Invasive plants in 21st Century landscapes.

Abstract

A plant species is defined as invasive if it is nonnative to the ecosystem under consideration, and if it causes or is likely to cause economic or environmental harm or harm to human health. Nonnative plant invasions are generally considered to have reached the Pacific Northwest in the mid-1800s with the arrival of European-American settlers. Invasive species such as sulfur cinquefoil, spotted knapweed, yellow starthistle, cheatgrass, and Japanese knotweed can displace native plants, disrupt ecosystems, affect biological diversity, increase soil erosion, reduce water quality, and change natural fire regimes. These and other invasive plants affect ecosystems from arid grasslands to forests,wetlands, and streams.

Citation

Rapp, Valerie. 2005. Invasive plants in 21st Century landscapes. Science Update 9. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p