substitute for each other in contributing to forest productivity. At the community level, the curvature of BPRs in terms of the elasticity of substitution (θ) declined from around 0.50 and converged at around 0.15, as the grain size increased from 0.01 to 1.00ha, all else being equal. Similarly, at the individual tree level, neighbourhood diversity coefficient, a linear proxy of θ, declined from around 0.08 and converged at around 0.03, as neighbourhood size increased from 0.01 to 1.00ha, all else being equal. Synthesis. Our study found a pronounced scale dependency of biodiversity–productivity relationship and quantified, for the first time, how biodiversity–productivity relationship scale up from 0.01 to 1.00ha. Our findings suggest that biodiversity–ecosystem functioning relationship can be generally scale-dependent and, hence, one must factor in this effect in biodiversity conservation and ecological restoration projects. Our findings also indicate that biodiversity–productivity relationship, predominantly determined by biological processes (i.e. complementarity and diminishing marginal productivity) at a small scale, can be increasingly influenced by statistical (i.e. spatial central limit theorem) and other (such as species–area relationship) processes as the scale increases.

Besides our current health concerns due to COVID-19, cancer is a longer-lasting and even more dramatic pandemic that affects almost a third of the human population worldwide. Most of the emphasis on its causes has been posed on genetic predisposition, chance, and wrong lifestyles (mainly, obesity and smoking). Moreover, our medical weapons against cancers have not improved too much during the last century, although research is in progress. Once diagnosed with a malignant tumour, we still rely on surgery, radiotherapy, and chemotherapy. The main problem is that we have focused on fighting a difficult battle instead of preventing it by controlling its triggers. Quite the opposite, our knowledge of the links between environmental pollution and cancer has surged from the 1980s. Carcinogens in water, air, and soil have continued to accumulate disproportionally and grow in number and dose, bringing us to today’s carnage. Here, a synthesis and critical review of the state of the knowledge of the links between cancer and environmental pollution in the three environmental compartments is provided, research gaps are briefly discussed, and some future directions are indicated. New evidence suggests that it is relevant to take into account not only the dose but also the time when we are exposed to carcinogens. The review ends by stressing that more dedication should be put into studying the environmental causes of cancers to prevent and avoid curing them, that the precautionary approach towards environmental pollutants must be much more reactionary, and that there is an urgent need to leave behind the outdated petrochemical-based industry and goods production.

Although they have received little attention, interspecific feeding associations are a particular predation behavior in which two or more different species temporary feed simultaneously on the same food sources to obtain greater success in predation. These collaborations can be either mutualistic, commensalistic, or parasitic. One of the best-known examples is the seabird–cetacean associations. Prey herding is the foraging tactic most used in these associations and consists of swimming around and under prey balls to trap them in the water column. Here we reported some new evidence of a fish–bird interspecific feeding association between the European seabass, Dicentrarchus labrax (Linnaeus, 1758) and the European shag, Gulosus aristotelis (Linnaeus, 1761). We analyzed this association through the photograph and video documentation provided by “citizen scientists” in the Mediterranean Sea. We collected reliable proofs of this behavior, at least, in three instances from observations made by recreational fishermen in the Kvarner bay (Croatia, North Adriatic Sea). From the photographs and videos made available, we attempted to reconstruct a predation strategy adopted by these associated species to better understand the advantage this provides during hunting. Although it is not yet clear whether this association is an opportunistic behavior of the European seabass or a mutualistic strategy used by both species to improve their catching success, this feeding association seems to increase the chances to defeat prey defense strategies. Notably, some behavioral imitation of hunting strategies may be put in place by seabasses, which often feed in association with dolphins and other birds using similar prey herding strategies.

This study examined the impact of climate change on plant species diversity of a savanna ecosystem, through an assessment of climatic trends over a period of forty years (1974&ndash, 2014) using Masvingo Province, Zimbabwe, as a case study. The normalised difference vegetation index (NDVI) was used as a proxy for plant species diversity to cover for the absence of long-term historical plant diversity data. Observed precipitation and temperature data collected over the review period were compared with the trends in NDVI to understand the impact of climate change on plant species diversity over time. The nonaligned block sampling design was used as the sampling framework, from which 198 sampling plots were identified. Data sources included satellite images, field measurements, and direct observations. Temperature and precipitation had significant (p &lt, 0.05) trends over the period under study. However, the trend for seasonal total precipitation was not significant but declining. Significant correlations (p &lt, 0.001) were identified between various climate variables and the Shannon index of diversity. NDVI was also significantly correlated to the Shannon index of diversity. The declining trend of plant species in savanna ecosystems is directly linked to the decreasing precipitation and increasing temperatures.

