canadian rockies

During our recent trip to the Canandian Rockies I focused on gaining a more thorough understanding of the biophyscial charateristics which may be used to define the region.

Not only was I impressed by the relative 'wild' character which still dominates throughout the area, but I began to understand how quickly ecological conditions can change in a

mountainous region such as the Canadian Rockies. The result of the amount of ecological diversity within the region, most notable as one moves east-west, or changes ones elevation,

is that the amount of biological diversity in such a narrow region, and at such a northern latitute, is quite impressive.

The natural history of interior southwestern Canada may be defined as a richly diverse community of plants and animals existing within extreme, and

sometimes dynamic, environmental conditions. The geological foundation on which the biota of this region exist, has been a constant and active influence

in the development of patterns and processes which currently appear throughout the land. Due to the relatively close proximity of the northern Rockies

to the Pacific Ocean, the regional climate patterns are largely influenced by Pacific weather. However, the region as a whole is not easily defined by any

one type of weather pattern or climatic regime. This is due largely to the extreme relief of the peaks that comprise the heart of the northern Rockies.

Weather can change rapidly as eastward moving air currents cool as they are forced rapidly up west-facing slopes, then just as quickly, drop once over the

crest of the Rockies onto the flat Alberta plains. With the variable climate and geology has come a stratification of life zones within the mountains. It is this

type of extreme variabililty which is the essence of the northern Rockies.

The Canadian Rockies are defined by the following parameters. They comprise a mountain range which extends from the Interior Plains on the

east to the Rocky Mountain Trench on the west, and from the Liard River in northern British Columbia to the southern boundary of Glacier National

Park, Montana. The portion of the region which our course studied, and completely circumnavigated, extended the northern boundary only to the border

of Banff and Jasper Provincial Parks. In addition we entered northern Montana to the east of Glacier rather than circling around the southern end of it.

The region is remarkable in that it is such a narrow and long chain of mountains with a high degree of natural integrity. Four areas of general interest can

be used to describe the region: geology, topography, climate, ecology.

 

Geology

The geology of the northern Rockies can be generally described as sedimentary rock up to 1.5 billion years old,

deposited mostly below sea level, over the years has been bent, broken and piled up. The mountain-building of the

Rockies began about 140 million years ago, tapering off around 45 million years ago. We approached the Canadian

Rockies via the Columbia River Basin, a wide,glacially-carved valley, with mountain ranges on either side. As one

moves north the continental plate forces that shaped the region become more and more obvious. The exposed basalt

and shale sedimentary formations crown the jagged peaks. The formation of the Canadian Rockies is considered to be

relatively young on a geological time scale and while the weathering of the mountain tops is extreme, the mountains

still largely reflect the character of their origin.

 

Topography

Ridges trending northwest/southeast are separated by parallel U-shaped valleys. The majority of the major rivers in the region flow through valleys

extending from the southwest to the northeast. On the western flanks of the Canadian Rockies many smaller rivers feed into the Columbia river which

flows to the south to Washington and eventually west to the Pacific Ocean. Erosion from continued glacial activity is predominant throughout the range

and glaciers up to 300 square kilometers still exist along the crest of the range.

 

Climate

The average mean annual temperature for all public weather stations on the valley floors is 2.6 degrees Celsius or approximately 23 degrees Fahrenheit.

The mean annual precipitation is 571 mm. As stated above the weather is strongly influenced by the extreme topography of the region. The eastern slope

is noticeably cooler and drier than the western slope,and strong chinook winds have the potential to rapidly warm the eastern slope in the winter.

 

Ecology

The stratification of the plant and animal communities in the Rockies is easily correlated to elevational zones. The two major, widespread life zones, are

the subalpine and the alpine. Below these zones exist a multitude of river valley and montane forest zones. Limestone-rich areas and the quartzite rich

areas have distinctive biological features. A great deal of the wilderness within the region still maintains a high degree of ecological integrity. Nearly all of

the native species are present, though only a fraction of the number which existed in the region only two hundred years ago. The present situation is one

in which many ecological systems of the region are experiencing stress, both from natural resource extractive industry, and development pressures.