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Species distribution data are crucial for assessing the conservation status of species (red listing, IUCN) and implementing international conservation targets, such as those set by the International Convention on Biological Diversity. Although there have been a number of efforts aimed at aggregating biodiversity data, information on the distribution of many taxa is still scanty (i.e. the Wallacean Shortfall). In this study, we use a large database, including over 19 million species occurrence records, to identify knowledge gaps in biodiversity inventories for butterfly records at a global level. Bayesian hierarchical spatial models were used to quantify the relationship between gaps in inventory completeness and the density of roads, protected areas and elevational range, the former variable being a proxy for accessibility, the latter two for attractiveness to recorders. Our results show that despite >100 years of butterfly sampling, knowledge of the distribution of butterflies is still limited in tropical areas. The results revealed that gaps in butterfly inventories are largely concentrated in areas of low elevational range, low density of protected areas and low road density. We conclude that the Wallacean Shortfall is a problem even for one of the best studied insect groups. In the light of these data limitations, we discuss prospects for filling gaps in butterfly inventories at the global scale within relatively short time frames. We argue that a combination of citizen science and quantitative tools may help to fill knowledge gaps and inform conservation decisions. © 2019 Elsevier Ltd

Aim: To quantify the influence of past archipelago configuration on present-day insular biodiversity patterns, and to compare the role of long-lasting archipelago configurations over the Pleistocene to configurations of short duration such as at the Last Glacial Maximum (LGM) and the present-day. Location: 53 volcanic oceanic islands from 12 archipelagos worldwide—Azores, Canary Islands, Cook Islands, Galápagos, Gulf of Guinea, Hawaii, Madeira, Mascarenes, Pitcairn, Revillagigedo, Samoan Islands and Tristan da Cunha. Time period: The last 800 kyr, representing the nine most recent glacial–interglacial cycles. Major taxa studied: Land snails and angiosperms. Methods: Species richness data for land snails and angiosperms were compiled from existing literature and species checklists. We reconstructed archipelago configurations at the following sea levels: the present-day high interglacial sea level, the intermediate sea levels that are representative of the Pleistocene and the low sea levels of the LGM. We fitted two alternative linear mixed models for each archipelago configuration using the number of single-island endemic, multiple-island endemic and (non-endemic) native species as a response. Model performance was assessed based on the goodness-of-fit of the full model, the variance explained by archipelago configuration and model parsimony. Results: Single-island endemic richness in both taxonomic groups was best explained by intermediate palaeo-configuration (positively by area change, and negatively by palaeo-connectedness), whereas non-endemic native species richness was poorly explained by palaeo-configuration. Single-island endemic richness was better explained by intermediate archipelago configurations than by the archipelago configurations of the LGM or present-day. Main conclusions: Archipelago configurations at intermediate sea levels—which are representative of the Pleistocene—have left a stronger imprint on single-island endemic richness patterns on volcanic oceanic islands than extreme archipelago configurations that persisted for only a few thousand years (such as the LGM). In understanding ecological and evolutionary dynamics of insular biota it is essential to consider longer-lasting environmental conditions, rather than extreme situations alone. © 2018 John Wiley & Sons Ltd

Aim: Land-use change typically goes hand in hand with the introduction of exotic species, which mingle with indigenous species to form novel assemblages. Here, we compare the functional structure of indigenous and exotic elements of ground-dwelling arthropod assemblages across four land-uses of varying management intensity. Location: Terceira Island (Azores, North Atlantic). Methods: We used pitfall traps to sample arthropods in 36 sites across the four land-uses and collated traits related to dispersal ability, body size and resource use. For both indigenous and exotic species, we examined the impact of land-uses on trait diversity and tested for the existence of non-random assembly processes using null models. We analysed differences in trait composition among land-uses for both indigenous and exotic species with multivariate analyses. We used point–biserial correlations to identity traits significantly correlated with specific land-uses for each element. Results: We recorded 86 indigenous and 116 exotic arthropod species. Under high-intensity land-use, both indigenous and exotic elements showed significant trait clustering. Trait composition strongly shifted across land-uses, with indigenous and exotic species being functionally dissimilar in all land-uses. Large-bodied herbivores dominated exotic elements in low-intensity land-uses, while small-bodied spiders dominated exotic elements in high-intensity land-uses. In contrast, with increasing land-use intensity, indigenous species changed from functionally diverse to being dominated by piercing and cutting herbivores. Main conclusions: Our study revealed two main findings: first, in high-intensity land-uses, trait clustering characterized both indigenous and exotic elements; second, exotic species differed in their functional profile from indigenous species in all land-use types. Overall, our results provide new insights into the functional role of exotic species in a land-use context, suggesting that, in agricultural landscape, exotic species may contribute positively to the maintenance of some ecosystem functions. © 2017 John Wiley & Sons Ltd