Terrestrial isopods have adapted to predatory pressures by evolving a variety of behaviors, which arise from a combination of specific traits, such as volvation and tonic immobility. Evolutionarily, these behavioral adaptations have been shown to increase the fitness of the individuals of the species who show them because the probability of being predated is reduced due to the loss of interest by the predator towards the immobile prey and the increase of interest towards the other mobile ones. Even if some of these behaviors have been shown to have a genetic basis, there is limited knowledge about the effects of environmental influences and predator-induced learning abilities on the antipredatory strategies of invertebrates, and isopods in particular. Our study aimed to understand the degree to which “nature” and “nurture” (i.e. environmental and genetic factors) and their interactions influence these antipredatory behaviors. There might be a difference in the behavior of wild and captive isopods in their volvation frequency and duration of tonic immobility due to environmental factors (i.e. predation) that induce learning-related behavioral changes. Therefore, we tested this hypothesis. We applied the three types of stimuli, which aim to simulate the interaction of the predator with the isopod. All three species showed a significant difference, between individuals collected in the field (wild) and raised in the laboratory (captive), in the reaction to the stimulus that simulates the fall from a bird’s beak or from the jaws of a lizard after a catch. Although volvation frequency was highly species- and stimulus-specific, the duration of tonic immobility and the delay in the response to each stimulus, when significant, was always higher in wild groups than captive ones. These substantial differences may reflect the evolutionary and ecological characteristics of each species and the importance of environmental pressures to shape the behavior of these invertebrates to optimize their life strategies.

Tropical forests inhabited by endangered orangutans, rhinos, tigers, and elephants in South-east Asia are threatened by deforestation, including oil palm expansion. Certification has been proposed to label sustainable palm oil production. However, from a remotely sensed time-series and imagery analysis (1984–2020), we discovered that most of the currently certified grower supply bases and concessions in Sumatra and Borneo are located in the 1990s large mammals habitat and in areas that were biodiverse tropical forests less than 30 years ago. In light of this dramatic evidence, we suggest that certification schemes claim for the “sustainable” production of palm oil just because they neglect a very recent past of deforestation and habitat degradation.

Limited research has been done to estimate the root biomass (belowground biomass) of savanna grasslands. The advent of remote sensing and related products have facilitated the estimation of biomass in terrestrial ecosystems, providing a synoptic overview on ecosystems biomass. Multispectral remote sensing was used in this study to estimate total biomass (belowground and aboveground) of selected tropical savanna grassland species. Total biomass was estimated by assessing the relationship between aboveground and belowground biomass, the Normalised Difference Vegetation Index (NDVI) and belowground biomass, and NDVI and total biomass. Results showed a positive significant relationship (p = 0.005) between belowground and aboveground biomass. NDVI was significantly correlated (p = 0.0386) to aboveground biomass and the Root Mean Square Error (RMSE) was 18.97 whilst the model BIAS was 0.019, values within acceptable ranges. A significant relationship (p = 0) was found between belowground biomass and NDVI and the RMSE was 5.53 and the model BIAS was 0.0041. More so, a significant relationship (p = 0.054) was observed between NDVI and total biomass. The positive relationships between NDVI and total grass biomass and the lack of bias in the model provides an opportunity to routinely monitor carbon stock and assess seasonal carbon storage fluctuations in grasslands. There is great potential in the ability of remote sensing to become an indispensable tool for assessing, monitoring and inventorying carbon stocks in grassland ecosystems under tropical savanna conditions.

Russian forests preserve biodiversity, host endemic species, store carbon, and are inhabited by indigenous people. However, in the last years, large areas of these forests have been damaged by different factors, mainly by logging and fires. This led to important tree loss even in protected areas. Despite it, no previous comprehensive research has been conducted to understand the trends and the causes of this tree loss. This study aims to investigate how Russian protected areas effectively contribute to nature conservation and can reduce forest loss within their borders. For the first time, we analysed the longest time-series available (2001–2018) of tree loss and fires in 201 Russian protected areas (those with the highest protection level). Studying the temporal trends of forest loss, we hypothesized that uncontrolled wildfire should result as the main cause of the forest loss expected within the highest protection areas of Russia and that logging and other anthropogenic activities - because prohibited in these areas - should be a minor threat. Instead, from Earth Observation datasets, we detected that even in the 201 areas with the highest protection, more than 2Mha of forests have been lost between 2001 and 2018. Fire contributed about 25% to this loss but was not the major driver. From a year-by-year analysis of the time series, we were able to disentangle the potential contribution of “other-than-fire” causes of loss. We found that, in 15 out of 18 years of our time series, causes not due to fire were the main driver of tree loss in these strictly protected areas, which reached a peak recently, between 2013 and 2018. Overall, of the 201 strictly protected areas in Russia, 135 experienced tree loss between 2001 and 2018. In 34 of them, the loss was higher than 10,000 ha, where a major percentage was attributable to fire only in 3 sites. In the other 31 protected areas, fire contributed to the total forest loss less than 50%. Our analysis also showed that five strictly protected areas experienced a massive tree loss (> 100kha) from 2001 to 2018. Among them, Lake Baikal, a World Heritage site, suffered an astonishing forest loss of 485 k ha, whose only 21% may be attributed to fire. Considering that we discovered that most of the causes of forest loss may be related to human activities, the situation could be controlled through better management and policy.

A relatively small number of broad-scale patterns describe the distribution of biodiversity across the earth. All of them explore biodiversity focusing on a mono or bi-dimensional space. Conversely, the volume of the forests is rarely considered. In the present work, we tested a global correlation between vascular plant species richness (S) and average forest canopy height (H), the latter regarded as a proxy of volume, using the NASA product of Global Forest Canopy Height map and the global map of plant species diversity. We found a significant correlation between H and S both at global and macro-climate scales, with strongest confidence in the tropics. Hence, two different regression models were compared and discussed to provide a possible pattern of the H–S relation. We suggested that the volume of forest ecosystems should be considered in ecological studies as well as in planning and managing natural sites, although in this first attempt, we cannot definitively prove our hypothesis. Again, high-resolution spatial data could be highly important to confirm the H–S relation, even at different scales.

