Wild bee abundance and diversity in an urban landscape: the importance of preserving native vegetation

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Nevertheless, some species are resilient to urbanization. As important pollinators, wild bees provide an ecosystem service to natural, agricultural and urban ecosystems. It is not clear to what degree the urban environment can be a refuge for wild bees. We assessed changes in the abundance, species richness, and composition of wild bee community along an urbanization gradient in a semi-arid climate. Over two years and on a monthly basis, bees were sampled using colored pan traps at six sites with different degrees of urbanization. A total of 525 individual bees belonging to 15 species were trapped. The abundance and species richness of bees was positively correlated with native vegetation and negatively correlated with urbanization with soil-nesting species completely absent from highly urbanized sites. The amount of native vegetation was found to be the most important driver of wild bee species abundance and diversity. Our results suggest that the degree of urbanization is an important factor that can cause loss of pollinator diversity. Nonetheless, the incorporation of areas with native vegetation in urban planning has the potential to mitigate the negative effect of urbanization. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction As cities expand, integrating the conservation of biodiversity and ecosystem services into urban planning and practices is of paramount importance for a sustainable future (Pereira et al. 2021). Pollination is a crucial ecosystem service not only in natural and agricultural ecosystems but also in urban areas. A 87.5% of angiosperm species are dependent on animal pollination (Ollerton et al. 2011). Through their influence on flowering plants, urban pollinators can provide a wide range of ecosystem services, including urban food production and soil formation (Langellotto et al. 2018; Wenzel et al 2020). Insect pollinators are of considerable conservation concern as they are vulnerable to a range of anthropogenic disturbances. Habitat destruction, land-use intensification, chemical exposure, exotic species and climate change are causing local and regional population declines or even extinctions of pollinator species (Potts et al. 2010). Urbanization is repeatedly stated as one potential driver of this “pollinator crisis” (Tylianakis 2013). However, research outcomes on the effects of the urbanization on pollinator communities are mixed and sometimes contradictory with solid evidence for positive and negative impacts. On one side, many researchers argue that, in the face of intensive agriculture, urban areas can be a refuge for pollinators. A recent study carried out in Europe found that Hymenoptera species, particularly bees, are resilient to urbanization, since a higher species richness was found in cities as compared to rural sites (Theodorou et al. 2020). On the other side researchers take the view that urbanization is a significant threat to pollinators (Bates et al., 2014; Desaegher et al., 2019 ). Bates et al. (2014) found that pollinator diversity and abundance where both negatively associated with higher levels of urbanization. Thus, the effects of urbanization on suitable pollinator communities remains a controversial issue and is likely dependent on urbanization intensity. Wild bees are important pollinators of wild and cultivated flowers. Wild bees are dependent on particular nest substrates and on flower resource availability, hence they are particularly susceptible to habitat and land use change (Choate et al. 2018 ). Furthermore, because of their limited flight ability, the presence of particular bee species may be jeopardized by the fragmented nature of the urban landscape. Concerning nesting behavior, some bees nest in the soil, while others nest above ground in stems, dead wood or even walls (cavity-nesting species). The regular disturbance in urban habitats (e.g. mowing, weeding, use of garden pesticides or soil plowing) may prevent the long-term establishment of soil-nesting bee species (Matteson et al. 2008). Depletion of nesting substrates combined with increases in urban cover is thought to affect ground nesting bees (Pereira et al. 2021). In contrast, cavity-nesting bees can be overrepresented in urban habitats, probably due to more nesting opportunities available in the urban landscape (Cane et al. 2006 ). Most wild bees are solitary (Michener 2000), and their typical foraging ranges are within 500 m of the nest site, although, if required, some bee species can forage at greater distances from the nest (Gathmann and Tscharntke 2002; Zurbuchen et al. 2010). Several studies have demonstrated that wild bee abundance is associated with floral resources (i.e. native or non-native vegetation), with increased bee abundance where native vegetation is the predominant resource (Frankie et al. 2005). Floral specialists can be negatively impacted in urban environments were native vegetation has been replaced with non-native, ornamental species (Frankie et al. 2005; Hernandez et al. 2009). The solitary lifestyle of most wild bees in conjunction with their limited foraging ranges make them dependent on proximal floral resources. Few bee diversity studies have been carried out on semi-arid urban areas. It is believed that the diversity of bees in Mexico (~ 2000 species) is intermediate between that of the United States and countries in Central America with most endemisms occurring in arid regions (Ayala et al. 1993 ). Here we address the hypothesis that wild bee diversity and abundance are negatively related to increasing urbanization, measured as the proportion of impervious surfaces (including roads, buildings, industrial areas, houses) in the landscape surrounding the study sites (2.5 km radius). We evaluate also the presence of native vegetation, agricultural land and bare-soil. Methods Study sites The study was carried out in the valley of the City of Querétaro (20°36′N 100°25′W), an urban area sprawling 21 km in a N to S direction and 9 km in a E to W direction with an approximate population 1.5 million. This urban landscape consists of diverse ecosystems ranging from densely populated urban areas, agricultural lands and tropical deciduous forest that can be found mainly on the slopes of the hills surrounding the valley. The tropical deciduous forest surrounding the city is not prestine but has suffered alterations from human activities like wood exctraction and livestock grazing. The