Harney Lake in the Malheur National Wildlife RefugeYou may have heard a little bit about the Malheur

Harney Lake in the Malheur National Wildlife RefugeYou may have heard a little bit about the Malheur National Wildlife Refuge on the news lately. It’s truly a bit unusual to hear non-stop updates about conditions in a wildlife refuge in a remote part of Oregon, but how much do you actually know about the landscape? Why is there a Wildlife Refuge in eastern Oregon in the first place?This photo was taken over part of the Malheur Wildlife Refuge in 1988. This spot is Harney Lake, one of several closed lake basins in the refuge. Much of Eastern Oregon qualifies as a desert; the Malheur Wildlife Refuge on average receives only about 250 mm (10 inches) of precipitation per year. It sits in lowlands bounded by faulted blocks such as Steens Mountain to the south and the high peaks of the Cascade Range to the west, which places this lowland in a rain-shadow desert. Moist air from the Pacific Ocean is forced to rise as it crosses the peaks of the Cascades and as the air rises the water rains out, leaving dry airmasses to move over the eastern part of the state.Although this location receives limited rainfall, it sits as an oasis in the desert. Moisture falling both on Steens Mountain and on the Cascades has drained into this basin for millions of years. During the Pleistocene, large glaciers grew in both of these mountainous areas and glaciers particularly from Steens Mountain flowed downhill into this basin. In the process, they carried sediment ground from the mountain, building thick deposits of fine-grained sediment easily moved by the wind. That sediment, called loess, has been distributed throughout the basin.During the glacial times, the extra water supplied by the melting glaciers flowed over the topographic boundaries, creating streams that flowed to the Pacific and allowed salmon to occupy these waters. However, 32,000 years ago a lava flow blocked the exit point to the basin, leaving it as a fully closed reservoir. After that closure, the extra water supplied a massive lake in the basin that even would occasionally overflow the lava dam.When the large glaciers collapsed, the climate warmed and on average the water level in the lake declined. The large lake in the basin split into separate basins that occasionally connect. The largest lake in the basin is Malheur Lake; typically during the rainy season it overflows and water spills into nearby Harney Lake pictured here. Harney Lake tends to be saltier than Malheur Lake as the water input to this basin carries salt with it.The edges of these lakes are occupied by marshlands that occasionally dry out. They’re built out of the loess brought to the basin by the glaciers and during dry years the lakes contract, exposing the sediment to the wind. Some of the loess then gets picked up and carried downwind, where it has built sand dunes. The combination of salt and loess makes this blowing dust a particularly hostile environment for life.Although these lakes may not seem like the most hospitable environment, compared to the dry deserts nearby, these lakes are a paradise. The Malheur Wildlife Refuge sits along the Pacific Flyway, a path taken by an estimated billion+ birds a year as they migrate north/south along the Pacific Coast. Many of the areas just inland from the Pacific Coast are mountainous or desert terrain, so lowland with lakes and vegetation along this route become stopoff points where the birds can rest and eat. Lake Malheur and the surrounding lakes are one such freeway reststop.This refuge is also a story of a threatened environment with some recovery thanks to the refuge. In the 1920s, humans introduced carp into these lakes to become a new food source. That introduction has been a disaster. Carp feed by sifting through the mud at the bottom of the lakes for insects and plants. In the process, they uproot the native plants and toss the loose loess sediment up into the water that blocks sunlight from deeper layers in the lakes. As a consequence, the fish supplies and food supplies for birds in the lake are at an estimated 2-7% of what they were a century ago.The refuge was originally established by President Roosevelt in 1908. At the time, the refuge was smaller and focused on the lake basins. However, ranchers in the surrounding community controlled the water supply and overused it, dramatically reducing water flows to the lakes. The lake levels dropped, exposing the sediment to the wind and causing dust storms. The only reason ranching and agriculture are possible in this basin today is that in 1935 the Federal Government was able to purchase the rights to the major water supply to the lake, preventing it from turning into a complete environmental disaster.During the 3 decades following the government’s purchase of the water supply and restoration of the lake, cattle ranching expanded in the basin. Starting in the 1960s, the government began limiting cattle ranching in the area to maintain a balance between the needs of the ranchers and the needs of other species, such as birds and trout, that also are used in the area. Although the memory of it is lost to everything other than textbooks, it was less than a century ago that the entire ranching landscape around this site was nearly destroyed because of overuse.Protecting a location like the Malheur Refuge from development protects not only the birds that travel through it, but it also protects the surrounding ecosystems. Those birds support ecosystems around the entire ocean basin. The introduction of one new species has made it nearly impossible for other fish to live in this basin, impacting the lives of anyone else who could have made use of this landscape. Changes to the water supply in this one site impact the landscape of the entire basin.Had it not been for this wildlife refuge, there’s a good chance the desert would have completely claimed this landscape, leaving no rancher anywhere wanting the land.-JBBImage credit: Wildernicehttps://flic.kr/p/6x9bCReferences:http://www.fws.gov/refuge/malheur/about/geology.htmlhttps://www.audubon.org/pacific-flywayhttp://nyti.ms/1O4W0H6http://bit.ly/1VTVTBp -- source link
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