Among tropical areas, Africa is considered to be poor in terms of biodiversity as compared with Amazon or South-East Asia, especially with respect to forest diversity. Despite this lower diversity, some African tropical zones, such as Ghana, harbour a plethora of species, particularly of trees. Unfortunately, as a result of anthropogenic impacts, biological diversity in West Africa dramatically decreased in the last decades, with very limited reference to evaluate the amount of the loss. Due to these growing pressure, a collection of relevant biodiversity information in this region seems to be urgent. We surveyed 127 temporary plots randomly distributed within 3 protected areas in Ghana and we collected data on tree (dbh>10 cm) species richness and their abundances. We also performed α, and β diversity analyses, and estimated the effective number of species, adopting various indices and approaches to provide further information on each assemblage. The main goals of this research were: (i) to provide a wide tree species database (abundance-based data), together with some biodiversity analyses; (ii) to estimate the sampling effort needed for next biodiversity surveys in the same and similar regions; and (iii) to calculate some indices useful to monitor the future of these protected areas both in terms of conservation and biodiversity research.

A central question about biodiversity is how so many species can coexist within the same ecosystem. The idea that ecological niches are critical for the maintenance of species diversity has received increasing support recently. However, a niche is often considered as something static, preconditioned, and unchanging. With the “Biodiversity-related Niches Differentiation Theory” (BNDT), we recently proposed that species themselves are the architects of biodiversity, by proportionally increasing the number of potentially available niches in a given ecosystem. Along similar lines, but independently, the idea of viewing an ecosystem of interdependent species as an emergent autocatalytic set (a self-sustaining network of mutually “catalytic” entities) was suggested, where one (group of) species enables the existence of (i.e., creates niches for) other species. Here, we show that biodiversity can indeed be considered a system of autocatalytic sets, and that this view offers a possible answer to the fundamental question of why so many species can coexist in the same ecosystem. In particular, we combine the two theories (BNDT and autocatalytic sets), and provide some simple but formal examples of how this would work.

[EN] The identity of the dominant root-associated microbial symbionts in a forest determines the ability of trees to access limiting nutrients from atmospheric or soil pools, sequester carbon and withstand the effects of climate change. Characterizing the global distribution of these symbioses and identifying the factors that control this distribution are thus integral to understanding the present and future functioning of forest ecosystems. Here we generate a spatially explicit global map of the symbiotic status of forests, using a database of over 1.1 million forest inventory plots that collectively contain over 28,000 tree species. Our analyses indicate that climate variables—in particular, climatically controlled variation in the rate of decomposition—are the primary drivers of the global distribution of major symbioses. We estimate that ectomycorrhizal trees, which represent only 2% of all plant species, constitute approximately 60% of tree stems on Earth. Ectomycorrhizal symbiosis dominates forests in which seasonally cold and dry climates inhibit decomposition, and is the predominant form of symbiosis at high latitudes and elevation. By contrast, arbuscular mycorrhizal trees dominate in aseasonal, warm tropical forests, and occur with ectomycorrhizal trees in temperate biomes in which seasonally warm-and-wet climates enhance decomposition. Continental transitions between forests dominated by ectomycorrhizal or arbuscular mycorrhizal trees occur relatively abruptly along climate-driven decomposition gradients; these transitions are probably caused by positive feedback effects between plants and microorganisms. Symbiotic nitrogen fixers—which are insensitive to climatic controls on decomposition (compared with mycorrhizal fungi)—are most abundant in arid biomes with alkaline soils and high maximum temperatures. The climatically driven global symbiosis gradient that we document provides a spatially explicit quantitative understanding of microbial symbioses at the global scale, and demonstrates the critical role of microbial mutualisms in shaping the distribution of plant species., This work was made possible by the Global Forest Biodiversity Database, which represents the work of over 200 independent investigators and their public and private funding agencies (see Supplementary Acknowledgements), Supplementary information is available for this paper at https://doi.org/10.1038/s41586-019-1128-0.

Most evolutionary biologists consider selfishness an intrinsic feature of our genes and as the best choice in social situations. During the last years, prolific research has been conducted on the mechanisms that can allow cooperation to emerge “in a world of defectors” to become an evolutionarily stable strategy. A big debate started with the proposal by W.D. Hamilton of “kin selection” in terms of cost sustained by the cooperators and benefits received by related conspecifics. After this, four other main rules for the evolution of cooperation have been suggested. However, one of the main problems of these five rules is the assumption that the payoffs obtained by either cooperating or defeating are quite well known by the parties before they interact and do not change during the time or after repeated encounters. This is not always the case in real life. Following each rule blindly, there is a risk for individuals to get stuck in an unfavorable situation. Axelrod (1984) highlighted that the main problem is how to obtain benefits from cooperation without passing through several trials and errors, which are slow and painful. With a better understanding of this process, individuals can use their foresight to speed up the evolution of cooperation. Here I show that a multi-armed bandit (MAB) model, a classic problem in decision sciences, is naturally employed by individuals to opt for the best choice most of the time, accelerating the evolution of the altruistic behavior and solving the abovementioned problems. A common MAB model that applies extremely well to the evolution of cooperation is the epsilon-greedy (e-greedy) algorithm. This algorithm, after an initial period of exploration (which can be considered as biological history), greedily exploits the best option e% of the time and explores other options the remaining percentage of times (1-e%). Through the epsilon-greedy decision-making algorithm, cooperation evolves as a multilevel process nested in the hierarchical levels that exist among the five rules for the evolution of cooperation. This reinforcement learning, a subtype of artificial intelligence, with trials and errors, provides a powerful tool to better understand and even probabilistically quantify the chances cooperation has to evolve in a specific situation.

