Taxa Research Articles

Genes involved in carbon, nitrogen, and sulfur cycling in an important estuarine ecosystem show coherent shifts in response to changes in environmental conditions

AbstractWhile metagenomics can provide insight into microbial community metabolic potential, understanding factors that influence gene abundance is necessary to maximize the information gained from this analysis. Gene abundances are influenced by chemical or physical conditions along with other factors, such as copy number variation between taxa, methodological biases, or issues associated with identification and classification. Here, we identify major drivers of spatiotemporal shifts in microbial gene relative abundance from multiple months, sites, and depths within Chesapeake Bay in 2017 using shotgun metagenomics. We compared changes in relative abundance of key genes for bacterial photosynthesis, nitrogen, and sulfur metabolism with each other and measured environmental variables. Major drivers of differences in key metabolic gene abundances are associated with environmental variables that largely change with depth and season (e.g., temperature, oxygen, phosphate). For sulfur oxidation, bacterial photosynthesis, and denitrification, genes within each process are generally significantly correlated with each other and with several environmental variables. For other processes, such as nitrification, nitrogen fixation, and dissimilatory nitrate reduction to ammonium, genes that encode enzymes within the same pathway are not well correlated. The lack of correlation typically results from differences in identified taxa carrying these genes, suggesting modular pathway structure, methodological errors, or discrepancies in gene copy number between taxonomic groups. To be suitable indicators of biogeochemical processes for models, genes or pathways should be strongly correlated with environmental variables and specific to and inclusive of all taxa mediating the associated process.

The natural history of Amblyomma maculatum sensu lato, a vector of Rickettsia parkeri rickettsiosis, in southern Arizona.

Amblyomma maculatum sensu lato (s.l.) is an ixodid tick found in the semi-arid southwestern United States and northern Mexico where it is a parasite of medical and veterinary significance, including as a vector for Rickettsia parkeri, a cause of spotted fever rickettsiosis in the Americas. To describe the comprehensive natural history of this tick, monthly small mammal trapping and avian mist netting sessions were conducted at sites in Cochise County Arizona, within the Madrean Archipelago region where human cases of R. parkeri rickettsiosis and adult stages of A. maculatum s.l. were previously documented. A total of 1949 larvae and nymphs were removed from nine taxonomic groups of rodents and ten species of birds and were used in combination with records for adult stages collected both from vegetation and hunter-harvested animals to model seasonal activity patterns. A univoltine phenology was observed, initiated by the onset of the annual North American monsoon and ceasing during the hot, dry conditions preceding the following monsoon season. Cotton rats (Sigmodon spp.) were significantly more likely to be infested than other rodent taxa and carried the highest tick loads, reflecting a mutual affinity of host and ectoparasite for microhabitats dominated by grass.

VISTA: A Tool for Fast Taxonomic Assignment of Viral Genome Sequences.

The rapid expansion of the number of viral genome sequences in public databases necessitates a scalable, universal, and automated preliminary taxonomic framework for comprehensive virus studies. Here, we introduce VISTA (Virus Sequence-based Taxonomy Assignment), a computational tool that employs a novel pairwise sequence comparison system and an automatic demarcation threshold identification framework for virus taxonomy. Leveraging physio-chemical property sequences, k-mer profiles, and machine learning techniques, VISTA constructs a robust distance-based framework for taxonomic assignment. Functionally similar to PASC (Pairwise Sequence Comparison), a widely used virus assignment tool based on pairwise sequence comparison, VISTA demonstrates superior performance by providing significantly improved separation for taxonomic groups, more objective taxonomic demarcation thresholds, greatly enhanced speed, and a wider application scope. We successfully applied VISTA to 38 virus families, as well as to the class Caudoviricetes. This demonstrates VISTA's scalability, robustness, and ability to automatically and accurately assign taxonomy to both prokaryotic and eukaryotic viruses. Furthermore, the application of VISTA to 679 unclassified prokaryotic virus genomes recovered from metagenomic data identified 46 novel virus families. VISTA is available as both a command line tool and a user-friendly web portal at https://ngdc.cncb.ac.cn/vista.

