back to Homepage   back to Conservation page

 

Part 1
Impacts on Biodiversity
 

 

Population growth, overconsumption and technology.

I = PAT

Impact on the environment has often been defined as the effect of
population x affluence x technology

Population: Growth of the human population is a major factor affecting the environment. Simply put, overpopulation means that there are more people than there are resources to meet their needs. Almost all the environmental problems we face today can be traced back to the increase in population in the world. The human population is at 6 billion; with an annual global growth rate of 1.8%, three more people are added to the earth every second. This represents an increase of almost 60% since 1970 and over 150% since the second world war. (Miller, 1992)

Affluence: Simultaneously, the world has experienced an annual economic growth rate of 2.7% over the past three years. Affluence is a problem because with increasing affluence comes an increase in the per capita resource utilization. Less than 20% of the world's population controls 80% of the world's wealth and resources. The high standard of living that accompanies the increased production and consumption of goods is the major cause of pollution and environmental degradation. (E.O. Wilson, 1994)

We discuss some of the principal causes of these problems and how they affect the processes and mechanisms which maintain biological diversity. This overview will be superficial at best. The problems of overpopulation, overconsumption, development and industrialization are intertwined and the causes are not singular and straightforward.

The relationship between human activity and biodiversity impacts:

 

It is not always easy to pin the blame for deterioration of natural ecosystems on any one cause. Human presence in the Great lakes ecosystem is a good example of this. The Great Lakes drain 20% of the world's freshwater. Despite their significant size, the biodiversity of the Great Lakes ecosystem is threatened for a number of reasons. Forty percent of the population of Canada lives along the Quebec-Windsor corridor (which divides the watershed), and the greatest density of industrial activity in North America is concentrated along the shores of Lakes Michigan, Huron, Erie and Ontario, which has led to large-scale pollution of water, air and soil. The Great Lakesgreat lakes.jpg have also been intensively overfished for many decades. Both pollution and overharvesting have also had a negative impact on the availability of suitable fish habitat, even in areas that are unpolluted enough for aquatic life to thrive in. Finally, the introduction of exotic species, both unintentionally, as a result of increased international traffic in the waters, and intentionally, to boost sport fishing, has decimated indigenous populations of aquatic organisms. Of the 12 or 13 distinct populations of lake trout that were endemic to Lake Superior, only 2 or 3 remain. This example illustrates how difficult it is to isolate the different stresses on a system and to pinpoint one singular cause of the decline in biodiversity of the Great Lakes.

Population stats in Quebec and Canada

The current population of Canada is 30.3 million and that of Quebec is 7.4 million. Between 1993 and 1997, the population of Quebec grew by 2%, less than half the national increase of 4.6%.

This gives Quebec an average annual growth rate of 0.6%, which means that by the year 2010, there will be over 8 million people living in Quebec and by the year 2050, there will be over 10 million. From these numbers, it is easy to see that even if we don't consume any more resources per person than we do today, we will still have to use up more resources to provide for the higher number of people who will live in this province. (Statistics Canada, CANSIM, Matrices 6367-6379)

The effects of overpopulation and overconsumption are not only felt locally or nationally. Pollution generated in one region can affect the air, water, vegetation or animals in another. The effect of global CO2 changes, loss of biodiversity and marine pollution do not respect political boundaries and ultimately affect everyone in the world. (Statistics Canada, 1994.)

 

 

Human activities and their impacts on biodiversity

click on an impact or activity for more information on it

 

Impacts

Habitat Removal and Alteration

Habitat fragmentation is the loss and subdivision of a habitat and the corresponding increase in other habitats in the landscape. Conversion of habitat represents the greatest threat to biodiversity in Canada, since almost all human activities cause alterations to the natural environment to a greater or lesser degree (see table). Almost 10% of Canada's ecoregions are estimated to be at high risk for loss of biodiversity because of habitat removal.

