Potential Shoreline Problems

Riparian habitats face many problems, partly due to their large commercial and recreational potential. We present here three major issues that affect them :


Shoreline alteration

Invasive species


We also put into perspective the impacts of these issues on fish, often forgotten since out of sight. Remember that it is important to have a global understanding of the environmental problems that affect your site before you try to implement solutions. In other words, you must consider as many factors as possible and predict the impact of your action on the ecosystem as a whole. It is best to consult professionals and get all the necessary information before taking any action. Feel free to contact the watershed organization or Comité ZIP in your area for assistance.




ErosionExcessive erosion has serious consequences. Shoreline erosion is a complex phenomenon explained by many factors, both of natural and human origin. It’s important to identify the causes of erosion before taking any action

Natural factors
-ice movement
-river current
-wind and the waves
-nature of shoreline materials

Human factors
- destruction of the riparian buffer zone
- changes in water levels due to dams
- waves from commercial and recreational boating
- trampling by visitors
Impacts of erosion
- loss of aquatic habitat and spawning grounds
- loss of biodiversity
- public safety issues (e.g., flooding, landslides and unstable banks)
- loss of productivity in plant and animal communities
- reduced recreational and aesthetic potential
- loss of land
- loss of heritage value
- loss of recreation-related spinoffs
- loss of land value
Possible solutions to reduce erosion
- Rehabilite the riparian buffer zone by planting species of shrubs and trees with spreading roots.
- Install a vegetated rock embankment, especially where waves and current are major factors
- Reduce overly steep slopes.
- Concentrate shoreline access to a few places, especially when trampling is a factor.
- Make pathways diagonal to keep runoff from eroding trails.
Did you know that...
- Erosion due to shipping affects only 15% of the banks of the St. Lawrence River, of which 85% is between Montréal and Sorel ?
The islands in Lac Saint-Louis that are protected by the Île-de-la-Paix Migratory Bird Sanctuary are eroding so fast that they could disappear in 20 years ?
The roots of plants, bushes and trees growing along rivers hold the soil in place and prevent excessive erosion?

Shoreline alteration

Modification des berges

It is very common to develop shorelines in unnatural ways. Generally, native vegetation is removed and replaced with a lawn. To prevent the erosion resulting from the removal of vegetation, a concrete wall or rock embankment is built along the shoreline. Lastly, facilities for easy access to the water are built without thinking about their impact on aquatic habitats. However, the impact of such facilities can be minimized by judiciously choosing their type, for example, floating or pile docks.

Research demonstrates that the riparian buffer zone is essential to keep our rivers healthy. The riparian buffer zone is a strip of vegetation several metres wide along the edge of a stream or river. To perform all of its functions, it must be composed of dense clusters of trees, shrubs and herbaceous plants. In 1998 the Québec government adopted a policy intended protect shorelines and floodplains. That policy prohibits shoreline alteration without written permission from the MDDEP.

Functions of the riparian buffer zone
Prevent shoreline erosion: The roots of plants growing in the buffer zone consolidate the soil and keep it in place during heavy rainfalls and snowmelt. Emergent plants also reduce the current and form a natural breakwater, hence reducing the water’s erosive potential.
Reduce mineral, pollutant and sediment inflow: Plants decrease runoff by absorbing water and later transpiring it. They also reduce the speed of runoff by forming a physical barrier. This enables the soil to gradually absorb the water. In addition, plant leaves decrease soil erosion by preventing direct exposure of the soil to wind and rain. In the presence of a riparian buffer zone, there are thus fewer fine particles that reach the river. Large quantities of particles aren’t desirable because they increase turbidity, destroy spawning grounds, and transport large quantities of nutrients and pollutants.
Act as a transition between terrestrial and aquatic environments: Wetlands are very rich in plant and animal species. Many animals come to the water to drink, feed or reproduce. Some animals are highly dependent on wetlands. Good examples are frogs and turtles. The buffer zone itself is a significant source of food because of the insects that fall into the water and that are eaten by fish.
Form a buffer zone to effectively absorb floods: Although most people equate flood with material damage, flooding is natural and necessary for the health of riparian ecosystems. A sufficiently wide riparian buffer zone helps prevent damage while allowing a productive ecosystem to flourish. For example, many species of fish, such as pike or perch, spawn in floodplains, while several species of plants need fluctuating water levels to survive. Because only homes built in the floodplain are damaged, it is preferable not to settle in such areas.
Solutions to shoreline alterations
Many organizations and companies specialize in restoring altered shorelines. They have developed an expertise that enables them to transform a heavily altered shoreline into one that looks natural and can accomplish many of its ecological functions.
Did you know that...
A riparian buffer zone just three metres wide can reduce herbicides by 99.5%, suspended solids by 85%, phosphorus by 85% and nitrogen by 75% in farm runoff?
Under the MDDEP policy for the protection of shorelines and floodplains (Politique de protection des rives, du littoral et des plaines inondables), special authorization is required to remove vegetation within 10 to 15 metres of the shoreline in order to build there?
Riparian habitats are vital for the survival of some 271 vertebrate species in Québec, representing 33% of all mammals, 50% of all birds, and 75% of all amphibians and reptiles ?
More than half the species of rare plants in Québec are associated with wetlands or riparian habitats ?
To learn more
- Buffer Strips and Water Quality: A Review of Literature
- ZIP Alma-Jonquière (in French)
- MDDEP: Effectiveness of a riparian buffer zone (in French)
- Politique de protection des rives, du littoral et des plaines inondables (in French)

Invasive species

Espèces envahissantesInvasive species are ones introduced intentionally or accidentally by humans into a new ecosystem. They are competitive and tend to dominate the ecosystem. They often replace the native species that used the ecological niche before they arrived.