area has a semi-arid climate (BSh) with mild temperatures year-round, and an average high temperature in May of 30.7°C. We selected 6 sites with a 2.5km radius that could cover most of the city (Fig. 1). Plant surveys were carried out in areas with native vegetation by means of 0.1 ha transects. Wild bee surveys Sites were monitored twice a month with three colored pan traps during 2022 and 2023. Pan-trapping is a standard passive method for capturing bees (Fortel et al. 2014). We used 500 ml plastic bowls colored blue, yellow and white. Pan traps were arranged in triplets, with each triplet consisting of a pan of each of the three colors randomly distributed at one of the corners of a wooden triangular board. Wooden boards containing pan triplets were hung at 1.5 m from the ground in an open area with vegetation at each site. Traps were activated by filling them with 400 ml of water with a drop of detergent, and left active for 72 hours. Specimens collected in pan traps were first washed with 100% ethanol and stored at -30°C for later processing. Individuals were then pinned, labeled, and identified to the family and genus level using taxonomical keys (Michener et al. 1994). All specimens are stored at the Facultad de Ciencias Naturales at the Universidad Autónoma de Querétaro. When possible, identification was carried out to the species level. To confirm the visual identifications of the specimens, DNA extraction from a specimen of each morphospecies was carried out using the DNeasy Blood & Tissue Kits (QUIAGEN ®). We homogenize tissue using liquid nitrogen and follow the extraction protocol as indicated on the manual. DNA concentration was quantified with the NanoDrop ND1000 (Thermo Fisher Scientific). Gene amplification of CO1 was performed using the Go Taq Polymerase Kit PROMEGA following the manufacturer’s instructions, the primers and PCR conditions as (Sheffield, et al. 2009). Sequences were edited on Chromas Pro v. 2.1.10.1(www.technelysium.com.au/chromas.html) deleting low quality bases. We ran BLAST sequence similarity search to look up species identity at the NCBI database and BOLD Systems. We keep the species name where percent identity was > 95%. For sequences not found or percent identity was < 95% we used the key the Bee Genera of North and Central America (Michener et al. 1994). All sequences have been deposited in GenBank (Supplementary Table 1). Landscape structure To characterize the landscape surrounding each study site, we used the QGIS software. Landscape characteristics were analyzed at a radius of 2.5 km centered on the centroid of the pan-trap triplets (area of 19.63 km 2 or 1963 ha) according to the Local Ecological Planning Program of the Municipality of Querétaro (Municipio de Querétaro 2014). This radius was chosen according to Desaegher et al. (2022) who established the minimum distance between sampling sites to avoid spatial pseudo-replication in a wild bee community survey as 5 km. We therefore chose to have a 2.5 km radius around our pan-traps to guarantee the sites independence. We used four mutually exclusive land-cover types: urban areas with impervious surfaces (including roads, buildings, industrial areas, houses), agricultural land, tropical deciduous forest, and bare soils areas (Fig. 1). Data analyses All analysis were carried out in R v 4.2.2 software. Species diversity was characterized by species richness and rank abundance distribution using the goeveg package. The observed cumulative species richness curve was computed using a bootstrapping procedure with 100 random reorganizations of sampling order. Kendall rank correlation tests were calculated to measure the association between landscape variables with species abundance and diversity. We also examined the effect of landscape variables on bee richness and abundance using generalized linear models (GLM). We compared bee abundance per sampling event in to the level of urbanization (low vs high) and to their nesting behavior (cavity vs ground)). We classified sites according to the Local Ecological Planning Program of the Municipality of Querétaro (Municipio de Querétaro 2014) as having a low level of urbanization if the area of impervious surfaces was less than a third of the total area of 19.63 km 2 . Results A total of 26 plant species were recorded in the areas with native tropical deciduous forest and are presented in Supplementary Table 2. Over the two years of survey a total of 525 individual bees belonging to 15 species were trapped, including the introduced Apis mellifera . They belonged to five families (Andrenidae, Apidae, Halictidae and Megachilidae) and 13 genera ( Apis, Ashmeadiella, Augochlora, Augochloropsis, Bombus, Diadasia, Exomalopsis, Eulaema, Lasioglossum, Macrotera, Melissodes, Osmia , and Xylocopa ). The native species we able to confirm by taxonomical keys, comparison with reference material and molecular markers were Apis mellifera L. 1758, Ashmeadiella cactorum Cockerell 1897,, Bombus sonorous Say 1837, Diadasia rinconis Cokerell 1897 and Melissodes communis Cresson 1878, Osmia subfasciata Cresson 1872 and Xylocopa sonorina Smith 1874. The most represented family was Apidae with six species followed by Halicitidae with four species. Species accumulation curves reached saturation after 25 sampling events, which indicates that we captured all the species potentially susceptible to pan-trapping in the urban area studied (Fig. 2 ). Apis mellifera was the only non-native bee found in our surveys. Species richness varied during the seasons reaching its highest values in spring (March and April) and autumn (October) (data not shown). Species richness was positively correlated with the amount of native vegetation (tau = 0.54) and negatively correlated with the amount of urbanized area (tau = -0.39) (Fig. 3 ). Generalized liner models also showed that native vegetation has a greater effect on species richness as measured by the size of the coefficient estimate (Table 1 ). The amount of agricultural land and bare soil was not correlated to species richness. Table 1 General linear models with Poisson distribution of errors for bee species richness Explanatory variable Estimate p value Urban -0.0008934 < 0.0001 Tropical decidous forest 0.0021327 < 0.0001 Agricultural land 0.0008932 0.772 Bare soil 0.0004919 0.091 Native bee species abundance varied during the seasons reaching its highest values in spring (April and May) (data not shown). Species abundance was positively correlated with the amount of native vegetation (tau = 0.46) and negatively correlated with the amount of