Regional Species Richness Research Articles

High aquatic macrophyte diversity in Norwegian lakes north of the Arctic Circle

Abstract Aquatic macrophytes recolonised inland waters following the last glacial retreat. The resulting diversity and the variables influencing it remain largely unexplored north of the Arctic Circle, including possible effects of past colonisation routes. Our understanding of species diversity north of the Arctic Circle has also been hampered by a lack of control in sampling effort. Here we use a newly assembled set of lake surveys from Norway to test: (1) whether regional richness (γ diversity) as well as turnover, net gain and loss (β diversity) of species differ between bioclimatic zones, latitudinal bands, and geographical regions; (2) how the environment and the spatial structure (e.g. dispersal constraints) may predict lake species richness (α diversity); and (3) how the changes in species β diversity between lakes are related to these environmental and spatial gradients. We expected high species turnover with longitude, net species loss with latitude and higher species richness in north‐east compared to mid Norway due to geographical dispersal barriers and past recolonisation routes. However, the regional species richness was similar across all geographical regions after correcting for sampling effort and spatial extent, with slightly lower richness in north Norway (−4%) and north‐east Norway (−11%) than expected by the species area relationship. Species β diversity (both turnover and loss) was also surprisingly low between most areas. Species richness per lake increased with lake area and temperature, showed a preferential peak at 10 μg/L total phosphorus, was sensitive to spatial structure, and largely indifferent to calcium (or alkalinity). In contrast, β diversity (mostly turnover) increased with differences in calcium, total phosphorus, and latitude, while not responding much to temperature and lake area. Species loss and gain between lakes were hardly related to any of the selected variables. Overall, species richness (α, γ) was higher than expected north of the Arctic Circle mostly due to species turnover with little net loss. These patterns suggested good dispersal abilities by aquatic plants, after controlling for sampling efforts and spatial extent. Conservation of aquatic plants should not be driven by the delineation of terrestrial vegetation zones, but through an understanding of the variables affecting aquatic plant diversity. Finally, northern lakes may be increasingly important as reservoirs of macrophyte diversity under global warming.

Phylogenetic, species richness and logistic influences on the biodiscovery process in Cnidaria

The extent to which any particular taxon supplies novel natural products depends on biological and evolutionary differences, and on decisions made by (or constraints on) biodiscovery scientists. The influences of different sources of variability on the biodiscovery process were examined in a study of the Cnidaria, a group recognised as an important source of novel marine natural products. The number of species with at least one novel metabolite within a genus was related to the number of species in the genus. This pattern implies that different genera do not differ in the probability of containing a species with novel natural products. Outlying points of this relationship were consistent with the ease of obtaining material through culturing organisms. The most productive five species were the sources of over 100 novel metabolites each. The distribution of novel metabolites across species showed no signs of exhausting novelty for the most productive source species. Novel metabolite drug likeness (ADMET-score) varied among genera. However, this pattern of variation was of the same degree as observed for molecular weights of metabolites, suggesting that differences among genera are generated by the decisions of analysts with different interests and do not reflect underlying biology. Biogeographic patterns of soft coral species with novel natural products were matched to regional species richness. Overall, the evidence for phylogenetic or spatial influences on the chance of finding novel metabolites was weak. The patterns are consistent with a constant chance of finding novel natural products across different species, with some constraints linked to ease of sampling or culturing and some reinforcement of biodiscovery in species that have previously been the source of novel metabolites.

Mammalian diversification bursts and biotic turnovers are synchronous with Cenozoic geoclimatic events in Asia

