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Driven to Destruction By Geoff Peach, The Lake Huron Centre for Coastal Conservation Cars, ATV’s, snowmobiles and heavy equipment can all cause environmental damage to beaches. Driving vehicles on beaches is a subject that has become controversial in recent years. Cottagers who have spent many years enjoying our lake will often have stories, or even photographs, of driving up and down the beach back in the 1940s and 50s. Today, cars are not acceptable, but all-terrain vehicles and snowmobiles sometimes find their way to our beaches. Some local contractors also find the beach a convenient way access job sites with their heavy equipment. Is there really a problem with driving a vehicle on a beach? The use of vehicles in beach areas is a practice that is being challenged throughout the world as a better understanding develops of beach ecology and the environmental consequences of allowing vehicles on beaches. At first glance, a beach may look pretty barren and lifeless. However, a closer look reveals there is life both within and on our beaches. Strand lines, which are the lines of debris that collect where the waves swash up on the beach , often contain considerable amounts of organic matter, which the bodies of decaying insects, bacteria and fungi break down, releasing nutrients into the sand which are used by plants in the nutrient poor dunes. Strand lines also contain fragments and seeds of dune plants and are important for sustaining dune development. U.S. Research has identified that vehicle traffic compacts beach sand at depth, but loosens the surface of the beach, making it more susceptible to wind erosion. The sand compacting effects of vehicle passage can extend to a depth of about 20 cm or more. The impacts related to the turning of wheels loosens the sand and brakes the roots of native beach plants as well as crushing seedlings of annuals and young plants of perennials like American Beachgrass (also known as Marram grass). Vehicle impact also decreases the rate of decay of organic material. The normal content of micro-organisms that aid in the decay of the material associated with the organic drift is normally very high, but become greatly reduced when vehicles pulverized the deposits. Research at the University of Guelph is also beginning to show that beneficial insect populations that call the beach home, are being impacted by vehicle use. In other related research, upper beach and dune areas subjected to either short or long-term vehicle and heavy pedestrian traffic were demonstrated to have decreased top and root production, amount of cover, and diversity of plant species compared with un-impacted areas. Impacted areas were also unable to develop a dune leading to an overall degradation of the beach. As these activities increased, so did the following characteristics: average wind velocities near the ground surface, evaporation drying out the sand (increasing erosion potential), wind-carried sand particles near the ground surface, soil pH, average soil temperature and range in temperature. These changes made environmental conditions more demanding for the remaining plants in the immediate area as well as for plants further inland. Some think that using snowmobiles avoids those impacts since the vehicle rides on snow above the ground. The reality is that beaches and dunes tend not to have large continuous covers of snow during winter, and snowmobile tracks have been observed to cut into the sand and tear up plant roots. The dune vegetation isn't dead, it’s just dormant. Dunes along Lake Huron are particularly vulnerable coastal features and have a low tolerance to human disturbance. Dunes have been subjected to increasing degradation in recent years as more people utilize the shoreline for recreation and relaxation. This despite the fact that Great Lakes dunes are considered to be a rare coastal feature, amounting to only 1.5 per cent of the total shoreline of Ontario’s Great Lakes shoreline. They also tend to have high concentrations of specialized and at-risk species. Some of the main human-related threats to dune habitats include: -Dune removal or alteration due to cottage development, or improper management. -Damage to plants and habitat from vehicles and excess foot traffic. -Invasion by alien, invasive plant species (made worse by unnatural disturbances to the beach and dunes) brought to the beach by vehicles. Since dunes are a limited, finite resource, it is critical that we manage our interaction with these features so that we do not lose the very resource we enjoy. Beaches are directly linked to dunes, and dune ecology, and so stewardship of dunes means we also have to include the proper care of beaches. As noted earlier, vehicle impacts to beaches can cause structural alterations that lead to increased beach erosion by wind. These alterations disrupt the delicate balance of physical conditions found in the beach-dune environment. In addition, sand compaction by vehicles in the upper beach and dune area can negatively impact dune plants that would otherwise reduce wind erosion of the beach. Current efforts by Environment Canada researchers have identified that degraded beaches can have high levels of E. coli occurring in the nearshore waters and swash zone (the wet sand where the waves run up the beach). They compared these areas with healthy beaches, where there was no evident increase in E. coli levels. The conclusion is that what we do to our beaches can contribute to water impairment as well. Driving vehicles in beach areas have important ecological implications. It is a practice that could compromise the ecological integrity and functioning of the dunes, ultimately requiring extensive conservation efforts by the community to turn things around. Municipalities should take a leadership role by restricting unauthorized vehicle use of any kind on Lake Huron’s beaches. The benefits of protecting our beaches and dunes extend well beyond environmental. Our beaches are important to our local coastal communities, both economically and socially. To download the Centre's factsheet on Vehicles and Beaches, go to http://lakehuron.ca/index.php?page=coastal-processes-2 |
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