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Species differ in their biological susceptibility to extinction, but the set of traits determining susceptibility varies across taxa. It is yet unclear which patterns are common to all taxa, and which are taxon-specific, with consequences to conservation practice. In this study we analysed the generality of trait-based prediction of extinction risk across terrestrial (including freshwater) vertebrates, invertebrates and plants at a global scale. For each group, we selected five representative taxa and within each group we explored whether risk can be related to any of 10 potential predictors. We then synthesized outcomes across taxa using a meta-analytic approach. High habitat specificity was a consistent predictor across vertebrates, invertebrates and plants, being a universal predictor of risk. Slow life-history traits – large relative offspring size, low fecundity, long generation length –, and narrow altitudinal range were also found to be good predictors across most taxa, but their universality needs to be supported with additional data. Poor dispersal ability was a common predictor of extinction risk among invertebrate and plant taxa, but not consistently among vertebrates. The remaining traits (body size, microhabitat verticality, trophic level, and diet breadth) were useful to predict extinction risk but only at lower taxonomical levels. Our study shows that despite the idiosyncrasies among taxa, universal susceptibility to extinction exists and several traits might influence extinction risk for most taxa. Informing conservation prioritization at lower taxonomic scales should however include taxon-specific trait-based predictors of extinction risk. [ABSTRACT FROM AUTHOR]

How a particular threat influences extinction risk may depend on biological traits. Empirical studies relating threats and traits are needed, but data are scarce, making simulations useful. We implemented an eco-evolutionary model to analyse how five threat types influence the extinction risk of virtual organisms differing in body size, maturity age, fecundity, and dispersal ability. The model consisted of observing the evolutionary shift in the mean trait values of an assemblage of organisms when a threat was added into the virtual world where they lived. If a positive shift was found in trait values, we considered that the threat negatively influenced organisms with lower values for that trait. Direct killing mostly affected organisms with slow life cycles (slower-living) and poorly dispersive organisms. Habitat loss caused a reduction in the average dispersal ability of organisms. Habitat fragmentation caused an increase of average dispersal ability, and had a negative effect on larger, less fecund organisms. Habitat degradation and the introduction of invasive competitors had similar effects, mostly affecting large and fast-living organisms, with habitat degradation also affecting highly fecund and poorly dispersive organisms. These results agree with previous empirical studies in which larger, slower-lived, and less fecund organisms are more vulnerable to a greater range of threats. On the other hand, our results challenge two commonly seen hypotheses in the literature: that organisms with high dispersal ability fare well under any high habitat loss scenarios, and that fast-living, highly fecund organisms always do well during environmental change. Our study shows that highly dispersive organisms may be the losers when habitat loss removes large continuous areas of habitat, and fast-living and highly reproductive organisms may be the losers when resources or energy availability dwindle to very low levels. Most importantly, our study underpins the importance of considering the type of threat when analysing the relation between traits and extinction. Even in simple scenarios such as the ones modelled here, different threats lead to different, sometimes opposite, extinction probabilities according to the biological traits of organisms. • New agent-based model to analyse the selectivity of extinction on biological traits. • Larger and slower-lived organisms more vulnerable to a wider range of threats. • Highly dispersive organisms unfavoured when continuous areas of habitat are removed. • Fast-living and highly reproductive organisms unfavoured when resources dwindle. • The type of threat must be considered when studying the selectivity of extinction. [ABSTRACT FROM AUTHOR]

• Management practices alter litter quality but not litter mass loss. • Decay rates were higher in grassy (Agrostis) than in cork-oak (Quercus) litters. • A higher proportion of eu-edaphic species was found in Agrostis treatments. • Mixed litter increased Collembola richness, fungal biomass, P and phenolic concentrations. • Mass loss was strongly related to the initial litter P and phenolic concentrations. Plant litter decomposition depends on the nutrient content and the amount of recalcitrant materials such as lignin and phenolic compounds. These traits are inherent to the plant species providing the litter. In agro-ecosystems, the type of land management may also shape litter traits and then influence the litter decomposition process. However, the effects of management practice/intensity on litter traits have not been addressed in previous studies, particularly in Mediterranean systems. Our aim was to test the effect of management practices on litter traits associated to nutritional quality and recalcitrance and the resulting effects on fungal biomass, Collembola communities and decomposition parameters in cork-oak agro-forest systems. A litterbag experiment was conducted using litter of dominant plant species, Quercus suber L. and Agrostis pouretii L., collected in an organic agro-forest system and in its neighbor conventional farm. We also tested the effects of litter mixtures using these two contrasting litter types, and the subsequent effects on Collembola communities and decomposition parameters. Land management influenced initial litter traits, mostly in terms of phenolics concentration, higher on the conventional site, and P concentrations, that were higher on the organic farm. After the decomposition experiment, fungal biomass was significantly higher on Quercus litters from the conventional management, while %P and %phenolics were significantly higher in litters from organic compared to conventional management. Collembola richness was significantly higher in Quercus treatments and in litter mixtures compared to single Agrostis litters. These recorded more epigeous species and collembolans with bigger body size, which apparently found more suitable habitat or resource availability in mixtures than in single Agrostis litters. Mixed litters also favored higher fungal biomass, and P and phenolics concentrations, in relation to single litters. Yet, land management and litter mixtures did not explain litter mass loss. Decay rates were higher in Agrostis than in Quercus litter, due to the differences in the initial litter traits (lignin, phenolics and P contents). Particularly, litter mass loss was positively related to P concentration and negatively associated to the concentration of phenolics. [ABSTRACT FROM AUTHOR]