urbanized area (tau = -0.33) (Fig. 4 ). Generalized liner models also showed that native vegetation had a more significant effect on species abundance as measured by the size of the coefficient estimate (Table 2 ). Table 2 General linear models with Poisson distribution of errors for bee abundance Explanatory variable Estimate p value Urban -0.00116 < 0.0001 Tropical decidous forest 0.00406 < 0.0001 Agricultural land -0.000191 0.132 Bare soil 0.0004374 0.078 The landscape surrounding two of the sampling sites presented less than a third of the total area covered by impervious surfaces. We considered these two sites as having a low level of urbanization as compared to the other four sites. The abundance of cavity nesting bees was not affected by urbanization level (Wilcoxon Rank Sum Test W = 400, p = 0.23). In contrast, the abundance of ground nesting bees was significantly lower in sites with a high level of urbanization (Wilcoxon Rank Sum Test W = 241, p < 0.0001) (Fig. 5 ). Discussion We have explored the amount of bee diversity that can be found in an urban semi-arid landscape and evaluated how urbanization affects species richness and diversity. We captured 15 species of bees, which we consider to be a strongly eroded bee diversity. Bee surveys using colored vane traps carried out in natural protected areas in this region of Mexico have estimates of more than 50 bee species (Dr. Robert Jones, Universidad Autónoma de Querétaro, pers.comm). It has been proposed that the extent to which wild bee biodiversity is impacted by urbanization depends likely on its intensity (e.g. amount of green areas, human population density) as well as the spatial scale of investigation (McKinney 2008). Our study was carried out in the sprawling 21 km long urban landscape that only has a 20% coverage of green spaces (OECD 2021). We found that the amount of impervious surfaces (roads, houses, buildings, etc.) around a 2.5 km radius of the sampling site has a negative impact on wild bee diversity and abundance. In contrast to our results, studies carried out in Europe, where green spaces account to an average of 42% of the city surface (European Environment Agency 2022), have reported that cities can harbor a greater wild be diversity than rural sites (Fortel et al. 2014; Theodorou et al. 2020). Moderate disturbances within urban environment could potentially increase landscape heterogeneity thereby increasing niche diversity and enhancing bee diversity (Winfree et al. 2009). Additionally, insect pollinator communities respond positively to small-scale (patch) habitat features associated with nesting and floral resources (Theodorou et al. 2017). This has promoted the creation of urban pollinator gardens that provide nesting sites and floral resources which are known to be a refuge for pollinators in the urban environment (Cano et al. 2022 ). We have found that bee diversity was positively associated with the amount of tropical deciduous forest (native vegetation of the area) that occurs mainly in the city boundaries. Suggesting that as we move from natural habitats with native vegetation towards the city center there is a general loss of bee species. A situation also reported in other studies where bees species richness was greatest at sites with the largest amount of permeable surface and naturally-occurring, native vegetation (Choate et al. 2018 ). The presence of native pollinators is, not surprisingly, associated with the presence of native vegetation (Frankie et al. 2005) and floral specialists can be absent in urban environments where native vegetation has been replaced with ornamental species (Hernandez et al. 2009). Our data also suggest that the ground nesting bees are more sensitive to urbanization when compared to cavity nesting bees. A long-term study carried out in Brazil has shown that the depletion of nesting substrates combined with increases in urban cover affects ground nesting bees (Pereira et al. 2021). The authors argue that the friable soil substrate that most ground nesting bees require is lost with urbanization. In order to preserve the important ecological service of pollination, cities should include policies that protect ground-nesting bees in their urban planning (Pereira et al. 2021). In conclusion, we have found a low diversity of bee species in a highly urbanized environment. Our results highlight the importance of the incorporation of native vegetation and friable soil in urban planning to prevent future losses. Declarations Author Contributions Statement A.P. & M.D. designed the study. A.P. and A.R. collected the samples. A.R. and M.D. carried ou the DNA extractions. A.P. wrote the main manuscript text. All authors reviewed the manuscript. Author Contribution A.P. & M.D. designed the study. A.P. and A.R. collected the samples. A.R. and M.D. carried out the DNA extractions. A.P. wrote the main manuscript text. All authors reviewed the manuscript. Acknowledgement We thank Robert W. Jones and Viviana Martínez Mandujano of the Insect Collection of the Universidad Autónoma de Querétaro for their help with the taxonomic identification of bee species. Data Availability Sequence data that support the findings of this study have been deposited in GenBank. All insect specimens are stored at the insect collection of the Facultad de Ciencias Naturales at the Universidad Autónoma de Querétaro. References Ayala, R., Griswold, T.L. and Bullock, S.H. 1993. The Native Bees of Mexico. In: Biological Diversity of Mexico: Origins and Distribution. Eds: Ramamoorthy, T.P., Bye, R. & Lot, A. Oxoford University Press. pp:179-227. 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Urban ecosystems , 11 , pp.161-176. Michener, C.D., 2000. The bees of the world (Vol. 1). JHU press. Michener, C.D., McGinley, R.J. and Danforth, B.N., 1994. The bee genera of North and Central America (Hymenoptera: Apoidea) . Smithsonian Institution Press. Municipio de Queréatro. 