What Happens When Peatlands are Disturbed?
Peat and the Carbon Cycle - A Climate Change Connection
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(For some supplemental information on the topic of climate change, please see this external page and hurry back!)
Peat extraction is a concern from a changing climate perspective because the industry generates Green House Gas (GHG) emissions in every facet of its operation from the land use changes involved with extraction, to the fossil fuel combustion of mining equipment. Then, once the peat has been extracted and processed, it is shipped to stores for sale where it is then driven home by consumers and left to decompose in their private gardens. This entire process, from extraction to garden, contributes to Canada’s over carbon emission and thus contributing to climate change.
Firstly, the land use change from undisturbed to mine revolves around the draining of the peatland. Removing the moisture from the area greatly increases the rate of decomposition in the peatland. This increase can be attributed to increasing the depth of the oxic zone (zone of oxygen availability). This increase carbon dioxide emission (CO2), but decreases methane emission (CH4). It has been found that the total CO2 emissions from a cutover peatland are approximately 3 times greater than that of an undisturbed site.
Following the drainage, the extraction of the living biomass from the peatland effectively causes the gross production of the wetland ecosystem to fall to zero. This prevents any new organic matter from developing and therefore successfully ends the carbon storage potential of the peatland through the accumulation of biomass.
The GHG emissions do not end there for the Canadian peat mining industry as their vehicles and extraction equipment are powered by fossil fuels. The horticultural product is then shipped to sellers via fossil fuel powered automobiles, and taken home by the consumer and incorporated into their garden care. Additionally, although the decomposition of extracted peat depends on many factors such as temperature, soil pH and water availability, the rates of decomposition are meaningfully higher in well aerated (oxygen rich) gardens than in natural peatlands.
(For some supplemental information on the topic of climate change, please see this external page and hurry back!)
Peat extraction is a concern from a changing climate perspective because the industry generates Green House Gas (GHG) emissions in every facet of its operation from the land use changes involved with extraction, to the fossil fuel combustion of mining equipment. Then, once the peat has been extracted and processed, it is shipped to stores for sale where it is then driven home by consumers and left to decompose in their private gardens. This entire process, from extraction to garden, contributes to Canada’s over carbon emission and thus contributing to climate change.
Firstly, the land use change from undisturbed to mine revolves around the draining of the peatland. Removing the moisture from the area greatly increases the rate of decomposition in the peatland. This increase can be attributed to increasing the depth of the oxic zone (zone of oxygen availability). This increase carbon dioxide emission (CO2), but decreases methane emission (CH4). It has been found that the total CO2 emissions from a cutover peatland are approximately 3 times greater than that of an undisturbed site.
Following the drainage, the extraction of the living biomass from the peatland effectively causes the gross production of the wetland ecosystem to fall to zero. This prevents any new organic matter from developing and therefore successfully ends the carbon storage potential of the peatland through the accumulation of biomass.
The GHG emissions do not end there for the Canadian peat mining industry as their vehicles and extraction equipment are powered by fossil fuels. The horticultural product is then shipped to sellers via fossil fuel powered automobiles, and taken home by the consumer and incorporated into their garden care. Additionally, although the decomposition of extracted peat depends on many factors such as temperature, soil pH and water availability, the rates of decomposition are meaningfully higher in well aerated (oxygen rich) gardens than in natural peatlands.
(This information for this graph was taken from Cleary et. al., 2005. It displays what percentage of carbon emissions are coming from what horticultural peat mining process or step)
From the above graph we see that by nearly two thirds in-garden decomposition of extracted peat is the largest GHG emitter in the Canadian peat industry. From this information we make take that to make a significant impact on reducing GHG emissions from peat extraction an appeal must be made to the consumer to make changes in their consumption habits. Increasing awareness, for example through this website is a start, however to create real change, the consumer must be provided with simple and cost-effective alternatives to horticultural peat.
