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Belgian Red List of Bees
Abstract and Figures
The Belgian Red List of bees is an assessment of the conservation status of Belgian bee species according to the IUCN guidelines for application of the international IUCN Red List criteria at regional and national levels. It identifies the extinction threat to species at this geographical scale. These results can be used to implement conservation actions to improve the threat status of species. This Red List publication summarizes the results of this exercise for all recorded Belgian bees. Overall, 32.8% of bees (i.e. 113 species) are considered threatened in Belgium. Considering the Near Threatened (i.e. 26 species; 6.8%) and Regionally Extinct (i.e. 45 species; 11.8%) bees, the present study suggests that more than half (i.e. 53.3%) of the assessed species (i.e. 184 species) are (nearly) threatened or extinct in Belgium. A further 42.3% of bees (i.e. 161 species) are considered as Least Concern. Out of a total of 403 bee species that are recorded for Belgium, 22 species that were observed only once in a single specimen were assigned to the category Not Applicable (NA). It is unclear whether they ever had a population in Belgium. Consequently, they are considered as absent of the country. Another 36 species (i.e. 9.4%) were classified as Data Deficient, as there was not enough information to assess their risk of extinction.
Considering the functional traits possibly associated with extinction risk, there is no major difference between opportunistic and specialised bees in threat status in Belgium. Besides a similar proportion of threatened species (i.e. 31-36%) among the three categories of sociality, (primitively) eusocial bees include a higher proportion of extinct species (i.e. 21.7%). Moreoever, bumblebees constitute the most impacted group with near 60% of Threatened or Near Threatened species as well as 20% of Regionally Extinct species. Finally, ground-nesting bees are more threatened (i.e. 32.5%) compared to bees nesting in existing cavities above ground (i.e. 23.6%), bees with specific nesting behaviours showing highly variable proportion of threatened species.
Regarding the spatial distribution of bees, the highest species richness is found in (i) the Condroz and Fagne-Famenne-Calestienne as well as Gaume regions, (ii) the Brussels-Capital area as well as Hageland and Droog Haspengouw, (iii) the sandy Flanders and (iv) the eastern Campine. Local diversity hotspots are found in particular habitats like calcareous grassland and heathlands. Southeastern Belgium, Hageland and Droog Haspengouw and Campine as well as the coastal dunes and East canton, present a high diversity of threatened species.
The main threats identified in the literature are habitat loss and fragmentation due to agricultural intensification (e.g. changes in agricultural practices including the use of fertilisers and pesticides) and urban development, as well as climate change.
Attention must be paid to the 9.4% of Data Deficient species for which a taxonomic impediment was encountered. For these, revisions of historical and present collections as well as an increase in taxonomic expertise and training among wild bee volunteers is necessary to resolves these impediments.
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... Worldwide, more than 20,000 bee species are distributed in 7 families (Michener 2007;Danforth et al. 2013). In Europe, there are 2,051 species ) divided into 77 genera, of which more than 403 species have been recorded in Belgium (Drossart et al. 2019). Within this global diversity of bees, about 20 species of social or solitary bees have been domesticated for agricultural production (Stout and Morales 2009). ...
... Great Britain, the Netherlands, and Belgium have well-established databases that facilitate monitoring of pollinator distribution through online platforms such as BWARS or Atlas Hymenoptera (Rasmont and Haubruge 2002;BWARS 2021). Thanks to remarkable collection efforts, Drossart et al. (2019) and Vereecken et al. (2022) were able to red-list Belgium and Brussels with only 9% and 1% data deficiency, respectively, in terms of bee collection. ...
... Whereas the summer bee communities (early June to late September) offer a greater variety of nesting behaviors with the emergence of a series of species belonging to the Megachilidae family. Nearly 50% of the 403 species of wild bees present on our territory nest under the ground Drossart et al., 2019). ...