Missing microbial eukaryotes and misleading meta-omic conclusions.

Meta-omics is commonly used for large-scale analyses of microbial eukaryotes, including species or taxonomic group distribution mapping, gene catalog construction, and inference on the functional roles and activities of microbial eukaryotes in situ. Here, we explore the potential pitfalls of common approaches to taxonomic annotation of protistan meta-omic datasets. We re-analyze three environmental datasets at three levels of taxonomic hierarchy in order to illustrate the crucial importance of database completeness and curation in enabling accurate environmental interpretation. We show that taxonomic membership of sequence clusters estimates community composition more accurately than returning exact sequence labels, and overlap between clusters can address database shortcomings. Clustering approaches can be applied to diverse environments while continuing to exploit the wealth of annotation data collated in databases, and selecting and evaluating these databases is a critical part of correctly annotating protistan taxonomy in environmental datasets. We argue that ongoing curation of genetic resources is crucial in accurately annotating protists in in situ meta-omic datasets. Moreover, we propose that precise taxonomic annotation of meta-omic data is a clustering problem rather than a feasible alignment problem.

Macrolide resistance is pervasive in oral streptococci in the Belgian general population: a cross-sectional survey.

Background. Commensal streptococci are common inhabitants of the oral microbiome and regulate its structure and function in beneficial ways for human health. They can, however, also be opportunistic pathogens and act as a reservoir of resistance genes that can be passed on to other bacteria, including pathogens. Little is known about the prevalence of these commensals in parents and their children and their antimicrobial susceptibilities in the Belgian general population.Gap Statement. The macrolide susceptibility of commensal oral Streptococci in Belgium is unknown.Methods. We assessed the prevalence and azithromycin susceptibility of commensal streptococcal species in the parents (n=38) and children (n=50) of 35 families in Belgium.Results. The most frequently detected taxonomic grouping was Streptococcus mitis/oralis, which was detected in 78/181 (43.1%) of the children's isolates and 66/128 (51.6%) of the parents' isolates. Of the 311 isolates collected in this study, 282 isolates (90.7%) had an azithromycin MIC value greater than the breakpoint of 0.25 mg l-1 and 146 isolates (46.9%) had azithromycin MICs greater than 2 mg l-1. There was no difference in the azithromycin MIC distribution of all streptococcal isolates between children and parents. All individuals were colonized by streptococci with azithromycin MICs greater than 0.25 mg l-1, and 87.5% of individuals had streptococci with MICs greater than 2 mg l-1.Interpretation. The most prevalent species identified in both age groups was S. mitis/oralis. All individuals harboured streptococci with macrolide resistance. This highlights the need for additional antimicrobial stewardship initiatives to reduce the consumption of macrolides in the general population.

Wolbachia in Antarctic terrestrial invertebrates: Absent or undiscovered?

Interactions between a host organism and its associated microbiota, including symbiotic bacteria, play a crucial role in host adaptation to changing environmental conditions. Antarctica provides a unique environment for the establishment and maintenance of symbiotic relationships. One of the most extensively studied symbiotic bacteria in invertebrates is Wolbachia pipientis, which is associated with a wide variety of invertebrates. Wolbachia is known for manipulating host reproduction and having obligate or facultative mutualistic relationships with various hosts. However, there is a lack of clear understanding of the prevalence of Wolbachia in terrestrial invertebrates in Antarctica. We present the outcomes of a literature search for information on the occurrence of Wolbachia in each of the major taxonomic groups of terrestrial invertebrates (Acari, Collembola, Diptera, Rotifera, Nematoda, Tardigrada). We also performed profiling of prokaryotes based on three marker genes and Kraken2 in available whole genome sequence data obtained from Antarctic invertebrate samples. We found no reports or molecular evidence of Wolbachia in these invertebrate groups in Antarctica. We discuss possible reasons underlying this apparent absence and suggest opportunities for more targeted future research to confirm bacteria's presence or absence.

