Post-fire seeding for erosion control: effectiveness and impacts on native plant communities

Published source details Beyers J.L. (2004) Post-fire seeding for erosion control: effectiveness and impacts on native plant communities. Conservation Biology, 18, 947-956.
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Summary

Large, severe wildfires remove vegetation cover and may expose mineral soil, leading to dramatic increases in erosion and runoff. Land-management agencies in the USA are required to assess conditions of burnt areas after wildfire and, where necessary, implement emergency watershed rehabilitation measures to help reduce erosion and associated threats. One of the most common treatments is broadcast seeding of grasses, usually from aircraft. Non-native annual or perennial grasses are typically used to provide quick, temporary cover to hold soil in place until native plants have reestablished. It has been argued that such grasses compete with native vegetation and do not effectively reduce erosion.

A literature review, including a questionnaire survey of rehabilitation specialists of the U.S. Department of Agriculture Forest Service (USFS), was undertaken to the effectiveness of postfire seeding for erosion control and impacts on native plant communities in the USA.

Around 67 papers (published and grey literature) pertinent to the review were identified covering forest, shrubland and grassland habitats. The review found that few available data exist on the effectiveness of erosion control by postfire seeding; less than half of the studies examined showed reduced erosion in response to seeding.

In all vegetation types for which there was information, successful growth of seeded grasses that was sufficient to reduce erosion, also appears to displace native or naturalized species, including shrub and tree seedlings.

Due to the competitiveness of the seeded grass species selected, they are sometimes also sown in an attempt to suppress noxious weeds in some postfire seeding operations e.g. in burned sagebrush Artemesia rangelands, postfire seeding is frequently used to replace non-native cheatgrass (drooping brome) Bromus tectorum with native or introduced bunchgrasses, with at least short-term success. In recent years, native species and sterile cereal grains have increasingly been used for seeding.

Use of aerially applied straw mulch has increased as well, but is applied over much less an area than is grass seeding, but with the risk of weed introduction from contaminated bales. It is largely confined to areas accessible by road where invasive non-native plants may already be part of the vegetation. Mulch treatments such as this are used to protect high value assets e.g. roads, streams and reservoirs, as it is highly effective at reducing erosion but is expensive to apply.

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http://www.blackwell-synergy.com/doi/full/10.1111/j.1523-1739.2004.00523.x