Oregon

Oregon's biodiversity spans diverse ecosystems from Pacific coastal waters to Cascade Range alpine zones, supporting endemic species across temperate rainforests, sagebrush steppe, and wetland complexes. The state's 104 assessed species are all critically endangered (IUCN Red List 2025), representing an unprecedented conservation crisis concentrated in birds (31 species) and invertebrates (73 species). The Willamette Valley's oak prairies and wetlands face particular pressure from agricultural conversion and urban expansion. Coastal estuaries critical for salmon runs experience degradation from development and altered hydrology. Eastern Oregon's sagebrush ecosystems suffer from invasive species, particularly cheatgrass, which increases wildfire frequency and intensity. Climate change exacerbates drought conditions in the Columbia River Basin, affecting both terrestrial and aquatic species. The Cascade Range's old-growth forests face logging pressure and increased wildfire risk due to altered fire regimes. Oregon's unique position as a Pacific Flyway corridor makes bird species especially vulnerable to habitat fragmentation. Marine species face ocean acidification and warming temperatures affecting the California Current ecosystem. The concentration of critically endangered species across both avian and invertebrate taxa suggests systemic ecosystem disruption rather than isolated species-specific threats, indicating widespread habitat degradation across the state's major bioregions.

Source: IUCN Red List 2025-2, GBIF, national survey data