Meta-analysis of the acoustic adaptation hypothesis reveals no support for the effect of vegetation structure on acoustic signalling across terrestrial vertebrates.

Acoustic communication plays a prominent role in various ecological and evolutionary processes involving social interactions. The properties of acoustic signals are thought to be influenced not only by the interaction between signaller and receiver but also by the acoustic characteristics of the environment through which the signal is transmitted. This conjecture forms the core of the so-called "acoustic adaptation hypothesis" (AAH), which posits that vegetation structure affects frequency and temporal parameters of acoustic signals emitted by a signaller as a function of their acoustic degradation properties. Specifically, animals in densely vegetated "closed habitats" are expected to produce longer acoustic signals with lower repetition rates and lower frequencies (minimum, mean, maximum, and peak) compared to those inhabiting less-vegetated "open habitats". To date, this hypothesis has received mixed results, with the level of support depending on the taxonomic group and the methodology used. We conducted a systematic literature search of empirical studies testing for an effect of vegetation structure on acoustic signalling and assessed the generality of the AAH using a meta-analytic approach based on 371 effect sizes from 75 studies and 57 taxa encompassing birds, mammals and amphibians. Overall, our results do not provide consistent support for the AAH, neither in within-species comparisons (suggesting no overall phenotypically plastic response of acoustic signalling to vegetation structure) nor in among-species comparisons (suggesting no overall evolutionary response). However, when considering birds only, we found weak support for the AAH in within-species comparisons, which was mainly driven by studies that measured frequency bandwidth, suggesting that this variable may exhibit a phenotypically plastic response to vegetation structure. For among-species comparisons in birds, we also found support for the AAH, but this effect was not significant after excluding comparative studies that did not account for phylogenetic non-independence. Collectively, our synthesis does not support a universal role of vegetation structure in the evolution of acoustic communication. We highlight the need for more empirical work on currently under-studied taxa such as amphibians, mammals, and insects. Furthermore, we propose a framework for future research on the AAH. We specifically advocate for a more detailed and quantitative characterisation of habitats to identify frequencies with the highest detection probability and to determine if frequencies with greater detection distances are preferentially used. Finally, we stress that empirical tests of the AAH should focus on signals that are selected for increased transmission distance.

The Malvaceae Collection at the Rio de Janeiro Botanical Garden: Ex Situ Conservation to Meet Target 8 of the Global Strategy for Plant Conservation

Ex situ conservation of plants is a current and urgent issue, especially in the Brazilian context. While Brazil has the world’s highest plant diversity, few consistent initiatives are aimed at conserving the potential of our living collections toward reaching Target 8 of the Global Strategy for Plant Conservation (GSPC). Objective II of GSPC calls for the conservation of plant diversity, with Target 8 specifying 75% of threatened plant species in ex situ collections. It was only after cataloging the collection of Malvaceae from the Rio de Janeiro Botanical Garden (JBRJ) for scientific publication that we realized the potential of this collection for ex situ conservation. With this in mind, we carefully catalog the individuals present, updating the names of species and counting their individuals. We found that Malvaceae is represented by 63 species and 216 individuals in the arboretum, 45 species native to America, 11 from Africa, 10 from Asia, and 3 from Oceania. Using IUCN criteria, only two species are threatened and two are data-deficient, with one or two individuals each. Based on these data and the specific biology of this taxonomic group, we identified the main problems and listed recommendations to make this collection more representative of the endangered taxa of the Brazilian flora. Therefore, we expect this effort to be a solid contribution to Target 8 mandated by GSPC, as well as a replicable pilot project for other taxonomic groups of Brazilian flora.

