Title

Does Western spruce budworm frass directly affect stream food webs?

Presenter Information

Brianna Matthew

Document Type

Oral Presentation

Location

SURC Ballroom C/D

Start Date

16-5-2013

End Date

16-5-2013

Abstract

The Western spruce budworm is the most destructive defoliator of coniferous forests in western North America, and the Teanaway region of central Washington currently has a heavy outbreak of budworms. In my prior research on samples collected in July and August 2011, I found that spruce budworm frass (solid excrement) has nitrogen content 3.5 times greater than litterfall, but these samples just measured deposition onto the forest floor. Some of this frass could fall directly in the low-nutrient streams that drain this region and that support endangered fish species such as bull trout and steelhead. Organic matter input to streams supports higher trophic levels such as insects and fish, so nitrogen-rich budworm frass that falls directly into stream channels could alter the stream food web and/or affect stream nutrient concentrations. It is unknown how much budworm frass falls directly into streams. In summer 2013, I will measure direct inputs of spruce budworm frass into three stream systems in the North Fork Teanaway River, and compare those sites to a control site with minimal budworm influence in Taneum Canyon. This will allow me to quantify the direct contribution of spruce budworm frass to stream systems in this region. As part of this summer research I will also evaluate the influence of budworm frass on stream nutrient concentrations. My work will contribute to a larger pool of data that will quantify the ecosystem impact of the spruce budworm outbreak in the Teanaway region.

Poster Number

19

Faculty Mentor(s)

Clay Arango

Additional Mentoring Department

Environmental Studies

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May 16th, 2:15 PM May 16th, 4:44 PM

Does Western spruce budworm frass directly affect stream food webs?

SURC Ballroom C/D

The Western spruce budworm is the most destructive defoliator of coniferous forests in western North America, and the Teanaway region of central Washington currently has a heavy outbreak of budworms. In my prior research on samples collected in July and August 2011, I found that spruce budworm frass (solid excrement) has nitrogen content 3.5 times greater than litterfall, but these samples just measured deposition onto the forest floor. Some of this frass could fall directly in the low-nutrient streams that drain this region and that support endangered fish species such as bull trout and steelhead. Organic matter input to streams supports higher trophic levels such as insects and fish, so nitrogen-rich budworm frass that falls directly into stream channels could alter the stream food web and/or affect stream nutrient concentrations. It is unknown how much budworm frass falls directly into streams. In summer 2013, I will measure direct inputs of spruce budworm frass into three stream systems in the North Fork Teanaway River, and compare those sites to a control site with minimal budworm influence in Taneum Canyon. This will allow me to quantify the direct contribution of spruce budworm frass to stream systems in this region. As part of this summer research I will also evaluate the influence of budworm frass on stream nutrient concentrations. My work will contribute to a larger pool of data that will quantify the ecosystem impact of the spruce budworm outbreak in the Teanaway region.