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Despite the perception that plant science focuses on strictly scientific criteria, this analysis finds that there is an aesthetic bias in regards to which plants, based on certain traits, receive more research attention. Scientists' research interests are often skewed toward charismatic organisms, but quantifying research biases is challenging. By combining bibliometric data with trait-based approaches and using a well-studied alpine flora as a case study, we demonstrate that morphological and colour traits, as well as range size, have significantly more impact on species choice for wild flowering plants than traits related to ecology and rarity. These biases should be taken into account to inform more objective plant conservation efforts.

Many believe that the quality of a scientific publication is as good as the science it cites. However, quantifications of how features of reference lists affect citations remain sparse. We examined seven numerical characteristics of reference lists of 50,878 research articles published in 17 ecological journals between 1997 and 2017. Over this period, significant changes occurred in reference lists’ features. On average, more recent papers have longer reference lists and cite more high Impact Factor papers and fewer non-journal publications. We also show that highly cited articles across the ecological literature have longer reference lists, cite more recent and impactful references, and include more self-citations. Conversely, the proportion of ‘classic’ papers and non-journal publications cited, as well as the temporal span of the reference list, have no significant influence on articles’ citations. From this analysis, we distill a recipe for crafting impactful reference lists, at least in ecology.

In an environment where the impact of research is central, scientists face the dilemma of choosing between orthodox writing for objectivity and sensational writing to provoke interest. The use of superlatives in high-ranking ecology journals has increased significantly in recent years, a writing behavior that works against scientific objectivity.

Global inland water biodiversity is under mounting stress facing future scenarios of climate change, biological invasions, pollution, diversion, damming of rivers, and increase of water abstractions. Apart from having isolated effects, all these stressors threats act synergistically and thus pose additional emerging threats to biodiversity and ecosystem services. Native to Northern Europe, the nuisance and potential toxic dinoflagellate Ceratium furcoides (Levander) Langhans 1925 is a silent invader that blooms in freshwater systems; it has one of the most rapid spread rates globally. We propose a framework to determine the worldwide most vulnerable areas for the invasion by C. furcoides shortly (2041-2060) by combining future scenarios of climate change (a proxy for invasiveness) derived from ecological niche models with future dam construction data (a proxy for invasibility). The nine models applied in four future scenarios of greenhouse gas emission from Coupled Model Intercomparison Project Phase 6 showed a general increase in areas suitable for the invasion success of C. furcoides. High susceptibility overlapped with areas densely occupied by large and medium-size dams and future dam construction projects. Considering that C. furcoides can reproduce from a single cell, produces resistant stages, and has several strategies to cope with local environmental constraints, early detection protocols, and mitigation actions are urgently needed to avoid biodiversity declines related to this invader.

Conservation planning aimed at halting biodiversity loss has seldom focused on groundwater environments due to the lack of suitable management tools and data. Using harpacticoid crustaceans as a test case, we explore the potential of implementing an approach based on Conservation-Relevant Hotspots for practical conservation of groundwater biodiversity. Conservation-Relevant Hotspots are identified by intersecting species richness, endemicity, and taxonomic distinctness with the aim to minimize the total area to protect. We show that, by targeting five Conservation-Relevant Hotspots that cover only 1.9% of the European land surface, one would protect as much as 44% of the harpacticoid crustacean richness, 93% of its endemicity, and 98% of its taxonomic distinctness. About 28% of the area occupied by these hotspots overlaps with protected areas, which calls for an increase in their protection coverage. Our framework proved a useful tool for conservation planning of environments where spatial or socio-economic constraints occur.

Measuring commonness and rarity is pivotal to ecology and conservation. Zeta diversity, the average number of species shared by multiple sets of assemblages, and Dark diversity, the number of species that could occur in an assemblage but are missing, have been recently proposed to capture two aspects of the commonness‐rarity spectrum. Despite a shared focus on commonness and rarity, thus far, Zeta and Dark diversities have been assessed separately. Here, we review these two frameworks and suggest their integration into a unified paradigm of the “rarity facets of biodiversity.” This can be achieved by partitioning Alpha and Beta diversities into five components (the Zeta, Eta, Theta, Iota, and Kappa rarity facets) defined based on the commonness and rarity of species. Each facet is assessed in traditional and multiassemblage fashions to bridge conceptual differences between Dark diversity and Zeta diversity. We discuss applications of the rarity facets including comparing the taxonomic, functional, and phylogenetic diversity of rare and common species, or measuring species' prevalence in different facets as a metric of species rarity. The rarity facets integrate two emergent paradigms in biodiversity science to better understand the ecology of commonness and rarity, an important endeavor in a time of widespread changes in biodiversity across the Earth., Despite a shared focus on commonness and rarity, Zeta diversity (average number of species shared by multiple sets of assemblages) and Dark diversity (species that could occur in an assemblage but are missing) have been thus far separate paradigms. We suggest integrating them into a unified framework of the “rarity facets of biodiversity” that integrate two emergent paradigms in biodiversity science to better understand the ecology of commonness and rarity. This is an important endeavor in a time of widespread changes in biodiversity across the Earth.

International audience; Scientists of different disciplines have recognized the valuable role of terrestrial caves as ideal natural laboratories in which to study multiple eco-evolutionary processes, from genes to ecosystems. Because caves and other subterranean habitats are semi-closed systems characterized by a remarkable thermal stability, they should also represent insightful systems for understanding the effects of climate change on biodiversity in situ. Whilst a number of recent advances have demonstrated how promising this fast-moving field of research could be, a lack of synthesis is possibly holding back the adoption of caves as standard models for the study of the recent climatic alteration. By linking literature focusing on physics, geology, biology and ecology, we illustrate the rationale supporting the use of subterranean habitats as laboratories for studies of global change biology. We initially discuss the direct relationship between external and internal temperature, the stability of the subterranean climate and the dynamics of its alteration in an anthropogenic climate change perspective. Owing to their evolution in a stable environment, subterranean species are expected to exhibit low tolerance to climatic perturbations and could theoretically cope with such changes only by shifting their distributional range or by adapting to the new environmental conditions. However, they should have more obstacles to overcome than surface species in such shifts, and therefore could be more prone to local extinction. In the face of rapid climate change, subterranean habitats can be seen as refugia for some surface species, but at the same time they may turn into dead-end traps for some of their current obligate inhabitants. Together with other species living in confined habitats, we argue that subterranean species are particularly sensitive to climate change, and we stress the urgent need for future research, monitoring programs and conservation measures.

Jargon is the specialised vocabulary of any science: it allows the creation of new terms to define concepts and it removes ambiguity from scientific communication. Yet, it may also hinder understanding for a broader audience. Given that the Journal of Limnology has jargon in its title, we here investigate the impact of the term ‘limnology’ on the way limnologists work, publish their research, and attract the interest of other scientists. We do so by comparing scientometric features of papers published from 1965 to 2020 that used the term ‘limnology’ against papers on similar topics but that used the term ‘lake ecology’ or ‘hydrobiology’, and to the marine counterpart of papers that used the term ‘oceanography’. We found that papers using the term limnology score worse than those of the other topics in terms of both publication output and scientific impact. Limnologists may need to use other terms in addition to ‘limnology’ to reach a broader scientific audience.