2014. Programa de Ordenamiento Ecológico Local del Municipio de Querétaro Gaceta Oficial del Ayuntamiento del Municipio de Querétaro No. 36. OECD. 2021. City Statistics: Green Areas. https://stats.oecd.org/Index.aspx?QueryId=119735 Accessed on March 8 th , 2024. Ollerton, J., Winfree, R., Tarrant, S., 2011. How many flowering plants are pollinated by animals? Oikos 120 , 321–326. https://doi.org/10.1111/j.1600-0706.2010.18644.x. Pereira, F.W., Carneiro, L. and Gonçalves, R.B., 2021. More losses than gains in ground-nesting bees over 60 years of urbanization. Urban Ecosystems , 24 (2), pp.233-242. Potts, S.G., Biesmeijer, J.C., Kremen, C., Neumann, P., Schweiger, O. and Kunin, W.E., 2010. Global pollinator declines: trends, impacts and drivers. Trends in ecology & evolution , 25 (6), pp.345-353. Sheffield, C. S., Hebert, P. D., Kevan, P. G., & Packer, L. (2009). DNA barcoding a regional bee (Hymenoptera: Apoidea) fauna and its potential for ecological studies. Molecular Ecology Resources, 9, 196-207. Theodorou, P., Albig, K., Radzevičiūtė, R., Settele, J., Schweiger, O., Murray, T.E. and Paxton, R.J., 2017. The structure of flower visitor networks in relation to pollination across an agricultural to urban gradient. Functional Ecology , 31 (4), pp.838-847. Theodorou, P., Radzevičiūtė, R., Lentendu, G., Kahnt, B., Husemann, M., Bleidorn, C., Settele, J., Schweiger, O., Grosse, I., Wubet, T. and Murray, T.E., 2020. Urban areas as hotspots for bees and pollination but not a panacea for all insects. Nature communications , 11 (1), p.576. Tylianakis, J.M., 2013. The global plight of pollinators. Science , 339 (6127), pp.1532-1533. Wenzel, A., Grass, I., Belavadi, V.V. and Tscharntke, T., 2020. How urbanization is driving pollinator diversity and pollination–A systematic review. Biological Conservation , 241 , p.108321. Winfree, R., Aguilar, R., Vázquez, D.P., LeBuhn, G. and Aizen, M.A., 2009. A meta‐analysis of bees' responses to anthropogenic disturbance. Ecology , 90 (8), pp.2068-2076. Zurbuchen, A., Landert, L., Klaiber, J., Müller, A., Hein, S. and Dorn, S., 2010. Maximum foraging ranges in solitary bees: only few individuals have the capability to cover long foraging distances. Biological Conservation , 143 (3), pp.669-676. Additional Declarations No competing interests reported. Supplementary Files SupplementaryTable1.pdf Supplementary Table 1. GenBank accession numbers for nucleotide sequences of bee species. SupplementaryTable2.pdf Supplementary Table 2. Plant species identified in the tropical deciduous forest in our study areas Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4214950","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":288915043,"identity":"14967f05-4caf-43bd-80fd-598564e66e54","order_by":0,"name":"Alberto Prado","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAqUlEQVRIiWNgGAWjYLACHgYb0rWkka7lMAmq+Wf3PvzwpuJ84nb20wlMN9uI0CJx57ix5JwztxN39uRuYM45Q4w1N9IYpHnbbiduOADSUkGEDvkbacy/edvOJW44/xaoxYAILQY30tiAthxI3HCDWFsM7xxjs5xzJtl4w423Gw4T5Re5223MN95U2MluOJ+78XEuMSHGIIHEPkCMBlQto2AUjIJRMAqwAgCJBDqnw9dbDQAAAABJRU5ErkJggg==","orcid":"","institution":"National Autonomous University of Mexico","correspondingAuthor":true,"prefix":"","firstName":"Alberto","middleName":"","lastName":"Prado","suffix":""},{"id":288915044,"identity":"a65943f2-304d-4ce4-9691-b075ce501419","order_by":1,"name":"Ana Sofía Ramírez-Infante","email":"","orcid":"","institution":"National Autonomous University of Mexico","correspondingAuthor":false,"prefix":"","firstName":"Ana","middleName":"Sofía","lastName":"Ramírez-Infante","suffix":""},{"id":288915045,"identity":"ce6df8e7-de8b-4be5-ba47-7de71dbc8cb0","order_by":2,"name":"Luis Hernández-Sandoval","email":"","orcid":"","institution":"Autonomous University of Queretaro","correspondingAuthor":false,"prefix":"","firstName":"Luis","middleName":"","lastName":"Hernández-Sandoval","suffix":""},{"id":288915048,"identity":"2a5a4719-47ee-4552-a5dd-c41eae972433","order_by":3,"name":"Marisol de-la-Mora","email":"","orcid":"","institution":"National Autonomous University of Mexico","correspondingAuthor":false,"prefix":"","firstName":"Marisol","middleName":"","lastName":"de-la-Mora","suffix":""}],"badges":[],"createdAt":"2024-04-03 22:29:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4214950/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4214950/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":54865195,"identity":"f2e7b669-390b-4ade-9756-d47c6fe184df","added_by":"auto","created_at":"2024-04-17 20:44:07","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2843786,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eA) \u003c/strong\u003eDistribution of the six studies sites where bees were sampled on periodic basis. \u003cstrong\u003eB-G)\u003c/strong\u003e Landscape characteristics at a 2.5 km radius surrounding the sampling sites. Urban areas with impervious surfaces in blue, agricultural land in orange, tropical deciduous forest in green, and bare soils areas in red.\u003c/p\u003e","description":"","filename":"floatimage1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4214950/v1/0ad5c67fb61d1148c5c0a031.jpg"},{"id":54865194,"identity":"cec7d83b-cf49-4fda-8083-13912e082d33","added_by":"auto","created_at":"2024-04-17 20:44:07","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":151446,"visible":true,"origin":"","legend":"\u003cp\u003eSpecies accumulation curve with confidence interval (100 randomizations). Insert: Whittaker rank-abundance curve.\u003c/p\u003e","description":"","filename":"floatimage2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4214950/v1/a65e3560b7638eac1d9cc151.jpg"},{"id":54864513,"identity":"a3dd6941-8c25-4d51-9785-216de617ab1e","added_by":"auto","created_at":"2024-04-17 20:36:07","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":253334,"visible":true,"origin":"","legend":"\u003cp\u003eSpecies richness and landscape structure in a 2.5 km radius. Species richness as a function of the amount of ha of A) urban areas, B) tropical deciduous forest, C) agricultural land and D) bare soil. Kendall rank correlation coefficient tau and associated p values are provided.\u003c/p\u003e","description":"","filename":"floatimage3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4214950/v1/6518a644f73050d0efd70312.jpg"},{"id":54864518,"identity":"e03143c4-a2d5-430a-a68d-79a09ecd1988","added_by":"auto","created_at":"2024-04-17 20:36:07","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":286016,"visible":true,"origin":"","legend":"\u003cp\u003eWild bee\u003cstrong\u003e \u003c/strong\u003especies abundance and landscape structure in a 2.5 km radius. Log species abundance as a function of the amount of ha of A) urban areas, B) tropical deciduous forest, C) agricultural land and D) bare soil. Kendall rank correlation coefficient tau and associated p values are provided.