page_title: Mackenzie River
section_title: Ecology
hierarchical_section_title: Mackenzie River / Ecology
caption_attribution_description: English: View over Mackenzie Delta from Cessna 172 - En route from Inuvik to Tuktoyaktuk - Northwest Territories - Canada - 01
context_page_description: The Mackenzie River is a river in the Canadian boreal forest. It is the longest river system in Canada, and includes the second largest drainage basin of any North American river after the Mississippi.
  The Mackenzie River flows through a vast, thinly populated region of forest and tundra entirely within the Northwest Territories in Canada, although its many tributaries reach into five other Canadian provinces and territories. The river's main stem is 1,738 kilometres long, flowing north-northwest from Great Slave Lake into the Arctic Ocean, where it forms a large delta at its mouth. Its extensive watershed drains about 20 percent of Canada. It is the largest river flowing into the Arctic from North America, and including its tributaries has a total length of 4,241 kilometres, making it the thirteenth longest river system in the world.
  The ultimate source of the Mackenzie River is Thutade Lake, in the Northern Interior of British Columbia. The Mackenzie valley is believed to have been the path taken by prehistoric peoples during the initial human migration from Asia to North America over 10,000 years ago, despite sparse evidence.
context_section_description: The Mackenzie River's watershed is considered one of the largest and most intact ecosystems in North America, especially the northern half. Approximately 63% of the drainage basin, or 1,137,000 km² (439,000 sq mi), is forested (mostly boreal forest). Wetlands comprise about 18%, or about 324,900 km² (125,400 sq mi), of the basin. More than 93% of forested areas are virgin old-growth forest. However, human activities such as oil extraction have threatened water quality in the headwaters of the Mackenzie River. In addition, a warming climate in northern parts of the watershed is melting permafrost and destabilizing soil through erosion.
  Most of the taiga consists of black spruce, aspen and poplar forest. In the north, the river's shores are lined with sparse vegetation like dwarf birch and willows, as well as extensive areas of muskeg and peat bogs. South of Great Slave Lake, there are much larger reaches of temperate and alpine forest, prairie, and fertile floodplain and riparian habitat.
  There are 53 fish species in the basin, none of them endemic. The Mackenzie River has a similar range of fish fauna to the Mississippi River system. It is believed that the two river systems were connected during the Ice Ages by meltwater lakes and channels, allowing fish in the two rivers to interbreed. Fish in the Mackenzie River proper include the northern pike, several minnow species, and lake whitefish. Fish in the southern half of the watershed are genetically isolated from those of the northern half due to large rapids on the Slave River preventing fish from swimming upstream.
  Migratory birds use the three major deltas in the Mackenzie River basin – the Mackenzie Delta and the inland Slave and Peace-Athabasca Deltas – as resting and breeding areas. The latter is located at the convergence of four major North American migratory routes, or flyways. As recently as the mid-twentieth century, more than 400,000 birds passed through during the spring and up to a million in autumn. Some 215 bird species in total have been catalogued in the delta, including species such as the whooping crane, peregrine falcon and bald eagle. The construction of the W.A.C. Bennett Dam on the Peace River has reduced the seasonal variations of water levels in the delta, causing damage to its ecosystem. Bird populations have seen a steady decline since the 1960s.
  Water mammals such as beavers and muskrats are extremely common in the Mackenzie Delta and surrounding areas of muskeg. The Mackenzie estuary is also a calving area for beluga whales.
caption: Lakes and black spruce forest in the Mackenzie Delta
exif: {"Image ImageDescription": "", "Image Make": "SONY", "Image Model": "DSC-HX300", "Image Orientation": "Horizontal (normal)", "Image XResolution": "350", "Image YResolution": "350", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "DSC-HX300 v1.00", "Image DateTime": "2013:08:06 12:34:31", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "286", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 51, 48, 48, 0, 0, 2, 0, 2, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail ImageDescription": "", "Thumbnail Make": "SONY", "Thumbnail Model": "DSC-HX300", "Thumbnail Orientation": "Horizontal (normal)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail Software": "DSC-HX300 v1.00", "Thumbnail DateTime": "2013:08:06 12:34:31", "Thumbnail JPEGInterchangeFormat": "38984", "Thumbnail JPEGInterchangeFormatLength": "8753", "Thumbnail YCbCrPositioning": "Co-sited", "EXIF ExposureTime": "1/500", "EXIF FNumber": "16/5", "EXIF ExposureProgram": "Landscape Mode", "EXIF ISOSpeedRatings": "80", "EXIF SensitivityType": "Recommended Exposure Index", "EXIF RecommendedExposureIndex": "80", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2013:08:06 12:34:31", "EXIF DateTimeDigitized": "2013:08:06 12:34:31", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF BrightnessValue": "2873/320", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "215/64", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "411/50", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3648", "EXIF ExifImageLength": "2736", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "38692", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Landscape", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF LensSpecification": "[43/10, 215, 14/5, 63/10]"}