Aim Historically, research on global distribution patterns has mostly concentrated on conspicuous organisms and thus a large proportion of biodiversity on Earth remains unmapped. We examined the global distribution of palpigrades, a poorly studied group of low dispersive arachnids specialized to subterranean life. We asked what is their typical range size, the ecological factors driving their distributions, and to what extent sampling bias may influence the observed patterns. Location Global. Taxon Palpigrades (Arachnida: Palpigradi) in the genus Eukoenenia. Methods We assembled a database of over 1000 localities and referring to 57 soil- and 69 cave-adapted palpigrades. We tested for differences in range sizes of soil- and cave-adapted species. We used variance partitioning analysis to explore the contribution of climate, nutrient availability and geology in driving observed distributions. Finally, we verified the potential correlation between the number of occurrence records and the number of palpigrades' researchers. Results Europe and Brazil emerged as centres of diversification of cave-adapted palpigrades. Conversely, the diversity of soil-adapted species was distributed over a broader geographical expanse, mainly in the Southern Hemisphere. Both cave and soil species had narrow distribution ranges, with a median value of 0.01 km(2); only a few parthenogenetic species were distributed over multiple continents. The distribution of cave- and soil-adapted palpigrades was primarily explained by climatic conditions, and secondarily by nutrient and habitat availability. In the Alps, the distribution of cave-adapted species also bears the signature of historical events related to glaciation cycles. We observed, however, a pronounced people-species correlation, suggesting that the observed patterns are not generalizable to poorly explored areas. Main conclusions Our study highlights enormous gaps in current knowledge about the biogeography of palpigrades. Even if the information is largely incomplete and biased, we show how data can be harnesses to draw a preliminary picture of the global distribution patterns of palpigrades. Thus, we offer a jumping-off point for future studies on the macroecology and conservation of poorly known organisms.

Understanding the variation in community composition and species abundances, i.e., β-diversity, is at the heart of community ecology. A common approach to examine β-diversity is to evaluate directional turnover in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distances. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 149 datasets comprising different types of organisms and environments. We modelled an exponential distance decay for each dataset using generalized linear models and extracted r2 and slope to analyse the strength and the rate of the decay. We studied whether taxonomic or functional similarity has stronger decay across the spatial and environmental distances. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm, and organismal features. Taxonomic distance decay was stronger along spatial and environmental distances compared with functional distance decay. The rate of taxonomic spatial distance decay was the fastest in the datasets from mid-latitudes while the rate of functional decay increased with latitude. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distances but a higher rate of decay along environmental distances. Marine ecosystems had the slowest rate of decay. This synthesis is an important step towards a more holistic understanding of patterns and drivers of taxonomic and functional β-diversity.

We investigated the ecological requirements in the emergence phase of two congeneric species of Aeshnidae, Aeshna grandis (Linnaeus 1758) and A. juncea (Linnaeus 1758), occurring in syntopy at the southernmost limit of their range. We sampled the exuviae of the two species at the peak of their emergence in three lakes in NW Italy. In each lake we defined 30 to 50 sampling plots along the lake borders where we checked for the presence of exuviae and collected data on the microhabitat composition. By modeling the response of the exuviae presence and abundance against the environmental parameters, we could highlight a partial differentiation in the ecological requirements of the two species at emergence. In particular, A. grandis is more influenced by the structure of the aquatic vegetation than A. juncea and the niche space occupied by A. grandis is wider, almost totally encompassing the one of A. juncea. We argue that A. grandis exploits microhabitats rich in aquatic plants to avoid competition with A. juncea. We suggest the preservation of well-structured aquatic vegetation as a key management practice to preserve the three studied populations of A. grandis, a species which has been recognized as Vulnerable for Italy according to the IUCN criteria.

Words are the building blocks of communicating science. As our understanding of the world progresses, scientific disciplines naturally enrich their specialized vocabulary (jargon). However, in the era of interdisciplinarity, the use of jargon may hinder effective communication among scientists that do not share a common scientific background. The question of how jargon limits the transmission of scientific knowledge has long been debated but rarely addressed quantitatively. We explored the relationship between the use of jargon and citations, using 21 486 articles focusing on cave research, a multidisciplinary field particularly prone to terminological specialization, and where linguistic disagreement among peers is frequent. We demonstrate a significant negative relationship between the proportion of jargon words in the title and abstract and the number of citations a paper receives. Given that these elements are the hook to readers, we urge scientists to restrict jargon to sections of the paper where its use is unavoidable.

International audience; Despite their ecological importance and diversity, spiders (Arachnida: Araneae) are underrepresented in conservation policies in comparison to other groups. We review all extant conservation tools focusing on spiders in Europe, highlighting general patterns, limitations, gaps, and future directions. We assembled a comprehensive online database reporting all available information concerning the legal protection and conservation status of 4,154 spider species. Existing international legislation has limited coverage, with only one species listed in the Bern Convention and EU Habitats Directive. At the national and subnational levels, 178 species are formally mentioned in the legislation of 19 European countries. Moreover, the International Union for Conservation of Nature (IUCN) includes assessments for 301 species worldwide, 164 of these threatened and eight native to Europe. In addition, spiders are mentioned in Regional Red Lists and Red Books in 28 out of 42 European countries considered in this review. Northern and Central European countries have the highest percentage of species assessed at the regional level in Red Lists and Red Books. The Mediterranean basin has the highest spider diversities in Europe but conservation efforts are lacking, both in terms of assessments and national or subnational legislation. Among European species, Dolomedes plantarius, Argyroneta aquatica and Eresus kollari are the most frequently mentioned in European conservation measures, possibly due to their ecological traits and their strict association with declining habitats. Considering the current threats to spiders in Europe, the protection of large areas of suitable habitat should be considered as the most effective approach to spider conservation.

Seagrasses play a vital role in structuring coastal marine ecosystems, but their distributional range and genetic diversity have declined rapidly in recent decades. To improve conservation of seagrass species, it is important to predict how climate change may impact their ranges. Such predictions are typically made with correlative species distribution models (SDMs), which can estimate a species' potential distribution under present and future climatic scenarios given species' presence data and climatic predictor variables. However, these models are typically constructed with species-level data, and thus ignore intraspecific genetic variability, which can give rise to populations with adaptations to heterogeneous climatic conditions. Here, we explore the link between intraspecific adaptation and niche differentiation in Thalassia hemprichii, a seagrass broadly distributed in the tropical Indo-Pacific Ocean and a crucial provider of habitat for numerous marine species. By retrieving and re-analysing microsatellite data from previous studies, we delimited two distinct phylogeographical lineages within the nominal species and found an intermediate level of differentiation in their multidimensional environmental niches, suggesting the possibility for local adaptation. We then compared projections of the species' habitat suitability under climate change scenarios using species-level and lineage-level SDMs. In the Central Tropical Indo-Pacific region, models for both levels predicted considerable range contraction in the future, but the lineage-level models predicted more severe habitat loss. Importantly, the two modelling approaches predicted opposite patterns of habitat change in the Western Tropical Indo-Pacific region. Our results highlight the necessity of conserving distinct populations and genetic pools to avoid regional extinction due to climate change and have important implications for guiding future management of seagrasses. National Natural Science Foundation of China, Grant/Award Number: 31971395 and 41761144057; European Commission, Grant/ Award Number: H2020-MSCA-IF-2019 and 882221; Foundation for Science and Technology (FCT), Grant/Award Number: UID/Multi/04326/2019, PTDC/BIA-CBI/6515/2020 and DL57; Thailand Research Fund, Grant/Award Number: RDG6130002; Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research, Grant/ Award Number: 18K05780 info:eu-repo/semantics/submittedVersion