This research thesis investigated into the critical issue of declining insect populations, particularly pollinators, in the crucial context of ecosystem functioning, agriculture, and human health. Focusing on bees, hoverflies, and apoid wasps, we explore the impact of landscape degradation, caused by agricultural intensification and urbanization, on pollinator communities in temperate agricultural and urban landscapes. Four case studies are presented, offering valuable insights and
recommendations for conservation and restoration efforts. The first study examined ecological diversification on two farms in early ecological transition, uncovering valuable data on wild bees and hoverflies. Results highlighted specific diversity with 101 bee species and 31 hoverfly species, indicating the potential for ecological diversification and agroecological practices to support rare and endangered pollinators. Building on this study, we investigated the impact of flower strips in
intercropping systems with winter wheat. Multifloral strips attracted a diverse range of hoverflies, presenting a promising ecological and economic solution for farmers. In urban landscapes, we analyzed pollen availability and foraging behavior of honeybee colonies along an urban-rural gradient in Tokyo. Landscape factors significantly influenced floral species visited by honeybees, offering valuable insights for urban planning. Lastly, we explored the nesting potential of
pavements for ground-nesting Hymenoptera in Brussels. We identify 22 species of wild bees and apoid wasps nesting in specific urban surfaces, providing essential recommendations for encouraging these pollinators. These studies underscored the significance of food and nesting resources for pollinator communities and advocated for conservation efforts in disturbed environments. Our findings contribute to the growing body of knowledge on agricultural and urban
ecology, paving the way for future scientific endeavors in this crucial field.
... Amidst these critical ecosystem service providers are bumblebees (Bombus), a genus of both wild and managed bees ranked among the highest contributors to crop production value in temperate and cold ecosystems of the northern hemisphere 7 . In the past decades, however, these predominantly cold-adapted pollinators have undergone sharp population reductions across continents [17][18][19] , with national reports of local extinctions of around 20-25% of species 20,21 and a continental report documenting negative population trends for more than 45% of species 6 . In spite of these already severe findings, it remains unknown whether this decline has already reached its climax or if we are only at the dawn of a much more dramatic collapse in bumblebee populations. ...
Habitat degradation and climate change are globally acting as pivotal drivers of wildlife collapse, with mounting evidence that this erosion of biodiversity will accelerate in the following decades. Here, we quantify the past, present and future ecological suitability of Europe for bumblebees, a threatened group of pollinators ranked among the highest contributors to crop production value in the northern hemisphere. We demonstrate coherent declines of bumblebee populations since 1900 over most of Europe and identify future large-scale range contractions and species extirpations under all future climate and land use change scenarios. Around 38–76% of studied European bumblebee species currently classified as ‘Least Concern’ are projected to undergo losses of at least 30% of ecologically suitable territory by 2061–2080 compared to 2000–2014. All scenarios highlight that parts of Scandinavia will become potential refugia for European bumblebees; it is however uncertain whether these areas will remain clear of additional anthropogenic stressors not accounted for in present models. Our results underline the critical role of global change mitigation policies as effective levers to protect bumblebees from manmade transformation of the biosphere.
... These declines have understandably received attention from naturalists and conservation biologists, as highlighted by numerous country checklists and reports (e.g. Drossart et al. 2019;Quaranta et al. 2018;Ghisbain & Rasmont 2022). What is slightly overshadowed however when considering the interaction between global changes and bees is the fact that changes in climate, landuse and global human trading systems can also facilitate the invasion and subsequent expansion of new bee species from other continents (reviewed in Ghisbain et al. 2021a). ...
At a time when nature conservation has become essential to ensure the long-term sustainability of our environment, it is widely acknowledged that conservation actions must be implemented within a solid taxonomic framework. In preparation for the upcoming update of the IUCN Red List, we here update the European checklist of the wild bees (sensu the IUCN geographical framework). The original checklist, published in 2014, was revised for the first time in 2017. In the present revision, we add one genus, four subgenera and 67 species recently described, 40 species newly recorded since the latest revision (including two species that are not native to Europe), 26 species overlooked in the previous European checklists and 63 published synonymies. We provide original records for eight species previously unknown to the continent and, as original taxonomic acts, we provide three new synonyms, we consider two names as nomina nuda, ten names as nomina dubia, three as species inquirenda, synonymize three species and exclude 40 species from the previous checklist. Around a hundred other taxonomic changes and clarifications are also included and discussed. The present work revises the total number of genera for IUCN Europe to 77 and the total number of species to 2,138. In addition to specifying the taxonomic changes necessary to update the forthcoming Red List of European bees, we discuss the sampling and taxonomic biases that characterise research on the European bee fauna and highlight the growing importance of range expansions and species invasions.
... Teasel-plant specialised bees: Population trends, threats and conservation actions Decline of teasel-plant specialised bees is reported in many European countries (e.g. Drossart et al., 2019;Gärdenfors, 2010 South-eastern European countries like Greece, Bulgaria, Romania, Hungary or Ukraine still host many teasel bee species, including the pantaloon bees reported here, which are considered umbrella species for species-rich communities. ...
