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Recent field surveys in the eastern Canary Islands (Spain), followed by contributions of new occurrence records through the citizen science platform iNaturalist.com and the social media photo repository Flickr.com have revealed the presence of an overlooked small carder bee species (genus Pseudoanthidium Friese (Megachilidae: Anthidiini)) on the islands of Lanzarote and Fuerteventura. Here, we combined morphology, DNA barcodes (mitochondrial cytochrome c oxidase subunit I, COI) and ecological data (distribution, altitudinal ranges and environmental niche classification) to describe this species as Pseudoanthidium (Pseudoanthidium) jacobii sp. nov. We provide an illustrated description along with diagnostic morphological characters to separate it from P. (P.) canariense (Mavromoustakis, 1954), the only other congeneric species known from the neighbouring islands of La Gomera, Tenerife and Gran Canaria and from which it is separated by a genetic distance of 2.7%. We also evaluated the extent of shared environmental niche space among the two Pseudoanthidium species, and our results show a significant difference in elevation range as well as a very small (less than 1%) overlap between the modelled climatic niche of P. jacobii and that of P. canariense. Given the extremely restricted geographic distribution and the fragile and isolated nature of the habitat and host plants of this new island endemic species, we assign it an IUCN conservation status of “EN” (endangered) and discuss avenues for future research on the ecology and conservation of wild bees in the Canary Islands and neighbouring regions.

BackgroundPredicting and explaining species occurrence using environmental characteristics is essential for nature conservation and management. Species distribution models consider species occurrence as the dependent variable and environmental conditions as the independent variables. Suitable conditions are estimated based on a sample of species observations, where one assumes that the underlying environmental conditions are known. This is not always the case, as environmental variables at broad spatial scales are regularly extrapolated from point-referenced data. However, treating the predicted environmental conditions as accurate surveys of independent variables at a specific point does not take into account their uncertainty.MethodsWe present a joint hierarchical Bayesian model where models for the environmental variables, rather than a set of predicted values, are input to the species distribution model. All models are fitted together based only on point-referenced observations, which results in a correct propagation of uncertainty. We use 50 plant species representative of the Dutch flora in natural areas with 8 soil condition predictors taken during field visits in the Netherlands as a case study. We compare the proposed model to the standard approach by studying the difference in associations, predicted maps, and cross-validated accuracy.FindingsWe find that there are differences between the two approaches in the estimated association between soil conditions and species occurrence (correlation 0.64-0.84), but the predicted maps are quite similar (correlation 0.82-1.00). The differences are more pronounced in the rarer species. The cross-validated accuracy is substantially better for 5 species out of the 50, and the species can also help to predict the soil characteristics. The estimated associations tend to have a smaller magnitude with more certainty.ConclusionThese findings suggests that the standard model is often sufficient for prediction, but effort should be taken to develop models which take the uncertainty in the independent variables into account for interpretation.

Abstract Red Lists are widely used as an indicator of the status and trends of biodiversity and are often used in directing conservation efforts. However, it is unclear whether species with a Least Concern status share a common relationship to environmental correlates compared to species that are on the Red List. To assess this, we focus here on the contribution and correlates of land use, climate, and soil to the occurrence of wild bees in the Netherlands. We used observation data and species distribution models to explain the relation between wild bees and the environment. Non‐threatened bees had a relatively higher variable importance of the land use variables to their models, as opposed to the climate variables for the threatened bees. The threatened bees had a smaller extent of occurrence and occupied areas with more extreme climatic conditions. Bees with a Least Concern status showed more positive responses to urban green spaces and Red List species showed a different response to climatic variables, such as temperature and precipitation. Even though Red List bees were found in areas with a higher cover of natural areas, they showed a more selective response to natural land use types. Pastures and crops were the main contributing land use variables and showed almost exclusively a negative correlation with the distribution of all wild bees. This knowledge supports the implementation of appropriate, species‐specific conservation measures, including the preservation of natural areas, and the improvement of land use practices in agricultural and urban areas, which may help mitigate the negative impacts of future global change on species' distributions.