We are starting to appreciate that microscopic animals are not as widespread as previously thought, but we still ignore to what extent and through which mechanisms the environment selects for specific communities or traits in microscopic animals. We here analyse the functional diversity of marine mite communities living in a seagrass meadow across two habitats: the leaves and the matte. The strictly benthic lifestyle and the conserved morphology of mites allow for unambiguous characterisation of their functional traits, while the discrete nature of the two habitats alleviates the uncertainty in their ecological characterisation. Our results show that habitat filters the distribution of certain traits favouring a higher diversity, dispersion, and evenness of functional traits in the matte than in the leaves. We further observed temporal variations in the functional diversity of communities, following the changes in biomass and structure of seagrass leaves. However, despite the stark differences between the two habitats, the filtering effect is partial and affects mostly relative species abundances. Our study emphasises the need of moving from a taxonomical towards a functional view of ecological studies of microscopic organisms. This integrative approach is key to achieve a mechanistic understanding of their habitat and distribution patterns. SM was supported by the CAWEB project “Testing macroecological theory using simplified systems”, funded by the European Commission through Horizon 2020 Marie Skłodowska-Curie Actions (MSCA) individual fellowships (Grant no. 882221). GGG was supported by an Erasmus + mobility fellowship, OLS ID 641798. NS was funded by the Research Talent Attraction Program (Regional Government of Madrid and University Complutense of Madrid) (2019-T2/AMB-13328).

International audience; Aim Species distribution models (SDMs) have emerged as essential tools in the equipment of many ecologists, useful to explore species distributions in space and time and answering an assortment of questions related to biogeography, climate change biology and conservation biology. Historically, most SDM research concentrated on well-known organisms, especially vertebrates. In recent years, these tools are becoming increasingly important for predicting the distribution of understudied invertebrate taxa. Here, we reviewed the literature published on main terrestrial arthropod predators (ants, ground beetles and spiders) to explore some of the challenges and opportunities of species distribution modelling in mega-diverse arthropod groups. Location Global. Methods Systematic mapping of the literature and bibliometric analysis. Results Most SDM studies of animals to date have focused either on broad samples of vertebrates or on arthropod species that are charismatic (e.g. butterflies) or economically important (e.g. vectors of disease, crop pests and pollinators). We show that the use of SDMs to map the geography of terrestrial arthropod predators is a nascent phenomenon, with a near-exponential growth in the number of studies over the past ten years and still limited collaborative networks among researchers. There is a bias in studies towards charismatic species and geographical areas that hold lower levels of diversity but greater availability of data, such as Europe and North America. Conclusions Arthropods pose particular modelling challenges that add to the ones already present for vertebrates, but they should also offer opportunities for future SDM research as data and new methods are made available. To overcome data limitations, we illustrate the potential of modern data sources and new modelling approaches. We discuss areas of research where SDMs may be combined with dispersal models and increasingly available phylogenetic and functional data to understand evolutionary changes in ranges and range-limiting traits over past and contemporary time-scales.

1. The use of functional diversity analyses in ecology has grown exponentially over the past two decades, broadening our understanding of biological diversity and its change across space and time. Virtually all ecological sub-disciplines recognise the critical value of looking at species and communities from a functional perspective, and this has led to a proliferation of methods for estimating contrasting dimensions of functional diversity.\ud \ud \ud \ud 2. Differences between these methods and their development generated terminological inconsistencies and confusion about the selection of the most appropriate approach for addressing any particular ecological question, hampering the potential for comparative studies, simulation exercises and meta-analyses.\ud \ud \ud \ud 3. Two general mathematical frameworks for estimating functional diversity are prevailing: those based on dissimilarity matrices (e.g. Rao entropy, functional dendrograms) and those relying on multidimensional spaces, constructed as either convex hulls or probabilistic hypervolumes.\ud \ud \ud \ud 4. We review these frameworks, discuss their strengths and weaknesses and provide an overview of the main R packages performing these calculations. In parallel, we propose a way for organising functional diversity metrics in a unified scheme to quantify the richness, divergence and regularity of species or individuals under each framework. This overview offers a roadmap for confidently approaching functional diversity analyses both theoretically and practically.

Ecological systems are the quintessential complex systems, involving numerous high-order interactions and non-linear relationships. The most used statistical modeling techniques can hardly accommodate the complexity of ecological patterns and processes. Finding hidden relationships in complex data is now possible using massive computational power, particularly by means of artificial intelligence and machine learning methods. Here we explored the potential of symbolic regression (SR), commonly used in other areas, in the field of ecology. Symbolic regression searches for both the formal structure of equations and the fitting parameters simultaneously, hence providing the required flexibility to characterize complex ecological systems. Although the method here presented is automated, it is part of a collaborative human–machine effort and we demonstrate ways to do it. First, we test the robustness of SR to extreme levels of noise when searching for the species-area relationship. Second, we demonstrate how SR can model species richness and spatial distributions. Third, we illustrate how SR can be used to find general models in ecology, namely new formulas for species richness estimators and the general dynamic model of oceanic island biogeography. We propose that evolving free-form equations purely from data, often without prior human inference or hypotheses, may represent a very powerful tool for ecologists and biogeographers to become aware of hidden relationships and suggest general theoretical models and principles. PC and VB were supported by Kone Foundation. PB and FR were partly funded by the project FCT-PTDC/BIABIC/119255/2010 - Biodiversity on oceanic islands: toward a unified theory. LC was supported by FCT through LASIGE Research Unit, ref. UIDB, UIDP/00408/2020. SM acknowledges support from the European Commission through Horizon 2020 Marie Sklodowska-Curie Actions (MSCA) individual fellowships (Grant no. 882221). info:eu-repo/semantics/publishedVersion

Spiders are able to arouse strong emotional reactions in humans. While spider bites are statistically rare events, our perception is skewed towards the potential harm spiders can cause to humans. Nevertheless, there is still limited understanding of the role of the media in spreading (mis)information about them thereby promoting this distorted perception of risk. We examined the human dimension of spiders through the lens of traditional media, by analysing spider‐related news published online in Italian newspapers between 2010 and 2020 (n = 314). We assessed the accuracy, circulation and sensationalistic content of each article, and assessed how each of these features drove news' share on social media. We observed a recent, exponential increase in the frequency of the news, particularly those focused on medically important spiders—the Mediterranean black widow Latrodectus tredecimguttatus and the Mediterranean recluse Loxosceles rufescens. The news quality was generally poor: 70% contained different types of error, 32% were sensationalistic, and in virtually none was an expert consulted. The risk scenario depicted by the media reports was unnecessarily alarmist, especially with regard to L. rufescens. A conservative estimate would suggest that less than 10% of the bites reported in the media reports analysed here were delivered by the species described in the report. Moreover, two out of three casualties associated with a bite of the Mediterranean recluse were fake news, while the third was unverifiable. Overstated news referring to spider bites was shared significantly more on social media, thus contributing to frame a distorted perception of the risk. This is important given that these negative sentiments may ultimately lead to lowering public tolerance towards spiders and reducing conservation efforts towards them. We discuss open questions and avenues for future research concerning the media coverage of widely feared animals, that will help bridge knowledge gaps regarding the role of traditional and social media in framing our perception of the natural world. A free Plain Language Summary can be found within the Supporting Information of this article.