\u003c/p\u003e","description":"","filename":"floatimage4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4214950/v1/9717cdc35d45fa2718840b78.jpg"},{"id":54864515,"identity":"61dd5942-b4af-47e0-a622-dca6bb81edf0","added_by":"auto","created_at":"2024-04-17 20:36:07","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":65956,"visible":true,"origin":"","legend":"\u003cp\u003eLevel of urbanization and bee abundance in relation to their nesting behavior. Abundance of cavity nesting bees was not affected by urbanization. Abundance of ground nesting bees was significantly lower in sites with a high level of urbanization (Wilcoxon Rank Sum Test W=241, p\u0026lt;0.0001)\u003c/p\u003e","description":"","filename":"floatimage5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4214950/v1/a33bad68049efb1ac4d7f41b.jpg"},{"id":58364790,"identity":"8d9b966e-acfc-4d20-a6ef-2751726a115a","added_by":"auto","created_at":"2024-06-14 12:10:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3967215,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4214950/v1/6c055e0d-60ea-4d9e-867b-6eeef9cd5265.pdf"},{"id":54864512,"identity":"a8aef822-50b8-439c-935c-bcbf744dec31","added_by":"auto","created_at":"2024-04-17 20:36:07","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":54129,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSupplementary Table 1. GenBank accession numbers for nucleotide sequences of bee species.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"SupplementaryTable1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4214950/v1/270d13e1c0ee5a1f0a0bd968.pdf"},{"id":54864517,"identity":"7b3afe7b-2244-428e-8b0e-9e082d2e5ab4","added_by":"auto","created_at":"2024-04-17 20:36:07","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":76517,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSupplementary Table 2. Plant species identified in the tropical deciduous forest in our study areas\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"SupplementaryTable2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4214950/v1/00553bb07b11a4170a03a278.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Wild bee abundance and diversity in an urban landscape: the importance of preserving native vegetation","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAs cities expand, integrating the conservation of biodiversity and ecosystem services into urban planning and practices is of paramount importance for a sustainable future (Pereira et al. 2021). Pollination is a crucial ecosystem service not only in natural and agricultural ecosystems but also in urban areas. A 87.5% of angiosperm species are dependent on animal pollination (Ollerton et al. 2011). Through their influence on flowering plants, urban pollinators can provide a wide range of ecosystem services, including urban food production and soil formation (Langellotto et al. 2018; Wenzel et al 2020). Insect pollinators are of considerable conservation concern as they are vulnerable to a range of anthropogenic disturbances. Habitat destruction, land-use intensification, chemical exposure, exotic species and climate change are causing local and regional population declines or even extinctions of pollinator species (Potts et al. 2010). Urbanization is repeatedly stated as one potential driver of this \u0026ldquo;pollinator crisis\u0026rdquo; (Tylianakis 2013). However, research outcomes on the effects of the urbanization on pollinator communities are mixed and sometimes contradictory with solid evidence for positive and negative impacts. On one side, many researchers argue that, in the face of intensive agriculture, urban areas can be a refuge for pollinators. A recent study carried out in Europe found that Hymenoptera species, particularly bees, are resilient to urbanization, since a higher species richness was found in cities as compared to rural sites (Theodorou et al. 2020). On the other side researchers take the view that urbanization is a significant threat to pollinators (Bates et al., 2014; Desaegher et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Bates et al. (2014) found that pollinator diversity and abundance where both negatively associated with higher levels of urbanization. Thus, the effects of urbanization on suitable pollinator communities remains a controversial issue and is likely dependent on urbanization intensity.\u003c/p\u003e \u003cp\u003eWild bees are important pollinators of wild and cultivated flowers. Wild bees are dependent on particular nest substrates and on flower resource availability, hence they are particularly susceptible to habitat and land use change (Choate et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Furthermore, because of their limited flight ability, the presence of particular bee species may be jeopardized by the fragmented nature of the urban landscape. Concerning nesting behavior, some bees nest in the soil, while others nest above ground in stems, dead wood or even walls (cavity-nesting species). The regular disturbance in urban habitats (e.g. mowing, weeding, use of garden pesticides or soil plowing) may prevent the long-term establishment of soil-nesting bee species (Matteson et al. 2008). Depletion of nesting substrates combined with increases in urban cover is thought to affect ground nesting bees (Pereira et al. 2021). In contrast, cavity-nesting bees can be overrepresented in urban habitats, probably due to more nesting opportunities available in the urban landscape (Cane et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eMost wild bees are solitary (Michener 2000), and their typical foraging ranges are within 500 m of the nest site, although, if required, some bee species can forage at greater distances from the nest (Gathmann and Tscharntke 2002; Zurbuchen et al. 2010). Several studies have demonstrated that wild bee abundance is associated with floral resources (i.e. native or non-native vegetation), with increased bee abundance where native vegetation is the predominant resource (Frankie et al. 2005). Floral specialists can be negatively impacted in urban environments were native vegetation has been replaced with non-native, ornamental species (Frankie et al. 2005; Hernandez et al. 2009). The solitary lifestyle of most wild bees in conjunction with their limited foraging ranges make them dependent on proximal floral resources. Few bee diversity studies have been carried out on semi-arid urban areas. It is believed that the diversity of bees in Mexico (~\u0026thinsp;2000 species) is intermediate between that of the United States and countries in Central America with most endemisms occurring in arid regions (Ayala et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1993\u003c/span\u003e). Here we address the hypothesis that wild bee diversity and abundance are negatively related to increasing urbanization, measured as the proportion of impervious surfaces (including roads, buildings, industrial areas, houses) in the landscape surrounding the study sites (2.5 km radius). We evaluate also the presence of native vegetation, agricultural land and bare-soil.