Conversion of lands to agriculture in the prairies has resulted in the loss of 87% of native shortgrass prairie habitat, 81% of native mixed-grass prairie habitat, almost all the tallgrass prairie habitat and 84% of the native aspen parkland habitat. Unfortunately, increased demands for food production are further accelerating the rate of conversion of lands with moderate agricultural value to farmland. In settled parts of Canada, 90% of wetlands have been drained. This poses a serious threat to biodiversity since these habitats are exceptionally rich in species.(CBIN 1998)

Poor agricultural practices also degrade soil quality and promote the loss of topsoil. Furthermore, agriculture has resulted in local reductions and extirpations of fauna associated with agricultural lands (e.g. grassland and scrubland birds, wild pollinating insects).

How habitat fragmentation affects processes that drive biodiversity : Habitat fragmentation not only affects species, but also affects the processes that drive biodiversity. Habitat fragmentation causes large populations to be broken into smaller populations which may be isolated from one another. These sub-populations may be too small to be viable or, if local extinction of species occurs, fragmentation cuts off the potential for repopulation since there are no intact populations nearby. (CBIN 1998)

 

Overharvesting/Overexploitation

After habitat loss, overharvesting has had the greatest effect on biodiversity. In fact, overharvesting and habitat loss often occur simultaneously, as removal of an organism from its environment can have irreversible impacts on the environment itself.

Humans have historically exploited plant and animal species in order to maximize short-term profit, at the expense of sustainability of the species or population. This exploitation follows a predictable pattern: initially, a species harvested from the wild can turn a substantial profit, encouraging more people to get involved in its extraction. This increased competition encourages the development of more large-scale and efficient methods of extraction, which inevitably deplete the resource. Eventually, quota systems are applied, leading to more competition, decreased earnings and the need for government subsidies to support the extraction industry. This sequence of events has been observed in the fishing industry (it is currently happening), the logging industry, and the grazing of cattle on public lands. The results for the resource are always the same: extreme population crashes, sometimes ending in global extinction.

The problem with biological resource extraction is when the rate of increase in demand for the resource far outstrips the reproductive rate of the population - demand outstrips supply - and drives the value of that resource higher, increasing the incentive to extract the and causing the population to eventually collapse. Such a fate has befallen whales, elephants, spotted cats, cod, old-growth forests, ginseng, parrots, tuna and passenger pigeons, just to name a few.

The unsustainability of biological resource extraction has, at its root, three main problems - a) too many people who want the resource, b) the short-term profit goals of extractors and lack of information about the ecology and c) life-histories of populations being harvested.

 

Pollution

Water
Most of Quebec's population (98%) and human activity occurs in the St. Lawrence watershed. Throughout the 20th century, degradation of the St. Lawrence has followed technological progress and urbanization and this has taken its toll. Pollution involves the addition of materials that are usually not present or present in very different amounts and can be due to the following factors:

toxic discharges: This includes metals, organic chemicals, and suspended sediments usually found in industrial and municipal effluents that are discharged directly into waterbodies. Toxic discharges can inversely impact the biota (living organisms) in an ecosystem by killing them, weakening them, or affecting their ability to carry out essential biological functions (feeding, reproducing, etc.).

bacterial contamination: For example, fecal coliforms that come from human waste are found in municipal effluent discharges. Potable water is treated to destroy fecal coliforms which can make people ill if ingested.

nutrient buildup: Of most concern are phosphorus and nitrogen which often originate as run-off from fertilizers applied on agricultural fields. These nutrients, naturally present in very low concentrations, stimulate rapid growth of algae and aquatic plants, ultimately limiting the amount of oxygen and light available to other organisms in the ecosystem. As well, aquatic environments can be degraded by habitat alteration and presence of invasive species, both of which are also addressed in this section of the website.