Air pollution can increase the risk of respiratory diseases, enhancing the susceptibility to viral and bacterial infections. Some studies suggest that small air particles facilitate the spread of viruses and also of the new coronavirus, besides the direct person-to-person contagion. However, the effects of the exposure to particulate matter and other contaminants on SARS-CoV-2 has been poorly explored. Here we examined the possible reasons why the new coronavirus differently impacted on Italian regional and provincial populations. With the help of artificial intelligence, we studied the importance of air pollution for mortality and positivity rates of the SARS-CoV-2 outbreak in Italy. We discovered that among several environmental, health, and socio-economic factors, air pollution and fine particulate matter (PM2.5), as its main component, resulted as the most important predictors of SARS-CoV-2 effects. We also found that the emissions from industries, farms, and road traffic - in order of importance - might be responsible for more than 70% of the deaths associated with SARS-CoV-2 nationwide. Given the major contribution played by air pollution (much more important than other health and socio-economic factors, as we discovered), we projected that, with an increase of 5-10% in air pollution, similar future pathogens may inflate the epidemic toll of Italy by 21-32% additional cases, whose 19-28% more positives and 4-14% more deaths. Our findings, demonstrating that fine-particulate (PM2.5) pollutant level is the most important factor to predict SARS-CoV-2 effects that would worsen even with a slight decrease of air quality, highlight that the imperative of productivity before health and environmental protection is, indeed, a short-term/small-minded resolution., Graphical abstract Image 1, Highlights • Air quality is linked to respiratory diseases and may facilitate microbial infections. • The prolonged exposure to air pollution can affect SARS-CoV-2 outbreak. • We found that air quality is the best predictor for SARS-CoV-2 mortality in Italy. • A prominent role is played by PM2.5 and emissions from industries and farms. • A worsening of air quality may inflate the death toll of similar future pandemics., Short summary: Artificial intelligence reveals that, in Italy, air pollution mainly due to fine particulate matter produced by industries, farms, and road traffic may severely affect the susceptibility to respiratory infections caused by SARS-CoV-like pathogens.

The total freshwater biodiversity is not fully known. In particular, freshwater invertebrates and microbes are poorly studied groups, and in tropical latitudes, that support most of the species of the world, the information is lacking. Although almost a hundred thousand of species live in fresh water, the species losses continue at the high rate and the probability of preserving much of the remaining biodiversity in fresh water seems to be very low. Freshwater ecosystems are increasingly influenced by multiple stressors that lead to loss of sensitive species and an overall reduction in diversity. Environmental change threatens freshwater biodiversity. This paper reports an extensive review of work that evaluates the current main threats for freshwater biodiversity, on a local and global scale.

Degradation, a reduction of the ecosystem’s capacity to supply goods and services, is widespread in tropical forests and mainly caused by human disturbance. To maintain the full range of forest ecosystem services and support the development of effective conservation policies, we must understand the overall impact of degradation on different forest resources. This research investigates the response to disturbance of forest structure using several indicators: soil carbon content, arboreal richness and biodiversity, functional composition (guild and wood density), and productivity. We drew upon large field and remote sensing datasets from different forest types in Ghana, characterized by varied protection status, to investigate impacts of selective logging, and of illegal land use and resources extraction, which are the main disturbance causes in West Africa. Results indicate that functional composition and the overall number of species are less affected by degradation, while forest structure, soil carbon content and species abundance are seriously impacted, with resources distribution reflecting the protection level of the areas. Remote sensing analysis showed an increase in productivity in the last three decades, with higher resiliency to change in drier forest types, and stronger productivity correlation with solar radiation in the short dry season. The study region is affected by growing anthropogenic pressure on natural resources and by an increased climate variability: possible interactions of disturbance with climate are also discussed, together with the urgency to reduce degradation in order to preserve the full range of ecosystem functions.

