Efforts to promote the future health of both wild bees and managed honeybee colonies should consider the density of wildflowers.
Improving other habitat measures, such as the amount of natural habitat surrounding crop lands, may increase bee diversity while having mixed effects on bee health.
The findings from the analysis of several thousand Michigan bees are listed below. The study looked at how bee habitat around small farm fields affects bee communities.
According to the University of Michigan's lead author of a study published in the journal Ecology, future land management needs to consider that improving habitat may not benefit pollinator health. The other authors are from two other universities.
"To promote pollinator health, we need to focus on improving specific habitat quality features that are linked to reducing pathogen prevalence," said Fearon.
The diversity of flowering plants worldwide is supported by the pollination of bees. In recent decades, both native bees and managed honeybee colonies have seen population declines, which are blamed on multiple interacting factors.
Fearon and her colleagues netted and trapped more than 5,000 bees at 14 winter squash farms in southeastern Michigan, where both honeybees and wild native bees pollinate the squash flowers.
Three common viral pathogens were found in the bees Lower virus levels were associated with greater species richness. There were between seven and 49 bee species at the farms.
The findings were published in February of 2021. The hypothesis says that increased biodiversity can reduce infectious disease transmission.
After the study was published, there was a question about whether or not the reduction in viral levels was due to the reduction in bee biodiversity or something else.
High-biodiversity communities have low rates of infectious disease, according to many studies. According to the study co-author, better habitat quality can lead to greater biodiversity.
Which is driving down disease risk? Does high-biodiversity affect disease prevalence? Is it possible that communities in high-quality habitat have healthier hosts who are more resistant to infections? According to our data, there are no apparent 'dilution effects' that have anything to do with the environment.
Habitat factors can have a direct influence on an animal's nutrition and immune system, as well as its susceptibility to pathogens, according to previous studies. Red squirrel living in fragmented habitats are more likely to have parasites than those living in continuous forest habitats.
Fearon and her co-authors were able to get to the root cause of their Michigan bee observations by using models.
New information about local and landscape-level habitat was added. The researchers defined high-quality bee habitat as areas that provide sufficient quantity and diversity of floral resources to sustain good pollination.
The key indicators of high quality habitat were floral richness and floral density. Landscape richness and proportion of natural areas around farm fields were the key characteristics. There were natural areas such as shrubland, grass pasture, and wildflower meadow.
Habitat can have both positive and negative effects on bee communities. There is evidence for a habitat-disease relationship where habitat quality has a direct impact on bee health.
Increased viral prevalence was associated with a higher proportion of natural area and a greater richness of land cover types.
According to study co-author Elizabeth Tibbetts, a professor in the U-M Department of Evolutionary Ecology and Biology, areas with greater floral abundance could provide better resources for bees to resist or fight off infections. Increased floral abundance may lead to reduced pathogen transmission.
The more natural area was associated with higher bee species diversity.
Fearon said that habitat quality in the surrounding landscape was a key driver of the dilution effect. Evidence for a habitat-driven biodiversity-disease relationship is provided by this.
Patterns of viral prevalence were impacted by habitat quality metrics. Depending on the relative strengths of the habitat-disease and biodiversity-disease pathways, habitat quality has the ability to decrease or increase viral prevalence in pollinators.
Improving habitat quality measures may affect bee health in different ways.
Habitat quality is an influence on pollinator pathogen prevalence through both habitat and disease pathways. It's called 10.1002/ecy.3933.
Journal information: Ecology
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