Abstract Chile's isolation and varied climates have driven the evolution of a unique biodiversity with a high degree of endemism. As a result, Chile encompasses diverse environments, including the Mediterranean‐type ecosystem, a global biodiversity hotspot. These environments are currently threatened by anthropogenic land use change impacting the integrity of local biomes and associated species. This area is the most intensively sampled in the country with high endemicity of native bee species. Characterizing habitat requirements of bees is a pressing priority to safeguard these insects and the ecosystem services they provide. We investigated broadscale patterns of bee (Hymenoptera: Apoidea: Anthophila) diversity using newly accessible expert‐validated datasets comprising digitized specimen records from Chilean and US collections, and novel expert‐validated‐type specimen data for the bees of Chile. We used a generalized dissimilarity modeling (GDM) approach to explore both compositional and phylogenetic β‐diversity patterns across latitudinal, altitudinal, climate, and habitat gradients in well‐sampled bee assemblages in Central Chile. Using the GDM measures of increasing compositional and environmental dissimilarity, we categorized and compared the most important drivers of these patterns and used them to classify “wild bee ecoregions” (WBEs) representing unique assemblages. Turnover of bee assemblages was explained primarily by latitudinal variation (proxy for climate) from south to north in Chile. However, temperature variations, precipitation, and the presence of bare soil also significantly explained turnover in bee assemblages. In comparison, we observed less turnover in phylogenetic biodiversity corresponding to spatial gradients. We identified six de novo ecoregions (WBEs), all with distinct taxa, endemic lineages, and representative species. The WBEs represent distinct spatial classifications but have similarities to existing biogeographical classifications, ecosystems, and bioclimatic zones. This approach establishes the baseline needed to prioritize bee species conservation efforts across this global biodiversity hotspot. We discuss the novelty of this classification considering previous biogeographical characterizations and their relevance in assessing conservation priorities for bee conservation. We argue that Chile's WBEs highlight areas in need of funding for bee species surveys and description, distribution mapping, and strengthening of conservation policies.

Apples are one of the most important global crops that relies heavily on insect pollination, which has been shown to increase apple production and value. However, recent reports indicate that apple production has been declining in certain regions, including in Bhutan. One of the potential causes of declining production are pollination deficits driven by a low abundance and diversity of pollinators, a phenomenon that has received little attention in Bhutan to date. Here, we present the first study examining the diversity of flying insects in Bhutanese apple orchards in relation to apple quality. During the apple flowering season, 1,006 insects comprising 44 unique (morpho-)species from the orders Hymenoptera, Diptera, and Lepidoptera were recorded using a standardized method of passive and active trapping within nine different orchards in Thimphu, Paro, and Haa districts, in the western part of Bhutan. During the harvest season, 495 apples were collected from these nine orchards, and we measured five different parameters; weight, size, sugar concentration, seed number, and malformation score. The most dominant flower visitors across all orchards were honey bees (mostly Apis mellifera, followed by A. cerana and A. dorsata). Orchards with a higher abundance of flying insects (both managed and wild) had better apple quality (weight, size and sugar concentration). Contrary to reports from other regions of the world, flower visitor diversity did not correlate with the quality of the apples. This represents the first study reporting on apple pollination in Bhutan and highlights the importance of pollinators and reinforces the need to develop pollinator friendly practices to ensure sustainable apple production.

Plants can be pollinated in many ways, with insect, wind and selfing as the most common modes. While it seems likely that the occurrence of pollination modes is correlated with environmental conditions, e.g. vegetation structure, and this remains uncertain. Here, we mapped the composition of pollination modes of different plant groups (woody species, herbs, and grasses) across (semi-)natural habitats and their distributions in relation to 3D vegetation structure in the Netherlands. We found insect pollination is the most common mode across (semi-)natural habitats for woody species and herbs. Woody species pollinated by insects showed an even higher percentage in dune, river swamp and swamp peat than in other habitat types, whereas herbs showed a higher percentage of insect pollination in dune than in other habitat types. Grasses were always pollinated by wind or wind-self in all habitats. Woody plants pollinated by wind showed a positive relationship with canopy densities in three different strata from 2 to 20 m vegetation, while insect pollination showed a positive relationship with the canopy density of 0.5 to 2 m vegetation. All grass presented negative relationships with canopy density. Herbs showed different relationships with canopy densities of different strata dependent on pollination modes. Insect-pollinated species increased with canopy densities of low strata but decreased with canopy density of high strata, whereas wind-pollinated species decreased with canopy density of both low and high strata. We conclude that habitat and vegetation structure are important factors driving the distribution of pollination modes.

Climate, landscape composition, management practice, and wild bee pollination are all variables thought to play significant roles in commercial apple production. However, how these variables affect production efficiency under field-realistic conditions has not been investigated at large geographical scales. We combined intensive standardized field surveys (using netting and pan traps) with structural equation models to explore the relative impact of biotic and abiotic variables on bee diversity, apple yield and fruit quality, and their ability to represent reliable proxies of apple production. Here we show that apple yields are mainly driven by management practice, without evidence for a significantly superior contribution by managed honey bees. Total wild bee diversity, while negatively correlated with honey bee dominance, promoted apple quality by enhancing seed set number. Our study demonstrates that even across a broad geographical range there is potential to harness wild bee diversity as nature-based solution and as a substitute to an exclusive reliance on honey bees in the context of commercial apple production.