Seaweed-Associated Diatoms (Bacillariophyta) in Dokdo of South Korea: I. Subphyla Melosirophytina, Coscinodiscophytina, and Class Mediophyceae

Dokdo is an island located in the easternmost part of Korea, which has high levels of biodiversity of birds and fish, especially marine invertebrates. However, the biodiversity of microalgae, especially diatoms (Bacillariophyta), is relatively unknown, despite their ecological importance as primary producers of the marine food web and bioindicators of environmental conditions associated with climate change. To understand the biodiversity of seaweed-associated diatoms from Dokdo, we collected macroalgae present at a depth 5–15 m by SCUBA diving on 17 October 2017. There were a large number of diatoms (over 130 species), even though it was a one-time survey. As it includes too many taxa to cover at once, voucher flora for other taxonomic groups will be provided through the continuous serial papers. This is the first series of seaweed-associated diatoms, with 26 species belonging to the subphyla Melosirophytina and Coscinodisophytina, and the class Mediophyceae. Among these, seven species including one new taxon were reported for the first time in Korea, which, along with the geopolitical characteristics of the survey area, proved that there is no domestic interest in seaweed-related diatoms. In particular, the appearance of species that have been reported in subtropical waters, such as the order Ardissoneales, requires continuous monitoring of marine seaweed-associated diatoms to confirm whether their colonization in Dokdo waters was due to climate change or species-specific water temperature tolerance.

Resilience of Phytoplankton and Microzooplankton Communities under Ocean Alkalinity Enhancement in the Oligotrophic Ocean.

Ocean alkalinity enhancement (OAE) is currently discussed as a potential negative emission technology to sequester atmospheric carbon dioxide in seawater. Yet, its potential risks or cobenefits for marine ecosystems are still mostly unknown, thus hampering its evaluation for large-scale application. Here, we assessed the impacts OAE may have on plankton communities, focusing on phytoplankton and microzooplankton. In a mesocosm study in the oligotrophic subtropical North Atlantic, we investigated the response of a natural plankton community to CO2-equilibrated OAE across a gradient from ambient alkalinity (2400 μmol kg-1) to double (4800 μmol kg-1). Abundance and biomass of phytoplankton and microzooplankton were insensitive to OAE across all size classes (pico, nano and micro), nutritional modes (autotrophic, mixotrophic and heterotrophic) and taxonomic groups (cyanobacteria, diatoms, haptophytes, dinoflagellates, and ciliates). Consequently, plankton communities under OAE maintained their natural chlorophyll a levels, size structure, taxonomic composition and biodiversity. These findings suggest a high tolerance of phytoplankton and microzooplankton to CO2-equilibrated OAE in the oligotrophic ocean. However, alternative application schemes involving more drastic perturbations in water chemistry and nutrient-rich ecosystems require further investigation. Nevertheless, our study on idealized OAE will help develop an environmentally safe operating space for this climate change mitigation solution.

The Taxonomic and Functional Diversity of Leaf-Litter Dwelling Ants in the Tropical Dry Forest of the Colombian Caribbean

There have been few advances in understanding the organization and dynamics of ants in tropical dry forests. The latter are a seriously threatened ecosystem, and ants are important indicators of diversity, disturbance, and restoration in forest ecosystems. Using diversity data and morphofunctional traits, we evaluated the spatial and temporal variation of taxonomic and functional ant groups; in addition, we explored the variation in functional traits and diversity among communities. Ants were sampled during the dry and rainy seasons using mini-Winkler bags. A total of 9 subfamilies, 57 genera, and 146 species were collected. Ant species composition and richness varied both spatially (75 to 119 species) and temporally (121 and 127 species). The fragments from N2 and N3 showed higher diversity than those from N1. The dissimilarity among all areas was moderate (50–60%), mainly attributable to species turnover processes (77%). Twenty functional groups were identified. The N3 fragments had the highest functional diversity, with lower resistance to species loss, while the N1 and N2 fragments reduced functional diversity and increased similarity among species. Our results highlight the importance of integrating a functional analysis with the taxonomic assessment of ants as an important contribution to understanding the organization and dynamics of this community of insects that inhabit the tropical dry forest.

