Oregon Lakes is a freshwater ecoregion in the western

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. It includes several closed basins in southern-central Oregon and adjacent parts of California and Nevada, including the

Harney Basin The Harney Basin is an endorheic basin in southeastern Oregon in the United States at the northwestern corner of the Great Basin. One of the least populated areas of the contiguous United States, it is located largely in northern Harney County, ...

Warner Valley The Warner Valley is a valley in south-central Oregon in the United States. It is a remote valley at the northwestern corner of North America's Basin and Range Province. The valley is home to a chain of lakes and wetlands known as the Warner ...

, and the basins of

Lake Abert Lake Abert (also known as Abert Lake) is a large, shallow, alkali lake in Lake County, Oregon, United States. It is approximately long and wide at its widest point. It is located northeast of the small, unincorporated community of Valley Fall ...

and Summer Lake."Oregon Lakes". Freshwater Ecoregions of the World. Accessed 18 September 2021

/ref>

Geography

The ecoregion includes several closed, or endorheic, basins. The ecoregions's streams empty into alkaline lakes or onto playas. The ecoregion is bounded on the north and east by the

Columbia River The Columbia River (Upper Chinook: ' or '; Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, C ...

basin, on the west by the upper basin of the

Klamath River The Klamath River (Karuk: ''Ishkêesh'', Klamath: ''Koke'', Yurok: ''Hehlkeek 'We-Roy'') flows through Oregon and northern California in the United States, emptying into the Pacific Ocean. By average discharge, the Klamath is the second larges ...

, on the southwest by the upper

Sacramento River The Sacramento River ( es, Río Sacramento) is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–S ...

watershed, and on the south and southeast by the closed

Lahontan Basin Lake Lahontan was a large endorheic Pleistocene lake of modern northwestern Nevada that extended into northeastern California and southern Oregon. The area of the former lake is a large portion of the Great Basin that borders the Sacramento Rive ...

.Howard, J., and C. Revenga (2009). "California’s freshwater biodiversity in a continental context". Science for Conservation Technical Brief Series. The Nature Conservancy of California. San Francisco, CA. 29 pp + Appendices. Accessed 18 September 2021

/ref> The ecoregion lies in the

rain shadow A rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds, known as its leeward side. Evaporated moisture from water bodies (such as oceans and large lakes) is carrie ...

of the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

, and has a semi-arid and

continental climate Continental climates often have a significant annual variation in temperature (warm summers and cold winters). They tend to occur in the middle latitudes (40 to 55 north), within large landmasses where prevailing winds blow overland bringing som ...

. The Oregon Lakes is mostly within the

Snake–Columbia shrub steppe The Snake–Columbia shrub steppe is an ecoregion defined by the World Wide Fund for Nature (WWF). This ecoregion receives little precipitation because it is within the rain shadow of the Cascade Range. It takes in a western portion of the Colu ...

terrestrial ecoregion, and the predominant vegetation is low shrubland and sparse grassland.

Fauna

The Oregon Lakes ecoregion has 23 native species of fish. These include two endemic species – the

Borax Lake chub The Borax Lake chub (''Siphateles boraxobius'') is a rare cyprinid fish found only in outflows and pools around Borax Lake, a small lake of the Alvord basin, Harney County, Oregon. This species typically reaches only in length, although some ...

(''Gila boraxobius''), which is found only in the Borax Lake basin in Oregon, and the

Warner sucker The Warner sucker (''Catostomus warnerensis'') is a rare species of freshwater ray-finned fish in the family Catostomidae. Native to Oregon in the United States and found only in the Warner Lakes, Warner Basin, its distribution extends just into ...

(''Catostomus warnerensis''), found in the

in Oregon and Nevada, where it inhabits the

Warner Lakes The Warner Lakes are a chain of shallow lakes and marshes in the Warner Valley of eastern Lake County, Oregon, United States. The lakes extend the length of the valley, covering approximately . The lakes are named in honor of Captain William H ...

and the valley's streams, sloughs, and ephemeral lakes.

References

{{reflist Freshwater ecoregions Ecoregions of California Endorheic basins of the United States Ecoregions of Oregon