By 1940, Oregon's fishers were virtually eliminated by trapping, poisoning and habitat loss.
More than 150 years of landscape changes, coupled with a rapidly expanding human population, have greatly altered Oregon's 96,000 square miles of diverse ranges and the wildlife species that depend on these habitats. Of the more than 8,000 species of plants and animals in Oregon, 286 have been identified by the state as "strategy species," those with small or declining populations, or otherwise at risk. In 2006, Oregon's Department of Fish and Wildlife released a comprehensive "Oregon Conservation Strategy," detailing proactive measures to conserve declining species and their habitats, and to prevent future state and federal endangered-species listings.
Loss, Degradation and Fragmentation of Habitat
Oregon's great gray owls are affected by loss of forest and grassland habitats.
Globally, habitat loss is widely considered to be the leading cause of species extinctions. Healthy populations of animals require large, connected and functional habitat patches. Since European settlement, much of Oregon's historic habitats have been lost or heavily altered, greatly affecting the state's fish and wildlife populations. In many areas, native habitat types, notably grasslands, have been converted to agriculture. Populations of many prairie-dependent species are declining as a result. Logging and thinning have altered much of the state's late successional and old-growth forests, critical habitat for the spotted owl, marbled murrelet and other declining species. And fire, a natural ecosystem process, has been suppressed, leading to increased forest tree densities, higher fuel loads, and ultimately more intense wildfires. Human communities, roads and dams have fragmented habitats and created barriers to the movement of fish and wildlife species. Besides affecting the ability of species to disperse and reproduce, such barriers make wildlife more susceptible to injury and death.
Invasive Species
Common snapping turtles, prohibited in Oregon, compete with native turtles for food and habitat.
Invasive species -- plants and animals not native to the ecosystem -- damage Oregon's habitats and may compete with native species for food or space. A number of invasive species have been identified in Oregon, among them the American bullfrog, Asian and silver carp, red-eared slider, common snapping turtle and feral swine. However, the invasive species of greatest concern are the quagga and zebra mussels, which profoundly disrupt food chains in Oregon's lakes. In response to the growing threat of invasive species, the Oregon Invasive Species Council was created by the state legislature in 2001.
Water Quantity and Quality
Northern leopard frog populations are declining, in part because of aquatic contaminants.
Quantity and quality of water are a key conservation issue, largely because of droughts the state has experienced in the early 21st century. In the summer, stream flow is diverted in many jurisdictions for agricultural and municipal uses. This directly affects the quality of the watershed habitat, and it also harms water quality, as reduced flow leads to increased temperature and nutrients. In the Pacific Northwest, migratory salmon are often seen as an indicator of watershed health, as they are vulnerable to higher water temperatures, reduced water quality and degraded stream habitat. Other fish, including the bull trout and Catlow tui chub, as well as a number of Oregon's frog and turtle species, are similarly affected by water temperature, quality and flow.
Institutional Barriers
Chinook salmon depend on Oregonians to maintain and restore aquatic and riparian habitat.
The "Oregon Conservation Strategy" cites institutional barriers as a key issue affecting the state's fish and wildlife. Such barriers include ambiguous or prohibitive requirements for financial assistance, a cumbersome permitting process, and conflicting regulations. These barriers impede or prevent willing landowners from completing projects that ultimately would benefit Oregon's fish and wildlife species. A lack of technical assistance and landowner outreach programs also limit participation. Ultimately, Oregon's strategy species and habitats would benefit from a voluntary conservation system that is streamlined, user-friendly, flexible and collaborative.
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