The compilation of terrestrial and aquatic invasive species includes highly-publicized examples such as cheatgrass, quagga mussels, tamarisk and the Emerald Ash Borer. The list also encompasses less well known, but still impactful, examples such as leafy spurge, Red shiner, Russian knapweed and Golden algae. (Download the complete list)

Invasive species pose an enormous environmental challenge to western forests and rangelands, water and agriculture. Left unchecked, invasive species permanently alter ecosystems and negatively impact the native species and local economies that depend upon them.

The Nature Conservancy has estimated that nationwide, invasive species management costs over $120 billion a year and affects more than 100 million acres – an area the size of California. Additionally, invasive species are estimated to have contributed to the decline of 42 percent of threatened and endangered species.

It is critical for land managers to have up-to-date information to plan and prioritize management decisions. Individual states have developed invasive species risk assessments within their boundaries.  But no such list has existed for the West until WGA surveyed invasive species coordinators in its member states and territories to develop the “Top 50 Invasive Species in the West.”

This first-of-its-kind risk assessment will enable state managers to better understand the regional-level risks posed by terrestrial and aquatic invasive species and improve cross-boundary management actions. Additionally, this effort of WGA’s Invasive Species Data Management Project will be used to populate the association’s West-wide Invasive Species Risk Assessment, created to help guide future work to battle invasive species.