Fractal Geometry in Vertebrate Respiratory Systems: A Comparative Analysis of Branching Patterns Across Species

This study investigates the application of fractal geometry to the analysis of vertebrate respiratory systems, focusing on the branching patterns of the bronchial tree across diverse species. Using a combination of mathematical modeling and computational visualization, we explore how fractal dimensions and branching characteristics reflect evolutionary adaptations to various habitats and physiological demands. The research encompasses a range of vertebrates, including humans, horses, dolphins, chickens, iguanas, and bullfrogs, representing diverse taxonomic groups and ecological niches. Our analysis reveals a clear gradient of complexity in respiratory structures, correlating strongly with metabolic rates and environmental adaptations. Mammals, particularly those adapted for high‐performance activities like horses, demonstrate the most complex fractal patterns, indicating highly efficient gas exchange systems. In contrast, ectothermic species such as iguanas and bullfrogs exhibit simpler structures, reflecting their lower metabolic demands and alternative respiratory strategies. The study employs fractal dimension calculations, L‐system modeling, and lacunarity analysis to quantify and visualize these differences. Our findings suggest that fractal analysis provides valuable insights into the relationship between form and function in vertebrate respiratory systems, offering a novel perspective on comparative physiology and evolutionary biology. This research not only enhances our understanding of respiratory system evolution but also has potential applications in biomimetic design, medical diagnostics, and ecological physiology. It demonstrates the power of interdisciplinary approaches, combining advanced mathematics with biological principles to uncover fundamental patterns in nature.

The mOTUs online database provides web-accessible genomic context to taxonomic profiling of microbial communities.

Determining the taxonomic composition (taxonomic profiling) is a fundamental task in studying environmental and host-associated microbial communities. However, genome-resolved microbial diversity on Earth remains undersampled, and accessing the genomic context of taxa detected during taxonomic profiling remains a challenging task. Here, we present the mOTUs online database (mOTUs-db), which is consistent with and interfaces with the mOTUs taxonomic profiling tool. It comprises 2.83 million metagenome-assembled genomes (MAGs) and 919090 single-cell and isolate genomes from 124295 species-level taxonomic units. In addition to being one of the largest prokaryotic genome resources to date, all MAGs in the mOTUs-db were reconstructed de novo in 117902 individual samples by abundance correlation of scaffolds across multiple samples for improved quality metrics. The database complements the Genome Taxonomy Database, with over 50% of its species-level taxonomic groups being unique. It also offers interactive querying, enabling users to explore and download genomes at various taxonomic levels. The mOTUs-db is accessible at https://motus-db.org.

Spatial Distribution and Temporal Variation of Megafauna in Circalittoral and Bathyal Soft Bottoms of the Westernmost Biodiversity Hotspot of the Mediterranean Sea: The Alboran Ridge

The Alboran Sea is the westernmost sub-basin of the Mediterranean Sea, and it is connected to the Atlantic Ocean through the Strait of Gibraltar. The Alboran Ridge is located in the middle of the Alboran Sea and represents a hotspot of biodiversity in the Mediterranean Sea. Besides their critical importance, there are few studies on the communities and changes in biodiversity, and they mostly concentrate on infralittoral and circalittoral bottoms. In this work, the composition, structure and bathymetric and temporal changes of megafauna of the Alboran Ridge were examined. Samples were collected from MEDITS surveys carried out between 2012 and 2022 at depths ranging from 100 to 800 m. Analyses were performed separately for each of the taxonomic groups: osteichthyes, chondrichthyes, crustaceans, molluscs, echinoderms and “other groups”. There was no common spatial organization for each of the faunistic groups studied, although most of them displayed differences between the shelf and the slope. The continental shelf was characterized by the highest values of community metrics such as abundance, biomass, species richness and mean weight of species for all groups except for chondrichthyes and crustaceans. Decreasing trends of some community metrics were detected in some of the faunistic groups throughout the study period.

Island colonization in flowering plants is determined by the interplay of breeding system, lifespan, floral symmetry, and arrival opportunity.