Air

Acid rain
Acid precipitation is the air pollutant that has the most significant impact on biodiversity in Canada. Despite legislation aimed at reducing acid rain and acid loading, it is predicted that we will lose fish, mollusk and amphibian populations in thousands of lakes because they will not be able to survive in acidified conditions. This is of particular concern in the Canadian Shield region of Quebec, whose countless lakes are sensitive to acidification because their drainage basins cannot neutralize acid inputs the way they can in more southern Quebec regions. (CBIN 1998)

 

 

Introduction of exotic species

The threat of exotic species to natural habitats falls into six categories:

habitat alteration: the effect of this impact on biodiversity is discussed above;

predation: the introduction of a predator that organisms have not previously been exposed to can profoundly affect food chains. Most obvious in the Great Lakes-St. Lawrence system was the introduction of the sea lamprey (Petromyzon marinus) which, combined with overharvesting, caused lake trout to be wiped out from the upper Great Lakes in the mid-1900s;

competition: exotic species can often outcompete native species for food and habitat acquisition, mainly because they have no local controls (disease and predators) to keep their population in check;

hybridization: As mentioned earlier in the text, geographic barriers help to maintain genetically diverse populations of organisms. Introduction of non-native species, whether intentional or not, has resulted in the interbreeding of native and non-native species, with the consequent decline of native species. It has been estimated that hybridization was a major factor in 38% of North American fish species extinctions.

disease and parasites: pest species accidentally introduced to an area provide the most dramatic example of the damage that exotics can pose to native species. For instance, an exotic beetle was the vector for Dutch Elm Disease, which has devastated elm trees in North America.

homogenization of ecosystems: all the above impacts combine to decrease the number of native species in a habitat and replace them with "weedy", widespread species - and thus cause regional homogenization of ecosystems. This is happening in rare wetland habitats that have been overtaken with the exotic plant, purple loosestrife (Lythrum salicaria), or in areas of the St. Lawrence river, where zebra mussels (Dreissena polymorpha) have literally "muscled" their way into the ecosystem, severely reducing the diversity of clam species in the river. (Ricciardi, 1998; Miller, 1989)

Species introductions can occur accidentally, when organisms "hitchhike" into new systems on other animals or objects. For instance, zebra mussels are thought to have been brought into the Great Lakes in the ballast water of tankers that travelled up the St. Lawrence Seaway.

Unintentional species introductions can also result from lack of education of the general public. For instance, releasing aquarium fishes or using exotic ornamental garden plants whose seeds escape into natural systems can increase the probability of an exotic species becoming established in our native ecosystems.

Examples of species introductions and their effects in Canada and Quebec

Dutch elm disease is a fungus spread by an exotic beetle that hitchhiked into Canada on imported elm planks from Europe in the 1930s. Within several decades, Dutch elm disease spread across the continent and destroyed as much as 95% of American Elm stands in North America.

Purple loosestrife purple loosestrife.jpg(Lythrum salicaria) is a perennial wetland herb that grows in sunny wetlands, and in other disturbed habitat. It is native to Eurasia and was accidentally introduced into North America over 200 years ago.

Because it has no natural enemies here, purple loosestrife has spread aggressively into wetlands throughout the northeast U.S. and Canada (particularly Quebec, Ontario and Manitoba). It forms dense stands that can destroy fragile wetland habitats by choking out native vegetation that serve as food sources or habitat for wildlife. Purple loosestrife itself has almost no food and shelter value to wildlife and can even present a threat to vulnerable marsh species, such as the swamp rose mallow, Hibiscus moscheutos, which COSEWIC has designated as at risk.

A great deal of money and research is being invested in controlling the spread of purple loosestrife.

White-tailed deer: In the mid-1900's, white-tailed deer were introduced to Anticosti Island for sport hunting. A combination of lack of predators and favorable climate have led to a deer population explosion on the island, whose numbers (over 100 000) are threatening the indigenous fauna of this small island only 220km long by 55km wide.