Recent studies have reported on dramatic cases of aerial insect population declines by focusing on the measure of the total biomass of caught insects. However, there is currently no consensus about how biomass patterns among sites and habitats might consistently capture the subtleties of changes in aerial insect community structure. Here, we investigated the relationship between the total biomass of wild bees collected using pan traps in urban, agricultural, and semi-natural habitats on one hand, and a spectrum of biodiversity metrics on the other hand, particularly species richness (SR), alpha diversity, functional diversity (FD) and three different forms of phylogenetic diversity (PD). Our results indicate that although biomass is significantly and highly correlated with the abundance of wild bees, it is generally significantly but only moderately and non-linearly correlated to the various facets of wild bee diversity among habitats. By contrast, we also found that all three measures of PD used are consistent across habitats, suggesting that a taxonomic hierarchy based on Linnaean classification could be used as a proxy for the measurement of PD in wild bees, particularly in other well-studied areas such as Western Europe where a multi-gene molecular phylogeny is unavailable as yet. Collectively, our results illustrate the clear limitations of biodiversity monitoring through measures of trapped insects biomass. We advocate for more robust measures of biodiversity trends in wild bees, requiring both standardized surveys, and the identification of caught specimens down to the species level to capture the subtleties of species, traits-based and phylogeny-based community changes across habitats or time. Scaling out this approach is an essential prerequisite for more global conservation planning tailored to the ecological requirements of the targeted insect species.

While shifts to high-intensity land cover have caused overwhelming biodiversity loss, it remains unclear how important natural land cover is to the occurrence, and thus the conservation, of different species groups. We used over 4 million plant species’ observations to evaluate the conservation importance of natural land cover by its association with the occurrence probability of 1 122 native and 403 exotic plant species at 1 km resolution by species distribution models. We found that 74.9% of native species, 83.9% of the threatened species and 77.1% rare species preferred landscapes with over 50% natural land cover, while these landscapes only accounted for 15.6% of all grids. Most species preferred natural areas with a mixture of forest and open areas rather than areas with completely open or forested nature. Compared to native species, exotic species preferred areas with lower natural land cover and the cover of natural open area, but they both preferred extremely high and low cover of natural forest area. Threatened and rare species preferred higher natural land cover, either cover of natural forest area or cover of natural open area than not threatened and common species, but rare species were also more likely to occur in landscapes with 0–25% cover of natural open area. Although more natural land cover in a landscape will not automatically result in more native species, because there is often a non-linear increase in species occurrence probability when going from 0% to 100% natural land cover, for conserving purposes, over 80% natural land cover should be kept in landscapes for conserving threatened and very rare species, and 60% natural land cover is the best for conserving common native species. Our results stress the importance of natural areas for plant species’ conservation. It also informs improvements to species conservation by increasing habitat diversity.

While shifts to high-intensity land cover have caused overwhelming biodiversity loss, it remains unclear how important natural land cover is to the occurrence, and thus the conservation, of different species groups. We used over 4 million plant species' observations to evaluate the conservation importance of natural land cover by its association with the occurrence probability of 1 122 native and 403 exotic plant species at 1 km resolution by species distribution models. We found that 74.9% of native species, 83.9% of the threatened species and 77.1% rare species preferred landscapes with over 50% natural land cover, while these landscapes only accounted for 15.6% of all grids. Most species preferred natural areas with a mixture of forest and open areas rather than areas with completely open or forested nature. Compared to native species, exotic species preferred areas with lower natural land cover and the cover of natural open area, but they both preferred extremely high and low cover of natural forest area. Threatened and rare species preferred higher natural land cover, either cover of natural forest area or cover of natural open area than not threatened and common species, but rare species were also more likely to occur in landscapes with 0-25% cover of natural open area. Although more natural land cover in a landscape will not automatically result in more native species, because there is often a non-linear increase in species occurrence probability when going from 0% to 100% natural land cover, for conserving purposes, over 80% natural land cover should be kept in landscapes for conserving threatened and very rare species, and 60% natural land cover is the best for conserving common native species. Our results stress the importance of natural areas for plant species' conservation. It also informs improvements to species conservation by increasing habitat diversity.