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\"\u003e\n \u003ch2\u003eStudy sites\u003c/h2\u003e\n \u003cp\u003eThe study was carried out in the valley of the City of Quer\u0026eacute;taro (20\u0026deg;36\u0026prime;N 100\u0026deg;25\u0026prime;W), an urban area sprawling 21 km in a N to S direction and 9 km in a E to W direction with an approximate population 1.5 million. This urban landscape consists of diverse ecosystems ranging from densely populated urban areas, agricultural lands and tropical deciduous forest that can be found mainly on the slopes of the hills surrounding the valley. The tropical deciduous forest surrounding the city is not prestine but has suffered alterations from human activities like wood exctraction and livestock grazing. The area has a semi-arid climate (BSh) with mild temperatures year-round, and an average high temperature in May of 30.7\u0026deg;C. We selected 6 sites with a 2.5km radius that could cover most of the city (Fig. 1). Plant surveys were carried out in areas with native vegetation by means of 0.1 ha transects.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\"\u003e\n \u003ch2\u003eWild bee surveys\u003c/h2\u003e\n \u003cp\u003eSites were monitored twice a month with three colored pan traps during 2022 and 2023. Pan-trapping is a standard passive method for capturing bees (Fortel et al. 2014). We used 500 ml plastic bowls colored blue, yellow and white. Pan traps were arranged in triplets, with each triplet consisting of a pan of each of the three colors randomly distributed at one of the corners of a wooden triangular board. Wooden boards containing pan triplets were hung at 1.5 m from the ground in an open area with vegetation at each site. Traps were activated by filling them with 400 ml of water with a drop of detergent, and left active for 72 hours. Specimens collected in pan traps were first washed with 100% ethanol and stored at -30\u0026deg;C for later processing. Individuals were then pinned, labeled, and identified to the family and genus level using taxonomical keys (Michener et al. 1994). All specimens are stored at the Facultad de Ciencias Naturales at the Universidad Aut\u0026oacute;noma de Quer\u0026eacute;taro. When possible, identification was carried out to the species level. To confirm the visual identifications of the specimens, DNA extraction from a specimen of each morphospecies was carried out using the DNeasy Blood \u0026amp; Tissue Kits (QUIAGEN \u0026reg;). We homogenize tissue using liquid nitrogen and follow the extraction protocol as indicated on the manual. DNA concentration was quantified with the NanoDrop ND1000 (Thermo Fisher Scientific). Gene amplification of CO1 was performed using the Go Taq Polymerase Kit PROMEGA following the manufacturer\u0026rsquo;s instructions, the primers and PCR conditions as (Sheffield, et al. 2009). Sequences were edited on Chromas Pro v. 2.1.10.1(www.technelysium.com.au/chromas.html) deleting low quality bases. We ran BLAST sequence similarity search to look up species identity at the NCBI database and BOLD Systems. We keep the species name where percent identity was \u0026gt;\u0026thinsp;95%. For sequences not found or percent identity was \u0026lt;\u0026thinsp;95% we used the key the Bee Genera of North and Central America (Michener et al. 1994). All sequences have been deposited in GenBank (Supplementary Table\u0026nbsp;1).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\"\u003e\n \u003ch2\u003eLandscape structure\u003c/h2\u003e\n \u003cp\u003eTo characterize the landscape surrounding each study site, we used the QGIS software. Landscape characteristics were analyzed at a radius of 2.5 km centered on the centroid of the pan-trap triplets (area of 19.63 km\u003csup\u003e2\u003c/sup\u003e or 1963 ha) according to the Local Ecological Planning Program of the Municipality of Quer\u0026eacute;taro (Municipio de Quer\u0026eacute;taro 2014). This radius was chosen according to Desaegher et al. (2022) who established the minimum distance between sampling sites to avoid spatial pseudo-replication in a wild bee community survey as 5 km. We therefore chose to have a 2.5 km radius around our pan-traps to guarantee the sites independence. We used four mutually exclusive land-cover types: urban areas with impervious surfaces (including roads, buildings, industrial areas, houses), agricultural land, tropical deciduous forest, and bare soils areas (Fig.\u0026nbsp;1).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\"\u003e\n \u003ch2\u003eData analyses\u003c/h2\u003e\n \u003cp\u003eAll analysis were carried out in R v 4.2.2 software. Species diversity was characterized by species richness and rank abundance distribution using the \u003cem\u003egoeveg\u003c/em\u003e package. The observed cumulative species richness curve was computed using a bootstrapping procedure with 100 random reorganizations of sampling order. Kendall rank correlation tests were calculated to measure the association between landscape variables with species abundance and diversity. We also examined the effect of landscape variables on bee richness and abundance using generalized linear models (GLM). We compared bee abundance per sampling event in to the level of urbanization (low vs high) and to their nesting behavior (cavity vs ground)). We classified sites according to the Local Ecological Planning Program of the Municipality of Quer\u0026eacute;taro (Municipio de Quer\u0026eacute;taro 2014) as having a low level of urbanization if the area of impervious surfaces was less than a third of the total area of 19.63 km\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 26 plant species were recorded in the areas with native tropical deciduous forest and are presented in Supplementary Table\u0026nbsp;2. Over the two years of survey a total of 525 individual bees belonging to 15 species were trapped, including the introduced \u003cem\u003eApis mellifera\u003c/em\u003e. They belonged to five families (Andrenidae, Apidae, Halictidae and Megachilidae) and 13 genera (\u003cem\u003eApis, Ashmeadiella, Augochlora, Augochloropsis, Bombus, Diadasia, Exomalopsis, Eulaema, Lasioglossum, Macrotera, Melissodes, Osmia\u003c/em\u003e, and \u003cem\u003eXylocopa\u003c/em\u003e). The native species we able to confirm by taxonomical keys, comparison with reference material and molecular markers were \u003cem\u003eApis mellifera\u003c/em\u003e L. 1758, \u003cem\u003eAshmeadiella cactorum\u003c/em\u003e