 

Sea Lamprey: The sea lamprey is a parasitic fish which attaches to other fish and feeds on them. Common on both sides of the Atlantic, the sea lamprey became problematic when the Welland Canal opened up earlier this century and the lamprey invaded the upper Great Lakes. There, its parasitism decimated stocks of important commercial fish such as lake trout and whitefish. Declines may not have been due solely to mortality from lampreys, but their attacks weakened fish and made them more vulnerable to predation and disease. Efforts have been underway to control the sea lamprey in the Great Lakes and St. Lawrence since the 1960's although it appears that sea lamprey numbers have not changed much since the 1950's.

Zebra mussels have been found attached to every species of clam in the St. Lawrence River and have decimated the populations of 5 of the 8 species found in the river. Zebra mussels were most likely introduced to the Great Lakes in the ballast water of tankers arriving from the Pontocaspian region and traveling up the St. Lawrence Seaway.

 

 

European starling: This bird was introduced to North America at the end of the 1800's when 50 breeding pairs were released in Central Park, New York City. The European Starling has become one of the most ubiquitous birds in North America, breeding everywhere south of the tundra zone. It remains in its habitat year round and has successfully outcompeted many native birds for nesting sites. This has led to a decrease in the diversity of urban-dwelling birds and has also created problems for farmers because of the excessive damage it can cause to crops. (Gaulthier and Aubry, 1996)

 

Climate change

Plants and animals are sensitive to fluctuations in temperature and climate. In the past, climate has varied considerably within short time scales. Evidence from fossils and paleobiological studies have indicated that these periods of rapid climate change have been associated with mass extinction events.

We are currently in a period of high climatic variability. The summer of 1988 brought on one of the worst droughts in history. Almost all scientists are in agreement about one thing: human activities are exacerbating climatic conditions and speeding up the rate of global warming. This is a direct result of the increase in production of greenhouse gases, such as CO2 (carbon dioxide) and CH4 (methane) due to the burning of fossil fuels and incomplete combustion from vehicles.

In addition, the release of anthropogenic chemicals called CFCs - chlorofluorocarbons - into the atmosphere has degraded the stratospheric ozone layer around the Earth, which shields the planet from harmful ultraviolet radiation. Changes in the integrity of the ozone layer has resulted in increased ultraviolet radiation reaching the Earth's surface. (CBIN)

What are the consequences of climate change to biodiversity?

What impact will global warming and increased ultraviolet radiation have on biodiversity? The results are inconclusive. Recent evidence suggests that increased UV has caused damage to some agricultural crops, and to organisms in wetlands and coastal environments. (CBIN)

In Quebec, global warming computer simulation models predict changes in air temperature of 2 to 6 °C and increased amounts of snow and rain. Effects will be different for different vegetation zones: the tundra zone will most likely shrink with increasing temperatures and aquatic algae that serves as the base of the food web for much wildlife may disappear as water temperatures warm up. In the South, the hardwood forest zone may expand and the growing season may be extended. However, increasing water temperatures will radically alter the ecology of freshwater ecosystems and wetlands, leading to increased phytoplankton, changes in distribution of invertebrate and fish species and the loss of coldwater species (like lake trout) altogether.

Studies on the effects of global warming point to two major facts: the speed of change is much more accelerated than in the past, which may pose a serious threat to slow-growing communities which cannot respond quickly, and which may shrink the range of plants that need cooler environments. Secondly, global warming may increase the frequency of climatic disturbances such as fires, disease, insects, storms, etc. As discussed in "Processes and Patterns of Biodiversity", disturbance is a crucial process that maintains biodiversity, changes in disturbance regimes may radically alter the diversity of an area. (MEF Quebec Implementation Strategy)

 

 

The relationship between human activities and impacts on biodiversity

In Quebec, agriculture, forestry, manufacturing and urbanization are key contributors to Quebec's economy and have a significant impact on natural areas. As the population increases and the demand for goods increases, there may be a growing conflict between further economic development and the maintenance of pristine ecosystems large enough to sustain viable wildlife populations. (CBIN 1998)