Asia's rich species diversity has been linked to its Cenozoic geodiversity, including active mountain building and dramatic climatic changes. However, prior studies on the diversification and assembly of Asian faunas have been derived mainly from analyses at taxonomic or geographic scales too limited to offer a comprehensive view of this complex region's biotic evolution. Here, using the class Mammalia, we built historical biogeographic models drawn on phylogenies of 1,543 species occurring across Asia to investigate how and when the mammal diversity in Asian regions and mountain hotspots was assembled. We explore the roles of in situ speciation, colonization, and vicariance and geoclimatic events to explain the buildup of Asia's regional mammal diversity through time. We found that southern Asia has served as the main cradle of Asia's mammal diversity. Present-day species richness in other regions is mainly derived from colonization, but by the Miocene, in situ speciation increased in importance. The high biodiversity present in the mountain hotspots (Himalayas and Hengduan) that flank the Qinghai-Tibetan plateau is a product of high colonization instead of in situ speciation, making them important centers of lineage accumulation. Overall, Neogene was marked by great diversification and migrations across Asia and surrounding continents but Paleogene environments already hosted rich mammal assemblages. Our study revealed that synchronous diversification bursts and biotic turnovers are temporally associated with tectonic events (mountain building, continental collisions) and drastic reorganization of climate (aridification of Asian interior, intensification of Asian monsoons, sea retreat) that took place throughout the Cenozoic in Asia.

Smaller, more diverse and on the way to the top: Rapid community shifts of montane wild bees within an extraordinary hot decade

AbstractAimGlobal warming is assumed to restructure mountain insect communities in space and time. Theory and observations along climate gradients predict that insect abundance and richness, especially of small‐bodied species, will increase with increasing temperature. However, the specific responses of single species to rising temperatures, such as spatial range shifts, also alter communities, calling for intensive monitoring of real‐world communities over time.LocationGerman Alps and pre‐alpine forests in south‐east Germany.MethodsWe empirically examined the temporal and spatial change in wild bee communities and its drivers along two largely well‐protected elevational gradients (alpine grassland vs. pre‐alpine forest), each sampled twice within the last decade.ResultsWe detected clear abundance‐based upward shifts in bee communities, particularly in cold‐adapted bumble bee species, demonstrating the speed with which mobile organisms can respond to climatic changes. Mean annual temperature was identified as the main driver of species richness in both regions. Accordingly, and in large overlap with expectations under climate warming, we detected an increase in bee richness and abundance, and an increase in small‐bodied species in low‐ and mid‐elevations along the grassland gradient. Community responses in the pre‐alpine forest gradient were only partly consistent with community responses in alpine grasslands.Main ConclusionIn well‐protected temperate mountain regions, small‐bodied bees may initially profit from warming temperatures, by getting more abundant and diverse. Less severe warming, and differences in habitat openness along the forested gradient, however, might moderate species responses. Our study further highlights the utility of standardized abundance data for revealing rapid changes in bee communities over only one decade.

Integrative taxonomic analysis of new collections from the central Angolan highlands resolves the taxonomy of African pipistrelloid bats on a continental scale

Abstract Ten years ago, the genus-level and species-level taxonomy of African pipistrelloid bats was in a state of flux. In spite of advances in the past decade, gaps in collecting from species-rich regions like Angola have hampered efforts to revise this group. We report on new collections of pipistrelle-like bats from the poorly sampled central highlands of Angola (1000–1500 m a.s.l.) as well as comparative material from lower-lying areas of Eswatini and South Africa. Specimens identified as Neoromicia anchietae, collected 400–700 km east of the holotype locality in the western highlands of Angola, were genetically and morphologically distinctive from N. anchietae s.l. from South Africa and Eswatini. We describe herein this latter lineage as a distinct species from low-lying areas of south-eastern Africa, distinct from N. anchietae s.s., which is therefore restricted to the central and western Angolan highlands. We also identified shallow to deep genetic divergence between different African regions in other recognized pipistrelloid species, such as conspecificity between the long-eared species Laephotis angolensis from Angola and Laephotis botswanae from northern Botswana, northern Namibia and south-western Zambia. Our phylogeny supports a recently proposed generic classification of African pipistrelloid bats.

