|Plants are an important part of the environment. They provide the foundation of most ecosystems and as primary producers they initiate the flow of energy from the Sun to all species.Human Impact on Natural EcosystemsHumans, by their very nature, have an impact on ecosystems. There are approximately 7 billion people on the Earth today and they need to be fed. In the process of feeding this substantial population we turn to agriculture. During this process we have a major impact on natural ecosystems. We cut down forests to find land that is capable of growing crops and in the mean time we are doing long-term damage to the Earth.|
Don river in Toronto
Hiker in a rainforest
|The cutting down of forests has a major effect on many global environmental concerns. The first is that deforestation is reducing the biodiversity of the planet, especially in tropical rainforests. In the tropical biomes, where rainforests are found, the people of the region are turning to agriculture for economic advancement and for the feeding of its population. Economic advancement may be the immediate need of the people of the region but it has a long-term impact on global environmental concerns. The rainforests are responsible for producing considerable amounts of the Earth’s oxygen and acting as a sink for carbon dioxide. The carbon dioxide ‘sink’ removes much of the greenhouse gases from the atmosphere as plants photosynthesize to produce carbohydrates.|
|The reason greenhouse gases are of a major concern is because they contribute to global warming. To explain how the greenhouse effect works you need to visual the Earth as a greenhouse where the atmosphere acts as the glass that protects the living things under it. Under normal conditions, ultraviolet light from the Sun passes through the atmosphere and warms the soil underneath. As the soil warms up it releases infrared radiation (heat). Some of this heat keeps the climate much like it is, but a majority would be released back into space. With an increase in greenhouse gases such as carbon dioxide, the heat cannot escape because the gas acts as an insulative barrier that keeps the heat in. The overall effect would be an increase in global temperatures. Most people would think that is a good thing since it would make for milder winters. However, this is not the case. As the temperature increases, extra moisture evaporating from the oceans would be trapped and this would result in an increase in severe weather. You may recall that the hurricane season of 2008 was one of the worst on record. Many scientists believe that this is primarily due to global warming.|
Different Types of Forestry
Slash and burn Photo by Antonio Cruz
Deforestation is not only happening in tropical regions. It is a worldwide issue since many developing and developed nations, such as Canada, still produce much of the world’s wood products. In Canada the method “slash and burn” is no longer used. “Slash and burn” was used when early settlers were clearing land in the most efficient way possible to establish fields for growing crops. This method is still used in many developing nations in an effort to turn forests into agricultural land.
Today, forestry methods have changed since society now realizes that forest products are something that should be treated as a renewable resource. Even though clear cutting is still used to clear the land of all trees to be used for forestry products, the land is usually replanted with species that will re-establish the forest. Still however, these types of replanting tend to be monocultures that have other disadvantages.
The use of selective harvest methods has also increased. In selective harvest forestry, only mature trees are selected for harvest and the rest of the forest is left intact. Although this method is more labour intensive, it does allow the forest to remain diverse in species that allows the ecosystem to remain healthy. It does have its drawbacks since it does not allow the forest to progress through normal succession stages to produce an old growth forest.
Using Plants for Remediation
Sulphur dioxide laden plume from nickel smelter in Sudbury, Ontario.
The use of plants for ecological remediation is still a relatively new concept. In ecological remediation the cause of the ecosystem’s collapse needs to be assessed and a plan of action taken.
In the areas around Sudbury, Ontario the past use of ground level smelters for nickel ores allowed the production of sulphur dioxide gas to be produced at ground level. This sulphur dioxide would combine with the moisture in the air to produce sulphuric acid. This acid laden air would fumigate entire forests with acid and cause entire forests to die. The areas that were fumigated were deforested and the absence of plants created a secondary problem. Without any roots to stabilize the soil, erosion caused the thin soil of the forest floor to be washed away with rain and in the process it exposed the bedrock underneath. A sterile landscape was created, where plants are unable to grow due to acidification and the absence of soil.
|The effects of ground level smelting near|
Photo used with permission for educational
purposes from the Society for Ecological
|The results of ecosystem restoration on the same|
site near Sudbury, Ontario
Photo used with permission for educational
purposes from the Society for Ecological
In an effort to restore the ecosystem, scientists explored a variety of options. The most promising has been the neutralization of the remaining soil with lime. In this remediation technique, lime is spread over the area where remediation is to take place. The lime neutralizes the acidic soil and provides a hospitable environment for plant growth. Within a short period of time the area has started to show signs of life as native plants invade the area.
A cotton-tailed rabbit surrounded by invasive garlic mustard, mugwort, and burdock.
Non-native invasive species of plants in an ecosystem can be accidental or intentional. An invasive species of plant is one that is introduced to an area that is not indigenous. Since it is not an indigenous plant it does not have any natural predators, parasites, or diseases to keep its population in check. As these invasive species are not challenged by any other ecological factors, they will often out compete the native species and eventually take over and cause them to die out. There are a number of invasive species in Canada that are displacing native species; these include garlic mustard, mugwort, burdock, purple loosestrife, and Eurasian water milfoil. In an effort to reduce the impact of water milfoil, the Ontario government has put into place a set of guidelines when people move watercraft from lake to lake to reduce the spread of milfoil. Without any natural methods to keep the populations of invasive species under control it is inevitable that they will spread into new areas.
The Use of Plants to Restore the Environment
While humans are very good at damaging the environment, plants are very good at cleaning up after our mess. In this assignment you will look at how living machines can be used to clean the air, water, and soil.
Part One: Research
- Use the Internet to research “living machines”, “bioremediation”, and “living wall”. Find three examples of these and conduct your initial research.
- Create a table that looks like this to organize your research. You need at least three references per example
|Organism Chosen||How the plant is used restore the environment||Challenges and risks of this type of remediation||Effectiveness of the method||Is this species local/native to Canada?|
Part Two: Report
Create a report – either in paragraph form or in the form of a pamphlet. Your report should include the following:
- Identify and explain your selection.
- Explain how the plants used are used to restore the natural environment.
- Discuss the effectiveness of the method you researched. The risks and challenges – paying attention to society impact and the environment in the area (before, during and after remediation)
- Explain how this may or may not be an effective method to restore the natural environment.
Provide your list of references.
Submit your research and your report to the submission box in Teams.