To determine the cost of running the economy while still maintaining integrity of the environment, we must consider the cost of industrial pollution prevention and cleanup of existing pollution in addition to the jobs that resource-dependent industries create, the contribution of these resources to Canada's productive capital, and the ability to be competitive internationally in that industry. (Statistics Canada,1994)

The GDP of Québec in 1991 was about $156 billion, of which 70% originates from primary resource extraction (agriculture, forestry, fishing) and manufacturing. It is evident that the economic prosperity of Quebec is heavily reliant on manufacturing and resource extraction. About one-quarter of all Canadian manufacturing takes place in Quebec, with paper, primary metals and food processing being the major activities. Quebec is also a significant producer of asbestos, gold, iron ore and copper.

Because manufacturing is heavily dependent on the availability of water for various processes, most of Quebec's manufacturing and agricultural activity takes place along the shores of the St. Lawrence River, making water contamination a major issue. In addition, the reliance of manufacturing and resource extraction on vast amounts of hydroelectric power makes water diversions (hydro dams) another issue of environmental concern. (Statistics Canada, 1994)

Agriculture

Agriculture has had a significant effect on biodiversity because of its prevalence over the landscape, particularly in the southern regions of Canada. Effects include habitat alteration (conversion to farmland for crops and grazing), exotic pest introductions and pollution from pesticides and fertilizers.

agricultural fields.jpgThere is the potential for agriculture to play a beneficial role in the conservation of certain plant species, mainly by protecting habitats from urbanization. This could be achieved by cultivation processes that integrate wild species into agricultural landscapes. (CBIN 1998)

Agricultural activity provides jobs for almost 124 000 Quebecers and contributes over $3.5 billion, or 2%, to Quebec's GDP. (Statistics Canada, 1994)

Agriculture has the greatest impact on the environment of any human activity both because of the degree of habitat alteration that occurs and because of the widespread geographical scale of this alteration. Some of the impacts include: global changes in atmospheric CO2 concentrations, changes in natural genetic plant stocks, changes in established ecosystems, the introduction of exotic species and large-scale drainage modifications which disrupt natural flood regimes and increase topsoil erosion. (Statistics Canada, 1994)

Loss of habitat/species: Loss of native habitat in Canada due to farming has been significant: we have lost more than 85% of shortgrass prairie, 80% of mixed-grass prairie, 85% of aspen parkland and almost all our native tallgrass prairie. Loss of habitat, combined with reliance on a few genetically-engineered crop strains instead of indigenous crops, have resulted in the endangerment of a disproportionately large number of plant and animal species in Canada. (CBIN, 1992)

Erosion: Soil erosion is an agricultural problem because natural vegetation has been removed from an area. As a result, surface water, or winds can carry away topsoil, the surface layer of soil that is rich in nutrients and beneficial microorganisms. In Quebec, it is estimated that 3.4 million tonnes of soil per year are eroded by water. Wind is a negligible factor in Quebec, although it plays an important role in soil erosion in the prairies. Soil erosion has a direct effect on habitat quality, making an area barren and unsuitable for plants that were native to that habitat. As well, soil that is washed away gets deposited in waterways, destroying fragile aquatic habitat. (Statistics Canada, 1994)

Chemical pollution: As water carries away soil, it can also cause the runoff of pesticides and fertilizers that are applied in abundance to commercial crops, and of cattle and livestock wastes. In Quebec in 1990-91, an average of 190 000 tonnes of nitrogen and 120 000 tonnes of phosphorus were applied to agricultural lands in the form fertilizers, or were present as livestock wastes. Excess nutrients that enter lakes and rivers as runoff can contribute to eutrophication of aquatic environments, altering and degrading the biodiversity of aquatic ecosystems. (Statistics Canada, 1994)

In Quebec, 34 000km2 (2.5% of the total area) are allocated to farmland, mostly in the St. Lawrence lowlands, where the soil is most fertile and where the highest diversity of native plants in Quebec is found, creating potential conflicts between conservation of biodiversity and agriculture.