The general dynamic model of oceanic island biogeography (GDM) has added a new dimension to theoretical island biogeography in recognizing that geological processes are key drivers of the evolutionary processes of diversification and extinction within remote islands. It provides a dynamic and essentially non-equilibrium framework generating novel predictions for emergent diversity properties of oceanic islands and archipelagos. Its publication in 2008 coincided with, and spurred on, renewed attention to the dynamics of remote islands. We review progress, both in testing the GDM’s predictions and in developing and enhancing ecological–evolutionary understanding of oceanic island systems through the lens of the GDM. In particular, we focus on four main themes: (i) macroecological tests using a space-for-time rationale; (ii) extensions of theory to islands following different patterns of ontogeny; (iii) the implications of GDM dynamics for lineage diversification and trait evolution; and (iv) the potential for downscaling GDM dynamics to local-scale ecological patterns and processes within islands. We also consider the implications of the GDM for understanding patterns of non-native species diversity. We demonstrate the vitality of the field of island biogeography by identifying a range of potentially productive lines for future research. © 2016 Cambridge Philosophical Society.

Recent findings based on molecular data support the occurrence in the Azores of several independently evolving lineages of the beetle genus Tarphius Erichson, 1845 (Coleoptera: Zopheridae Solier, 1834) and higher species richness masked by cryptic diversity, needing formal taxonomic description. All Tarphius from the Azores are revised using an integrative taxonomic approach, using evidence from morphology, morphometrics and molecular data to delimit species. Our results reveal that Azorean Tarphius comprise at least five phyletic lineages, two of which share a similar morphology, despite being divergent at the molecular level. A total of four new species are described grouped into two complexes: I) two new species in the "complex tornvalli" with the new taxa Tarphius relictus sp. Nov. (Terceira) and Tarphius furtadoi sp. Nov. (São Jorge, Faial and Pico) and; ii) two new species in the "complex azoricus-wollastoni-depressus" with the new taxa Tarphius gabrielae sp. Nov. (Pico) and Tarphius floresensis sp. Nov. (Flores). Descriptions, photographs of holotypes and morphological details, and remarks on diagnostic features comparing similar species are presented. Additional information on the distribution and conservation status of the 12 described species in the archipelago is also provided. © 2017 Magnolia Press.

Species abundance distributions (SAD) are central to the description of diversity and have played a major role in the development of theories of biodiversity and biogeography. However, most work on species abundance distributions has focused on one single spatial scale. Here we used data on arthropods to test predictions obtained with computer simulations on whether dispersal ability influences the rate of change of SADs as a function of sample size. To characterize the change of the shape of the SADs we use the moments of the distributions: the skewness and the raw moments. In agreement with computer simulations, low dispersal ability species generate a hump for intermediate abundance classes earlier than the distributions of high dispersal ability species. Importantly, when plotted as function of sample size, the raw moments of the SADs of arthropods have a power law pattern similar to that observed for the SAD of tropical tree species, thus we conjecture that this might be a general pattern in ecology. The existence of this pattern allows us to extrapolate the moments and thus reconstruct the SAD for larger sample sizes using a procedure borrowed from the field of image analysis based on scaled discrete Tchebichef moments and polynomials. © 2017 The Author(s).