Cockerell 1897,, \u003cem\u003eBombus sonorous\u003c/em\u003e Say 1837, \u003cem\u003eDiadasia rinconis\u003c/em\u003e Cokerell 1897 and \u003cem\u003eMelissodes communis\u003c/em\u003e Cresson 1878, \u003cem\u003eOsmia subfasciata\u003c/em\u003e Cresson 1872 and \u003cem\u003eXylocopa sonorina\u003c/em\u003e Smith 1874. The most represented family was Apidae with six species followed by Halicitidae with four species. Species accumulation curves reached saturation after 25 sampling events, which indicates that we captured all the species potentially susceptible to pan-trapping in the urban area studied (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eApis mellifera\u003c/em\u003e was the only non-native bee found in our surveys. Species richness varied during the seasons reaching its highest values in spring (March and April) and autumn (October) (data not shown). Species richness was positively correlated with the amount of native vegetation (tau\u0026thinsp;=\u0026thinsp;0.54) and negatively correlated with the amount of urbanized area (tau = -0.39) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Generalized liner models also showed that native vegetation has a greater effect on species richness as measured by the size of the coefficient estimate (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The amount of agricultural land and bare soil was not correlated to species richness.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eGeneral linear models with Poisson distribution of errors for bee species richness\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExplanatory variable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEstimate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUrban\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e-0.0008934\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTropical decidous forest\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0.0021327\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAgricultural land\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.0008932\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.772\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBare soil\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.0004919\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.091\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eNative bee species abundance varied during the seasons reaching its highest values in spring (April and May) (data not shown). Species abundance was positively correlated with the amount of native vegetation (tau\u0026thinsp;=\u0026thinsp;0.46) and negatively correlated with the amount of urbanized area (tau = -0.33) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Generalized liner models also showed that native vegetation had a more significant effect on species abundance as measured by the size of the coefficient estimate (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eGeneral linear models with Poisson distribution of errors for bee abundance\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExplanatory variable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEstimate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUrban\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e-0.00116\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTropical decidous forest\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e0.00406\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAgricultural land\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.000191\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.132\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBare soil\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.0004374\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.078\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe landscape surrounding two of the sampling sites presented less than a third of the total area covered by impervious surfaces. We considered these two sites as having a low level of urbanization as compared to the other four sites. The abundance of cavity nesting bees was not affected by urbanization level (Wilcoxon Rank Sum Test W\u0026thinsp;=\u0026thinsp;400, p\u0026thinsp;=\u0026thinsp;0.23). In contrast, the abundance of ground nesting bees was significantly lower in sites with a high level of urbanization (Wilcoxon Rank Sum Test W\u0026thinsp;=\u0026thinsp;241, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe have explored the amount of bee diversity that can be found in an urban semi-arid landscape and evaluated how urbanization affects species richness and diversity. We captured 15 species of bees, which we consider to be a strongly eroded bee diversity. Bee surveys using colored vane traps carried out in natural protected areas in this region of Mexico have estimates of more than 50 bee species (Dr. Robert Jones, Universidad Aut\u0026oacute;noma de Quer\u0026eacute;taro, pers.comm). It has been proposed that the extent to which wild bee biodiversity is impacted by urbanization depends likely on its intensity (e.g. amount of green areas, human population density) as well as the spatial scale of investigation (McKinney 2008). Our study was carried out in the sprawling 21 km long urban landscape that only has a 20% coverage of green spaces (OECD 2021). We found that the amount of impervious surfaces (roads, houses, buildings, etc.) around a 2.5 km radius of the sampling site has a negative impact on wild bee diversity and abundance. In contrast to our results, studies carried out in Europe, where green spaces account to an average of 42% of the city surface (European Environment Agency 2022), have reported that cities can harbor a greater wild be diversity than rural sites (Fortel et al. 2014; Theodorou et al. 2020). Moderate disturbances within urban environment could potentially increase landscape heterogeneity thereby increasing niche diversity and enhancing bee diversity (Winfree et al. 2009). Additionally, insect pollinator communities respond positively to small-scale (patch) habitat features associated with nesting and floral resources (Theodorou et al. 2017). This has promoted the creation of urban pollinator gardens that provide nesting sites and floral resources which are known to be a refuge for pollinators in the urban environment (Cano et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWe have found that bee diversity was positively associated with the amount of tropical deciduous forest (native vegetation of the area) that occurs mainly in the city boundaries. Suggesting