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7.2.1.b
Adaptations of Ecosystems to Climate Change
This includes natural terrestrial ecosystems and managed landscapes – agriculture and forestry. See also Section 7.2.1a Hydrology.
In Ontario, as globally, the most vulnerable regions and communities have limited ability to adapt to the effects of changes in climate. Northern natural areas of boreal forest, tundra, and the few built communities are threatened the most by climate change. They are least able to cope with these changes.
In 2005, there are few scientific publications to be found, especially concerning benchmarks and causes of changes in wildlife population, either of any one species population or diversity of species population. The Species at Risk Program – SAR – is overwhelmed with the number of species that must be researched. An ecosystem approach is being developed to integrate research and analysis into a bigger picture, especially in the Carolinian zone of southwestern Ontario.
In 2000, Windsor area in Southwestern Ontario, was home to representatives of 49% of plant families found in the tropics. It is predicted that this will increase to 75%, while Toronto will change from 42% to 65% by the end of the century. There are 4 more whole forest families represented in the southern area of central Ontario.
Beginning in the 1940s normal temperatures increased noticeably through the 1960s and 1970s. They changed the most during the 1990s. The 1990s recorded the greatest difference compared to normal temperatures.
There also has been a decrease in the coldest temperatures recorded. LOWS ARE NOT SO LOW NOW!
During El Nino and La Nina events years, the effects from these atmospheric-oceanic events in the Pacific Ocean increased Ontario temperatures up 20%. Atmospheric-oceanic events add to the already complex list of factors that influence natural variability in climate. Climate change projections for changes in temperature add to this natural uncertainty and variability.
As the climate warms the breeding times of populations in ecosystems change, for example, flowering times of Ontario species are earlier. The dymamics of the food chains and webs are affected. There may be some implications for human health. For example, an increase in rodent populations such as the deer mouse after these events has been tied to viral outbreaks of respiratory illness in southwestern United States.
Climate change and heat island effects in our big cities, such as Toronto, are considered as “likely” contributing factors to increased temperatures in Ontario.
Nature’s water cycle and carbon cycle are the keys to adaptation and mitigation for terrestrial ecosystems and human or built systems. All vegetation locks up carbon with water as carbohydrates during photosynthesis in order to grow. The fiber, wood, and starch produced by photosynthesis all reduce the amount of carbon dioxide in the air. Large trees will lock up more carbon than young or dwarf trees. Vegetation is acting as a carbon sink.
The length of time the carbon is removed from the carbon cycle depends on the differences in lifetime and in size of the mature plant. Vegetation releases carbon dioxide when respiring, rotting, decaying or burning. Vegetation is acting as a carbon source.
Melting of the permafrost and shorter winters will increase the rate of decay of the vegetation of forest floor and tundra. Warmer temperatures with more carbon dioxide in the air may increase the growth rate. Monitoring of forest canopies to record the amount of carbon dioxide released above the canopy will help to determine whether our Ontario forests are in fact carbon sources or sinks overall.
The rate of CO2 uptake by trees is very dependent on the type of tree and the age of the stand. For most species, there is very little carbon accumulation in the first decade of growth.Fast growing species are the exception, but mature quickly, become saturated as a sink, and unless harvested become a sink again.
The graph below examines three types of trees over a half century to compare how much wood they produce.
NEW FORESTS UP TAKE CARBON SLOWLY
Source: National Climate Change Process Sinks Table Report Science and Impacts of Climate Change CD Presentation Graphics MSC Environment Canada/ ESS Natural Resources Canada, December
ACTIVITY 1
1. Which tree type locks up the most carbon in its lifetime?
2. How old do trees generally have to be to become carbon sinks?
Research: What other information do you need before making a decision as to what species to plant in a hectare?
Managed forests of trees selected for rapid harvesting may be too tall and thin to withstand extreme events such as ice storms. Check out the damage (MNR – 1998) in the Eastern Ontario Model forests. More forest research to prepare for the effects of climate change is needed.
Restoration of ecosystems by planting need to consider the species that can withstand warmer temperatures and winters with less snow cover and more ice rain. Some experiments with choices of tree species and their response to climate change are underway.
Over 70 species and 2100 trees were planted by volunteers in a long-term research project organized by the Association for Canadian Educational Resources (ACER), Arborvitae, and Humber Arboretum.
On-going measurements of each tree planted by community volunteers will provide data as to planting methods, species choices, and success rate. This site, towards the northern edge of the Carolinian zone, is located in the Toronto urban heat island. This planting is an experiment in the present for communities to work with natural ecosystems for the future – under the warmer conditions of climate change.
Increases in temperature increase the rate of evaporation from the soil and evapotranspiration from agricultural crops, managed forests, and all natural ecosystems.
Scientists specializing in the Great Lakes and St. Lawrence ecosystems have worked together to prepare the list of actions that can be taken to reduce the effects of climate change for the International Joint Commission. Most of these recommendations for adaptive actions would also apply to other watersheds in Ontario.
ACTIVITY 2
Choose one recommendation and discover what that changes would have to be made in your area.
Plant and animal species will change as some are over-stressed and tend to migrate north with temperature change. In response to global warming, Ontario’s climate is projected to warm by more than 5 oC in the next century. Last century the temperature only increased by 0.7 oC.
