Item 2: Ordinance on West Eugene Wetlands Burn Ban Exemption

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percentage are completely consumed by fire, resulting in an end to additional sprout production. In the last few years at Willow Creek, manual removal of woody plants has been implemented in conjunction with controlled burns, to help speed progress toward achieving site management goals. Burning also appears to reduce the use of prairie habitats by meadow voles, which are small rodents that eat vegetation. During peak years of vole abundance (such as in 2001 and 2005), they can have substantial negative impacts on native prairie communities because of their herbivory (grazing) of native prairie plants. We still have much to learn about fire effects in Willamette Valley prairies. The response of prairie species to management treatments such as fire or mowing are complex and may vary from year to year depending upon a variety of environmental factors, from fire behavior to precipitation patterns. As we continue to implement controlled burns, long term monitoring and data collection efforts will be a key to helping us improve our prairie management strategies as well as refine our restoration priorities. 3. Benefits and Potential Drawbacks to Controlled Ecological Burns Reviewing the landscape history of the Willamette Valley provides the perspective that fire has been an important component of the "natural" ecosystem for thousands of years, and monitoring data for recent controlled burns supports the idea that many native prairie plants benefit from such fires. One of the reasons herbaceous prairie plants benefit from fire is because the fires that burn in these prairies are of low intensity and are of short duration. During a low intensity controlled burn, the dried leaf litter is consumed, but the meristems (growing points) of the plants are left unharmed, protected in the crown of the plant or buried underground. The precise reasons for the benefits of fire are not fully understood, but a variety of mechanisms have been proposed. For some species, seeds may lie dormant in the soil until the heat from a fire breaks the seed coat and stimulates germination. The burning of leaf litter that occurs during a fire releases nutrients and makes them available to plants when they otherwise would not be, providing a sort of fertilizer effect. When the leaf litter is burned, the bare soil that is left behind may be a better microenvironment for germination of seeds of native prairie plants, due to increased light and better contact with the soil. Other biological functions, such as soil microbial activity, may also be stimulated by fire. Of course, fires can have negative effects as well. Most animals are able to move out of the way of typical prairie fires, and we have observed only a minor amount of vertebrate wildlife mortality (small numbers of dead garter snakes) in previous controlled burns in West Eugene. Invertebrates, especially those that are present in the leaf litter, may be more subject to mortality by controlled burns, but their populations can usually persist if some areas of habitat are always left unburned. Because of this possibility, The Nature Conservancy burns more no more than 1/3 of the habitat of the endangered Fender's blue butterfly at Willow Creek in any one year. Controlled ecological burns will always need to be treated with caution because of the potential for fire to spread beyond the burn unit. Safety is always the paramount consideration, and it is d d 4