Biological diversity analysis is among the most informative approaches to describe communities and regional species compositions. Soil ecosystems include large numbers of invertebrates, among which soil bugs (Crustacea, Isopoda, Oniscidea) play significant ecological roles. The aim of this study was to provide advices to optimize the sampling effort, to efficiently monitor the diversity of this taxon, to analyze its seasonal patterns of species composition, and ultimately to understand better the coexistence of so many species over a relatively small area. Terrestrial isopods were collected at the Natural Reserve “Saline di Trapani e Paceco” (Italy), using pitfall traps monthly monitored over 2 years. We analyzed parameters of α‐ and β‐diversity and calculated a number of indexes and measures to disentangle diversity patterns. We also used various approaches to analyze changes in biodiversity over time, such as distributions of species abundances and accumulation and rarefaction curves. As concerns species richness and total abundance of individuals, spring resulted the best season to monitor Isopoda, to reduce sampling efforts, and to save resources without losing information, while in both years abundances were maximum between summer and autumn. This suggests that evaluations of β‐diversity are maximized if samples are first collected during the spring and then between summer and autumn. Sampling during these coupled seasons allows to collect a number of species close to the γ‐diversity (24 species) of the area. Finally, our results show that seasonal shifts in community composition (i.e., dynamic fluctuations in species abundances during the four seasons) may minimize competitive interactions, contribute to stabilize total abundances, and allow the coexistence of phylogenetically close species within the ecosystem.

The development of a unique index to represent the real diversity of a community is still a challenge. The difficulties to find a single, reliable, diversity metric is mostly due to the fact that the indices allowing an estimation of the number of species actually present in a sample do not provide information on how species abundances are distributed within a community. Although some diversity measures attempted to weigh richness in relation to the total abundance, the homogeneity (evenness) of individuals within species is not integrated into them. The most common diversity indices have been "summarized" by Hill in 1973 in a single equation and, subsequently, different indicators have been proposed to estimate the "absolute" and the “effective” number of species present in a study area in an attempt to find a unified treatment of all standard diversity indices and to compare the true diversity among community. However, the choice of one of the effective number of species indices depends on what aspects of diversity of the study sites the research aims to investigate and could bias the study and mislead the interpretation of the comparative results. Moreover, effective Hill numbers account for only the observed, and not the expected (i.e. the absolute) diversity of the studied community. To compare and interpret the effective number of species with one single metric and analyze the diversity data with techniques that do not depend on a traditional non-parametric index, we developed an absolute measure of diversity based on the effective number of species and derived from the Hill numbers of order 0, 1, and 2. We tested the new index against previously-proposed absolute diversity estimators and the first three Hill numbers taken alone. We simulated the new index's behavior with different gradients of richness, abundance and evenness and we, finally, empirically tested it on tree communities of three biomes (boreal, temperate and tropical forests) of the United States and on a coral reef community of Cuba. This new index proved to be the first reliable and comparable measure, which combines both the absolute richness and the evenness of a community related to the most used traditional indices in a unique, simple and comprehensive numerical value that would represent the absolute effective diversity (AED) of any biological community.

The globalization of the palm oil trade poses a menace to the ecosystem integrity of Southeast Asia. In this short communication, we briefly discuss why palm oil certifications may have failed as an effective means to halt forest degradation and biodiversity loss. From a comparison of multiple new datasets, we analysed recent tree loss in Indonesia, Malaysia, and Papua New Guinea, and discovered that, from 2001 to 2016, about 40% of the area located in certified concessions suffered from habitat degradation, deforestation, fires, or other tree damages. Certified concessions have been subject to more tree removals than non-certified ones. We also detect significant tree loss before and after the start of certification schemes. Beyond non-governmental organisations' concern that Roundtable on Sustainable Palm Oil (RSPO) and Palm Oil Innovation Group (POIG) certifications allow ongoing clearance of any forest not identified as of high conservation values (HCV) or high carbon stock (HCS), we suggest an alarming and previously overlooked situation, such as that current "sustainable palm oil" is often associated with recent habitat degradation and forest loss. In other words, certified palm oil production may not be so sustainable.

Motivation The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene. Main types of variables included The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record. Spatial location and grain BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2). Time period and grain BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year. Major taxa and level of measurement BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates. Software format .csv and .SQL., Global Ecology and Biogeography, 27 (7), ISSN:1466-822X, ISSN:1466-8238

Although tropical rainforests preserve high levels of biodiversity, they are among the most threatened ecosystems globally due to large-scale fragmentation as a result of anthropogenic activities. Overall, fast human-driven habitat destruction is suspected to be one of the major causes of species extinction. The mosaic of vegetation types, which contributes to the incredible diversity of the tropics is highly impacted by large-scale fragmentation. The main causes of such habitat fragmentation are selective logging for valuable timber and agricultural clearance. The knowledge of the short and long-term effects of removing selected species in the tropical rainforests are scarce and need to be further investigated. Some studies about the effects of tropical forest disturbance in the short term have been conducted, but in the long term, there is limited knowledge. In this paper, I consider a system of coupled ordinary differential equations (ODEs) that modelled the dynamics of tropical rainforest subject to selective logging to understand how and why weeds and vine displace and limit tree species. From the empirical data collected on canopy height and plant diversity and the model proposed, I have the evidence of a decreasing tree diversity in tropical forests subject to management in comparison with to the same but untouched forests.