Vegetation complexity and pool size predict species richness of forest birds

Disentangling regional and local drivers of species richness in communities is a long-term focus of ecology. Regional species pools affect local communities by providing their constituent species. Additionally, the amount and variety of resources enhance diversity locally. Here, we investigated whether the same ecological factor (vegetation complexity) shapes both regional and local species richness and thus drives local diversity both indirectly (via pool size) and directly (via facilitating the coexistence of species). We studied passerine birds of woodlands and forests in eastern Australia. We quantified regional species pool size and sampled local bird communities at 63 transects spanning 3,000 km. We estimated canopy height both regionally using satellite imagery and locally using vegetation sampling in the field. We studied how species pool size changed with regional canopy height and water availability, and how local species richness changed with pool size and local canopy height. Local species richness increased with both local canopy height and the size of the regional species pool. Pool size, in turn, increased with regional canopy height, which itself increased with water availability. Moreover, local species richness expressed as a proportion of the regional pool also increased with local canopy height. In sum, vegetation complexity indexed by canopy height had a doubly positive effect on local species richness: indirectly by promoting a large regional species pool and directly by facilitating the coexistence of disproportionately many species locally. Regional pools were larger in tall forests probably due to the legacy of extensive moist forests that once covered most of Australia, thus providing a sizeable potential for speciation, diversification, and species persistence. Local species richness was greater in tall, more productive forests with more vegetation layers likely due to more and varied resources (i.e., more potential niches), allowing the coexistence of more individuals and species of consumers.

Global water consumption impacts on riverine fish species richness in Life Cycle Assessment

Reduced river discharge and flow regulation are significant threats to freshwater biodiversity. An accurate representation of potential damage of water consumption on freshwater biodiversity is required to quantify and compare the environmental impacts of global value chains. The effect of discharge reduction on fish species richness was previously modeled in life cycle impact assessment, but models were limited by the restricted geographical scope of underlying species-discharge relationships and the small number of species data. Here, we propose a model based on a novel regionalized species-discharge relationship (SDR). Our SDR-based model covers 88 % of the global landmass (2320 river basins worldwide excluding deserts and permanently frozen areas) and is based on a global dataset of 11,450 riverine fish species, simulated river discharge, elevation, and climate zones. We performed 10-fold cross-validation to select the best set of predictors and validated the obtained SDRs based on observed discharge data. Our model performed better than previous SDRs employed in life cycle impact assessment (Kling-Gupta efficiency coefficient about 4 times larger). We provide both marginal and average models with their uncertainty ranges for assessing scenarios of small and large-scale water consumption, respectively, and include regional and global species loss. We conducted an illustrative case study to showcase the method's applicability and highlight the differences with the currently used approach. Our models are useful for supporting sustainable water consumption and riverine fish biodiversity conservation decisions. They enable a more specific, reliable, and complete impact assessment by differentiating impacts on regional riverine fish species richness and irreversible global losses, including up-to-date species data, and providing spatially explicit values with high geographical coverage.

Influence of landscape composition on wild bee communities: Effects of functional landscape heterogeneity

Landscapes dominated by conventional agriculture reduce and simplify natural habitats, with negative consequences for ecosystem regulating services. We examined differences in structure and composition of bee communities across biotic and abiotic gradients to investigate how these communities respond to land-use changes associated with agriculture. Studies like ours which evaluates the relative effect of different components of spatial heterogeneity remain uncommon and are important to conserve pollinator fauna. The diversity of floral resources and habitat richness including the configuration and composition of landscape heterogeneity have been shown to influence the diversity of wild bees on a landscape scale. In this study, we examined how wild bee communities respond to landscape heterogeneity in a semi-arid productive region of Entre Ríos Argentina. We modeled the effect of landscape heterogeneity on wild bee community abundance, species richness, and Chao-1 diversity. We sampled bees using pan traps in four common land-uses in the region (forest plantations, pasture/croplands, mixed use areas and native espinal savanna) for five months in the spring-summer of 2014–2015. We identified 96 bee species among 3407 bees collected in the four habitat types. Pasture/croplands along with native espinal savanna supported the highest abundance, richness, and diversity of bees. Species composition of wild bee communities differed between land uses, with numerous species unique to each land use. Across all land use types, diversity of flower resources consistently supported more abundant and diverse wild bee communities. The richness of habitats along with the diversity of floral resources acted synergistically over wild bee communities. Our findings further clarify the relationship between land-use and wild bee communities, which provide valuable pollination services to crops and native plants. Continued expansion of large-scale monoculture forest plantations will likely come at the expense of the native floral resources, which are a key component to support regional bee species richness. Promoting landscapes with a diversity of crops and flower resources are important for the conservation of pollinators that are key for the functioning of ecosystems.