As of 2005, the only part of the Canadian peat industry being accounted for in Canada’s official GHG inventory is the fossil fuel combustion by extraction, processing and shipping machinery. In the year 2000 these particular emissions accounted for around 62,000 ton CO2 equivalents. This was 0.008% of Canada’s total emissions of 726,000,000 ton CO2 equivalents. Although this is a very small percentage, the Canadian peat industry carbon emission grew 83% from the year 1990 to 2000, displaying rapid growth. It has been calculated in a paper by Cleary et. al., 2005 that in 2000 the true emissions from the Canadian peat industry was 893, 300 ton CO2 equivalents. This brings the percentage of total Canadian emissions from 0.008% to 0.12%. The Canadian peat industry’s contribution to Canada’s GHG emission is comparatively very small but is a growing component.
With only approximately 16,000-17,000 ha of peatlands being used for the peat extraction industry, this translates to only 0.01% of Canada’s peatlands being used for horticultural peat. Under present natural to impacted peatland ratios, draining and extraction operations fail to result in a significant deficit to net carbon storage. However, it has been calculated that only 5% of peatlands in Canada (or a specific region) must be drained and/or harvested to result in net carbon source over a net carbon sink. In many parts of the world, this ratio has already been exceeded, and it is expected the global loss will only increase into the future. What does this mean? It means that Canada only has to mine 5% of its peatland to turn those area in GHG emitters, instead of GHG storage areas.
Peatlands and climate change is an intensely complicated issue due to the many natural and human forces that drive both phenomenons. For example, some peatlands across the world have been drained to facilitate forestry operations, resulting in carbon storage. To further complicate the issue is the fact that the methane (CH4) produced by the anaerobic decomposition in peatlands has a greater radiative forcing potential than carbon dioxide. This means that CH4 is 21 times more efficient at trapping infrared radiation, which then warms the atmosphere. It has been found that CH4 emission drops 12-50% over impacted peatlands compared with natural sites, however it is important to note that CO2 emissions were 235-255% greater at the cutover sites compared with the natural site. This is very significant and facilitates the argument that any reduction in CH4 by mining peatlands could be mitigated by the highly significant increases in CO2 emissions. This theory gains further credit through the fact that CH4 is a short lived gas in the atmosphere as opposed to CO2 which lasts a much longer time.
Damage to peatlands may put into effect a positive feedback loop of worsening climate change. A positive feedback loop can be thought of as a system that keeps reinforcing itself. In contrast, a negative feedback loop is a self controlling system. For example, a pack of wolves eats all the deer in a region and the deer population crashes, meaning no more food for the wolves. This then causes the world population to crash, allowing the deer population to recover once again. This system is self controlling. Instead, in this positive feedback loop of worsening climate change, the disturbed peatlands emit more carbon into the atmosphere which then warms the planet. This warmer planet destroys more peatlands, emitting more carbon and etc. You can see how this system keeps reinforcing itself and worsening the problem. To clarify, an illustration can be seen below. However, this is a largely simplified version of how the degradation of peatlands can make climate change worse. It is important to realize a multitude of factors are taking place under the umbrella of “climate change”.
From the above graph we see that by nearly two thirds in-garden decomposition of extracted peat is the largest GHG emitter in the Canadian peat industry. From this information we make take that to make a significant impact on reducing GHG emissions from peat extraction an appeal must be made to the consumer to make changes in their consumption habits. Increasing awareness, for example through this website is a start, however to create real change, the consumer must be provided with simple and cost-effective alternatives to horticultural peat.
As of 2005, the only part of the Canadian peat industry being accounted for in Canada’s official GHG inventory is the fossil fuel combustion by extraction, processing and shipping machinery. In the year 2000 these particular emissions accounted for around 62,000 ton CO2 equivalents. This was 0.008% of Canada’s total emissions of 726,000,000 ton CO2 equivalents. Although this is a very small percentage, the Canadian peat industry carbon emission grew 83% from the year 1990 to 2000, displaying rapid growth. It has been calculated in a paper by Cleary et. al., 2005 that in 2000 the true emissions from the Canadian peat industry was 893, 300 ton CO2 equivalents. This brings the percentage of total Canadian emissions from 0.008% to 0.12%. The Canadian peat industry’s contribution to Canada’s GHG emission is comparatively very small but is a growing component.
