Wednesday, December 1, 2010
Human Impact on Grasslands of Nose Hill, by Jason Ma
"You never know how precious something is until you finally lose it." This famous saying expresses how I felt after one of my research studies on the grasslands of Nose Hill. Although Nose Hill has an area of 11.3 km squared, it is one of the largest urban parks in Canada and in North America. This is horrendous in the fact itself. A natural area as small as 11.3 km squared is now the largest or second largest park on an entire continent! However this wasn't what gave me a sense of despair. It was during one of my Adopt a Park activities provided me with a realization of the devastation of human impact to the Nose Hill grasslands.
First of all, to give everyone a better understanding of the beauty and importance of Nose Hill's grasslands, let’s take a look at the wild life and vegetation. The grasslands were dominated by native plants such as Rough Fescue-Parry Oat grass, Rough Fescue - Golden Beans and Western Wheat Grass. As for the wild life, there were 151 species of vertebrate wildlife reported to occur in Nose Hill Park in 1993 conducted by Kansas Et Al. This list included 127 bird, 22 mammal and 2 amphibian species. Also it was noticed that native Rough Fescue grassland, are the primary breeding habitat for the largest number of bird species. Hence you can see there was great biodiversity in Nose Hill's natural ecology.
Nevertheless as the City of Calgary's population boomed, thousands and thousands of people now use and used Nose Hill as a recreation site. The magnificent Nose Hill Grasslands have and has been dramatically affected by human activities. It was recorded that as of 1997, an average of 5,426 persons per week visited Nose Hill Park during summer. It can be logically assumed that the numbers in 2010 are multiple times greater. These cyclists and dog walkers have and have caused the introduction of invasive species,
An exponential decrease in the population of wildlife species, fragmentation and alienation of rare habitats and finally higher mortality rates.
Currently the Grasslands occupied by native plants comprise of 452.8-ha which is 46.2% of the Park’s grasslands. The majority of the grasslands (53.8%) are now invasive or non-native grassland communities. These invasive species includes: Bluegrass (203.6-ha), Western Wheatgrass – Bluegrass phase (157.3-ha), Smooth Brome (114.8-ha), Smooth Brome-Quack Grass (43.1-ha), and Alfalfa-Wheatgrass (8.8-ha). It’s absolutely frightening that in less than a few decades of human interference that the primary vegetation in Nose Hill's Grasslands is composed of invasive plants from Asian and Europe. However whats worse is that anthropogenic introduction of this invasive vegetation has directly impacted the animals of Nose Hill. It has been noted that the lowest bird species richness was observed in non-native grasslands especially in the Western Wheatgrass –bluegrass phase plant community. Furthermore the invasive vegetation has brought destruction upon the natural fescue grass habitats, causing many species to relocate to other areas.
Another massive anthropogenic effect on Nose Hill was the habitat fragmentation as well as alienation that the rough trails cyclists and dog walkers made as they randomly roamed the Park. The creation of hundreds of trails around the park greatly disturbed the livelihood of natural wild life. Fragmentation of habitat occurs when large contiguous patches of native land are broken up into smaller, isolated pieces (Noss and Csuti 1997). Fragmentation can take the form of blocks of land or linear strips. These fragments of habitat render the wildlife to be immovable and subjected to isolation in its local area. This Initial exclusion occurs for species that occur only in the areas subject to development. These are usually animals with a very narrow distribution occurring in only a few patches of suitable habitat. Isolation
Of habitats through barriers to movement can then occur, effectively reducing habitat availability. In addition wildlife may avoid using habitat that is floristically and structurally intact because of the presence of human activity and associated sensory disturbance. This is known as habitat alienation. Due to habitat alienation and fragmentation, species like the Swainson's Hawk, Prairie Falcon, Peregrine Falcon, Short-eared Owl, Common Night Hawk, Sprague's Pipit, Baird's Sparrow, Long tailed Weasel, American Badger, Wandering Garder Snake and the Red-sided Garder Snake are now classified as scarce or rare. This isn't too surprising since bio indicators like the American Badger and the Sharp tailed Grouse, which are very sensitive to human disturbance hasn't been spotted for over a decade.
Finally another major problem that dramatically increases the mortality rate of wildlife is the dogs. As cute and loyal as our canine friends may be, they are incredibly troublesome in Nose Hill Park. They chase and disturb the natural community so often that almost all of the sensitive species of wild life has to relocate or face being chased to death. In fact some dogs will even kill and prey on little rodents such as mice and gophers.
After learning of all these terrible effects of human impact, my environment club and I decided to visit Nose Hill Park and do a litter pick up as part of Parks Calgary's Adopt a Park program. The litter pickup that day validated some of the habitat destruction and loss that people are causing. First off, there were fields and fields of invasive species. Then the thirty four students picked up over 60 pounds of trash in merely an hour! When I saw the overly stuffed bags of garbage, the disappointment and frustration was overwhelming. Yet this just comes to illustrate the disastrous effects human impact on Nose Hill. Despite the work the City of Calgary has been doing to minimize and mitigate the anthropogenic effects, we must all take action! Doing simple things such as being part of the Churchill Environment Club and going to the park to pick up litter or even just to educate your family and friends can accumulate to make a real difference.
Check the actual blog at http://www.grasslands-nosehill.blogspot.com/