Which is the richest of them all? Comparing area-adjusted plant diversities of Mediterranean- and tropical-climate regions

Mediterranean- and tropical-climate regions harbour the richest regional-scale floras globally. Until recently, however, comparisons of their diversities have been hindered by a lack of comprehensive inventories of tropical floras. Using taxonomically verified floras, we analyse area-adjusted plant diversities of five Mediterranean- and 35 tropical-climate regions to determine which are the most species-rich regions on Earth. On average, the Neotropics and tropical Southeast Asia support the most diverse floras globally. However, the area-adjusted diversities of the richest floras in these tropical regions are matched by those of two Mediterranean-climate floras, namely the Cape (second richest) and Mediterranean Basin (sixth richest). Except for Madagascar and Burundi, the Afrotropical regions were substantially less diverse than other tropical floras and half of the Afrotropical floras were poorer than the least diverse Mediterranean-climate region, namely Central Chile. We evaluate the likely ecological and evolutionary drivers of these plant diversity patterns in terms of three hypotheses that are apposite for global scale comparisons, namely water-energy dynamics, biome stability, and ecological heterogeneity. Water-energy dynamics appear to have little influence in explaining these diversity patterns: nodes of high global plant diversity are associated with climates that support year-round plant production (tropical climates) and those where the growing season is constrained by a winter rainfall regime (Mediterranean-type climates). Moreover, while the Afrotropics have higher primary production than the Neotropics and Southeast Asian tropics, they have markedly lower plant diversity. Instead, these patterns appear to be consistent with the hypothesis that the synergy of historical biome stability (reducing extinction rates) and high ecological heterogeneity (promoting speciation rates) better explain global patterns of regional-scale plant diversity.

Accelerating the discovery of rare tree species in Amazonian forests: integrating long monitoring tree plot data with metabolomics and phylogenetics for the description of a new species in the hyperdiverse genus Inga Mill.

In species-rich regions and highly speciose genera, the need for species identification and taxonomic recognition has led to the development of emergent technologies. Here, we combine long-term plot data with untargated metabolomics, and morphological and phylogenetic data to describe a new rare species in the hyperdiverse genus of trees Inga Mill. Our combined data show that Inga coleyana is a new lineage splitting from their closest relatives I. coruscans and I. cylindrica. Moreover, analyses of the chemical defensive profile demonstrate that I. coleyana has a very distinctive chemistry from their closest relatives, with I. coleyana having a chemistry based on saponins and I. cylindrica and I. coruscans producing a series of dihydroflavonols in addition to saponins. Finally, data from our network of plots suggest that I. coleyana is a rare and probably endemic taxon in the hyper-diverse genus Inga. Thus, the synergy produced by different approaches, such as long-term plot data and metabolomics, could accelerate taxonomic recognition in challenging tropical biomes.

Gene flow, genomic homogenization and the timeline to speciation in Amazonian manakins.

Phylogeographical studies of the most species-rich region of the planet-the Amazon basin-have repeatedly uncovered genetically distinctive, allopatric lineages within currently named species, but understanding whether such lineages are reproductively isolated species is challenging. Here we harness the power of genome-wide data sets together with detailed phylogeographical sampling to both characterize the number of unique lineages and infer levels of reproductive isolation for three parapatric manakin species that make up the genus Pipra. The mitochondrial and nuclear genomes both support six distinctive lineages. The youngest lineages are now highly admixed with each other across major portions of their geographical ranges with one lineage now extinct in a genomically unadmixed state. In contrast, the oldest sets of lineages-dated to 1.4 million years-exhibit narrow hybrid zones. By fitting demographic models to parapatric lineage pairs we found that levels of gene flow and genomic homogenization decline with increasing evolutionary age. Only lineages descending from the basal node at 1.4 million years ago in the genus experience negligible gene flow, possess genomes resistant to homogenization and are separated by narrow hybrid zones. We conclude that a million years or more were required for Pipra manakins to become reproductively isolated. We suggest the six lineages be reclassified as two or three reproductively isolated species. Our unique approach to quantifying reproductive isolation in parapatric lineages could be applied broadly to other phylogeographical studies and would help determine species classification of the plethora of newly identified lineages in the Amazon basin and other regions.