This book provides the basis for a Conservation Action Plan for these wild bee species, including the Dark Pantaloon Bee (Dasypoda braccata), the Spiny Pantaloon Bee (Dasypoda spinigera), the Swollen Pantaloon Bee (Dasypoda suripes), the Silvery Pantaloon Bee (Dasypoda argentata), the Large Scabious Mining Bee (Andrena hattorfiana) and the Scabious Resin Bee (Trachusa interrupta), four of which are classified as Endangered on the European Red List and two as Near Threatened. These species are considered umbrella species for the conservation of teasel-plant rich grassland communities. For each of these species, a comprehensive review of the known information on taxonomy and systematics, biology and ecology, functions and values, historical and current distribution and demography, habitat and resource availability and threats is provided. This review will provide the information necessary to identify major knowledge gaps and necessary conservation action for these wild bee species.
... In the grasslands, this possibly led to some plant species that at the moment of pollen collection had the highest net benefit, being dominant. These data also corroborate the general belief that Bombus terrestris is a generalist, polylectic bee species that uses many different food sources, both in time and space, depending on the best food sources that are currently available (Drossart et al. 2019). They further indicate that the generalist polylectic behavior of B. terrestris is context dependent and that B. terrestris colonies can thrive on a species-poor diet as long as pollen is available in sufficient quantities (Genissel et al. 2002, Vanderplanck et al. 2014, Kämper et al. 2016, Ceulemans et al. 2017. ...
The current decline in pollinators may disrupt ecosystems and ecosystem services with potentially harmful effects on nature and human society. While the importance of habitat loss and fragmentation, pollution and increased disease risk in driving pollinator decline has been clearly demonstrated, the impact of resource diversity is less well understood. In this study, we investigated the effect of pollen diversity and composition on reproductive success and fitness of Bombus terrestris colonies. We asked the question whether a higher plant diversity results in a more diverse diet, lower pathogen incidence and a higher colony fitness. To answer these questions, colonies of lab‐reared bumblebees were placed in species‐poor heathlands and species‐rich semi‐natural grasslands that strongly differed in plant community composition and diversity. We examined pollen loads on the bodies of foragers and identified the plant taxa present in the realized diet via DNA metabarcoding of the ITS2 marker. Liquid chromatography–mass spectrometry (LC–MS) was used to compare peptide composition of pollen samples from both habitats. Colony fitness was assessed by counting the number of sexuals produced by the colony at the end of its cycle. At the same time, colonies were examined for parasite incidence. Pollen composition and diversity on pollinators' bodies differed significantly between bees foraging in grasslands and heathlands. Concomitantly, peptide composition differed significantly between pollen samples from grasslands and heathlands. Contrary to our prediction, colonies developed significantly better in heathland sites than in grasslands. In addition, the relationship between colony fitness and pollen diversity was weak and varied between the two habitats. Pathogen incidence was very low and not affected by habitat. Overall, our results indicate that plant diversity is not necessarily a good predictor of colony fitness, and that vegetation composition and associated differences in both the quantity and quality of pollen are more important than pollen diversity per se.
... Andrena ovatula (Kirby, 1802), A. wilkella (Kirby, 1802), Bombus hortorum (Linnaeus, 1761) (indicator species in IPSF traps), B. vestalis (Geoffroy, 1785) are near threatened species. Lasioglossum minutulum (Schenck, 1853) and Stelis signata (Latreille, 1809) are classified as vulnerable in Belgium and Nomada fuscicornis Nylander, 1848 (the cuckoo bee of Panurgus calcaratus (Scopoli, 1763) which was not present in our sampling) is endangered [88]. Semiochemical traps are also damaging for oligolectic bee species such as Chelostoma campanularum (Kirby, 1802), Megachile ericetorum Lepeletier, 1841 and Melitta leporina (Panzer, 1799). ...