Aims: The 50th anniversary of the publication of the seminal book, The Theory of Island Biogeography, by Robert H. MacArthur and Edward O. Wilson, is a timely moment to review and identify key research foci that could advance island biology. Here, we take a collaborative horizon-scanning approach to identify 50 fundamental questions for the continued development of the field. Location: Worldwide. Methods: We adapted a well-established methodology of horizon scanning to identify priority research questions in island biology, and initiated it during the Island Biology 2016 conference held in the Azores. A multidisciplinary working group prepared an initial pool of 187 questions. A series of online surveys was then used to refine a list of the 50 top priority questions. The final shortlist was restricted to questions with a broad conceptual scope, and which should be answerable through achievable research approaches. Results: Questions were structured around four broad and partially overlapping island topics, including: (Macro)Ecology and Biogeography, (Macro)Evolution, Community Ecology, and Conservation and Management. These topics were then subdivided according to the following subject areas: global diversity patterns (five questions in total); island ontogeny and past climate change (4); island rules and syndromes (3); island biogeography theory (4); immigration–speciation–extinction dynamics (5); speciation and diversification (4); dispersal and colonization (3); community assembly (6); biotic interactions (2); global change (5); conservation and management policies (5); and invasive alien species (4). Main conclusions: Collectively, this cross-disciplinary set of topics covering the 50 fundamental questions has the potential to stimulate and guide future research in island biology. By covering fields ranging from biogeography, community ecology and evolution to global change, this horizon scan may help to foster the formation of interdisciplinary research networks, enhancing joint efforts to better understand the past, present and future of island biotas. © 2017 John Wiley & Sons Ltd

Background In this contribution we present detailed distribution and abundance data for arthropod species identified during the BALA - Biodiversity of Arthropods from the Laurisilva of the A zores (1999-2004) and BALA2 projects (2010-2011) from 18 native forest fragments in seven of the nine Azorean islands (all excluding Graciosa and Corvo islands, which have no native forest left). New information Of the total 286 species identified, 81% were captured between 1999 and 2000, a period during which only 39% of all the samples were collected. On average, arthropod richness for each island increased by 10% during the time frame of these projects. The classes Arachnida, Chilopoda and Diplopoda represent the most remarkable cases of new island records, with more than 30% of the records being novelties. This study stresses the need to expand the approaches applied in these projects to other habitats in the Azores, and more importantly to other less surveyed taxonomic groups (e.g. Diptera and Hymenoptera). These steps are fundamental for getting a more accurate assessment of biodiversity in the archipelago. © Borges P et al.

This work provides evidence that the "hollow curve" is a consistent pattern in the range size distribution of taxonomic and ecological groups of arthropod pasture dwelling species. Many of the inconsistent results relating range size to herbivores diet breadth are probably due to historical constraints in the colonization of the islands and particular characteristics of the habitats studied (e.g. types of resources available). The positive relationship between range size and abundance may be explained by the "resource usage model". However, the slope of the regression line relating distribution to abundance was similar for different groups which suggests there is no difference in the way that the species’ local abundance scales with distribution in the four assemblages of species studied and that there is a close relationship between the trophic groups studied. This suggests that the “resource availability model” could be the explanation for the distribution and abundance of pasture spider and insect species. More work needs to be conducted in order to evaluate the relationship between diet breadth, habitat specialization and range size in the islands.

Reliable taxonomy underpins communication in all of biology, not least nature conservation and sustainable use of ecosystem resources. The flexibility of taxonomic interpretations, however, presents a serious challenge for end-users of taxonomic concepts. Users need standardised and continuously harmonised taxonomic reference systems, as well as highquality and complete taxonomic data sets, but these are generally lacking for nonspecialists. The solution is in dynamic, expertly curated web-based taxonomic tools. The Pan-European Species-directories Infrastructure (PESI) worked to solve this key issue by providing a taxonomic e-infrastructure for Europe. It strengthened the relevant social (expertise) and information (standards, data and technical) capacities of five major community networks on taxonomic indexing in Europe, which is essential for proper biodiversity assessment and monitoring activities. The key objectives of PESI were: 1) standardisation in taxonomic reference systems, 2) enhancement of the quality and completeness of taxonomic data sets and 3) creation of integrated access to taxonomic information. New information This paper describes the results of PESI and its future prospects, including the involvement in major European biodiversity informatics initiatives and programs. © de Jong Y et al.