The counteracting effects of anthropogenic speciation and extinction on mammal species richness and phylogenetic diversity

AbstractAimHuman activities are causing massive increases in extinction rates but might also lead to drastic increases in speciation rates; for example, after human‐mediated spread of species to otherwise unreachable landmasses. The long‐term net anthropogenic effects on biodiversity therefore remain uncertain. Our aim was to assess the combined anthropogenic effects of extinctions and speciations on biodiversity over geological time‐scales.LocationGlobal.Time periodPresent and predicted future.Major taxa studiedTerrestrial mammals.MethodsWe estimated known anthropogenic and predicted future extinctions based on Red List categories from the International Union for Conservation of Nature. We inferred potential anthropogenic speciations, assuming that all introductions to isolated landmasses would, over time, evolve into distinct species. We then estimated changes in regional and global species richness and phylogenetic diversity attributable to these extinctions and speciations.ResultsWe demonstrated that if all species introduced onto new landmasses develop into new species, the number of anthropogenic speciation and extinctions eventually become similar. However, even after accounting for an anthropogenic increase in speciation, our estimates suggest recovery times for phylogenetic diversity of several millions of years.Main conclusionsOur results highlight that although humans are causing drastic biodiversity losses, human‐driven speciation could eventually counterbalance these losses in species numbers, whereas phylogenetic diversity, at least within our simulation scenarios, would remain permanently reduced. This conclusion, however, requires our pressures on biodiversity to cease soon and requires us to consider geological time‐scales rather than changes over this century.

Patterns of Phenotypic Evolution Associated with Marine/Freshwater Transitions in Fishes.

Evolutionary transitions between marine and freshwater ecosystems have occurred repeatedly throughout the phylogenetic history of fishes. The theory of ecological opportunity predicts that lineages that colonize species-poor regions will have greater potential for phenotypic diversification than lineages invading species-rich regions. Thus, transitions between marine and freshwaters may promote phenotypic diversification in trans-marine/freshwater fish clades. We used phylogenetic comparative methods to analyze body size data in nine major fish clades that have crossed the marine/freshwater boundary. We explored how habitat transitions, ecological opportunity, and community interactions influenced patterns of phenotypic diversity. Our analyses indicated that transitions between marine and freshwater habitats did not drive body size evolution, and there are few differences in body size between marine and freshwater lineages. We found that body size disparity in freshwater lineages is not correlated with the number of independent transitions to freshwaters. We found a positive correlation between body size disparity and overall species richness of a given area, and a negative correlation between body size disparity and diversity of closely related species. Our results indicate that the diversity of incumbent freshwater species does not restrict phenotypic diversification, but the diversity of closely related taxa can limit body size diversification. Ecological opportunity arising from colonization of novel habitats does not seem to have a major effect in the trajectory of body size evolution in trans-marine/freshwater clades. Moreover, competition with closely related taxa in freshwaters has a greater effect than competition with distantly related incumbent species.

Spatial and temporal extents of natural disturbances differentiate deadwood-inhabiting fungal communities in spruce primary forest ecosystems

Understanding the processes shaping the composition of assemblages at multiple spatial scales in response to disturbance events is crucial for preventing ongoing biodiversity loss and for improving current forest management policies aimed at mitigating climate change and enhancing forest resilience. Deadwood-inhabiting fungi represent an essential component of forest ecosystems through their association with deadwood decomposition and the cycling of nutrients and carbon. Although we have sufficient evidence for the fundamental role of deadwood availability and variability of decay stages for fungal species diversity, the influence of long-term natural disturbance regimes as the main driver of deadwood quantity and quality has not been sufficiently documented. We used a dendroecological approach to analyse the effect of 250-years of historical natural disturbance and structural habitat elements on local (plot-level) and regional (stand-level) species richness of deadwood-inhabiting fungi. We used data collected from 51 study plots within nine best-preserved primary spruce forest stands distributed across the Western Carpathian Mountains. Historical disturbances shaped the contemporary local and regional species richness of fungi, with contrasting impacts of disturbance regime components at different spatial scales. While local diversity of red-listed species has increased due to higher disturbance frequency, regional diversity of all species has decreased due to higher severity historical disturbances. The volume of deadwood positively influenced the species richness of deadwood-inhabiting fungi while canopy openness had a negative impact. The high number of observed rare species highlights the important role of primary forests for biodiversity conservation. From a landscape perspective, we can conclude that the distribution of species from the regional species pool is - at least to some extent - driven by past spatiotemporal patterns of disturbance events. Natural disturbances occurring at higher frequencies that create a mosaic forest structure are necessary for fungal species - especially for rare and endangered taxa. Thus, both the protection of intact forest landscapes and forest management practises that emulate natural disturbance processes are recommended to support habitats of diverse fungal communities and their associated ecosystem functions.