In an epoch of fast and dramatic changes in ecosystems, a complete survey of biodiversity and an analysis of its spatial patterns from the field shall be associated with satellite imagery, which can provide a synoptic observation in space and time of the territory. This work presents the preliminary results of a new approach to monitor the biodiversity of a well-defined area, which takes into account species diversity and the landscape characteristics in terms of ecosystems diversity (land cover classes). We developed a Multilevel Biodiversity Index (MBI) and we tested it in a study site of 400 km2, belonging to the Central Mediterranean Ecoregion and consisting of forested areas, scrublands and steppes (Murge). With the aim to reach a global land cover classification system and a standardisation of the biodiversity surveys, the MBI can be easily adapted to study areas of different ecoregions on Earth. This index could certainly be useful for future studies and to address environmental policies in order to protect vulnerable ecosystems and assign a conservation priority rank that takes into account the presence of diversity both in terms of species and ecosystems. Keywords: Biodiversity, Monitoring, Multilevel biodiversity index, Satellite analyses, Mediterranean ecoregion, Field and RS monitoring

Terrestrial isopods are a well-studied invertebrate taxon in Sicily and in the surrounding islands (Maltese archipelago included). During the last 30years their systematics, ecology and biogeography have been analysed by many authors. The size and the diverse geological origin of the Sicilian archipelago represents an ideal open laboratory in which to study some biogeographical patterns, such as the species-area relationship (SAR). Since many species show limited adaptation to broad physiological conditions and low mobility, and, therefore, their active dispersion is very slow, SAR can be a useful means to examine biogeographical patterns of isopods. Here we analyse their biogeography and whether there is a relationship between the area and the habitat variability of the island surveyed, and whether these factors have an either direct or coupled influence on species richness and ecology. Moreover, we evaluate a potential relationship between Isopoda species richness and the distance from the centre of dispersion (Sicily). Finally, we test for a difference in species and habitat richness between volcanic and non-volcanic islands. Our results show a positive correlation between the area and the habitat, more significant than that between the area and the species, leading us to speculate that habitat diversity has an influence on the SAR of isopods. We find a significantly higher richness of both species and habitats on non-volcanic islands. Finally, our analysis confutes the hypothesis that the number of isopod species on the archipelago’s islets declines with the distance from Sicily. We suggest some potential explanations.

Several biological aspects of juvenile specimens of Raja radula were investigated from February to May 2017 in the central Mediterranean Sea. Diet, sex ratio, disc width-weight relationships, and size-frequency distribution were analyzed. Stomach content analysis of 127 collected specimens showed that juveniles of R. radula actively feed on small benthic crustaceans, particularly on amphipods and isopods (Idotea balthica) (%IRI values of 62.74% and 12.39%, respectively). Although the Levin's index value (Bi = 0.44) indicated that juveniles of R. radula are a moderately stenophagous feeders, active mostly on crustaceans, the analysis of the prey-specific (Pi) biomass of the main preys vs. the frequency of their occurrence (%F) showed no clear dominance. The analysis of the sex ratio showed no significant difference in sex distribution. However, there were significant differences in mean size between sexes: females were, on average, larger than males, and also the b value (slope of the curve) of the disc width-weight relationships was higher in females.

Several studies have reported significant emission of greenhouse gasses (GHG) from beaver dams, suggesting that ponds created by beavers are a net source of CO2 and CH4. However, most evidence come from studies conducted in North America (on Castor canadensis) without a parallel comparison with the Eurasian beaver's (Castor fiber) impacts and a critical consideration of the importance of the carbon deposition in dam sediments. The most abundant population of the Eurasian beaver lives in Russia, notably within the River Ob watershed in Western Siberia which is the second largest floodplain on Earth. Consequently, we assessed the holistic impact of Eurasian beavers on the multiple carbon pools in water and on other related biogeochemical parameters of the Ob's floodplain streams. We compared dammed and flowing streams in a floodplain of the middle course of the river. We found that beavers in western Siberia increase the stream emission of methane by about 15 times by building their dams. This is similar to what has been documented in North America. A new finding from the present study is that Siberian beavers facilitate 1) nutrient recycling by speeding up the nutrient release from particulate organic matter; and 2) carbon sequestration by increasing the amount of dissolved organic carbon. This carbon becomes in part recalcitrant when buried in sediments and is, therefore, removed from the short-term carbon cycle. These new results should be taken into consideration in river management and provide a further reason for the conservation and management of Eurasian Beavers.

In this article, we report and discuss the results obtained from a survey of plants, microorganisms (bacteria and fungi), and soil elements along a chronosequence in the first 600m of the Maliy Aktru glacier's forefront (Altai Mountains, Russia). Many glaciers of the world show effects of climate change. Nonetheless, except for some local reports, the ecological effects of deglaciation have been poorly studied and have not been quantitatively assessed in the Altai Mountains. Here, we studied the ecological changes of plants, fungi, bacteria, and soil elements that take the form of a primary ecological succession and that took place over the deglaciated soil of the Maliy Aktru glacier during the last 50year. According to our measurements, the glacier lost about 12m per year during the last 50years. Plant succession shows clear signs of changes along the incremental distance from the glacier forefront. The analysis of the plant α- and β-diversity confirmed an expected increase of them with increasing distance from the glacier forefront. Moreover, the analysis of β-diversity confirmed the hypothesis of the presence of three main stages of the plant succession: (a) initial (pioneer species) from 30 to 100m; (b) intermediate (r-selected species) from 110 to 120–150m; and (c) final (K-selected species) from 150 to 550. Our study also shows that saprotrophic communities of fungi are widely distributed in the glacier retreating area with higher relative abundances of saprotroph ascomycetes at early successional stages. The evolution of a primary succession is also evident for bacteria, soil elements, and CO2 emission and respiration. The development of biological communities and the variation in geochemical parameters represent an irrefutable proof that climate change is altering soils that have been long covered by ice.