Even small increases in present temperature increase vulnerability to change. A subtle warming of 1-2 oC can significantly change land use and biodiversity especially in rural areas. Land which receives more than the critical level of 2800 corn heat units (CHU) can be linked to the historic disappearance of inland wetlands in Ontario. Selections of varieties of corn, soybeans, and fruit are made based on CHU. Soil which receives more than 2800 CHU can be used for higher value cash crops.
Warmer annual temperatures will shift the 2800 CHU line northward and land use changes could be made from wooded or wetland areas to agriculture. 2900 CHU is the present northern range of Carolinian forest in Ontario. The area with at least 3200 CHU shows 4% forest cover remaining. With affordable irrigation these areas may lose even more Carolinian woods to become market garden crops. (Environment Canada.)
The figure below represents the Landcover and Threshold Corn Heat Units* (2900, 3200) for Southwestern Ontario in 2000. The lighter coloured areas indicate agricultural lands while the darker areas indicate remnant hardwood forests.
Source: Klaassen and Auld, Environment Canada 2000 C-CIARN Workshop Jan. 2001
ACTIVITY 3
1. Research and find the equivalent of the CHU lines in average temperatures. 2. Move the lines shown to the predicted temperature lines for 2040. Or beyond.
The above map shows mostly Managed Landscapes- that is agriculture and forestry change and manage the natural landscape. Actions to reduce the risk to managed landscapes such as agriculture and forestry will also reduce the costs of disasters due to climate change. Changing dates of planting, fertilizing, and harvesting along with the demand for irrigation will have to be part of adaptation of agriculture especially in southwestern Ontario.
The following recommendations for adaptive action have also been developed by scientists with experience in these areas.
ACTIVITY 4 1. Choose one recommendation and research what that means in your area. 2. What steps would need to be taken in Ontario.
Source for the three above charts: International Joint Commission (IJC) Climate Change and Water Quality in the Great Lakes Region. May2003 www.ijc.org
ACTIVITY 5
1. Choose one recommendation and discover what that means in your area.
2. What steps would need to be taken in Ontario.
Invasive, non-native heat tolerant species may carry new disease vectors or will replace less heat tolerant native plants or animals. Increased temperatures will cause farmers and foresters to select more heat tolerant species to maintain crop production.
Ontario fall color tours may be less colorful or change their timing as deciduous trees do not experience the cold nights and warm days needed to trigger fall changes.
Natural secession in wetlands, receding shorelines, decrease in spawning and nursery areas for Great Lakes fish species, tree species distribution and richness, forest insect and disease outbreaks are conditions that are all sensitive to climate change.
Ontario as a province stretches over a range of latitude so large that 3 major terrestrial ecosystems form bands across the province.
- Southern – Mixed hardwood
- Middle -Boreal
- North- Tundra.
The boundary lines are predicted to move north – Ontario will see more savanna in the southwest and a change from mixed forest to temperate deciduous forest in the southeast as early as 2030. (Bioscience, American Inst. of Biological Sciences, 51, 9)
A 500 km northward shift in climate over the next century will be faster than the plants can migrate. See pollen core analysis. Following the last glacial period 12,000 years ago, maximum tree migration rates averaged from 10 – 40km per century. White spruce had a peak rate of 200 km per century. Present woodlots, unable to keep pace with climate change, will be more likely to become too stressed to survive and native biodiversity will be lost. The Great Lakes Basin will experience 50-75 % decrease in leaf area and 10-25% decrease in runoff according to the average simulated change for the area.
ACTIVITY 6
1. Invasive species may be native or alien/foreign to an area. Define the difference.
2. How do trees migrate?
ACTIVITY 7 Research: Use internet, newspaper articles or journals to do one of these or equivalent:
1. Follow the spread of Virginia Opossums already in the Bruce Peninsula by 2004 !
2. Track the path of rabies since it crossed the border into Ontario along the St. Lawrence.
Ozone concentrations have been shown to reduce growth – affect photosynthesis – to reduce food making or carbon gain by trees. Experiments have been done with seedlings and mature trees, one on a 160-year-old tree. All show a linear decrease in photosynthesis with an increase in exposure to ozone.
Increasing temperatures and CO2 concentrations will tend to offset the effects of increasing ozone so the overall effect may be neutral. Improved integration of forest process models is needed to better predict future conditions.
Increased temperature generally increases productivity but there many other factors to consider. Drier conditions for forest areas mean increased frequency of fires. See earlier ecosystem sections.
Research for multiple environmental stress interactions at the forest level, even at the tree level, is very limited. Interactions between atmospheric CO2, soil, water and nutrient limitations, carbon sequestration, and species composition; between CO2 and troposphere O3 on plant water-use efficiency need more research.
The migration rates of tree species and the rate of ecosystem establishment under climate change both need long-term studies dealing with long-term monitoring of forest composition and growth. Forests will also be directly impacted by warmer temperatures as humans convert more forests to farmland. The greater number of heat days will allow farmers to grow more and different crops.
A combination of permanent ground-based forest monitoring plots and improved remote-sensing technologies could help create a baseline to better predict the future of our forests under climate change.
ACTIVITY 8
1. Which two changes in two major climate conditions are responsible for all the sensitivities categories listed?
2. List the beneficial effects of climate change for Ontario’s Great Lakes Region.
ACTIVITY 9 Research
1. Where are the international one-hectare biodiversity forest research plots located in Ontario? Hint: check EMAN and ACER websites.