About 100 million m3 of water per year are needed for irrigation of crops in Quebec (2% of total water use in the province). However, irrigation is only the fourth most water-dependent activity after thermal power generation, manufacturing and municipal use.

Agriculture also depends on chemical inputs for fertilization and pesticides. In 1990, almost 470 000 tonnes of commercial fertilizer were applied to crops in all of Quebec, or 0.47 tonnes per hectare of farmland. In addition, over $43 million were spent on pesticides for crops in Quebec in 1990. Both pesticide and fertilizer application has increased significantly in Canada over the last few decades. This results higher amounts of non-point source air, water and soil pollution. (Statistics Canada, 1994)

Fishing

Fishing and related activities generate approximately $89 million per year (less than 1% of the GDP) and provide over 10 000 jobs to Quebecers. (Statistics Canada, Human activity and the environment, p. 86 p.30)

While fisheries may not play a major economic role in Quebec, their impact on biodiversity is, nonetheless, significant. Fishing can affect aquatic ecosystems through overharvesting of populations, nutrient additions (aquaculture), introduction of exotic fish and invertebrate species, habitat alterations and pollution. (Thibault, p.273)

Approximately 1000 species of fish reside in Canada, 200 are freshwater species and the remaining are marine species. To date, 4 Canadian species have become globally extinct, 2 have been extirpated in Canada, and 53 are currently listed as species at risk by COSEWIC (see Conservation Efforts in Canada). Overfishing has played an important role in the decline and extinction of many species. For example, Atlantic cod populations have been decimated by overfishing, and the rare blue walleye, endemic to Lake Erie and ecologically unique, was overfished to extinction. Overfishing in the Atlantic provinces has not only caused decreases in the numbers of fish but has also resulted in changes to their community composition. On the Georges Bank, between 1963 and 1986, the proportion of cod in catches dropped from 55% to 11% while the proportion of less desirable "dogfishes" has increased from 2% to 41%. In the case of Pacific coast salmon, halibut and herring, overfishing is compounded by the degradation and loss of freshwater spawning habitat.

In Quebec, marine catch consists of approximately 62% groundfish (cod, haddock, turbot) and 29% shellfish with 83 000 tonnes of fish harvested per year (based on 1991 numbers). However, this represents a significant reduction in the biomass of bottom species harvested in the St. Lawrence estuary between 1981 and 1990. Continued decreases in biomass are attributed primarily to loss and degradation of habitat because of destructive fishing practices and, secondarily, to chemical pollution from upstream urban centers.

Aquaculture is another human activity that is increasingly affecting biodiversity of fish, mainly by the accidental release of unhealthy fish or non-native strains that hybridize with native populations and decrease their fitness and genetic diversity (hybridization is further discussed under "exotic species introductions"). As well, wastes from fish farms are a significant source of nutrient loads which degrade often pristine aquatic habitats. (CBIN, 1992)

 

Forestry

The value of forest production in clearcut logging.jpgQuebec exceeded $1 billion in 1991 (1% of the GDP) and generated over 80 000 jobs. Of the total area of accessible productive forest (>500 000 km2), 87% is owned by the provincial government, while 12.5% is privately owned. Areas of productive forest are located primarily in the boreal forest ecozone, in the regions of Saguenay-Lac St. Jean, Abitibi-Temiscamingue and Cote-Nord. (Statistics Canada, 1994; Thibault, p.337)

Almost 2400 sq. kilometres of forest were logged in 1991; 81% of those were clearcut. Conversely, less than 1000 sq. kilometres were replanted. Despite the decreasing importance of this resource to the national economy, harvest volumes have increased over the past 25 years. (Statistics Canada,1994)

Like fishing, forestry is not a significant contributor to the GDP of Quebec, yet the manner in which it is carried out can pose serious threats to forest ecosystems. Clear cutting, the dominant mode of logging in Quebec, can have devastating impacts on a region by removing wildlife habitat, causing loss of nutrient-rich topsoil and destroying aquatic ecosystems by siltation. Clear-cutting not only alters habitats, but removes the potential for the habitat to reestablish following logging disturbance. Soil regeneration is extremely slow. Mature tree communities, required by many plant and animal species for habitat, can take decades, even centuries to grow again. And if degraded spawning habitat were to return to its original state, there may not be fish populations left to use it. Finally, logging roads have fragmented the ecosystem and made it vulnerable to edge effects, such as invasive species like parasitic cowbirds and weeds that flourish in disturbed habitats (and opportunistic humans).