Robust metagenomic evidence that local assemblage richness increases with latitude in ground‐active invertebrates of North America

Biodiversity monitoring is imperative for understanding how changing climate may impact the distributions of taxa from single species to the spatial distribution of biological diversity. Large‐scale and cross‐taxa biodiversity monitoring also allows an empirical understanding of biogeographic patterns across taxa. One such pattern, where in taxonomic richness peaks at tropical latitudes are typically treated as a biogeographical rule with few notable exceptions. Here we leveraged the invertebrate pitfall collections of the National Ecological Observatory Network (NEON) across North America to describe patterns of local taxonomic richness across taxa and across taxonomic scale. We focused on Arthropoda, Annelida and Mollusca. Additionally, we estimated regional species richness using expert‐identified samples of three NEON sentinel taxa: Carabidae, Culicidae and Ixodida. To sample pitfall animals, we filtered storage ethanol and employed environmental DNA‐barcoding methodologies to amplify and sequence extracted DNA from the filtrate for two regions of a mitochondrial gene. We assigned taxonomic names to these sequences at 97% similarity to reference sequences and calculated local taxonomic richness at the levels of species, genus, family and order. We calculated local species richness for 12 common invertebrate taxa. We used generalized linear models to describe the relationships between taxonomic richness and spatial, climatic and abundance predictor variables. At four taxonomic scales, ranging from species to order, taxonomic richnessincreased significantly as a function of latitude. Of the twelve invertebrate taxa weexamined, seven mirrored this positive latitudinal gradient in species richness. At theregional scale, two of three NEON Sentinel Taxa showed positive latitudinal gradientsin species richness. Temperature, precipitation, abundance and sequence read numberplayed minor roles in explaining patterns of taxonomic richness. When considering these mostly temperate sites that span 46 degrees of latitude, we found no support for the expected negative latitudinal gradients across taxa and taxonomic scales. Instead, for many of these taxa and taxonomic scales, we observed significant, positive richness gradients with increasing latitude among ground‐dwelling invertebrate communities. Thus, one of the most ‘general' patterns in biogeography was not found for most invertebrate taxa across temperate latitudes.

When humans work like beavers: riparian restoration enhances invertebrate gamma diversity and habitat heterogeneity

Restoration has the potential to increase habitat heterogeneity through the creation of unique habitat patches that, in turn, increase regional species richness or gamma diversity. While biological diversity and habitat heterogeneity are important factors to consider under a shifting climate, restoration actions and outcomes rarely examine these components. In this study, we examined the effects of riparian beaver dam analog (BDA) restoration on aquatic invertebrate diversity and habitat heterogeneity. Although the effects of BDAs on hydrology, geomorphology, and salmonid habitat have been explored, we are unaware of any studies assessing their effects on aquatic invertebrate diversity and the food web that supports them. We sampled aquatic invertebrates, basal carbon resources, dissolved nutrients, turbidity, and water temperature in pre‐ and post‐BDA pond, side channel, and mainstem habitat over a three‐year period. The BDAs functioned similarly to natural beaver dams and created slow‐water environments that accumulated fine particulate organic material and increased pelagic phytoplankton production. Nonmetric multidimensional scaling, permutation multivariate analysis of variance, and Mantel's tests demonstrated that these changes led to the formation of a unique invertebrate community populated by lentic macroinvertebrates and zooplankton, which increased beta‐diversity and gamma diversity. Further, BDAs in our study maintained high densities of invertebrates and buffered water temperatures in comparison to adjacent lotic habitats. These results support our hypothesis that BDAs can enhance invertebrate beta and gamma diversity through the creation and colonization of unique pond habitat and improve habitat and resource heterogeneity for native fishes under variable climate conditions.