Through the Habitats Directive (92/43/EEC) and the financial investmentsof the LIFE projects, Europe has become an experimental arena for biologicalconservation. With an estimated annual budget ofEUR20 billion, the EU Biodi-versity Strategy for 2030 has set an ambitious goal of classifying 30% of itsland and sea territory as Protected Areas and ensuring no deterioration inconservation trends and the status of protected species. We analysed LIFEprojects focused on animals from 1992 to 2018 and found that investmentin vertebrates was six times higher than that for invertebrates (EUR970 versusEUR150 million), with birds and mammals alone accounting for 72% of speciesand 75% of the total budget. In relative terms, investment per speciestowards vertebrates has been 468 times higher than that for invertebrates.Using a trait-based approach, we show that conservation effort is primarilyexplained by species'popularity rather than extinction risk or body size.Therefore, we propose a roadmap to achieve unbiased conservation targetsfor 2030 and beyond.1. IntroductionOverwhelming evidence exists that most Earth ecosystem processes are beingaltered by human activities, suggesting that we may have entered a human-dominated geological epoch--the'Anthropocene'[1]. It is largely accepted thathumans are causing the sixth mass species extinction [2], which can be considereda clarion call to increase global efforts to study, halt, and possibly reverse theongoing negative environmental trends. Europe is no exception, given that it hasa long experience of human disturbance and consequent biodiversity loss [3]. Atthe same time, since the Habitats Directive (92/43/EEC) was established in 1992,the European Union (EU) has acted as a global test case for practical conservationand restoration of natural habitats and their wild flora and fauna.Although the Habitats Directive and the parallel financial investment on LIFEprojects--the EU flagship funding instrument for the environment and climate© 2020 The Authors. Published by the Royal Society under the terms of the Creative Commons AttributionLicense http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the originalauthor and source are credited.

We studied the ecology, distribution, and phylogeography of Tephroseris balbisiana, a rare plant whose range is centered to the South-Western Alps. Our aim was to assess the extent of intraspecific variability within the nominal species and the conservation status of isolated populations. We studied genetic diversity across the whole species range. We analyzed leaf traits, which are distinctive morphological characters within the Tephroseris genus. A clear pattern of genetic variation was found among populations of T. balbisiana, which clustered according to their geographic position. On the contrary, there was a strong overlap in the morphological space of individuals across the species&rsquo, range, with few peripheral populations diverging in their leaf morphology. Studying habitat suitability by means of species distribution models, we observed that T. balbisiana range is primarily explained by solar radiation and precipitation seasonality. Environmental requirements could explain the genetic and morphological uniformity of T. balbisiana in its core distribution area and justify genetic, morphological, and ecological divergences found among the isolated populations of the Apennines. Our findings emphasize the need to account for the whole diversity of a species, comprising peripheral populations, in order to better estimate its status and to prioritize areas for its conservation.

Data supporting this study and R code to generate graphs and analyses are available in the Dryad Digital Repository: https://dx.doi.org/10.5061/dryad.1rn8pk0s0 [54]., Electronic supplementary material is available online at https://doi.org/10.6084/m9.figshare. c.5217460., Through the Habitats Directive (92/43/EEC) and the financial investments of the LIFE projects, Europe has become an experimental arena for biological conservation. With an estimated annual budget of €20 billion, the EU Biodi versity Strategy for 2030 has set an ambitious goal of classifying 30% of its land and sea territory as Protected Areas and ensuring no deterioration in conservation trends and the status of protected species. We analysed LIFE projects focused on animals from 1992 to 2018 and found that investment in vertebrates was six times higher than that for invertebrates (€970 versus €150 million), with birds and mammals alone accounting for 72% of species and 75% of the total budget. In relative terms, investment per species towards vertebrates has been 468 times higher than that for invertebrates. Using a trait-based approach, we show that conservation effort is primarily explained by species’ popularity rather than extinction risk or body size. Therefore, we propose a roadmap to achieve unbiased conservation targets for 2030 and beyond, R.C. is funded by the Helsinki Institute of Sustainability Science (HELSUS) and the University of Helsinki. S.M. is supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 882221.

Being characterized by the absence of light and a reduced environmental cyclicity, the subterranean domain is generally regarded as temporally stable. Yet, in the proximity of cave entrances (twilight zones), patterns of sunlight and darkness can be detected within the 24-hour day–night cycle. In parallel, changes in the abiotic and biotic conditions are expected; however, these patterns have been rarely explored in animal communities dwelling in the twilight zone. We performed a biological investigation in a small abandoned mine in the Western Alps, monitoring it once per season, both during the day and at night. At each survey, we collected data on the spatial distribution of the resident species, their activity patterns, and the main microclimatic parameters. We observed significant daily variations in the environmental conditions during winter and spring, namely higher temperature, relative humidity and availability of trophic resources at night. In conjunction with these disparate nocturnal conditions, the abundance of troglophile species was also higher, as well as the activity patterns of one of the most frequent species inhabiting the entrance area – the orb-weaver spiderMetamenardi. We further documented temporal changes in the composition of the parietal community, due to species using the mine as a diurnal, nocturnal or overwintering shelter. Overall, our results suggest that the communities of the twilight zone are not temporally stable and we highlight the importance of taking into account not only their seasonal, but also their daily variations.

We studied the ecological continuum between caves and the associated network of fissures – Milieu Souterrain Superficiel (MSS) – in an hypogean site in the Graian Alps, Italy. Over one year, we surveyed the faunal assemblages by means of pitfall traps placed in the caves and specific subterranean sampling devices (SSD) buried in the MSS. We used generalized linear mixed models (GLMMs) and generalized additive mixed models (GAMMs) to compare the spatial and temporal dynamics of the subterranean invertebrates inhabiting the two environments. As expected, arthropod communities occurring near the surface were characterized by minor level of subterranean adaptations, and conversely, subterranean species were more abundant and diversified at higher depths, both in the caves and in the MSS. Diversity and abundance of external elements in the superficial layers were found to be highly seasonal dependent, with minor values in winter compared to the other seasons. We provided information about the faunal assemblages dwelling in the two hypogean compartments, and we characterized the microclimatic conditions therein. We discussed the existence of an ecological gradient of specialization extending from the surface to the deep hypogean layers, which can be interpreted in light of the microclimatic changes occurring at increasing depths and the parallel decrease in available organic matter.