The manufacturing of wood products by the pulp and paper industry is also a major source of water pollution and organic enrichment in aquatic ecosystems.

 

Urbanization

Between 1871 and 1991, the proportion of Canadians living in urban centers increased from19% to 77%, even though urban centers occupy only 0.7% of the total area of Canada. However, urban centers have been expanding over the last few decades into their surrounding rural areas (this is known as urban sprawl). Of all of Canada's urban centers, only Vancouver has not spread because it is locked between ocean and mountains.

Seventy-eight percent of Quebec residents live in urban centers. In the twenty years spanning 1971 to 1991, the total area of the Montreal Urban Community increased from 2674 km2 in 1971 to 3509 km2, the Quebec City area increased from 907 km2 to 3150 km2, and the Sherbrooke and Trois-Rivieres became classified as urban centers. The majority of large cities are located within the St. Lawrence lowlands, which is a very biologically rich ecozone. This leads to the inevitable conflicts between efforts to conserve biodiversity and the need to accommodate burgeoning urban sprawl. (Statistics Canada, 1994)

Manufacturing

Manufacturing generates the greatest number of jobs and the highest proportion of Quebec's GDP. Manufacturing is energy- and water-intensive and its main effect on biodiversity has been pollution of air, water and soil. Sometimes, these effects have been very dramatic: PCB wastes from manufacturing were accumulated and biomagnified in wildlife populations and caused reproductive failure of animals that fed high on the food chain, such as osprey and peregrine falcons. Air emissions from the Inco steel smelter in Sudbury, Ontario were directly responsible for a significant portion of the acid rain that has decimated terrestrial and aquatic ecosystems in eastern North America. The relationship between manufacturing and pollution is also discussed in the "Pollution" section above.

 

Globalization

The proliferation of international trade treaties in the last few decades has led to an increase in global movement of goods. While globalization itself is not directly detrimental to the environment, certain aspects of increased transportation, particularly oceanic shipping traffic, have placed a strain on natural systems by facilitating the immigration of species to new habitats, introducing pollutants into aquatic ecosystems, and altering and destroying coastal habitats.

The greatest impact of globalization has been the introduction of exotic species to native habitats. This has occurred most often through the release of ballast waters from ships. Ships take up water in their ballast from their point of origin for stabilization as they cross the oceans and release it when they arrive at their port of destination. This ballast water may contain many plants and animals native to other regions of the world. Some of these organisms survive the crossing and proliferate in the Great Lakes and St. Lawrence River and may be extremely damaging to the native wildlife because they have no natural predators. Examples of exotic species that arrived in the St. Lawrence river in this way include the zebra mussel and the spiny water flea. The issue of exotic species is discussed in greater detail in the "Introduction of exotic species" section .

Increased shipping traffic also means increased probabilities of accidental spills of substances that pose a risk to aquatic wildlife, such as crude oil and the increased release of fuels to aquatic ecosystems.

Since harbors are necessary for shipping traffic, their construction, as well as canal cutting and dredging, require that coastal habitats be modified and sometimes destroyed. For example, a channel was excavated through the center of the St. Lawrence river to create the Maritime Passage, permitting marine vessels to get to the Great Lakes. The dredging of the St. Lawrence also provided a new invasion route for exotics. The sea lamprey, for example, gained access to the Great Lakes through the Welland Canal and was able to establish itself and decimate populations of native fish species within a couple of decades.

 

 

 

next section

Part 2: Species vs Landscape Protection