that as we move from natural habitats with native vegetation towards the city center there is a general loss of bee species. A situation also reported in other studies where bees species richness was greatest at sites with the largest amount of permeable surface and naturally-occurring, native vegetation (Choate et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The presence of native pollinators is, not surprisingly, associated with the presence of native vegetation (Frankie et al. 2005) and floral specialists can be absent in urban environments where native vegetation has been replaced with ornamental species (Hernandez et al. 2009). Our data also suggest that the ground nesting bees are more sensitive to urbanization when compared to cavity nesting bees. A long-term study carried out in Brazil has shown that the depletion of nesting substrates combined with increases in urban cover affects ground nesting bees (Pereira et al. 2021). The authors argue that the friable soil substrate that most ground nesting bees require is lost with urbanization. In order to preserve the important ecological service of pollination, cities should include policies that protect ground-nesting bees in their urban planning (Pereira et al. 2021). In conclusion, we have found a low diversity of bee species in a highly urbanized environment. Our results highlight the importance of the incorporation of native vegetation and friable soil in urban planning to prevent future losses.\u003c/p\u003e"},{"header":"Declarations","content":" \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eAuthor Contributions Statement\u003c/strong\u003e \u003cp\u003eA.P. \u0026amp; M.D. designed the study. A.P. and A.R. collected the samples. A.R. and M.D. carried ou the DNA extractions. A.P. wrote the main manuscript text. All authors reviewed the manuscript.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eA.P. \u0026amp; M.D. designed the study. A.P. and A.R. collected the samples. A.R. and M.D. carried out the DNA extractions. A.P. wrote the main manuscript text. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe thank Robert W. Jones and Viviana Mart\u0026iacute;nez Mandujano of the Insect Collection of the Universidad Aut\u0026oacute;noma de Quer\u0026eacute;taro for their help with the taxonomic identification of bee species.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eSequence data that support the findings of this study have been deposited in GenBank. All insect specimens are stored at the insect collection of the Facultad de Ciencias Naturales at the Universidad Aut\u0026oacute;noma de Quer\u0026eacute;taro.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAyala, R., Griswold, T.L. and Bullock, S.H. 1993. The Native Bees of Mexico. In: Biological Diversity of Mexico: Origins and Distribution. Eds: Ramamoorthy, T.P., Bye, R. \u0026amp; Lot, A. Oxoford University Press. pp:179-227.\u003c/li\u003e\n\u003cli\u003eBates, A.J., Sadler, J.P., Fairbrass, A.J., Falk, S.J., Hale, J.D. and Matthews, T.J., 2011. 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Urban areas as hotspots for bees and pollination but not a panacea for all insects. \u003cem\u003eNature communications\u003c/em\u003e, \u003cem\u003e11\u003c/em\u003e(1), p.576.\u003c/li\u003e\n\u003cli\u003eTylianakis, J.M., 2013. The global plight of pollinators. \u003cem\u003eScience\u003c/em\u003e, \u003cem\u003e339\u003c/em\u003e(6127), pp.1532-1533.\u003c/li\u003e\n\u003cli\u003eWenzel, A., Grass, I., Belavadi, V.V. and Tscharntke, T., 2020. How urbanization is driving pollinator diversity and pollination\u0026ndash;A systematic review. \u003cem\u003eBiological Conservation\u003c/em\u003e, \u003cem\u003e241\u003c/em\u003e, p.108321.\u003c/li\u003e\n\u003cli\u003eWinfree, R., Aguilar, R., V\u0026aacute;zquez, D.P., LeBuhn, G. and Aizen, M.A., 2009. A meta‐analysis of bees\u0026apos; responses to anthropogenic disturbance. \u003cem\u003eEcology\u003c/em\u003e, \u003cem\u003e90\u003c/em\u003e(8), pp.2068-2076.\u003c/li\u003e\n\u003cli\u003eZurbuchen, A., Landert, L., Klaiber, J., M\u0026uuml;ller, A., Hein, S. and Dorn, S., 2010. Maximum foraging ranges in solitary bees: only few individuals have the capability to cover long foraging distances. \u003cem\u003eBiological Conservation\u003c/em\u003e, \u003cem\u003e143\u003c/em\u003e(3), pp.669-676.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4214950/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4214950/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eUrbanization is considered to be a major threat to biodiversity, habitat destruction and fragmentation hamper the establishment and dispersal of many species. Nevertheless, some species are resilient to urbanization. As important pollinators, wild bees provide an ecosystem service to natural, agricultural and urban ecosystems. It is not clear to what degree the urban environment can be a refuge for wild bees. We assessed changes in the abundance, species richness, and composition of wild bee community along an urbanization gradient in a semi-arid climate. Over two years and on a monthly basis, bees were sampled using colored pan traps at six sites with different degrees of urbanization. A total of 525 individual bees belonging to 15 species were trapped. The abundance and species richness of bees was positively correlated with native vegetation and negatively correlated with urbanization with soil-nesting species completely absent from highly urbanized sites. The amount of native vegetation was found to be the most important driver of wild bee species abundance and diversity. Our results suggest that the degree of urbanization is an important factor that can cause loss of pollinator diversity. Nonetheless, the incorporation of areas with native vegetation in urban planning has the potential to mitigate the negative effect of urbanization.\u003c/p\u003e","manuscriptTitle":"Wild bee abundance and diversity in an urban landscape: the importance of preserving native vegetation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-17 20:36:02","doi":"10.21203/rs.3.rs-4214950/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"24485d36-2e14-4ff8-a970-18544129180f","owner":[],"postedDate":"April 17th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-06-14T12:02:20+00:00","versionOfRecord":[],"versionCreatedAt":"2024-04-17 20:36:02","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4214950","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4214950","identity":"rs-4214950","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}