Multiple habitats need protecting to save UK bumblebees, finds 10-year citizen science study
IMAGE: WHITE-TAILED BUMBLEBEE (BOMBUS_LUCORUM) ON CHRYSANTHEMUM SEGETUM. view more
CREDIT: PIETER HARINGSMA
A study using 10 years of citizen science data from the Bumblebee Conservation Trust’s BeeWalk scheme has found that a variety of targeted conservation approaches are needed to protect UK bumblebee species. The findings are published the British Ecological Society’s Journal of Applied Ecology.
Researchers at the Bumblebee Conservation Trust, Karlsruhe Institute of Technology and the University of Edinburgh, have used 10 years of bumblebee abundance data, collected by citizen scientists, to provide the most detailed overview currently possible of bumblebee habitat requirements across the UK.
The researchers found a wide range of differences between bumblebee species in the types of habitat they are associated with. This suggests that a one-size-fits-all approach to bumblebee conservation will not effectively protect all species and that conservation efforts need to be carefully tailored to particular species.
The study identified types of habitat that could be targeted for bumblebee conservation. Arable areas were found to be important for rare species like the large garden bumblebee (Bombus ruderatus), the largest species in the UK. Whereas large areas of semi-natural land, like moorland, were important for several species such as the moss and the brown-banded carder bees (Bombus muscorum and Bombus humilis), and the bilberry bumblebee (Bombus monticola).
Dr Penelope Whitehorn, at the Karlsruhe Institute of Technology, who led the study, said: “Our results suggest that reversing the loss of semi-natural areas such as wetlands may be the single most generally effective action for bumblebee conservation, while improving habitats in urban and arable areas could benefit particular rare species. As one of the most nature-depleted countries in the world it’s really important that we better protect our native species and habitats in the UK.”
Effective conservation requires in-depth knowledge of different species’ requirements which in turn depends on detailed habitat survey data. In this study these data were provided by a long-running citizen science project, which the researchers see as essential in both collecting the data and engaging the public in conservation.
Dr Whitehorn said: “Our study highlights the value of citizen science for understanding bumblebees and their habitats. Citizen science also gives everyone a chance to contribute to protecting these species.”
The study also identified differences in habitat association within bumblebee species. The queens and males of several species were particularly associated with areas of scrub, bracken and herbs, suggesting that these habitats are good for nesting. In contrast, workers were more commonly associated with hedges and lanes, suggesting these are good for providing food.
A third of the UK’s 24 species of bumblebee are listed as species of conservation concern because they’re being found in fewer places. “Bumblebees are mostly threatened by loss and degradation of nesting and feeding habitat” said Richard Comont, Science Manager at the Bumblebee Conservation Trust.
“Bumblebees need areas with lots of flowers available from March right through to September/October. Bees lose this vital resource when habitats are lost entirely because they’re either built on or changed into other environments or degraded through things like pesticide use.”
In the study the researchers used 10 years of data from the Bumblebee Conservation Trust’s BeeWalk scheme, a citizen science project involving over 500 volunteers across the UK who carry out monthly monitoring walks, identifying and counting bumblebees.
The researchers combined data from the BeeWalk scheme with land cover data, climate date and detailed observer-collected habitat data. These combined data sources allowed the researchers to look at associations between 14 UK bumblebee species and types of habitat.
As with many studies that rely on volunteers to collect data, the researchers did detect biases. Volunteers often selected survey sites to monitor bumblebees that were close to where they live, creating a bias towards urban areas. However, the researchers say the scale and distribution of volunteer efforts still covered a wide range of UK landscapes, allowing for statistically robust findings.
On the next steps in this area of research, Dr Whitehorn said: “We’d like to find out why different species are associated with different habitats, so we can create and preserve the right conditions for them in the future. We also need to better understand how shifting climate and land uses might affect bumblebees and their habitats.”
-ENDS-
CAPTION
Great yellow bumblebee (Bombus distinguendus) on Centaurea nigra.
CAPTION
BeeWalk survey in Penally, Wales.
CREDIT
Clare Flynn
JOURNAL
Journal of Applied Ecology
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Animals
ARTICLE TITLE
The effects of climate and land use on British bumblebees: Findings from a decade of citizen-science observations
ARTICLE PUBLICATION DATE
23-May-2022
Organic farming or flower strips – which
is better for bees?
Research team including Göttingen University assess the efficiency of agri-environmental measures from different perspectives
IMAGE: FLOWER STRIPS NEXT TO A CONVENTIONAL WHEAT FIELD NEAR SEBEXEN IN THE DISTRICT OF NORTHEIM, GERMANY. view more
CREDIT: CONSTANZA GEPPERT
How effective environmental measures in agriculture are for biodiversity and wild bee populations depends on various factors and your perspective. This is shown by agroecologists from the University of Göttingen, Germany and the Centre for Ecological Research in Vácrátót, Hungary. The research team found that when assessing the effectiveness of different measures, whether in the field (organic farming) or next to the field (flower strips in conventional farming), biodiversity benefits should be evaluated differently. Like-for-like comparisons of environmental measures could easily be misleading, according to the scientists. The research was published in the journal Basic and Applied Ecology.
The researchers studied ten agricultural landscapes near Göttingen, each containing three winter wheat fields: one organic field, one conventional field with flower strips, and one conventional field without flower strips. For two years, the abundance of wild bees was recorded at the edges of each of these thirty fields. The results showed that a simple comparison of the data sampled at specific sites could lead to the conclusion that conventional fields with strips of flowers might attract many more bees than organic fields but this is not the full story.
"When we looked more closely, this did not give us a complete picture because it did not take into account that flower strips only cover about five percent of conventional fields which has significantly fewer bees overall than the organic farmland," explains Professor Teja Tscharntke, Department of Agroecology at Göttingen University. Dr Péter Batáry, group leader at the Centre for Organic Research in Vácrátót, Hungary goes onto say: "In short, organic farming, which typically has more wild plants than conventional fields, is actually more successful than conventional fields with flower strips in promoting bees."
The missing piece of the jigsaw is the fact that fields of grain in organic farming yield only half the harvest of conventional farming. When the loss in wheat yield is taken into account, a ten-hectare area of organic farmland should be compared to five hectares of conventional farmland plus five hectares of flower strips, which would lead to 3.5 times more bees but the same yield. In this scenario, organic farming would not be the best way to support wild bees.
"These data and considerations show that different benchmarks and criteria should be taken into account when evaluating agri-environmental measures. It is only when we take into account the area along with the yield together with the type of farming that we can achieve a balanced understanding of the ecological and economic effectiveness of environmental measures," the authors say.
CAPTION
Students in an organic wheat field near Bodensee, a municipality in the district of Göttingen, Germany.
CREDIT
Sinja Zieger
JOURNAL
Basic and Applied Ecology
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Scale-dependent effectiveness of on-field vs. off-field agri-environmental measures for wild bees
ARTICLE PUBLICATION DATE
15-May-2022
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