The threshold zones between the epigean and hypogean environments are generally characterized by less harsh ecological conditions than deep subterranean habitats, and usually support a greater abundance of organisms. Transitional habitats such as these should be more easily colonised by alien species, especially by those possessing exaptations suitable for subterranean life. In spite of this, few studies have been conducted to unravel the ecological dynamics between native and alien species in the habitats situated at the epigean/hypogean interface. A unique test case is offered by cave-dwelling Meta orb-weaver spiders in Great Britain (Araneae: Tetragnathidae). One species, M. menardi, is a widespread native, whilst M. bourneti is believed to be a recently introduced (1940s) species, that has since become established in the south-eastern part of the country. Species distribution models (SDM) were used to predict current and future habitat suitability for the two species, generating hypotheses regarding their distribution in different global warming scenarios. Model projections indicate that the two species respond to similar environmental variables. Seasonal temperature variations at the surface and elevation are the main factors explaining the distribution of both species, whereas annual precipitation, daily temperature range and limestone distribution contributed little to the model performance. It is predicted that due to climate change, there will be poleward shifts in the ranges of both species. However, the native species M. menardi will primarily be able to exploit suitable areas which will appear northward to their current distribution, and M. bourneti will colonise empty niches left available by its congeneric. The analytical framework employed in this paper may be easily adapted to other subterranean systems and species, stimulating future studies focusing on the distribution of native and alien species in extreme environments.

Subterranean ecosystems present ideal opportunities to study mechanisms underlying responses to changes in climate because species within them are often adapted to a largely constant temperature. We have characterized the thermal conditions of caves in the Western Alps, and relate these hypogean climate data to the occurrence of Troglohyphantes troglobiontic spiders (Araneae, Linyphiidae). Our data indicate that present distributions reflect Pleistocence glaciation events and also point to specific responses as a consequence of changes in temperature. Constant temperatures recorded inside caves provide an approximation of the mean annual temperature outside, thus we extend the results to a regional scale. Ecological niche modeling is used to predict habitat suitability both in the Pleistocene and under future global warming scenarios. These analyses point toward a future decline in habitat suitability for subterranean spiders and the potential extinction of the most restricted endemic species.

It is said that the quality of a scientific publication is as good as the science it cites, but the properties of high-quality reference lists have never been numerically quantified. We examined seven numerical characteristics of reference lists of 50,878 primary research articles published in 17 ecological journals between 1997 and 2017. Over this 20-years period, there have been significant changes in reference lists’ properties. On average, more recent ecological papers have longer reference lists, cite more high Impact Factor papers, and fewer non-journal publications. Furthermore, we show that highly cited papers across the ecology literature have longer reference lists, cite more recent and impactful papers, and account for more self-citations. Conversely, the proportion of ‘classic’ papers and non-journal publications cited, as well as the temporal range of the reference list, have no significant influence on articles’ citations. From this analysis, we distill a recipe for crafting impactful reference lists.

The Internet and social media have profoundly changed the way the public receives and transmits news. The ability of the web to quickly disperse information both geographically and temporally allows social media to reach a much wider audience compared to traditional mass media. A powerful role is played by sharing, as millions of people routinely share news on social media platforms, influencing each other by transmitting their mood and feelings to others through emotional contagion. Thus, social media has become crucial in driving public perception and opinion. Humans have an instinctive fear of large carnivores, but such a negative attitude may be amplified by news media presentations and their diffusion on social media. Here, we investigated how reports of predator attacks on humans published in online newspapers spread on social media. By means of multi-model inference, we explored the contribution of four factors in driving the number of total shares (NTS) of news reports on social media: the graphic/sensationalistic content, the presence of images, the species, as well as the newspaper coverage. According to our results, the information delivered by social media is highly biased toward a graphic/sensationalistic view of predators. Thus, such negative coverage might lead to an unjustified and amplified fear in the public with consequent lower tolerance toward predators and decrease in the support for conservation plans. However, because social media represents a powerful communication tool, its role might be reversed to positive if used appropriately. Thus, constant engagement of scientists on social media would be needed to both disseminate more accurate information on large carnivores and stem the tide of misinformation before its widespread diffusion, a crucial step for effective predator conservation., VP was financially supported by the Excellence Project CGL2017-82782-P financed by the Spanish Ministry of Science, Innovation and Universities, the Agencia Estatal de Investigación (AEI) and the Fondo Europeo de Desarrollo Regional (FEDER, EU). VP was also funded by a GRUPIN research grant from the Regional Government of Asturias (Ref.: IDI/2018/000151). GB was financially supported by a collaboration contract with the MUSE–Museo delle Scienze of Trento (Italy).

SummaryThe use of n-dimensional hypervolumes in trait-based ecology is rapidly increasing. By representing the functional space of a species or community as a Hutchinsonian niche, the abstract Euclidean space defined by a set of independent axes corresponding to individuals or species traits, these multidimensional techniques show great potential for the advance of functional ecology theory.In the panorama of existing methods for delineating multidimensional spaces, the R package hypervolume [Glob. Ecol. Biogeogr. (2014) 23:595–609] is currently the most used. However, functions for calculating the standard set of functional diversity (FD) indices—richness, divergence, and regularity—have not been developed within the hypervolume framework yet. This gap is delaying its full exploitation in functional ecology, meanwhile preventing the possibility to compare its performance with that of other methods.We develop a set of functions to calculate FD indices based on n-dimensional hypervolumes, including alpha (richness), beta (and respective components), dispersion, evenness, contribution, and originality. Altogether, these indices provide a coherent framework to explore the primary mathematical components of FD within a multidimensional setting. These new functions can work either with hypervolume objects or raw data (species presence or abundance and their traits) as input data, and are versatile in terms of input parameters and options.These functions are implemented within BAT (Biodiversity Assessment Tools), an R package for biodiversity assessments. As a coherent corpus of functional indices based on a common algorithm, it opens the possibility to fully explore the strengths of the Hutchinsonian niche concept in community ecology research.

Invasive alien species represent a serious threat to global biodiversity, causing considerable damage to native ecosystems. To better assess invasion risks, it is essential to better understand the biological processes that determine the success or failure of invasions. The catadromous Chinese mitten crab Eriocheir sinensis, whose native distribution is the Pacific Coast of China and Korea, has successfully invaded and established populations in North America and Europe. In Japan, where E. sinensis is also regarded as potentially invasive and multiple introduction vectors exist, the species is not yet established. These settings can be used to explore niche-based processes underlying the apparent failure of a biological invasion. We first quantified native and invasive realized niches of E. sinensis in freshwater habitats using geometrical n-dimensional hypervolumes. Based on the assumption of niche conservatism, we then projected habitat suitability of this species in Japan using species distribution models (SDMs) calibrated with distinct sets of distribution data: native occurrences, invasive occurrences, and both. Results showed that E. sinensis has undergone either niche shifts or niche contractions during invasions in different areas of the world. Projections from SDMs indicate that although part of Japan is suitable for E. sinensis, this does not include the freshwater habitats around the Ariake Sea, which is considered to be a suitable marine environment for E. sinensis larvae. The mismatch between suitable freshwater and marine environments provides a possible explanation for the failure of establishment of E. sinensis in Japan to date. Our findings have useful general implications for the interpretation of biological invasions.

