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United States Department of Agriculture

Agricultural Research Service

Research Project: Managing and Conserving Diverse Bee Pollinators for Sustainable Crop Production and Wildland Preservation

Location: Pollinating Insect-biology, Management, Systematics Research

Title: Limited direct effects of a massive wildfire on its sagebrush steppe bee community

Author
item Cane, James - Jim
item Love, Byron

Submitted to: Ecological Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2016
Publication Date: 5/10/2016
Citation: Cane, J.H., Love, B.G. 2016. Limited direct effects of a massive wildfire on its sagebrush steppe bee community. Ecological Entomology. doi: 10.1111/een.12304.

Interpretive Summary: Fire can affect bees directly, through exposure to heating and smoke during the combustion phase. Direct effects include mortality, injury and displacement affecting at most two generations of bees—adults and any of their young produced prior to the fire event. To study the direct effects of fire on a bee community, two criteria must be met. First, bees must be sampled soon after the fire event, before colonists arrive from outside the burn. Second, sampling locations must be far enough into the burned habitat to ensure that bees observed are survivors, and not merely foragers nesting outside of the burn perimeter. In this study, bees were systematically sampled from sunflowers both outside the burn and at surviving patches immediately following a massive wildfire in sagebrush steppe habitat in southern Idaho. This fast-moving wildfire burned primarily at night. Because adult females are in their nests at night, we hypothesized females of bee species with shallow underground nests would be safe from lethal heat, whereas females with shallow or aboveground nests would not. We also hypothesized that fire would kill proportionately more males, as they typically sleep aboveground. We found that adult bees were present at all burned sites foraging at a much diminished flora, and active nests were observed within 3 weeks after the fire. Fire reduced species richness and altered the community of bees using sunflowers. The sex ratio did not shift as expected, possibly due to survivors aggregating in remaining patches of sunflowers. Floral specialization may be more important than nesting habit for the retention of adult bees surviving the direct effects of fire.

Technical Abstract: Fire can affect bees directly, through exposure to heating and smoke during the combustion phase. Direct effects include mortality, injury and displacement affecting at most two generations of bees—adults and any progeny produced prior to the fire event. To study the direct effects of fire on a bee community, two criteria must be met. First, bees must be sampled soon after the fire event, before colonists could arrive from outside the burn. Second, sampling locations must be far enough into the burned habitat to ensure that bees observed are survivors, and not merely foragers nesting outside of the burn perimeter. In this study, bees were systematically sampled from sunflowers both outside the burn and at surviving patches immediately following a massive wildfire in sagebrush steppe habitat in southern Idaho USA. This fast-moving wildfire burned primarily at night. Because adult females are in their nests at night, we hypothesized females of bee species with nests < 10cm underground would be safe from lethal heat, whereas females with shallow or aboveground nests would not. We also hypothesized that fire would kill proportionately more males, as they typically sleep aboveground. Adult bees were present at all burned sites foraging at a much diminished flora, and active nests were observed within 3 weeks after the fire. Fire reduced species richness and altered the community composition of the guild of bees using sunflowers. The sex ratio did not shift as expected, possibly due to survivors aggregating in remaining patches of sunflowers. Floral specialization may be more important than nesting habit for the retention of adult bees surviving the direct effects of fire.

Last Modified: 09/20/2017
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