• Different cropping systems influence differently soil fauna communities. • Herbicide in no-tillage system affected only collembolans but they recovered. • Mites did not fully recover from insecticide especially in tillage treatments. • Collembola were generally more resilient to insecticide than mites. • Enchytraeids were the least sensitive to the soil managements tested. Different soil management in crop cultures like maize can produce a variety of effects on soil fauna. Conventional cropping includes soil tillage, promoting organic matter losses and destruction of soil structure, whereas no-tillage cropping includes a herbicide application which can potentially affect soil fauna. In both management systems, insecticides are often used, such as pyrethroid insecticides, to prevent insect pests. Understanding the impact of these different cropping systems in their different phases on soil mesofauna and investigating the ability of soil communities to recover may provide important information to select cropping strategies which are more protective of soil biodiversity. With this aim, a terrestrial model ecosystem experiment was performed over eighty-nine days. The test treatments, all including maize, were: undisturbed soil; conventional tillage; conventional tillage with insecticide; no-tillage soil with herbicide; no-tillage soil with herbicide and insecticide. In each TME, soil samples from 0 to 5 and 5–10 cm of the top layer were collected from which collembolans and mites were identified to species, genus or subfamily level, and enchytraeid abundance was determined. Soil tillage did not affect soil communities, but insecticide application did. For collembolans and enchytraeids, the impact of the insecticide was independent of soil management, but for mites, insecticide impact was longer in conventional tillage than in no-tillage system. Changes on collembolan abundance, in general, did not promote changes in mean community trait values and functional diversity. Data suggest that no-tillage management is more protective to soil fauna than conventional tillage. [ABSTRACT FROM AUTHOR]

Here we build on the manifesto 'World Scientists' Warning to Humanity, issued by the Alliance of World Scientists. As a group of conservation biologists deeply concerned about the decline of insect populations, we here review what we know about the drivers of insect extinctions, their consequences, and how extinctions can negatively impact humanity. We are causing insect extinctions by driving habitat loss, degradation, and fragmentation, use of polluting and harmful substances, the spread of invasive species, global climate change, direct overexploitation, and co-extinction of species dependent on other species. With insect extinctions, we lose much more than species. We lose abundance and biomass of insects, diversity across space and time with consequent homogenization, large parts of the tree of life, unique ecological functions and traits, and fundamental parts of extensive networks of biotic interactions. Such losses lead to the decline of key ecosystem services on which humanity depends. From pollination and decomposition, to being resources for new medicines, habitat quality indication and many others, insects provide essential and irreplaceable services. We appeal for urgent action to close key knowledge gaps and curb insect extinctions. An investment in research programs that generate local, regional and global strategies that counter this trend is essential. Solutions are available and implementable, but urgent action is needed now to match our intentions. • We are pushing many ecosystems beyond recovery, resulting in insect extinctions. • Causes are habitat loss, pollution, invasives, climate change, and overexploitation. • We lose biomass, diversity, unique histories, functions, and interaction networks. • Insect declines lead to loss of essential, irreplaceable services to humanity. • Action to save insect species is urgent, for both ecosystems and human survival. [ABSTRACT FROM AUTHOR]

The fate of humans and insects intertwine, especially through the medium of plants. Global environmental change, including land transformation and contamination, is causing concerning insect diversity loss, articulated in the companion review Scientists ' warning to humanity on insect extinctions. Yet, despite a sound philosophical foundation, recognized ethical values, and scientific evidence, globally we are performing poorly at instigating effective insect conservation. As insects are a major component of the tapestry of life, insect conservation would do well to integrate better with overall biodiversity conservation and climate change mitigation. This also involves popularizing insects, especially through use of iconic species, through more media coverage, and more inclusive education. Insect conservationists need to liaise better with decision makers, stakeholders, and land managers, especially at the conceptually familiar scale of the landscape. Enough evidence is now available, and synthesized here, which illustrates that multiple strategies work at local levels towards saving insects. We now need to expand these locally-crafted strategies globally. Tangible actions include ensuring maintenance of biotic complexity, especially through improving temporal and spatial heterogeneity, functional connectivity, and metapopulation dynamics, while maintaining unique habitats, across landscape mosaics, as well as instigating better communication. Key is to have more expansive sustainable agriculture and forestry, improved regulation and prevention of environmental risks, and greater recognition of protected areas alongside agro-ecology in novel landscapes. Future-proofing insect diversity is now critical, with the benefits far reaching, including continued provision of valuable ecosystem services and the conservation of a rich and impressive component of Earth's biodiversity. • Human and insect well-being intertwine. • Philosophical, psychological, and scientific basis of insect conservation is robust. • Solutions are available for averting further insect decline. • Effective localized principles and solutions must now be actioned globally. • Engaging civil society on the value of insects for human well-being is urgent. [ABSTRACT FROM AUTHOR]