Broad bean weevils (BBWs-Coleoptera: Chrysomelidae) are serious pests of field bean seeds that hamper the promotion of this crop in the diversification of European cropping systems. Recent research has identified different semiochemical lures and trap devices for the development of semiochemical-based control strategies of BBWs. In this study, two field trials were carried out in order to provide necessary information supporting the implementation of sustainable field use of semiochemical traps against BBWs. More particularly, three principal objectives were followed including (i) the identification of the most efficient traps for BBWs capture and the influence of trapping modality on BBWs sex-ratio, (ii) the assessment of eventual collateral effects on crop benefits including aphidophagous and pollinator insects such as Apidae, Syrphidae and Coccinellidae, (iii) the assessment of the crop developmental stage influence on the capture by semiochemical traps. Three different semiochemical lures were tested in combination with two trapping devices across two field trials in early and late flowering field bean crops. The crop phenology and climate parameters were integrated into the analyses to interpret the spatiotemporal evolution of the captured insect populations. A total of 1380 BBWs and 1424 beneficials were captured. White pan traps combined with floral kairomones were the most efficient traps for the capture of BBWs. We demonstrated that the crop phenology (c.f., the flowering stage) exerted strong competition on the attractiveness of semiochemical traps. Community analysis revealed that only one species of BBWs was captured in field bean crops (i.e., Bruchus rufimanus), and no trend was highlighted concerning the sex ratios according to the trapping devices. The beneficial insect community included 67 different species belonging to bees, hoverflies and ladybeetles. Semiochemical traps manifested a strong impact on beneficial insect communities that included some species under extinction threats and need to be further adapted to minimize such collateral effects. Based on these results, recommendations are provided for the implementation of the most sustainable BBWs control method that minimizes the impact on the recruitment of beneficial insects, which is an important ecosystem service for faba bean crops.
Om bijen een duwtje een rug te geven probeert de Provincie Oost-Vlaanderen in haar natuurdomeinen beter rekening te houden met bijen bij het beheer. Daarom voerde Natuurpunt Studie in 2020 een gedegen inventarisatie uit van de wildebijengemeenschap in het Kloosterbos. Hierbij werd het gebied verspreid over de vliegperiode 4 keer bezocht. Waarbij naast het inventariseren van de aanwezige bijensoorten ook gekeken werd naar huidige en potentiële nest- en foerageerplaatsen en de beheer-en inrichtingsmaatregelen die mogelijk kunnen genomen worden om het biotoop geschikter te maken voor bijen. We vonden in het gebied 51 soorten bijen terug, waarvan er 6 soorten op de Rode lijst van bedreigde soorten staan. Daarnaast werden ook enkele interessante zweefvliegen waargenomen in het gebied.
Dit rapport biedt handvaten om ondanks de negatieve omgevingsfactoren tóch meer kansen te scheppen voor wilde bijen in het gebied.
In dit rapport wordt een bijenplan voorgesteld in opdracht van en voor de gemeente Boutersem, gebaseerd op een uitgebreide inventarisatie van de wilde bijen in de gemeentelijke groengebieden. In 2021 werden doorheen het vliegseizoen één of meerdere bezoeken gebracht aan 17 gemeentelijke groengebieden. De aanwezige bijen werden er geïnventariseerd en er werd een evaluatie gemaakt van de geschiktheid voor wilde bijen in termen van bloemenaanbod, boven- en ondergrondse nestgelegenheid en het microklimaat. Daarnaast werd per gebied ook het huidige beheer bekeken in functie van wilde bijen, en worden aanbevelingen gedaan om de geschiktheid voor wilde bijen verder te verbeteren.
Tijdens dit onderzoek in Lanaken werd in de loop van 2021 op verschillende locaties in beheer van de gemeente Lanaken de wilde bijenfauna onderzocht. Samen met de historische waarnemingen in de waarnemingen.be-database levert dit een indrukwekkende soortenlijst op van 183 soorten, waarvan er in 2021, tijdens het terreinwerk in het kader van het bijenplan ongeveer 150 werden gezien. 32 soorten die we vonden werden nog niet eerder gevonden in Lanaken. Dat Lanaken naar Vlaamse normen een uitzonderlijk rijke bijenfauna herbergt, was al bekend, maar ook het openbare groen in Lanaken levert hier dus een belangrijke bijdrage aan. Het ecologische groenbeheer dat nu al zoveel mogelijk plaatsvindt, is dus een uitstekende zaak voor bijen. Toch is hier en daar nog winst te halen voor wilde bijen, daarom hebben we voor elk gebied enkele aanbevelingen opgelijst, samen met een bespreking van de aanwezige bijensoorten.
In 2020 en 2021 werd onderzoek uitgevoerd naar het voorkomen van wilde bijen in enkele wegbermen en parken in de gemeente Knokke-Heist. Daarnaast werd, in de jaren voordien, onderzoek uitgevoerd op de Zwinvlakte en in de Zwinduinen en -polders.
Het eerste deel van dit rapport bevat een korte introductie tot wilde bijen in België, en wilde bijen in de stad in het algemeen. Je vindt er de basis over de ecologie van wilde bijen en welke basisfactoren wilde bijen nodig hebben.