With only approximately 16,000-17,000 ha of peatlands being used for the peat extraction industry, this translates to only 0.01% of Canada’s peatlands being used for horticultural peat. Under present natural to impacted peatland ratios, draining and extraction operations fail to result in a significant deficit to net carbon storage. However, it has been calculated that only 5% of peatlands in Canada (or a specific region) must be drained and/or harvested to result in net carbon source over a net carbon sink. In many parts of the world, this ratio has already been exceeded, and it is expected the global loss will only increase into the future. What does this mean? It means that Canada only has to mine 5% of its peatland to turn those area in GHG emitters, instead of GHG storage areas.
Peatlands and climate change is an intensely complicated issue due to the many natural and human forces that drive both phenomenons. For example, some peatlands across the world have been drained to facilitate forestry operations, resulting in carbon storage. To further complicate the issue is the fact that the methane (CH4) produced by the anaerobic decomposition in peatlands has a greater radiative forcing potential than carbon dioxide. This means that CH4 is 21 times more efficient at trapping infrared radiation, which then warms the atmosphere. It has been found that CH4 emission drops 12-50% over impacted peatlands compared with natural sites, however it is important to note that CO2 emissions were 235-255% greater at the cutover sites compared with the natural site. This is very significant and facilitates the argument that any reduction in CH4 by mining peatlands could be mitigated by the highly significant increases in CO2 emissions. This theory gains further credit through the fact that CH4 is a short lived gas in the atmosphere as opposed to CO2 which lasts a much longer time.
Damage to peatlands may put into effect a positive feedback loop of worsening climate change. A positive feedback loop can be thought of as a system that keeps reinforcing itself. In contrast, a negative feedback loop is a self controlling system. For example, a pack of wolves eats all the deer in a region and the deer population crashes, meaning no more food for the wolves. This then causes the world population to crash, allowing the deer population to recover once again. This system is self controlling. Instead, in this positive feedback loop of worsening climate change, the disturbed peatlands emit more carbon into the atmosphere which then warms the planet. This warmer planet destroys more peatlands, emitting more carbon and etc. You can see how this system keeps reinforcing itself and worsening the problem. To clarify, an illustration can be seen below. However, this is a largely simplified version of how the degradation of peatlands can make climate change worse. It is important to realize a multitude of factors are taking place under the umbrella of “climate change”.
Peatlands are a main feature of the boreal forests of Canada, regions storing more carbon than any other terrestrial ecosystem on the planet. As such, the conservation of these areas will be key in both preventing climate change as well as adapting to it. Boreal forests are the best equipped to withstand the effects of rapid climate change due to their intactness (they are relatively untouched compared with other areas). Some of these climate change fueled changes include the northward expansion of habitat, increased forest fire risk, increases in incidences of pest outbreaks, and degraded water resources.
Effects on Water Quality and Local Hydrology
To understand the effect of peat disturbance on water quality, a somewhat detailed knowledge of biological and chemical processes must be present. We will however try and simplify these processes to explain their importance.
The main first step in peat extraction is the drainage of the wetland. The subsequent drying can then cause changes to the chemistry of the surface layers of peat. In an undamaged peatland, the mineralization of nutrients is kept in balance by both plant up-take and microbial immobilization (mineralization is the process by which an organism holds inorganic compounds, such as nutrients. Microbial immobilization is process that keeps nutrients from moving in the system). This means there can be minimal leeching of these nutrients into water, as well as little erosion. The fact there is little erosion means the concentration of suspended sediments (a potential type of water pollutant) in peatland run-off is low.
