Consequences of climate and landscape changes on populations of bumblebees (Hymenoptera: Apidae: Bombus) in Belgium

It is widely acknowledged that climate and landscape changes are currently the most pervasive drivers of ecosystem change worldwide and will also play an important role in the future. Therefore, a thorough understanding of the mechanisms involved in the responses of populations and communities to these environmental changes is a pre-requisite to predict and mitigate the long-term effects of these changes on biodiversity. Bumblebees are among the most essential pollinators for their services to both natural ecosystems and agricultural production. However they currently experiment a strong decline fostered by habitat fragmentation and loss (e.g. diminution of open landscapes) and agricultural intensification. Indeed, changes in the structure of rural landscapes increase the fragmentation and isolation of populations leading to loss of genetic diversity. Moreover, agricultural intensification and standardization of production processes eliminate bumblebee food sources such as leguminous. More recently, several studies have implicated changes in climate in the bumblebee decline. Furthermore, climate and landscape changes are assumed to underlie a multitude of environmental pressures that may have a greater joint impact on biodiversity than when operating in isolation. The aim of this project is therefore to qualify and quantify the relationship between landscape changes, climate change and changes in populations of bumblebees. We use a comparative approach based on past and present landscape composition and structure, historical climate records and bumblebees data in Belgium. This will provide key elements for understanding the processes responsible for the decline of populations of bumblebees, which will in the longer term allow designing conservation strategies to halt biodiversity loss of these essential pollinators

Drastic shifts in the Belgian bumblebee community over the last century

peer reviewedCliPS - Fédération Wallonie Bruxelle

A century of local changes in bumblebee communities and landscape composition in Belgium

peer reviewedBELBEES 2013 Integrative analysis of BELgian wild BEE decline to adapt mitigation management policy - Sources fédérale

A century of temporal stability of genetic diversity in wild bumblebees

Since the 1950s, bumblebee (Bombus) species are showing a clear decline worldwide. Although many plausible drivers have been hypothesized, the cause(s) of this phenomenon remain debated. Here, genetic diversity in recent versus historical populations of bumblebee species was investigated by selecting four currently restricted and four currently widespread species. Specimens from five locations in Belgium were genotyped at 16 microsatellite loci, comparing historical specimens (1913-1915) with recent ones (2013-2015). Surprisingly, our results showed temporal stability of genetic diversity in the restricted species. Furthermore, both historical and recent populations of restricted species showed a significantly lower genetic diversity than found in populations of co-occurring widespread species. The difference in genetic diversity between species was thus already present before the alleged recent drivers of bumblebee decline could have acted (from the 1950's). These results suggest that the alleged drivers are not directly linked with the genetic variation of currently declining bumblebee populations. A future sampling in the entire distribution range of these species will infer if the observed link between low genetic diversity and population distribution on the Belgium scale correlates with species decline on a global scale

A century of temporal stability of genetic diversity in wild bumblebees

peer reviewe

Belgian Red List of Bees

BELBEES 2013 Integrative analysis of BELgian wild BEE decline to adapt mitigation management policy - Sources fédérale

Multi-decadal improvements in the ecological quality of European rivers are not consistently reflected in biodiversity metrics

Humans impact terrestrial, marine and freshwater ecosystems, yet many broad-scale studies have found no systematic, negative biodiversity changes (for example, decreasing abundance or taxon richness). Here we show that mixed biodiversity responses may arise because community metrics show variable responses to anthropogenic impacts across broad spatial scales. We first quantified temporal trends in anthropogenic impacts for 1,365 riverine invertebrate communities from 23 European countries, based on similarity to least-impacted reference communities. Reference comparisons provide necessary, but often missing, baselines for evaluating whether communities are negatively impacted or have improved (less or more similar, respectively). We then determined whether changing impacts were consistently reflected in metrics of community abundance, taxon richness, evenness and composition. Invertebrate communities improved, that is, became more similar to reference conditions, from 1992 until the 2010s, after which improvements plateaued. Improvements were generally reflected by higher taxon richness, providing evidence that certain community metrics can broadly indicate anthropogenic impacts. However, richness responses were highly variable among sites, and we found no consistent responses in community abundance, evenness or composition. These findings suggest that, without sufficient data and careful metric selection, many common community metrics cannot reliably reflect anthropogenic impacts, helping explain the prevalence of mixed biodiversity trends.We thank J. England for assistance with calculating ecological quality and the biomonitoring indices in the UK. Funding for authors, data collection and processing was provided by the European Union Horizon 2020 project eLTER PLUS (grant number 871128). F.A. was supported by the Swiss National Science Foundation (grant numbers 310030_197410 and 31003A_173074) and the University of Zurich Research Priority Program Global Change and Biodiversity. J.B. and M.A.-C. were funded by the European Commission, under the L‘Instrument Financier pour l’Environnement (LIFE) Nature and Biodiversity program, as part of the project LIFE-DIVAQUA (LIFE18 NAT/ES/000121) and also by the project ‘WATERLANDS’ (PID2019-107085RB-I00) funded by the Ministerio de Ciencia, Innovación y Universidades (MCIN) and Agencia Estatal de Investigación (AEI; MCIN/AEI/10.13039/501100011033/ and by the European Regional Development Fund (ERDF) ‘A way of making Europe’. N.J.B. and V.P. were supported by the Lithuanian Environmental Protection Agency (https://aaa.lrv.lt/) who collected the data and were funded by the Lithuanian Research Council (project number S-PD-22-72). J.H. was supported by the Academy of Finland (grant number 331957). S.C.J. acknowledges funding by the Leibniz Competition project Freshwater Megafauna Futures and the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung or BMBF; 033W034A). A.L. acknowledges funding by the Spanish Ministry of Science and Innovation (PID2020-115830GB-100). P.P., M.P. and M.S. were supported by the Czech Science Foundation (GA23-05268S and P505-20-17305S) and thank the Czech Hydrometeorological Institute and the state enterprises Povodí for the data used to calculate ecological quality metrics from the Czech surface water monitoring program. H.T. was supported by the Estonian Research Council (number PRG1266) and by the Estonian national program ‘Humanitarian and natural science collections’. M.J.F. acknowledges the support of Fundação para a Ciência e Tecnologia, Portugal, through the projects UIDB/04292/2020 and UIDP/04292/2020 granted to the Marine and Environmental Sciences Centre, LA/P/0069/2020 granted to the Associate Laboratory Aquatic Research Network (ARNET), and a Call Estímulo ao Emprego Científico (CEEC) contract.Peer reviewe