Pathways of introduction
-Commercial shipping: They may be in ballast water or clinging to the hull of ships.
-Recreational boating: They may be clinging to the hull or in water at the bottom of the boat.
-Horticulture: They may escape from water gardens, as individual plants or as seeds.
-Stocking: Some species are intentionally introduced for hunting and fishing. It is later realized that they are invasive and harmful to the ecosystem.
-Release: Some species are released from pet shops (e.g., red-eared turtles and goldfish) or by fishermen (e.g., bait fish and earthworms).

Impacts of invasive species on shorelines
Modification to the water flow, depth and drainage in wetlands, affecting the distribution of plant species as well as nutrients in the water.
- Loss of biodiversity since they compete with native species for space and nutrients, and may transmit diseases and parasites.
Loss of genetic diversity when invasive species breed with native species. The mixing of genes changes the gene pool and may result in poorer adaptation to environmental conditions in Québec. This may ultimately lead to the lost of the original native species. In addition, offspring from interbreeding are often infertile, reducing the chances of the species to perpetuate itself.
Modification in some fisheries, often leading to sharp decline. Invasive species have a negative impact on commercial species by competing for food and space, eating native species, or introducing new diseases and parasites against which native species have no immune protection.
Solutions to the introduction of invasive species
It is important to detect as early as possible that an invasive species has been introduced into an ecosystem to have some hope of eradicating or controlling it. Several ways exist to eradicate invasive species.
- Mechanically: Individuals are pulled up, trapped or captured. This solution only works if the population is of limited size.
Chemically: Pesticides and poisons are used. This method has negative impacts on other species in the ecosystem.
- Biologically: Another species is introduced that is a predator or a natural parasite of the invasive species.
The best way to fight this problem, however, is to inform the public about measures that can prevent the dispersion of invasive species.
Means to prevent the introduction of invasive species
- Inspect your boat carefully.
- Never release live bait—whether fish, crustaceans or insects—into the water.
- Never move species from one body of water to another.
- Never choose purple loosestrife or water chestnut to embellish your water garden.
- Never release goldfish, turtles or other non-native species into natural habitats
Bien inspecter son bateau
Follow the instructions below every time you use your boat on a lake or river. These recommendations apply as much to small boats (canoes and kayaks) as to motorboats.
Inspect your boat and gear (paddle, spray skirt, elastic bridge, rope, engine and hull). Remove all animals and plants that are visible before leaving.
Empty your boat as soon as it is ashore (check watertight tanks, the hold and engine).
Wash and dry your boat and gear to eliminate species that aren’t visible to the naked eye.
- Some aquatic species can survive more than two weeks out of the water, so it is important to:
    - Rinse your boat and your equipment with hot water (at least 40°C), or ;
    - Spray high-pressure (250-psi) water on the boat and trailer, or
    - Simply let the sun dry out your boat and gear for at least five days before using it on another lake or river.
Did you know that ...
- The fight against invasive species costs taxpayers millions of dollars every year ?
- There are some 80 invasive species along the St. Lawrence River ?
- Invasive plant species represent approximately 13% of the flora in wetlands along the St. Lawrence River ?
Invasive plants cover nearly 50% of the wetlands between Lac Saint-Louis and Contrecoeur ?
To learn more...
- Fact sheets on invasive species
- Invasive Plant Species of the St. Lawrence Wetlands

Impact on fish

Espèces envahissantesThe habitats where fish live and breed are threatened by the issues above. Protecting fish habitats, and thus fish populations, is important for the economy since fishing-related spending in Québec amounts to more than one billion dollars.

Shoreline alterations lead to :
-faster erosion and an overload of sediment ;
-increased water temperature since trees no longer shade the water ;
-the destruction of wetland habitats where fish feed and breed ;
-poorer water due to increased concentration of pollutants and nutrients from in runoff; and
-lower oxygen content in water due to the proliferation of aquatic plants nourished by nutrient-rich runoff.

The overload of sediment from excessive erosion:
- clogs and irritates the gills of fish, affecting their ability to obtain oxygen from water;
- increases how susceptible fish are to diseases;
- destroys spawning grounds by covering them with unsuitable sediment; and
- suffocates fish eggs and fry buried in the gravel substrate.
Invasive species threaten fish species and populations because they:
- increase the predation rate on some species;
- decrease the survival rate of species that are more sensitive to changes in their environment;
- introduce new diseases and parasites; and
- compete with native species for food, spawning grounds and space.
Did you know that...
- approximately 20% of all species introduced into Great Lakes and St. Lawrence River ecosystems are fish? Good examples are carp, sea lamprey, clingfish (two species) and brown trout.
- Québec lakes and rivers are home to approximately 100 species of freshwater fish ?
recreational boating may have a negative impact on all life stages of fish? It may alter the habitat by increasing turbidity, destroying aquatic vegetation and degrading spawning grounds.