The utilisation of the ecospace and the change in diversity through time has been suggested to be due to the effect of niche partitioning, as a global long-term pattern in the fossil record. However, niche partitioning, as a way to coexist, could be a limited means to share the environmental resources and condition during evolutionary time. In fact, a physical limit impedes a high partitioning without a high restriction of the niche's variables. Here, we propose that niche emergence, rather than niche partitioning, is what mostly drives ecological diversity. In particular, we view ecosystems in terms of autocatalytic sets: catalytically closed and self-sustaining reaction (or interaction) networks. We provide some examples of such ecological autocatalytic networks, how this can give rise to an expanding process of niche emergence (both in time and space), and how these networks have evolved over time (so-called evoRAFs). Furthermore, we use the autocatalytic set formalism to show that it can be expected to observe a power-law in the size distribution of extinction events in ecosystems. In short, we elaborate on our earlier argument that new species create new niches, and that biodiversity is therefore an autocatalytic process.

The study the biodiversity is not just an attempt to understand the differences or similarities between species, habitats or genomes. It also includes an understanding of how nature regulates the processes that characterise ecosystems and ensure their functionality. It means as well to increase the ability to predict the impact of current and future anthropogenic actions on nature (Midgley et al. 2002). Biodiversity is what makes the Earth a unique planet. In the Universe, for all we know, or at least in our galaxy, life is the exception rather than the rule (Dick 1999). And even if a day when we are able to document the presence of living beings on other planets will come, this will also be an exception. The appearance of life is a phenomenon that has always fascinated mankind since without it, our human species would have never existed and no hairless biped would have studied life, with great admiration, and destroyed it with equal force (Cardinale et al. 2012).

The alterations in the salinity profile are an indirect, but potentially sensitive, indicator for detecting changes in precipitation, evaporation, river run-off, glacier retreat, and ice melt. These changes have a high impact on the growth of coastal plant species, such as mangroves. Here, we present estimates of the variability of salinity and the biomass of a stenoecious mangrove species (Heritiera fomes, commonly referred to as Sundari) in the aquatic subsystem of the lower Gangetic delta based on a dataset from 2004 to 2015. We highlight the impact of salinity alteration on the change in aboveground biomass of this endangered species that, due to different salinity profile in the western and central sectors of the lower Gangetic plain, shows an increase only in the former sector, where the salinity is dropping and low growth in the latter, where the salinity is increasing.

We combined two existing datasets of vegetation aboveground biomass (AGB) (Proceedings of the National Academy of Sciences of the United States of America, 108, 2011, 9899; Nature Climate Change, 2, 2012, 182) into a pan-tropical AGB map at 1-km resolution using an independent reference dataset of field observations and locally calibrated high-resolution biomass maps, harmonized and upscaled to 14477 1-km AGB estimates. Our data fusion approach uses bias removal and weighted linear averaging that incorporates and spatializes the biomass patterns indicated by the reference data. The method was applied independently in areas (strata) with homogeneous error patterns of the input (Saatchi and Baccini) maps, which were estimated from the reference data and additional covariates. Based on the fused map, we estimated AGB stock for the tropics (23.4 N-23.4 S) of 375 Pg dry mass, 9-18% lower than the Saatchi and Baccini estimates. The fused map also showed differing spatial patterns of AGB over large areas, with higher AGB density in the dense forest areas in the Congo basin, Eastern Amazon and South-East Asia, and lower values in Central America and in most dry vegetation areas of Africa than either of the input maps. The validation exercise, based on 2118 estimates from the reference dataset not used in the fusion process, showed that the fused map had a RMSE 15-21% lower than that of the input maps and, most importantly, nearly unbiased estimates (mean bias 5Mg dry massha-1 vs. 21 and 28Mgha-1 for the input maps). The fusion method can be applied at any scale including the policy-relevant national level, where it can provide improved biomass estimates by integrating existing regional biomass maps as input maps and additional, country-specific reference datasets.

For a long time ecologists have questioned on the variations of biodiversity across the latitudinal gradient. Recently, it has emerged that the changes in s-diversity are caused simply by changes in the sizes of species pools. In this study, the species pool size and the fractal nature of ecosystems was combined to clarify some general patterns of this gradient. Considering temperature, humidity and NPP as the main variables of an ecosystem niche and as the axis of the polygon in the Cartesian plane, it is possible to build fractal hypervolumes, whose fractal dimension rises up to three moving towards the equator. It follows that the best figure that graphically synthesizes the evolutionary forces that fit this ecosystem hypervolume is the fractal cauliflower.

Because of their biological and ecological characteristics terrestrial isopods are considered as bioindicators of ecosystem health and several studies have shown that their distribution and abundance are influenced by environmental factors, such as weather, soil texture, composition and vegetation structure. However, few quantitative data are available on the relationship between single species of terrestrial isopods, meteorological variables and coastal zonation. This study aims to clarify relationships between terrestrial isopod populations, coastal zones and weather conditions of a protected area in Sicily. The terrestrial isopods were sampled using pitfall traps, and we verified the association between each species abundance and three different (lower, medium and upper) coastal zones. Furthermore, we analyzed correlations between isopod abundances and meteorological conditions (temperature and precipitation). The results showed a close relationship between some isopod species and coastal zone types, as well as a positive correlation of most of the species abundances with temperature and a negative one with precipitation.

