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ARS Home » Pacific West Area » Logan, Utah » Pollinating Insect-Biology, Management, Systematics Research » Research » Research Project #441895

Research Project: How fuels management impacts native bee communities

Location: Pollinating Insect-Biology, Management, Systematics Research

Project Number: 2080-21000-019-070-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2023
End Date: Jul 31, 2024

In January 2022, the USDA Forest Service began a 10-year strategy to mitigate the negative impacts of wildfire on communities and improve the resilience of national forests. Fuel management strategies include prescribed burns and thinning. We want to measure how the native bee communities respond to these fuel management programs. These data can then be integrated into the Forest Service fire management recommendations to improve the outcomes for native bees alongside reducing the negative impacts of wildfires. These actions will build on existing Federal mandates for multiuse lands by emphasizing pollinator needs in managing for resilient plant communities. The ARS Pollinating Insect- Biology, Management, Systematics Research unit will work with the USFS Region 4 Pollinator Coordinator as well as Forest Managers to select survey locations in the USFS Priority Landscapes. We will aim to survey locations with three treatments: (1) past treatment: recent fuel management treatment (in the past few years) and known wildfire history, (2) upcoming treatment: areas where fuel management treatments are scheduled for the next two years, and (3) control areas: where fuel management treatments are not planned in the near future (4+ years out). These three treatment areas will be location matched to be at similar elevations, regions, and forest age/communities. The number of replicates (matched treatment sites) will then be dependent on access and suitability, but will be optimized to provide statistical power. We will place nest traps (provided nesting material including dead Phragmites reeds) at sites throughout the peak bee activity period (June-September, dependent on elevation) in order to survey the local cavity nesting community. To capture changes in the bee community over time, as is expected with plant community succession following management treatments, we will repeat surveys at the same locations for at least 3 years, with additional years added provided sufficient funding availability. Additionally, we will survey slash piles for suspected bee nesting substrates, bring material back to the lab for inspection and rear out any insects nesting in the woody material. Slash piles could represent potential ecological traps for bees if the material is collected and burned by the USFS before bee emergence.

Fuels management treatment sites and matched control sites where we will place trap nests at will be selected with the assistance of the USFS Region 4 Botanist and local Forest managers. Trap material will be assembled into corrugated boxes and 10 boxes each will be places at each site. Nest boxes will either be secured to trees or attached to t-posts. We will target the center of the site to avoid edge effects. Nest boxes will all be placed by mid-July and collected in September. Completed nests will then be x-rayed at the USDA PIRU lab and kept in cold storage until the spring when they will be moved to incubators and allowed to rear out. We will then identify and adults that emerge. We will visit slash piles across diverse habitats and collect a subsample of pile materials that are most likely to have bee nesting, such as wood with beetle damage or pithy stems (e.g. brambles) that may have been removed during the fuel treatment. In addition, trap nests will be placed near slash piles to document the local cavity-nesting bee community. Material will be cataloged and brought back to the PIRU. There, material will be sorted by type and collection location, and placed in netted enclosures. Enclosures will then be monitored for bee (and other insect) emergence until the following year. Trap nests will be x-rayed and emergence will be monitored the following year. All bees will be identified to species, and all other insects identified to the lowest taxonomic level that we can accomplish. Timing of emergence will be recorded to help inform management recommendations for when to burn piles.