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.

1. Although caves are generally perceived as isolated habitats, at the local scale, they are often interconnected via a network of fissures in the bedrock. Accordingly, caves in close proximity are expected to host the same, or very similar, animal communities.

Aim To disentangle the role of evolutionary history, competition and environmental filtering in driving the niche evolution of four closely related subterranean spiders, with the overarching goal of obtaining a mechanistic description of the factors that determine species' realized distribution in simplified ecological settings. Location Dinaric karst, Balkans, Europe. Taxon Dysderidae spiders (Stalita taenaria, S. pretneri, S. hadzii and Parastalita stygia). Methods We resolved phylogenetic relationships among species and modelled each species' distribution using a set of climatic and habitat variables. We explored the climatic niche differentiation among species with n-dimensional hypervolumes and shifts in their trophic niche using morphological traits related to feeding specialization. Results Climate was the primary abiotic factor explaining our species' distributions, while karstic and soil features were less important. Generally, there was a high niche overlap among species, reflecting their phylogenetic relatedness, but on a finer scale, niche shifts explained the realized distribution patterns. Trophic interaction was another important factor influencing species distributions ? the non-overlapping distributions of three morphologically indistinguishable Stalita species is seemingly the outcome of competitive exclusion dynamics. The distribution of the fourth species, Parastalita stygia, overlaps with that of the other species, with several instances of coexistence within caves. As inferred from the morphology of the mouthparts, the mechanism that minimizes interspecific competition is the shift in the trophic niche of P. stygia towards a more specialized diet. Main conclusions We showed that similarity in niches only partly correlated with the phylogenetic distance among species, and that overlaps in species distributions are possible only when a parallel shift in diet occurs. Our work emphasized how even simplified environments still maintain the potential for diversification via niche differentiation. Ultimately, we provide an ecological explanation for the diversification of life in an important hotspot of subterranean diversity.

Five decades ago, a landmark paper in Science titled The Cave Environment heralded caves as ideal natural experimental laboratories in which to develop and address general questions in geology, ecology, biogeography, and evolutionary biology. Although the 'caves as laboratory' paradigm has since been advocated by subterranean biologists, there are few examples of studies that successfully translated their results into general principles. The contemporary era of big data, modelling tools, and revolutionary advances in genetics and (meta)genomics provides an opportunity to revisit unresolved questions and challenges, as well as examine promising new avenues of research in subterranean biology. Accordingly, we have developed a roadmap to guide future research endeavours in subterranean biology by adapting a well-established methodology of 'horizon scanning' to identify the highest priority research questions across six subject areas. Based on the expert opinion of 30 scientists from around the globe with complementary expertise and of different academic ages, we assembled an initial list of 258 fundamental questions concentrating on macroecology and microbial ecology, adaptation, evolution, and conservation. Subsequently, through online surveys, 130 subterranean biologists with various backgrounds assisted us in reducing our list to 50 top-priority questions. These research questions are broad in scope and ready to be addressed in the next decade. We believe this exercise will stimulate research towards a deeper understanding of subterranean biology and foster hypothesis-driven studies likely to resonate broadly from the traditional boundaries of this field. S.M acknowledge support by the CAWEB project “Testing macroecological theory using simplified systems”, funded by the European Commission through Horizon 2020 Marie Skłodowska-Curie Actions (MSCA) individual fellowships (Grant no. 882221). I.R.A. was supported by Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., under the Norma Transitória – DL57/2016/ CP1375/CT0003. D.E. was supported by IFREMER and by the CERES “Climate change and European Aquatic Resources” project funded by European Commission through Horizon 2020 research and innovation programme (Grant no. 678193). C.F., Z.F., and M.Z. were supported by the Slovenian Research Agency (program P1-0184, project N1-0069). J.E.K. was funded by NSF awards DEB1754231 and IOS1933428, and EDGE award 1923372. F.M. was supported by the French National Research Agency projects CONVERGENOMICS (ANR-15-CE32-0005) and EUR H2O’Lyon (ANR-17-EURE-0018). A.M. was supported by the ANCAVE project “Anchialine caves to understand evolutionary processes”, funded by the European Commission through Horizon 2020 Marie Skłodowska-Curie Actions (MSCA) individual fellowships (Grant no. 745530). P.A.V.B. was supported by the project AZORESBIOPORTAL – PORBIOTA (ACORES-01-0145-FEDER-000072), financed by FEDER in 85% and by Azorean Public funds by 15% through Operational Program Azores 2020. A.S.P.S.R. was supported by VILLUM FONDEN (Grant no. 15471) and by a Carlsbergfondet grant (CF19-0609). T.G.P. was supported by Vale S.A. and Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG) for individual fellowship (RDP 00092-18). T.P. was supported by the Karst Research Programme P6-0119, LifeWatch ERIC, RI-SI LifeWatch, and EU H2020 project eLTER. info:eu-repo/semantics/publishedVersion

1. Being the largest extant amphibian in the world, the IUCN Critically Endangered Chinese giant salamander Andrias davidianus is a charismatic species with great international public interest. While threats such as commercial overexploitation and habitat degradation have been extensively documented to affect natural populations of A. davidianus, still no information is available about the species sensitivity to climate change. 2. Here, we develop an ensemble of species distribution models (SDMs) for A. davidianus and projected its habitat suitability under present-day and future climate change scenarios. We based our SDMs on bioclimatic and topographic predictors, and recent (2012–2018) field-collected occurrence data across the whole distribution range of the species. 3. The ensemble SDMs exhibited good predictive capacity and suggested that slope, maximum temperature of warmest month, precipitation of driest month, and isothermality are the most influential predictors in determining distribution patterns in this species. The projections of our models point to a pronounced impact of climate changes over A. davidianus, with more than two-thirds of its suitable range expected to be lost in all scenarios of future climates tested. 4. In concert with the numerous other threats that are affecting this species, climate change poses a serious hindrance to the long-term survival of A. davidianus. We emphasise the urgent need of undertaking strict measures to manage this species and safeguard the few remaining available suitable habitats. We suggest that adaptive management strategies including designation of new reserves should be considered to mitigate the impacts of climate change on A. davidianus.

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.

A main goal of ecological and evolutionary biology is understanding and predicting interactions between populations and both abiotic and biotic environments, the spatial and temporal variation of these interactions, and the effects on population dynamics and performance. Trait-based approaches can help to model these interactions and generate a comprehensive understanding of ecosystem functioning. A central tool is the collation of databases that include species trait information. Such centralized databases have been set up for a number of organismal groups but is lacking for one of the most important groups of predators in terrestrial ecosystems – spiders. Here we promote the collation of an open spider traits database, integrated into the global Open Traits Network. We explore the current collation of spider data and cover the logistics of setting up a global database, including which traits to include, the source of data, how to input data, database governance, geographic cover, accessibility, quality control and how to make the database sustainable long-term. Finally, we explore the scope of research questions that could be investigated using a global spider traits database., This paper was written as a result of a workshop at the International Congress of Arachnology in Christchurch, New Zealand 2019. We would like to thank the ICA organizing committee and the International Society of Arachnology for their support, the Macquarie University Species Spectrum Research Center and a Pentti Tuomikoski Grant from the Finnish Museum of Natural History for financial support. JOW was supported by a Discovery Early Career Researcher Award of the Australian Research Council (DE190101338).

