Introduction to Climate Change:
During the industrial revolution, human population has been exponentially increasing, which in turn causes detrimental affects to the surrounding ecosystem. Greenhouse gases as well as ozone layer depletion due to CFC’s contribute to a warming effect on the Earth’s surface. As a result, many species populations have decreased, become endangered or extinct. This can occur through processes such as effects on invasive species, pathogens, temperature and air pollution (Hulme, 2016).
Invasives in Toronto:
During the BIOL4095 class hike at the Glendon campus at York University, Toronto, Ontario, Professor Dawn Bazely informed the class about the never-ending changes to the ecosystem that is present as a result of human interference. For example, invasive plants such as the dog-strangling vine can be seen in every patch of forest habitat on Glendon campus. Unfortunately, with warmer climate causing extended spring periods, the dog-strangling vine has an advantage by growing earlier, expanding its range and stealing the opportunity for native plants to germinate or flourish. Many invasive species are also known to have an advantage over the native species, as they may be better adapted to climatic changes, as well as have fewer natural enemies. This in turn affects species such as the monarch butterfly, whose larvae depend on milkweed to survive, as monarchs begin laying their eggs on the vine. Another indirect effect on native Toronto plant species through invasive species is insects. With warmer temperatures, insects such as the Asian longhorn beetle have an increased survival rate. This in turn is a detriment to broad-leaf trees in Ontario as the larvae tunnel through the tree, which reduced the flow of nutrients and kills the tree.
Effects on agriculture in Toronto:
In addition, climate change can also affect species in Toronto more directly. Warmer average temperatures put a strain on many species since adapted to a particular climate. This will cause many species to begin to expand north, into cooler climates, and species that are more south to migrate to Toronto. Nonetheless, due to habitat fragmentation, many populations may go extinct due to reduced gene flow and genetic variation. In addition, warmer temperatures can reduce the fruit set of some plants, as can be seen in tomatoes (LeBoeuf, 2004). This may ultimately cause the species to go extinct.
Effects on pathogens:
With change in climate such as warmer temperatures and wetter conditions, the activity and survival of many pathogens increase. These pathogens reduce the fitness of plant populations and can eventually lead to extinction (Dukes, et al., 2009). This can create as problem for agricultural activities as many crops may die. For example, Colletotrichum graminicola, commonly known as Anthracnose Leaf Blight, as well as Setosphaeria turcica, or Northern Leaf Blight, are both fungi, which will eventually kill corn crops when spread. Management strategies such as tillage can be used to reduce residues and ultimately decrease the probability of the disease occurring (OMAFRA, 2009). Air pollution is an also known negative effect on plant populations, including crops. Pollutants such as oxidants, sulfur dioxide, fluoride and ammonia, can injure the plants by killing their tissues, which can eventually lead to death (OMAFRA, 2009).
In conclusion, climate change can affect plant species in Ontario both directly and indirectly through processes such as increased temperatures, invasive species, and pathogen productivity, as well as degraded air quality. Unfortunately, these are not the only impacts climate change has on plants and other inhabitants of Earth. As human population continues to grow, resource availability declines and demand increases. The pressure put on species as they fight for survival is inevitable under these sets of conditions. Without continuous innovative mitigation strategies, the habitable nature of Earth will vanish.
Dukes, J. S., Pontius, J., Orwig, D., Garnas, J. R., Rodgers, V. L., Brazee, N., .Cooke, B., Theoharrides, K., Stange, E., Harrington, R., Ehrenfeld, J., Gurevitch, J., Lerdau, M., Stinson, K., Wick, R., & Ayres, M. (2009). Responses of insect pests, pathogens, and invasive plant species to climate change in the forests of northeastern North America: What can we predict? Canadian Journal of Forest Research, 39(2), 231-248.
LeBoeuf, J. (2004). The Effect of Extreme Temperatures on the Tomato and Pepper Crop. Retrieved November 30, 2016, from http://www.omafra.gov.on.ca/english/crops/facts/info_tomtemp.htm
Griffiths, H. (2003). Effects of Air Pollution on Agricultural Crops. Retrieved November 30, 2016, from http://www.omafra.gov.on.ca/english/crops/facts/01-015.htm
Hulme, Mike (2016). Concept of Climate Change. The International Encyclopedia of Geography. Wiley-Blackwell/Association of American Geographers (AAG). Retrieved 16 May 2016.
OMAFRA. (2009). Diseases of Field Crops: Corn Diseases. Retrieved November 30, 2016, from http://www.omafra.gov.on.ca/english/crops/pub811/14corn.htm