Among flowering plants, self-compatibility, longer lifespan, and generalized pollination syndrome are each thought to increase the lifetime odds of finding a mate, particularly in isolated locales. An accumulated body of evidence supports the role of breeding system in island colonization, but less is known about the impact of other traits and their interactions during establishment. We employ a global dataset of 3222 flowering plant species from 169 families to estimate the effects of traits on the probability of island occurrence. Our analyses additionally account for taxonomic group membership and assess the role of island arrival opportunity. Self-compatibility is strongly associated with island colonization. A longer lifespan and generalized pollination syndrome are also associated with increased island colonization, although this is influenced by their interaction with breeding system. The probability of island colonization is highly dependent on taxonomically conserved unmeasured traits and arrival opportunity. As expected, mate limitation appears to increase with dispersal distance, although many other factors are at play. We find that arrival opportunity and breeding system are the primary drivers of island colonization relative to other life-history traits we account for here, lending additional support for the positive role of uniparental reproduction in establishment following long-distance dispersal.

Cell cycle time in the root apical meristem of angiosperms and its dependence on holoploid DNA content.

In the angiosperm root apical meristem, the holoploid DNA content is not directly related to cell cycle time. Instead, ploidy, chromosome number, and taxa emerge as key factors that influence this interaction. It is commonly considered that cell cycle time in the angiosperm root apical meristem is directly related to the holoploid DNA content, and this is one of the manifestations of the nucleotypic effect. In this paper, we significantly expanded the previously reported data on cell cycle time using the thymidine method and the rate-of-cell-production method and investigated the nucleotypic effect in different taxonomic groups, in diploids with varying numbers of chromosomes, and in species of different ploidy levels. The nucleotypic effect was most pronounced in diploids with a chromosome number of less than 17, especially in the orders Asparagales and Liliales. In diploids with 17 and a greater number of chromosomes, and in polyploids, the nucleotypic effect was only evident in these two orders and was practically absent in the rest of angiosperms, which have generally lower the holoploid DNA content and average DNA content per chromosome. Overall, our work demonstrates that in angiosperms the relationship between cell cycle time in the root apical meristem and the holoploid DNA content is complex and not homogeneous and it is not directly related to cell cycle time. Instead, ploidy, chromosome number, and taxa emerge as key factors that influence this interaction.

To the top or into the dark? Relationships between elevational and canopy cover distribution shifts in mountain forests

Numerous studies have reported that observed species shifts in mountain areas lag behind expectations under current warming trends, however, the mechanisms remain poorly understood. One important mechanism might be microclimatic heterogeneity causing migration of species to cooler conditions under closed forest canopies, but evidence is scarce. We here compared the distributions of 710 species (11 taxonomic groups including fungi, plants, and animals) along an elevation gradient (287–1419 m a.s.l.) in a temperate low mountain range between 2006–2008 and 2016–2017 to address this open question. We characterized each species' distribution (peak and breadth) based on their abundance along two environmental gradients: elevation and canopy cover. We then analysed changes in species' distribution peaks, asking whether shifts in canopy distribution and initial distribution characteristics explain variation in elevational distribution shifts. Across all taxa, the mean shift in elevational distribution peak was + 35.3 m (i.e. upslope). Species' baseline distribution peaks were strong predictors of elevational distribution shifts with stronger upslope shifts in low‐elevation and open‐forest species. Even though we observed considerable variation in the responses among species, canopy distribution shifts had a significant negative effect on elevational distribution shifts overall and in six taxonomic groups. We suggest that this is related to cooler microclimatic conditions under closed compared to open forest canopies. Shifts to closed‐canopy forests may thus partly compensate for elevational distribution shifts, highlighting the conservation value of heterogeneous landscapes featuring microclimatic refugia. Yet, it is likely that other mechanisms, such as habitat limitation, are also at play. Future studies need to quantify the potential of microclimatic refugia under accelerating forest dynamics, considering the interplay of canopy cover and other factors driving microclimate, and to illuminate the complex climate change response mechanisms among species and taxonomic groups.