Invasive alien species are a major threat to biodiversity. Thus, it is fundamental to implement control strategies at the early stages of invasions. In the framework of the Italian-Swiss Alien Invasive Species in Lake Maggiore cooperative programme, we performed an extensive study on the occurrence and ecology of alien crayfish, one of the most significant invaders of freshwater habitats. From April 2017 to July 2018, we inspected seventy-five sites along the coastline to verify crayfish occurrence. We recorded, for the first time, the signal crayfish Pacifastacus leniusculus. Additionally, we found few individuals and remains of the red swamp crayfish Procambarus clarkii, and confirmed the presence of a consistent population of the spinycheek crayfish Orconectes limosus. Given the high number of O. limosus&rsquo, individuals found, it was possible to perform in-depth biometric and ecological analyses for this abundant species only. We observed no significant differences of biometric measures between males and females of O. limosus. We explore its habitat preferences with a generalized linear model, detecting a significant relationship between mean annual temperatures and the presence of shelters of this species. These results, together, have direct implications for planning rapid management response actions on alien crayfish in large and deep lakes.

Aim Species distribution models (SDMs) are an effective tool to explore the potential distribution of terrestrial, freshwater and marine organisms; however, SDMs have been seldom used to model ichthyoplankton distributions, and thus, our understanding of how larval stages of fishes will respond to climate change is still limited. Here, we developed SDMs to explore potential impacts of climate change on habitat suitability of ichthyoplankton. Location Yangtze Estuary, China. Methods Using long-term ichthyoplankton survey data and a large set of marine predictor variables, we developed ensemble SDMs for five abundant ichthyoplankton species in the Yangtze Estuary (Coilia mystus, Hypoatherina valenciennei, Larimichthys polyactis, Salanx ariakensis and Chelidonichthys spinosus). Then, we projected their habitat suitability under present and future climate conditions. Results The ensemble SDMs had good predictive performance and were successful in estimating the known distributions of the five species. Model projections highlighted two contrasting patterns of response to future climates: while C. mystus will likely expand its range, the ranges of the other four species will likely contract and shift northward. Main conclusions According to our SDM projections, the five ichthyoplankton species that we tested in the Yangtze Estuary are likely to respond differently to future climate changes. These projected different responses seemingly reflect the differential functional attributes and life-history strategies of these species. To the extent that climate change emerges as a critical driver of the future distribution of these species, our findings provide an important roadmap for designing future conservation strategies for ichthyoplankton in this region.

Background A spider taxonomy and ecology field course was organised in Kilpisjarvi Biological Station, northern Finland, in July 2019. During the course, four 50 × 50 m plots in mountain birch forest habitat were sampled following a standardised protocol. In addition to teaching and learning about spider identification, behaviour, ecology and sampling, the main aim of the course was to collect comparable data from the Kilpisjarvi area as part of a global project, with the purpose of uncovering global spider diversity patterns. New information A total of 2613 spiders were collected, of which 892 (34%) were adults. Due to uncertainty of juvenile identification, only adults are included in the data presented in this paper. The observed adult spiders belong to 51 species, 40 genera and 11 families, of which the Linyphiidae were the most rich and abundant with 28 (55%) species and 461 (52%) individuals. Lycosidae had six species and 286 individuals, Gnaphosidae five species and 19 individuals, Thomisidae four species and 24 individuals, Theridiidae two species and 23 individuals. All other six families had one species and less than 40 individuals. The most abundant species were the linyphiid Agnyphantes expunctus (204) and the lycosids Pardosa eiseni (164) and Pardosa hyperborea (107).

Legal and illegal wildlife trade is a multibillion dollar industry that is driving several species toward extinction. Even though wildlife trade permeates the Tree of Life, most analyses to date focused on the trade of a small selection of charismatic vertebrate species. Given that vertebrate taxa represent only 3% of described species, this is a significant bias that prevents the development of comprehensive conservation strategies. In this short contribution, we discuss the significance of global wildlife trade considering the full diversity of organisms for which data are available in the IUCN database. We emphasize the importance of being fast and effective in filling the knowledge gaps about non-vertebrate life forms, in order to achieve an in-depth understanding of global trading patterns across the full canopy of the Tree of Life, and not just its most appealing twig., Highlights • Global wildlife trade is a multibillion dollar industry that is driving several species toward extinction. • Most analyses on global wildlife trade are biased toward vertebrates. • Multiple datasets suggest that a huge fraction of illegal and legal traded wildlife is plant and invertebrates. • It is fundamental to fill this knowledge gap about global trade of non-vertebrate life forms.

Caves are excellent model systems to study the effects of abiotic factors on species distributions due to their selective conditions. Different ecological factors have been shown to affect species distribution depending on the scale of analysis, whether regional or local. The interplay between local and regional factors in explaining the spatial distribution of cave-dwelling organisms is poorly understood. Using the troglophilic subterranean spider Artema nephilit (Araneae: Pholcidae) as a model organism, we investigated whether similar environmental predictors drive the species distribution at these two spatial scales. At the local scale, we monitored the abundance of the spiders and measured relevant environmental features in 33 caves along the Jordan Rift Valley. We then extended the analysis to a regional scale, investigating the drivers of the distribution using species distribution models. We found that similar ecological factors determined the distribution at both local and regional scales for A. nephilit. At a local scale, the species was found to preferentially occupy the outermost, illuminated, and warmer sectors of caves. Similarly, mean annual temperature, annual temperature range, and solar radiation were the most important drivers of its regional distribution. By investigating these two spatial scales simultaneously, we showed that it was possible to achieve an in-depth understanding of the environmental conditions that governs subterranean species distribution.

The geometry of the Hutchinson’s hypervolume derives from multiple selective pressures defined, on one hand, by the physiological tolerance of the species, and on the other, by intra- and interspecific competition. The quantification of these evolutionary forces is essential for the understanding of the coexistence of predators in light of competitive exclusion dynamics. We address this topic by investigating the ecological niche of two medium-sized troglophile spiders (Meta menardi and Pimoa graphitica). Over one year, we surveyed several populations in four subterranean sites in the Western Italian Alps, monitoring monthly their spatial and temporal dynamics and the associated physical and ecological variables. We assessed competition between the two species by means of multi regression techniques and by evaluating the intersection between their multidimensional hypervolumes. We detected a remarkable overlap between the microclimatic and trophic niche of M. menardi and P. graphitica, however, the former —being larger in size— resulted the best competitor in proximity of the cave entrance, causing the latter to readjust its spatial niche towards the inner part, where prey availability is scarcer (“step back effect”). In parallel to the slight variations in the subterranean microclimatic condition, the niche of the two species was also found to be seasonal dependent, varying over the year. With this work, we aim at providing new insights about the relationships among predators, demonstrating that energy-poor environments such as caves maintain the potential for diversification of predators via niche differentiation and serve as useful models for theoretical ecological studies.