Drainage facilitated decomposition leads to the leaching of previously immobilized nutrients in the once only partly decomposed plants. Peat mining can lead to significantly higher concentrations of nutrients and suspended solids in waters down-stream. Such consequences of peat mining can lead to environmental changes in the nearby waterways, in local eutrophication and in biodiversity. Eutrophication being a complex lake process that takes place when too many nutrients are present in the lake water. For more information on eutrophication, please see this site.
Through study it has been determined that the transport of nitrogen, suspended solids and dissolved solid loads is much higher in mine disturbed peatlands than from natural peatlands. This illustrates that peat extraction activities lead to elevated loads compared with other peatland utilisations. However these observed effects will often be strongly dependent on the surrounding climate. What does this mean? It means that various studies have seen a number of different water pollutants increase due to peat mining activities, however their extent relies on many complicated factors. As with any natural system being influenced by human activities, there is never a simple answer.
Once again, as drainage is the key first step in the extraction process, the hydrology of peatlands are therefore extremely altered by the process. As expected, this drainage affects the peatlands themselves by drying them out. Depending on the type of peatland, this drying can cause shrinkage, cracking and a permanent structural change in the peat. This may stunt any natural restoration of the area, which will perhaps instead change to a different landscape, allowing instead trees and woody shrubs to grow, forever changing the ecosystem.
The hydrologic change may have consequences on the adjacent environment as well, as any change to a catchment will lead to effects on other parts of the system. Since peatlands are described as a “wet sponge” and wet sponges are not efficient at up-taking more water, it is arguable that mined areas will have a larger water storage capacity. However, studies have found this not to be the case, as cutover areas have increased storm flow. This may be attributed to a high number drainage ditches placed to initially for draining of the peatland.
Increases to Forest Fire Risks
Peatlands are generally some of the wettest landscapes, however when dry becomes a very effective combustible material susceptible to fires that can then spread to surrounding vegetation. Peatlands may become dry due to environmental causes such as droughts, or human activities such as drainage. Increased instances of fire can lead to effects on the peatland, as well as have negative implications for any human populations living in the area.
Fire can destroy living organisms in the peatland. Depending of the type of plant, it may or may not regenerate quickly after the fire has passed. Fire may also kill any soil organisms through heating, reducing their populations. Fire can also destroy any plant litter and surface peat. This loss of peat layers can lead to considerable impacts on the rate of peat accumulation, as well as the carbon cycle of the system. Fire also has the ability to release nutrients as the burnt plant material makes formally immobilized nutrients more available. This can lead to a net loss of nutrients from the peatland through gaseous loss or water run-off. Finally, fire can lead to a hydrological change in the peatland. Since fire reduces plant coverage, the transpiration rate (rate at which water is lost from plants) may be suppressed leading to more surface water. Additionally, due to the removable of the low density peat material, what is left of the peatland has less of a capacity to retain and store water.
In terms of implications on human populations in surrounding areas, peatland drainage has been blamed for forest fires affecting regions such as Russia and Indonesia. During the summer 2011 heat wave, wild fires spread across Russia resulting in wild fires that killed thousands of people. A similar occurrence took place in Indonesia in 1998, where peatland fires covered the country as well as neighbouring areas. Locally, this is a large concern to cottage owners in Manitoba that live near potential peat extraction sites. They are worried similar fires as seen in Russia could affect their properties as well.
Impacts on Wildlife
Finally, by the very nature of peatland creation, peatlands are very fragile ecosystems that do not bounce back quickly from disturbance or damage. Currently restoration efforts are being explored; however anything done may not result in a full return to the peatlands previous functional capacity. Besides peat extraction’s obvious damage to wildlife through the removal habitat, it can also have negative impacts through the fragmentation of valuable intact habitat. Peat extraction requires landscapes and ecosystems to be altered. Many areas that are harvested for peat matter or under consideration for harvest are in remote locations with no road access. The boreal regions of Canada have peat deposits in layers ranging a few metres thick. If these areas are to be mined, more roads would need to be constructed for ease of transportation to and from the extraction site.