A key challenge in island biogeography is to quantity the role of dispersal in shaping biodiversity patterns among the islands of a given archipelago. Here, we propose such a framework. Dispersal within oceanic archipelagos may be conceptualized as a spatio-temporal process dependent on: (1) the spatial distribution of islands, because the probability of successful dispersal is inversely related to the spatial distance between islands and (2) the chronological sequence of island formation that determines the directional asymmetry of dispersal (hypothesized to be predominantly from older to younger islands). From these premises, directional network models may be constructed, representing putative connections among islands. These models may be translated to eigenfunctions in order to be incorporated into statistical analysis. The framework was tested with 12 datasets from the Hawaii, Azores, and Canaries. The explanatory power of directional network models for explaining species composition patterns, assessed by the Jaccard dissimilarity index, was compared with simpler time-isolation models. The amount of variation explained by the network models ranged from 5.5% (for Coleoptera in Hawaii) to 60.2% (for Pteridophytes in Canary Islands). In relation to the four studied taxa, the variation explained by network models was higher for Pteridophytes in the three archipelagos. By the contrary, small fractions of explained variation were observed for Coleoptera (5.5%) and Araneae (8.6%) in Hawaii. Time-isolation models were, in general, not statistical significant and explained less variation than the equivalent directional network models for all the datasets. Directional network models provide a way for evaluating the spatio-temporal signature of species dispersal. The method allows building scenarios against which hypotheses about dispersal within archipelagos may be tested. The new framework may help to uncover the pathways via which species have colonized the islands of a given archipelago and to understand the origins of insular biodiversity. © 2015 The Authors.

Background: For a remote oceanic archipelago of up to 8 Myr age, the Azores have a comparatively low level of endemism. We present an analysis of phylogeographic patterns of endemic Azorean island arthropods aimed at testing patterns of diversification in relation to the ontogeny of the archipelago, in order to distinguish between alternative models of evolutionary dynamics on islands. We collected individuals of six species (representing Araneae, Hemiptera and Coleoptera) from 16 forest fragments from 7 islands. Using three mtDNA markers, we analysed the distribution of genetic diversity within and between islands, inferred the differentiation time-frames and investigated the inter-island migration routes and colonization patterns. Results: Each species exhibited very low levels of mtDNA divergence, both within and between islands. The two oldest islands were not strongly involved in the diffusion of genetic diversity within the archipelago. The most haplotype-rich islands varied according to species but the younger, central islands contributed the most to haplotype diversity. Colonization events both in concordance with and in contradiction to an inter-island progression rule were inferred, while a non-intuitive pattern of colonization from western to eastern islands was also inferred. Conclusions: The geological development of the Azores has followed a less tidy progression compared to classic hotspot archipelagos, and this is reflected in our findings. The study species appear to have been differentiating within the Azores for

Oceanic islands host a disproportionately high fraction of endangered or recently extinct endemic species. We report on species extinctions among endemic Azorean beetles following 97% habitat loss since AD 1440. We infer extinctions from historical and contemporary records and examine the influence of three predictors: geographical range, habitat specialization and body size. Of 55 endemic beetle species investigated (out of 63), seven can be considered extinct. Single-island endemics (SIEs) were more prone to extinction than multi-island endemics. Within SIEs restricted to native habitat, larger species were more extinction-prone. We thus show a hierarchical path to extinction in Azorean beetles: species with small geographical range face extinction first, with the larger bodied ones being the most threatened. Our study provides a clear warning of the impact of habitat loss on island endemic biotas. Azores, body size, endemic beetles, extinction, habitat destruction, oceanic islands. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Analyses of species-diversity patterns of remote islands have been crucial to the development of biogeographic theory, yet little is known about corresponding patterns in functional traits on islands and how, for example, they may be affected by the introduction of exotic species. We collated trait data for spiders and beetles and used a functional diversity index (FRic) to test for nonrandomness in the contribution of endemic, other native (also combined as indigenous), and exotic species to functional-trait space across the nine islands of the Azores. In general, for both taxa and for each distributional category, functional diversity increases with species richness, which, in turn scales with island area. Null simulations support the hypothesis that each distributional group contributes to functional diversity in proportion to their species richness. Exotic spiders have added novel trait space to a greater degree than have exotic beetles, likely indicating greater impact of the reduction of immigration filters and/or differential historical losses of indigenous species. Analyses of species occurring in native-forest remnants provide limited indications of the operation of habitat filtering of exotics for three islands, but only for beetles. Although the general linear (not saturating) pattern of trait-space increase with richness of exotics suggests an ongoing process of functional enrichment and accommodation, further work is urgently needed to determine how estimates of extinction debt of indigenous species should be adjusted in the light of these findings. © 2014 PNAS.