To obtain realistic forecasts of the impacts of climate change on species habitat suitability, novel approaches based on species distribution models (SDMs) are being developed and scrutinized. We argue here that, when dealing with data from long-term monitoring programmes, incorporating a temporal weight on the occurrence points may result in a more realistic prediction of a species' potential distribution. Using larval fish presence records collected from 1999 to 2013 in the Yangtze Estuary, China, we compared the performance of ensembles of standard SDMs versus SDMs constructed with weighted time-series presence records in predicting the present and future distributions of the larval stages of two dominant fish. The results of the ensemble SDMs showed that weighted presence records can significantly improve SDM performance, as measured through standard validation metrics. The SDM projections suggest that suitable habitat for both species will decrease under future climate scenarios, with one species (Stolephorus commersonnii) predicted to be more susceptible to climate change than the other (Engraulis japonicus). In addition to range contraction, model projections suggest that the future habitats of both species will shift northward--an implication of climate change that should be considered in future management and conservation strategies for the Yangtze Estuary.

In light of recent alarming trends in human population growth, climate change, and other environmental modifications, a “Warning to humanity” manifesto was published in BioScience in 2017. This call reiterated most of the ideas originally expressed by the Union of Concerned Scientists in 1992, including the fear that we are “pushing Earth's ecosystems beyond their capacities to support the web of life.” As subterranean biologists, we take this opportunity to emphasize the global importance and the conservation challenges associated with subterranean ecosystems. They likely represent the most widespread nonmarine environments on Earth, but specialized subterranean organisms remain among the least documented and studied. Largely overlooked in conservation policies, subterranean habitats play a critical role in the function of the web of life and provide important ecosystem services. We highlight the main threats to subterranean ecosystems and propose a set of effective actions to protect this globally important natural heritage.

Janzen's hypothesis (1967; American Naturalist) predicts that tropical habitats with reduced thermal seasonality would select for species with narrow thermal tolerance, thereby limiting dispersal among sites of different elevations showing little overlap in temperature. These predictions have so far been tested by confronting tropical and temperate mountain communities, leaving unresolved the question of their generalization to habitats with low thermal seasonality outside the tropics. We provide the first extension of Janzen's hypothesis to temperate habitats, by testing for differences in thermal tolerance and elevational range among congeneric alpine spiders (Araneae: Linyphiidae: Troglohyphantes) occurring along a steep gradient of decreasing thermal seasonality with increasing cave depth. Using species from the same temperate region rather than from distinct biogeographic regions avoids confounding the effects of short- and long-term climatic variability on thermal tolerance and elevational range extent. Following Jansen's assumptions, we predicted that cave habitats with low thermal seasonality would select for narrow thermal tolerance. Also, specialized subterranean species would exhibit both narrower elevational range extents and smaller realized thermal niche breadths. Initially, we showed that thermal seasonality and the overlap in temperature across caves were considerably lower in deep than in shallow cave habitats. Then, we measured thermal tolerance and used morphological traits to quantify the degree of specialization to subterranean life of 11 spider species. We found that thermal tolerance decreased with increasing subterranean specialization. Deep subterranean species reached their critical temperature at 1-4 degrees C above their habitat temperature, whereas shallow subterranean species withstood a twofold larger temperature increase. At last, we demonstrated that a species' elevational range extent and the variation of temperature encountered across its range decreased with increasing specialization to deep subterranean life. Our integrative work, being grounded in organismal and habitat measures, represents the first generalization of Janzen's framework to caves and provides a conceptual framework to disentangle the effect of long-term climate variability on subterranean biodiversity patterns. Extending Janzen's thoughts to a broader range of ecosystems is key to understanding how the ecological specialization-dispersal trade-off may constrain the response of species to climate change. A free Plain Language Summary can be found within the Supporting Information of this article.

Spiders (Arachnida: Araneae) are widespread in subterranean ecosystems worldwide and represent an important component of subterranean trophic webs. Yet, global-scale diversity patterns of subterranean spiders are still mostly unknown. In the frame of the CAWEB project, a European joint network of cave arachnologists, we collected data on cave-dwelling spider communities across Europe in order to explore their continental diversity patterns. Two main datasets were compiled: one listing all subterranean spider species recorded in numerous subterranean localities across Europe and another with high resolution data about the subterranean habitat in which they were collected. From these two datasets, we further generated a third dataset with individual geo-referenced occurrence records for all these species. Data from 475 geo-referenced subterranean localities (caves, mines and other artificial subterranean sites, interstitial habitats) are herein made available. For each subterranean locality, information about the composition of the spider community is provided, along with local geomorphological and habitat features. Altogether, these communities account for > 300 unique taxonomic entities and 2,091 unique geo-referenced occurrence records, that are made available via the Global Biodiversity Information Facility (GBIF) (Mammola and Cardoso 2019). This dataset is unique in that it covers both a large geographic extent (from 35° south to 67° north) and contains high-resolution local data on geomorphological and habitat features. Given that this kind of high-resolution data are rarely associated with broad-scale datasets used in macroecology, this dataset has high potential for helping researchers in tackling a range of biogeographical and macroecological questions, not necessarily uniquely related to arachnology or subterranean biology.

Macroecologists seek to identify drivers of community turnover ( β -diversity) through broad spatial scales. However, the influence of local habitat features in driving broad-scale β -diversity patterns remains largely untested, owing to the objective challenges of associating local-scale variables to continental-framed datasets. We examined the relative contribution of local- versus broad-scale drivers of continental β -diversity patterns, using a uniquely suited dataset of cave-dwelling spider communities across Europe (35–70° latitude). Generalized dissimilarity modelling showed that geographical distance, mean annual temperature and size of the karst area in which caves occurred drove most of β -diversity, with differential contributions of each factor according to the level of subterranean specialization. Highly specialized communities were mostly influenced by geographical distance, while less specialized communities were mostly driven by mean annual temperature. Conversely, local-scale habitat features turned out to be meaningless predictors of community change, which emphasizes the idea of caves as the human accessible fraction of the extended network of fissures that more properly represents the elective habitat of the subterranean fauna. To the extent that the effect of local features turned to be inconspicuous, caves emerge as experimental model systems in which to study broad biological patterns without the confounding effect of local habitat features.

International audience; Over the last two decades there has been an exponential increase in the use of correlative species distribution models (SDMs) to address a variety of topics in ecology, biogeography, evolution, and conservation biology. Conversely, the use of these statistical methods to study the potential distribution of subterranean organisms has lagged behind, relative to their above-ground (epigean) counterparts. The reason for this is possibly related to a number of peculiarities of subterranean systems, which pose important limits, but also opportunities, for these correlative models. The aim of this forum is to explore the caveats that need to be made when generalizing these statistical techniques to caves and other subterranean habitats. We focus on the typical bias in spatial datasets of cave-dwelling species, and provide advice for selecting the model calibration area. In parallel, we discuss the potential use of different large scale surface variables to represent the subterranean condition. A more widespread adoption of these statistical techniques in subterranean biology is highly attractive and has great potential in broadening our knowledge on a variety of ecological topics, especially in the fields of climate change and biodiversity conservation. Their use would especially benefit the study of the biogeographic patterns of subterranean fauna and the impact of past and future climate change on subterranean ecosystems.