The Cottonwood Biome...A Delicate Ecosystem...
Southern Alberta is far from being known as a biological diverse place. With its wind strewn empty plains, and seemingly endless fields of grain and tall grass, with the occasional deer or porcupine, there seems to be little diversity to the plants and animals here. When Stafford first arrived in this region from Nova Scotia he said, "This is the greatest void of nothing I have ever seen!"
To the untrained eye, there is little to note about the ecology of southern Alberta. But to the outdoors enthusiasts, the botanists, biologists and geographers, Southern Alberta is 'teaming with life', so to say! It is an exciting center of a biome called "The Plains Cottonwood Biome"
Plains Cottonwood Biome...
Deep in the heart of the Oldman River and its tributaries, is a forest biome referred to the Cottonwood Forest Biome. The heart of this biome is the Poplar Tree. Poplar trees in Southern Alberta can exceed heights of 75 feet or more, with the largest being recorded at over 100 feet. These giant trees give rise to a special habitat for many endangered and exotic species throughout southern Alberta.
Cottonwood biomes, for thousands of years, have been established on the Oldman River and tributary rivers. Taking advantage of adequate moisture from the River, and river rich silt from periodic flooding, various types of tall standing Poplars have taken root in the riparian (river) valleys of the Oldman river and tributaries. (See Map) The most dense and beautiful of Cottonwood forests along the Oldman and tributaries, are found in a 100 km stretch of the Oldman River from Fort MacLeod to Brocket (see photo). Another stretch of pristine Cottonwood forest can be found, just north and east of Waterton on the Belly river.
In Southern Alberta, cottonwood forests are found along 1500 km of river and occupy an area of 700km2.
Trees of the Cottonwood Forests...
The types of trees that form in the cottonwood forests are from the Poplar family. The three main species include
1. Western Plains Cottonwood (Populus deltoides)
2. Narrow Leafed Cottonwood (Populus angustifolia)
3. Balsaam Poplar. (Populus Balsamifera)
(see leaf identification)
The Life cycle of the Cottonwood, or Poplar tree, in the riparian valleys of Southern Alberta, tell us that this ecosystem is EXTREMELY delicate! According to the article, Drought Induced Mortality of Cottonwoods along Rivers in Alberta, Canada, the great river cottonwoods of Alberta are in grave danger! Why so? According scientists such as those who work at the Helen Schuler Coulee Center, and Dr. Rood, the riparian Cottonwoods rarely germinate their seeds. In other words, Populas trees rarely reproduce themselves in the Cottonwood biome. In fact, it takes a significant flood for Populas trees in the Cottonwood biome to renew their population. So what is damaged, destroyed, and harvested takes almost 50 years (or more) to repopulate, and even then with great difficulty. In the article (Rood et. al), the greatest threat to Southern Alberta's greatest forests, are from damming. Cottonwoods are rarely seeing flood like conditions, and thus are not renewing themselves. Another interesting point is that the Cottonwoods take advantage of flood conditions to grow and thrive throughout the year. When dams, such as the Oldman River Dam are constructed, Cottonwood forests, homes to many species, are also put in grave danger, as they rely on flood like conditions to supply water and fresh silt for growth.
Many Dangers are presented to our precious cotton wood forests. Droughts which are common in Southern Alberta deplete the water table which these trees need to survive. Human city growth have infringed of the riparian homestead, and more often then not, the riparian trees are sacrificed for the growth of city expansions, and little or no land is set aside for their protection and enjoyment by future generations. Dutch Elm, a killer fungus, blocks the water conducting vessels of the tree and has been an increasing problem for our Poplar trees in southern Alberta. The last significant threat to the future of our Cottonwood forests is the damming of rivers which rejuvenate water table levels and provide fresh silt for growth. The future, doesn't look good for our Cottonwood biomes, unless we work
together to ensure their protection!