Het tweede deel behandelt het terreinonderzoek dat specifiek voor dit rapport werd verricht in gebieden in Knokke-Heist. We behandelen eerst de algemene resultaten van het onderzoek en plaatsen ze in de context van andere Vlaamse steden en gemeenten, we belichten de meest bijzondere soorten en soorten waarvoor de regio een belangrijke verantwoordelijkheid draagt.
Verschillende typische kust- en duinsoorten werden tijdens dit onderzoek aangetroffen. De huidige soortenlijst (september 2022) bevat niet minder dan 140 soorten. Hiermee staat de gemeente Knokke-Heist momenteel op de tweede plaats van de soortenrijkste gemeentes in West-Vlaanderen, na Brugge. In dit rapport worden enkele kapstoksoorten in detail besproken. Het gaat om de Schorviltbij & Schorzijdebij, Donkere zijdebij, Kortsprietgroefbij, Wafelbloedbij, Zilverenfluitje en Duinkegelbij, Witgevlekte tubebij en Grashommel. Deze soorten dienen als kapstok waarvoor specifiek aandacht aan kan worden besteed bij het beheer en de inrichting van de openbare ruimte.
Daarnaast worden 13 gebieden en 7 wegbermen meer in detail besproken, waarbij we bekijken welke soorten er te vinden zijn en hun relatie met de hulpbronnen die ze nodig hebben. We geven ook een evaluatie van de waarde van het gebied voor bijen op basis van de aanwezige hulpbronnen. Vervolgens worden specifieke aanbevelingen geformuleerd om het gebied waardevoller te maken voor bijen.
Tot slot bevat dit rapport ook algemeen beheeradvies dat toegepast kan worden in het openbaar groen binnen de gemeente, worden enkele bijenvriendelijke plantenlijsten toegevoegd en worden suggesties voor vervolgonderzoek in de gemeente gegeven.
Pollinators are experiencing declines globally, negatively affecting the reproduction of wild plants and crop production. Well-known drivers of these declines include climatic and nutritional stresses, such as a change of dietary resources due to the degradation of habitat quality. Understanding potential synergies between these two important drivers is needed to improve predictive models of the future effects of climate change on pollinator declines. Here, bumblebee colony bioassays were used to evaluate the interactive effects of heat stress, a reduction of dietary resource quality, and colony size. Using a total of 117 colonies, we applied a fully crossed experiment to test the effect of three dietary quality levels under three levels of heat stress with two colony sizes. Both nutritional and heat stress reduced colony development resulting in a lower investment in offspring production. Small colonies were much more sensitive to heat and nutritional stresses than large ones, possibly because a higher percentage of workers helps maintain social homeostasis. Strikingly, the effects of heat stress were far less pronounced for small colonies fed with suitable diets. Overall, our study suggests that landscape management actions that ensure access to high-quality resources could reduce the impacts of heat stress on bee decline.
Halictidae, with 84 species in Belgium, is the most frequently encountered bee family from early spring to late summer, and nearly a quarter of wild bees occurring in the country belong to this family. A total of 60,338 specimens were studied from Belgium and neighboring regions such as Luxembourg. This book presents abundantly illustrated keys for identifying species. Each of them is accompanied by a short diagnose, detailed photos of the male and the female, a map of geographical distribution, a phenological graph, a commentary on the pollinated plants, the social behavior, nesting mode, habitat and status on the red lists. After analysis of our data, we find that 46% of species fall into the categories “regionally extinct” to “vulnerable”. The main causes of this scarcity are due to the intensification of agriculture and urbanization. In the conclusions and recommendations, we review some ways to improve the health of wild bee populations, with specific examples for Halictidae.
Pollination is a critical ecosystem service underpinning the productivity of agricultural systems across the world. Wild insect populations provide a substantial contribution to the productivity of many crops and seed set of wild flowers. However, large-scale evidence on species-specific trends among wild pollinators are lacking. Here we show substantial inter-specific variation in pollinator trends, based on occupancy models for 353 wild bee and hoverfly species in Great Britain between 1980 and 2013. Furthermore, we estimate a net loss of over 2.7 million occupied 1 km² grid cells across all species. Declines in pollinator evenness suggest that losses were concentrated in rare species. In addition, losses linked to specific habitats were identified, with a 55% decline among species associated with uplands. This contrasts with dominant crop pollinators, which increased by 12%, potentially in response agri-environment measures. The general declines highlight a fundamental deterioration in both wider biodiversity and non-crop pollination services.