The mechanisms that allow species to evolve, coexist, compete, cooperate or become extinct are becoming always more understood. At the same time, the factors that allow species to coexist in a given time within the same environment are still debated. Many theories and hypotheses suggest that competition tends to differentiate the ecological requirements after repeated interactions and to allow the presence of many different species in the same area (i.e. biodiversity). After all, a thorough understanding of the evolutionary dynamics of biodiversity, which could somehow explain the current distribution patterns and mechanisms of coexistence, must consider the biogeographic and phylogenetic approaches. Here I propose a new graphic model that reviews the past and present, and sometimes debated, trends in biodiversity and evolutionary science, pointing out the importance of the avoidance of competition, the biological history, the endogenosymbiosis and the three-dimensionality as the main forces that structure ecosystems and allow the evolution of biological diversity. This model is an attempt to explain and summarize some of the mechanisms that underlie the current presence of the awesome number of species that currently inhabit our planet.

Even if the will to follow a sustainable lifestyle in the Western countries is increasing, many developing countries are experiencing their phase of economic growth, threatening and overexploiting their environment. This study compares the Living Planet Index and the Human Development Index, and suggests that societies follow common patterns of development, from the indigenous lifestyle to undeveloped society, through a developing stage, towards a developed state. According to these common steps each society exploits local, regional and sometimes global natural resources to nourish its economic growth. If developing countries will not undertake strategies to skip the ‘intermediate’ stage of overexploitation of natural resources during their growing phase, Earth systems may not be able to keep alive the global biodiversity, and provide ecosystem services that sustain humanity.

Funding Information: We are thankful to the GlobBiomass project team and Frank Martin Seifert (ESA) for valuable suggestions and stimulating scientific discussions. We are thankful to Takeo Tadono (JAXA EORC), Masato Hayashi, (JAXA EORC), Kazufumi Kobayashi (RESTEC), Åke Rosenqvist (soloEO), and Josef Kellndorfer (EBD) for support with the use and interpretation of the ALOS PALSAR mosaics. Support by the CCI Land Cover project team, in particular Sophie Bontemps (UCL), is greatly acknowledged. The help from Martin Jung (MPI-BGC) in feature selection and Ulrich Weber (MPI-BGC) for data processing for the GSV-to-AGB conversions is greatly acknowledged. Forest inventory data for the validation of the AGB map were made available by, among others, Ben de Jong; the Prince Edward Island Department of Communities, Land and Environment – Forests, Fish and Wildlife Division; and the Nova Scotia Department of Natural Resources. Inventory data were also provided by the Sustainable Landscapes Brazil project supported by the Brazilian Agricultural Research Corporation (EMBRAPA), the US Forest Service, the USAID, and the US Department of State. We thank the three anonymous reviewers, contributors to the short comments, Geerten Hengeveld, and Jérôme Chave for reviewing and improving the manuscript. Funding Information: Financial support. This research has been supported by the European Space Agency (ESRIN contract no. 4000113100/14/I-NB) and the Russian Science Foundation (grant no. 19-77-30015). Funding Information: Acknowledgements. The National Centre for Earth Observation was supported by the UK Natural Environment Research Council. The FOS data collection for Russia was performed within the framework of the state assignment of the Center for Forest Ecology and Productivity of the Russian Academy of Sciences (no. AAAA-A18-118052590019-7). The Russian ground data preparation and pre-processing were financially supported by the Russian Science Foundation (project no. 19-77-30015). Publisher Copyright: © 2021 Maurizio Santoro et al. The terrestrial forest carbon pool is poorly quantified, in particular in regions with low forest inventory capacity. By combining multiple satellite observations of synthetic aperture radar (SAR) backscatter around the year 2010, we generated a global, spatially explicit dataset of above-ground live biomass (AGB; dry mass) stored in forests with a spatial resolution of 1 ha. Using an extensive database of 110 897 AGB measurements from field inventory plots, we show that the spatial patterns and magnitude of AGB are well captured in our map with the exception of regional uncertainties in high-carbon-stock forests with AGB >250 Mgha-1, where the retrieval was effectively based on a single radar observation. With a total global AGB of 522 Pg, our estimate of the terrestrial biomass pool in forests is lower than most estimates published in the literature (426-571 Pg). Nonetheless, our dataset increases knowledge on the spatial distribution of AGB compared to the Global Forest Resources Assessment (FRA) by the Food and Agriculture Organization (FAO) and highlights the impact of a country's national inventory capacity on the accuracy of the biomass statistics reported to the FRA. We also reassessed previous remote sensing AGB maps and identified major biases compared to inventory data, up to 120 % of the inventory value in dry tropical forests, in the subtropics and temperate zone. Because of the high level of detail and the overall reliability of the AGB spatial patterns, our global dataset of AGB is likely to have significant impacts on climate, carbon, and socio-economic modelling schemes and provides a crucial baseline in future carbon stock change estimates. publishersversion published