Types of Flora and Fauna
White Tailed Deer...
white tailed deer
It isn't uncommon to see white tailed deer in Southern Alberta. In Southern Alberta, and all of Alberta, from the periods of 1890-1930's deer and elk were a rare animal on the parries, as ranching, farming and settlement destroyed their habitat. However since parks and habitat have been set apart for such animals, the deer have made a dramatic comeback in Alberta. In fact for some ranchers, deer possess a significant threat as they eat cattle feed. In cities too, it isn't uncommon to see deer on the sides of roads, eating the grass. They tend to eat Saskatoon bushes, Sage, and Juniper in this region.
Prairie Rattle Snake...
(Prairie Rattle Snake)
It is also some what common to see Rattle Snakes in the region of Southern Alberta. Though there venom isn't as deadly as their relatives world wide, they can still make a human significantly sick, and if left untreated, a Rattle Snake bite can be poisonous. Prairie Rattle Snakes are only found in the semi arid plains of Southern Alberta, and nowhere else in Alberta. The coulees make a fine home for the Rattlers. They can feed on Field Mice and small rodents, and the coulees provide significant shade and moisture for the Rattler to survive. Be careful when ever you are walking in the coulees, as Rattlers always pose a threat. They can be heard by their distinct rattling noise, which is always a sign that they are somewhat aggravated.
Types of Native Grasses...
Since the uplift of the Rocky Mountains, a lot of moisture that would normally fall on Southern Alberta has intercepted by the Rocky Mountains making this area quite arid. Ever since, Southern Alberta has been a predominantly a grassland environment with many types of grasses. During this time, large amounts of rodents such as the Richardsons Ground Squirrel have called these grasslands home. And so followed ecosystem of distinct plants, herbivores and carnivores to this grassy region. Types of common grasses in Alberta include the Rough Fescue Grass, Blue Gamma Grass, Little Bluestram Grass, Wheat Grass, Spear Grass, and June Grass. Besides being dominated by prairie grasses, sage is also very common in Southern Alberta.
(Click in images for a larger view)
Blue Gamma Grass
Sage Brush in Fall colors.
It often gets dry in the grasslands of Alberta, throughout the year, especially in Summer and Autumn. It isn't uncommon for grass fires to get out of control.
(Grass fire in Alberta)
Portrait of an endangered species: "Swift Fox"
It is interesting to note that there are "20 species of Alberta fish and wildlife are in serious risk of dying out in our province, 2 species are already gone. only 55 per cent of the 535 species found in Alberta are considered healthy." (Alberta Fish and Wildlife)
The Swift Fox (Vulpes velox) was entirely eradicated by the booming population and growth of Alberta and Southern Alberta during the early part of the 20th century. With increased agricultural growth and immigration to the region many foxes such as the Swift Fox were eradicated with loss of habitat. Many were also killed off in a government effort to control wild predators in the region at that time. With no habitat and declining numbers, the swift fox entirely disappeared from this region.
The Swift Fox is now entirely found in Southern Alberta at present date, reintroduced since 1985 to this region. The success has been limited, and often regarded with a negative eye by Alberta farmers. Though the Swift Fox mainly calls the grasslands home, it was not uncommon to see the animal hunting for food in southern Alberta's river bottoms. The animal was once very common to the river valleys of this region, and with careful care, management, and protection of the Cottonwood biome from a booming Alberta economy, this extremely rare species will once again call the cottonwood forest home again.
Alberta Environments Endangered Species List
http://www.cws-scf.ec.gc.ca "Environment Canada"
Date of visit, November 1999. (Also credit with fox picture)
Helen Schuler Coulee Center
Use of Tree identification picture, and various information
Drought Induced Mortality of Cottonwoods along Rivers in Alberta, Canada
Rood et Al. 1995
White tailed deer image from http://www.whitetaildeer.com/
Prairie Rattle Snake from Microsoft Encarta.com
Pictures of Grasses, Sage, and forest fire- Alberta: A Natural History W.C. Hardy
MisMat Publishing, 1975