The various land-use changes of peatland has resulted in the large scale fragmentation of remaining peatland habitats. These still undisturbed peatlands are “islands” among human activity. This is an issue in Europe, and to a smaller extent North America including Canada. It is possible these fragmented habitats are not sustainable over the long run as these ecosystems require maintenance through larger hydrological regimes. The hydrology of the peatland and the region can be severely impacted by the human activities surrounding and taking place within it. Drainage around the peatland may eventually overcome the entire remnant.
Vulnerable Populations
_ Species may be sensitive to these
changes in the landscape, especially with increased access. In order to assess
populations that are at risk or potentially at risk, the following information
must be collected:
- Information on the population
- Population trends: stable, increasing, declining
- Information on habitat
- Habitat quality and availability
- Information on interrelated species
- Predators
- Competitors
- Hunters: human harvest
When monitoring populations for wildlife management planning, certain social values need to be considered such as the subsistence needs of aboriginal people, cultural roles of wildlife in communities, opportunities for licensed hunting, wildlife viewing opportunities. There are a diversity of perspectives when managing for species, viewpoints and opinions are influenced by background, knowledge base, experience and personal connection. Factors that influence populations that require monitoring include predation, hunting, disease, habitat, climate and access.
Access is the biggest threat to native species populations. Roads in remote areas increase transmission of disease, parasites, and invasive species, as well as increase access to and from the areas of hunters and poachers. Roads create predator corridors and fragment habitat, as well as increase edge ratio to create more islands. It has been well documented in England that fragmentation as been linked to with declines in peatland plant species. Certain specialist animal species restricted to peatland habitat will see their numbers decline through shear loss of livable area, as well as separation from other populations decreasing the amount of breeding taking place.
Looking at the example of moose in Manitoba, access is the biggest threat to moose populations on the east side of the province. Moose are specifically vulnerable around trails. Access roads have allowed increased movement of predators, such as wolves and bears, in the area for hunting corridors. Access roads also allow white-tailed deer into moose habitat, and white-tail deer carry parasites and disease that are fatal to moose, such as brain worm. Roads also highly fragment moose habitat, which is sparse as it is, and create habitat islands. Poaching may also increase as a result of access roads, however it is hard to monitor the effect of poaching efforts on any population.
- Information on the population
- Population trends: stable, increasing, declining
- Information on habitat
- Habitat quality and availability
- Information on interrelated species
- Predators
- Competitors
- Hunters: human harvest
When monitoring populations for wildlife management planning, certain social values need to be considered such as the subsistence needs of aboriginal people, cultural roles of wildlife in communities, opportunities for licensed hunting, wildlife viewing opportunities. There are a diversity of perspectives when managing for species, viewpoints and opinions are influenced by background, knowledge base, experience and personal connection. Factors that influence populations that require monitoring include predation, hunting, disease, habitat, climate and access.
Access is the biggest threat to native species populations. Roads in remote areas increase transmission of disease, parasites, and invasive species, as well as increase access to and from the areas of hunters and poachers. Roads create predator corridors and fragment habitat, as well as increase edge ratio to create more islands. It has been well documented in England that fragmentation as been linked to with declines in peatland plant species. Certain specialist animal species restricted to peatland habitat will see their numbers decline through shear loss of livable area, as well as separation from other populations decreasing the amount of breeding taking place.
Looking at the example of moose in Manitoba, access is the biggest threat to moose populations on the east side of the province. Moose are specifically vulnerable around trails. Access roads have allowed increased movement of predators, such as wolves and bears, in the area for hunting corridors. Access roads also allow white-tailed deer into moose habitat, and white-tail deer carry parasites and disease that are fatal to moose, such as brain worm. Roads also highly fragment moose habitat, which is sparse as it is, and create habitat islands. Poaching may also increase as a result of access roads, however it is hard to monitor the effect of poaching efforts on any population.
ENVR 4000 Sustainable Water Management 2012