Northern BC (Bulkley-Nechako and Fraser-Fort George): Finding our farm pollinators
About this Brief
This research brief was prepared by the BC Food Web team, based on a report prepared for the Climate Change Adaptation Program.
Insects pollinate many crops. In some cases, this process is essential for food production (and hence, food security); however, in other cases, insect pollination may not be essential but can greatly increase yields. Understanding the pollination services being provided in an area requires information on a number of factors, but it starts with quantifying the number and types of pollinator species as well as their abundance.
While much research has been done in the Lower Mainland and Okanagan regions, there are research gaps further north in B.C., such as in the Bulkley-Nechako and Fraser-Fort George (BNFFG) Regional Districts. Producers, agronomists, and government scientists are interested in gaining a better understanding of the pollinator communities in these regions. Having a baseline pollinator assessment also allows us to understand how these communities change over the years, particularly with climate change.
The goals of this research were to:
- Quantify pollinator diversity in northern areas
- Quantify relative abundance of pollinators
- Identify the pollinators closely associated with crop plants
The project sampled 18 farm sites in the BNFFG region. Most of the sites grew crops at least somewhat dependent on insect pollination. The two methods of sampling used were pan traps and vane traps. Vane traps were used as a supplementary method to pan traps, as they provide a longer-term measure of pollinator diversity. Pan trap samples were taken from both field edges and field interiors to assess for differences in pollinator abundance and diversity and to see the influence of adjoining land use.
Three different colours of pan traps were used (yellow, blue, white) as different insects are attracted to different colours. For each round of sampling, pan traps were left for one rain-free 24-hour period while vane traps were left all season. Collections of samples were taken every two to three weeks from May to August 2021. Insects were sorted in Petri dishes and unlikely or known non-pollinator specimens were set aside. All other items were separated by unique morphological features and each unique specimen was sent for identification via DNA barcoding. The remaining specimens were identified using a combination of the barcoding results and morphological identification keys.
Researchers identified 224 likely or known pollinator species. The majority of likely pollinator species collected were flies (109 species), followed by bee species (72) and moth and butterfly species (30). The most numerous species was the fly Sylvicola punctatus. Six bee species and one hoverfly species accounted for approximately 30% of all pollinator species collected.
Differences in species richness between pan traps from the edges of fields versus the field interiors were minimal. There was, however, a difference in the abundance of several pollinators between field edges and interiors. Field edges had substantially more pollinators in two fly families, three bee families, and 12 hoverfly species. Some species were exclusively found in either field edges or field interiors. Bumblebees and sweat bees were more numerous in interiors.
Seven out of 13 sites used for forage crop production or pasture were hayed. Species richness increased modestly on the sites that were not hayed, while species richness declined substantially on sites that were hayed. Interestingly, on sites that would later be hayed, pollinator species richness was higher early in the season than on similar sites that were not slated for haying.
Understanding the pollinator community allows for producers to best manage the land for maintaining and enhancing pollination services for their crops.
Generally, pollinator biodiversity will benefit if you:
- Preserve what you have: identify areas with native plants that are currently used by pollinators, and forest-adjacent areas with sandy soils (often used for nesting) and limit disturbances in these areas (i.e., don’t mow, till, or compact soil).
- Allow native plants to bloom in field margins and non-productive areas
- Retain forest patches in agricultural areas
- Consider selecting cover crops that can provide nectar and/or pollen (some suggestions: https://xerces.org/publications/guidelines/cover-cropping-for-pollinators-and-beneficial-insects)
- Create new pollinator habitat: if you are considering planting for pollinator habitat enhancement, Pollinator Partnership Canada has planting guides for each ecoregion of Canada (https://pollinatorpartnership.ca/en/ecoregional-planting-guides) and an interactive tool to help in selecting plants (https://pollinatorpartnership.ca/en/find-your-roots)
Are you interested in managing your land to enhance pollinator biodiversity?
More information about conserving pollinator biodiversity and habitat enhancement is available at xerces.org and pollinatorpartnership.ca.
One-pager fact sheets are currently being developed on native plants that can be grown to increase pollinator diversity in the BNFFG region, and where seeds can be purchased locally. The fact sheets will be posted on this page once completed.
About this Research
This brief is based on the following report:
White, A. F. & Huber, D. P.W. (2022). Pollinator assessment and agricultural crop/climate analysis for the Bulkley-Nechako and Fraser-Fort George regions of BC. Climate Change Adaptation Program.
- 224 pollinator insect species were identified in the Bulkley-Nechako and Fraser-Fort George (BNFFG) Regional Districts
- Some insect groups are more abundant and/or diverse near forests, such as mason bees who are important pollinators of alfalfa
- Forest edges are critical habitat for supporting pollinator biodiversity on farms
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