A Strategy to Provide a Present and Future Scenario of Mexican Biodiversity of Tardigrada

Although the number of known tardigrade taxa in Mexico has increased significantly in the last ten years, the knowledge of their diversity faces challenges, as more than half of the Mexican territory has no records of this phylum. Thus, we developed a strategy to provide a present and future scenario for understanding the Mexican biodiversity of Tardigrada, described the distribution patterns of the current recorded species, calculated the estimated richness, and the estimated taxonomic effort needed to complete the national inventory. We obtained 474 records of 105 taxa, belonging to 42 genera and 75 species, distributed in 12 of the 14 biogeographical provinces of Mexico. We found that 54.72% of the species are present in more than three world regions and 3.79% of species that have been recorded only in Mexican provinces. Distribution patterns could be recognized for 11 species, two of which have a Nearctic distribution, seven are Neotropical and two are distributed in both regions. The Mexican biogeographical provinces with the greatest diversity of tardigrades, both at specific and generic level, were the Transmexican Volcanic Belt (TVBP) and the Sierras Madre Oriental (SMOrP) and Sierra Madre Occidental (SMOcP), which have been previously identified as particularly species-rich regions. Diversity estimation methods predict that more than 290 species of tardigrades could be found in Mexico.

Evaluating ecological uniqueness over broad spatial extents using species distribution modelling

Local contributions to beta diversity (LCBD) can be used to identify sites with high ecological uniqueness and exceptional species composition within a region of interest. Yet, these indices are typically used on local or regional scales with relatively few sites, as they require information on complete community compositions difficult to acquire on larger scales. Here, we investigated how LCBD indices can be predicted over broad spatial extents using species distribution modelling and examined the effect of scale changes on beta diversity quantification. We used Bayesian additive regression trees (BARTs) to predict warbler species distributions in North America based on observations recorded in the eBird database. We then calculated LCBD indices for observed and predicted data and compared the site‐wise difference using direct comparison, a spatial association test and generalized linear regression. We also examined the relationship between LCBD values and species richness in different regions and at various spatial extents. Our results showed that species distribution models provided uniqueness estimates highly correlated with observed data. The form and variance of the LCBD–richness relationship varied according to the region and the total extent size. The relationship was also affected by the proportion of rare species in the communities. Therefore, sites identified as unique over broad spatial extents may vary according to regional characteristics. These results show that species distribution modelling can be used to predict ecological uniqueness over broad spatial extents, which could help identify beta diversity hotspots and important targets for conservation purposes in unsampled locations.

Altitude and temperature drive anuran community assembly in a Neotropical mountain region

AbstractUnderstanding the spatial variation in species richness and the mechanisms that limit species range sizes along geographical gradients belong to the central research issues in macroecology. Here, we aim to test the topographic and climatic effects on anuran species richness and community composition in mountainous regions in the Brazilian Atlantic Forest biome. We used Individual‐Based Rarefaction Curve (interpolation and extrapolation), Generalized Additive Model (GAM), Midpoint method and Principal Coordinates Analysis (PCoA) to analyze the topographic and climatic effects on anuran community composition, richness, and range sizes in a global biodiversity hotspot. Our results showed that altitude and annual mean temperature and temperature seasonality were the main drivers of species altitudinal range sizes and community assembly in mountainous regions. In conclusion, Anuran community richness peaked at intermediate altitudes following thus a hump‐shaped pattern and corroborated the Rapoport's altitudinal rule as range sizes increased with altitude in mountainous regions from the Atlantic Forest biome. This study revealed new insights into the patterns and drivers of Neotropical anuran communities.Abstract in Portuguese is available with online material.

The first record of Neodilatilabrum Dekkers, 2008 (Stromboidea, Neostromboidae, Strombidae) in Australia

Presented herein are the first verifiable records of Neodilatilabrum Dekkers, 2008 in Australia. The two examples of Neodilatilabrum robustum (Sowerby, 1875) come from Point Cartwright and Dingo Beach, Queensland. These specimens represent an anomaly, being morphologically similar to a localized South China Sea population. The possible modalities to explain its presence at this locality are discussed. This discovery reaffirms the importance of proactive engagement between citizen scientists and institutional workers to enable a greater understanding of regional species richness.