Implementation of complementary methods for bat sampling in a karstic landscape in central–northern Guatemala, Central America

The use of complementary sampling methods for bats is recommended to improve inventories of species. Here we performed direct and indirect sampling in caves, in the main river, and in various forest vegetation covers in a karst landscape in central–northern Guatemala. We determined efficiency and complementarity between methods. Using mist nets and with an effort of 2,670 m²h, we captured 296 individuals of 19 species. Using ultrasonic microphones and after 71 hours of recording, we obtained 1,598 effective files of 16 species/sonotypes. Using a harp trap and after 79 hours of operation, we captured 939 individuals of 12 species. In total, we report 34 species/sonotypes. Regarding the percentage of species richness sampled, according to an extrapolation to double the sampling effort, this varied between 69.8 % and 91.5 %, which we consider satisfactory. The percentages of complementarity between methods were over 70 %, notably high between mist nets and ultrasonic microphones (91 %). To date in Guatemala, inventories have been incomplete, mainly because they are biased by the use of mist nets and the capture of bats of the Phyllostomidae family. Training and implementation of non–extensively used methods such as acoustic detection is needed to improve our knowledge about this taxonomic group and provide fundamental information for conservation strategies. Dataset published through GBIF (DOI: 10.15470/3vcvof). Key words: Harp trap, Karstic caves, Lanquín, Mist nets, Riparian environments, Ultrasonic microphones

30 years of terrestrial insect richness patterns across elevation: What have we learned? A global meta-analysis.

Understanding elevation variation in biodiversity is a classic question in ecology and has implications for understanding climate change impacts on mountain ecosystems. While insects are the largest group of animals, the global trend in insect species richness with elevation is unknown. To date, single studies and taxa-specific syntheses have provided no single picture, finding variable patterns of insect richness with elevation. A global synthesis across systems would provide a better understanding of how insect species richness changes with elevation and the possible environmental correlates of those patterns. We used published studies of terrestrial insect elevation gradients from 1990 to 2020 to ask: How do insect species richness change with elevation, and which environmental variables best explain this relationship statistically? With 1486 sites spanning 151 species richness-elevation gradients from 80 studies from four diverse insect taxonomic groups and five biomes, we found that overall proportional richness reached a low-elevation plateau and then decreased. We also show that mean annual temperature and seasonality best explain this trend. We suggest best practices and areas of interest for the future of insect richness-elevation studies, including underrepresented groups, geographic areas, and more standardized methods.

Projecting Untruncated Climate Change Effects on Species' Climate Suitability: Insights From an Alpine Country.

Climate projections for continental Europe indicate drier summers, increased annual precipitation, and less snowy winters, which are expected to cause shifts in species' distributions. Yet, most regions/countries currently lack comprehensive climate-driven biodiversity projections across taxonomic groups, challenging effective conservation efforts. To address this gap, our study evaluated the potential effects of climate change on the biodiversity of an alpine country of Europe, Switzerland. We used a state-of-the art species distribution modeling approach and species occurrence data that covered the climatic conditions encountered across the full species' ranges to help limiting niche truncation. We quantified the relationship between baseline climate and the spatial distribution of 7291 species from 12 main taxonomic groups and projected future climate suitability for three 30-year periods and two greenhouse gas concentration scenarios (RCP4.5 and 8.5). Our results indicated important effects of projected climate changes on species' climate suitability, with responses varying by the taxonomic and conservation status group. The percentage of species facing major changes in climate suitability was higher under RCP8.5 (68%) compared to RCP4.5 (66%). By the end of the century, decreases in climate suitability were projected for 3000 species under RCP8.5 and 1758 species under RCP4.5. The most affected groups under RCP8.5 were molluscs, algae, and amphibians, while it was molluscs, birds, and vascular plants under RCP4.5. Spatially, by 2070-2099, we projected an overall decrease in climate suitability for 39% of the cells in the study area under RCP8.5 and 10% under RCP4.5, while projecting an increase for 50% of the cells under RCP8.5 and 73% under RCP4.5. The most consistent geographical shifts were upward, southward, and eastward. We found that the coverage of high climate suitability cells by protected areas was expected to increase. Our models and maps provide guidance for spatial conservation planning by pointing out future climate-suitable areas for biodiversity.