Bumblebees (Bombus spp.) are declining in most parts of Western Europe. Many studies have highlighted the role of agricultural intensification and urbanisation in this decline, and some have also shown the influence of landscape composition on bumblebee populations. However, very few studies have explored bumblebee communities prior to the onset of these major land use changes, and those studies that do are mostly based on low-resolution spatial data. Here, we perform a comparative analysis based on detailed landscape composition and bumblebee occurrence records between the early twentieth century (1910–1930) and the contemporary period (2013–2015) in four localities representative of Belgium. We show that bumblebee assemblages changed drastically over this period, and that the decline in richness was strongest in areas with the greatest increase in urbanization and agricultural intensification. The one locality still retaining a high proportion of grasslands, orchards and woodlands with the smallest overall change in landscape composition still hosts a rich bumblebee fauna, very similar than in the past. We provide recommendations for land use management based on these findings. We also warn about the importance of other factors such as land use intensity, climatic conditions and altitude, which should be included in any future study addressing changes in bumblebee populations related to land use changes.
Three Endangered, seven Vulnerable and 40 Near Threatened species from the European Red List of Bees were recorded in Slovenia. Their distribution in Slovenia is overviewed and the importance of local populations for their survival in Europe is evaluated. Among the Endangered species the Slovenian population of Colletes graeffei is important. The species has also its locus typicus in Slovenia. Interesting is the case of Epeolus cruciger which is very numerous in Slovenia due to transition to a secondary host, Colletes hederae. Its other host, Colletes succinctus, is endangered in
Slovenia.
Abstract Human activities can generate a wide variety of direct and indirect effects on animals, which can manifest as environmental and genetic stressors. Several phenotypic markers have been proposed as indicators of these stressful conditions but have displayed contrasting results, depending, among others, on the phenotypic trait measured. Knowing the worldwide decline of multiple bumblebee species, it is important to understand these stressors and link them with the drivers of decline. We assessed the impact of several stressors (i.e. natural toxin-, parasite-, thermic- and inbreeding- stress) on both wing shape and size and their variability as well as their directional and fluctuating asymmetries. The total data set includes 650 individuals of Bombus terrestris (Hymenoptera: Apidae). Overall wing size and shape were affected by all the tested stressors. Except for the sinigrin (e.g. glucosinolate) stress, each stress implies a decrease of wing size. Size variance was affected by several stressors, contrary to shape variance that was affected by none of them. Although wing size directional and fluctuating asymmetries were significantly affected by sinigrin, parasites and high temperatures, neither directional nor fluctuating shape asymmetry was significantly affected by any tested stressor. Parasites and high temperatures led to the strongest phenotype modifications. Overall size and shape were the most sensitive morphological traits, which contrasts with the common view that fluctuating asymmetry is the major phenotypic marker of stress.
Overall, 9.2% of bees are considered threatened in all of Europe, while at the EU 27 level, 9.1% are threatened with extinction. A further 5.2% and 5.4% of bees are considered Near Threatened in Europe and the EU 27, respectively (101 species at both levels). However, for 1,101 species (56.7%) in Europe and 1,048 species (55.6%) at the EU 27, there was not enough scientific information to evaluate their risk of extinction and thus, they were classified as Data Deficient. When more data become available, many of these might prove to be threatened as well.
Looking at the population trends of European bee species, 7.7% (150 species) of the species have declining populations, 12.6% (244 species) are more or less stable and 0.7% (13 species) are increasing. The population trends for 1,535 species (79%) remains unknown.
A high proportion of threatened bee species are endemic to either Europe (20.4%, 400 species) or the EU 27 (14.6%, 277 species), highlighting the responsibility that European countries have to protect the global populations of these species. Almost 30% of all the species threatened (Critically Endangered, Endangered, or Vulnerable) at the European level are endemic to Europe (e.g., found nowhere else in the world).
The species richness of bees increases from north to south in Europe, with the highest species richness being found in the Mediterranean climate zone. In particular, the Iberian, Italian and Balkan peninsulas are important areas of species richness. Regarding the distribution of
endemic species, southern Europe shows the highest concentration of endemism. The largest numbers of threatened species are located in south-central Europe and the pattern of distribution of Data Deficient species is primarily concentrated in the Mediterranean region.
The main threat to European bees is habitat loss as a result of agriculture intensification (e.g., changes in agricultural practices including the use of pesticides and fertilisers), urban development, increased frequency of fires and climate change.