Successful conservation plans are conditioned by our ability to detect anthropogenic change in space and time and various statistical analyses have been developed to handle this critical issue. The main objective of this paper is to illustrate a new approach for spatial analysis in conservation biology. Here, we propose a two-step protocol. First, we introduce a new disturbance metric which provides a continuous measure of disturbance for any focal communities on the basis of the surrounding landscape matrix. Second, we use this new gradient to estimate species and community disturbance thresholds by implementing a recently developed method called Threshold Indicator Taxa ANalysis (TITAN). TITAN detects changes in species distributions along environmental gradients using indicators species analysis and assesses synchrony among species change points as evidence for community thresholds. We demonstrate our method with soil arthropod assemblages along a disturbance gradient in Terceira Island (Azores, Portugal). We show that our new disturbance metric realistically reflects disturbance patterns, especially in buffer zones (ecotones) between land use categories. By estimating species disturbance thresholds with TITAN along the disturbance gradient in Terceira, we show that species significantly associated with low disturbance differ from those associated with high disturbance in their biogeographical origin (endemics, non-endemic natives and exotics) and taxonomy (order). Finally, we suggest that mapping the disturbance community thresholds may reveal areas of primary interest for conservation, since these may host indigenous species sensitive to high disturbance levels. This new framework may be useful when: (1) both local and regional processes are to be reflected on single disturbance measures; (2) these are better quantified in a continuous gradient; (3) mapping disturbance of large regions using fine scales is necessary; (4) indicator species for disturbance are searched for and; (5) community thresholds are useful to understand the global dynamics of habitats. © 2013 Cardoso et al.

There is a broad consensus that habitat disturbance and introduction of non-indigenous species may dramatically modify community structure, particularly in insular ecosystems. However, it is less clear whether emergent macroecological patterns are similarly affected. The positive interspecific abundance-occupancy relationship (IAOR) is one of the most pervasive macroecological patterns, yet has rarely been analyzed for oceanic island assemblages. We use an extensive dataset for arthropods from six islands within the Azorean archipelago to test: (1) whether indigenous and non-indigenous species are distributed differently within the IAOR; and (2) to the extent that they are, can differences can be attributed to two indices of disturbance. We implemented modeling averaged methods using five of the most common IAOR models to derive an averaged IAOR fit for each island. After testing if species colonization status (indigenous versus non-indigenous) may explain the residuals of the IAOR, we identified true negative and positive outliers and tested the effect of colonization status on the likelihood of a species being a positive or negative outlier. We found that the indigenous and non-indigenous species are randomly distributed on both sides of the overall IAOR. Only for Flores Island, were non-indigenous species more aggregated than indigenous species. We were unable to detect a meaningful relationship between deviation from the IAOR and disturbance, despite the undoubted impact of both severe habitat loss and non-indigenous species on these oceanic islands. Our results show that the non-indigenous species have been integrated alongside indigenous species in the contemporary Azorean arthropod communities such that they are mostly undetectable by the study of the IAOR. © 2013 Elsevier Masson SAS.

The IUCN Red List is the most useful list of species that are at risk for extinction worldwide, as it relies on a number of objective criteria. Nevertheless, there is a taxonomic bias that excludes species with small body sizes, narrow distribution ranges and low dispersal abilities, which constitute the vast majority of the planet's biota, particularly local endemics. By evaluating each IUCN criterion separately, we (i) identify the shortcomings for invertebrate applications, (ii) explain how risk categories may be wrongly applied due to inapplicable and/or misleading thresholds, (iii) suggest alternative ways of applying the existing criteria in a more realistic way and (iv) suggest possible new criteria that were not considered in the current evaluation framework but that could allow a more comprehensive and effective assessment of invertebrates. By adapting the criteria to rely more explicitly on the Area of Occupancy and the Extent of Occurrence, their respective trends and by using ecological modelling methods, the criteria's applicability would be increased. The change in some thresholds or, eventually, the creation of sub-categories would further increase their adequacy. Additionally, co-extinction could be introduced as an explicit part of the classification process. As a case study, we evaluated 48 species of Azorean arthropods and Iberian spiders according to the current criteria. More than one-quarter (27%) of all evaluated species were classified as Critically Endangered, 19% as Endangered, 6% as Vulnerable and 8% as Least Concern. The remaining 40% did not have enough data to reach a classification. © 2011 Elsevier Ltd.