BUGS AND BEAVERS

LIVING WITH BLACK FLIES

In 2006, the City of Estérel renewed a only toxic to the mosquito and black fly larvae and has program to eradicate mosquitoes and proved safe for humans, mammals, birds, fish, all other black flies to improve the quality of life of wildlife and the environment. its residents and visitors, and protect Black flies are small, bloodsucking insects them from the threat of the West Nile approximately 1-3 mm long, black or grey with short Virus. The product used in these legs and antennae. There are over 1800 known carefully targeted applications is a species. They appear in the Spring and disappear in microbial control agent called Bacillus early Summer. Black flies need water to procreate and thuringiensis israelensis or Bti. lay eggs. The larvae attach themselves to submerged objects where they develop into adults, swim to the air The public’s concern for the above and fly to breeding site nearby. The males then environmental effects associated with seek nourishment from pollen and nectar but the chemical insecticides has prompted the females search out blood needed to produce their eggs. switch to more bio-degradable agents Female black flies track their victims by the moisture and carbon dioxide emitted during that are highly selective, targeting a very perspiration. While biting, saliva is injected into the wound, preventing blood from clotting narrow range of pests. In this case, Bti is and setting off the allergic reaction that makes the bite itch.

Some suggestions to living with black flies:

*Avoid the outdoors during periods of peak black fly activity. Black flies only feed during the day and rarely bite indoors or late at night.

*Wear light colored clothing. It attracts less than dark.

*Use eco-friendly repellents. Catnip oil or oil of lemon eucalyptus are choices in organic bug repellents and pleasant smelling alternatives to chemicals.

*Eliminate all stagnant water, even the tiniest ones: saucers under plants, clogged gutters, birdbaths and rain puddles, playpens and slides.

*If you have a decorative pond, stock it with mosquito and larvae-eating fish like Gambusia

THE BEAVER: PROBLEM OR SOLUTION

Where would we be without the beaver ? A major lure to early explorers from the late 1600’s was the fur trade of beaver pelts. In Europe, fur top-hats were the fashion rage and the export from the New World so lucrative that the powerful Hudson’s Bay Company honoured the beaver on its corporate shield. In 1833 the beaver was included in the insignia for the incorporation of the City of Montreal. Facing extinction by the mid 19th century, the beaver was saved by the whims of fashion; now silk top-hats are de rigeur and the demand for beaver pelts have declined.

The adult beaver, the largest rodent in North America, can weigh as much as 35 kg, stands 30 cm tall, with a wide flat tail about 25 cm long. It is semi-aquatic, using its tail as a rudder and an emergency signal in the water. Through a life span of twenty years, it is busy as a beaver, building its habitat, cutting and felling trees, leaving a telltale signature: pyramid shaped tree trunks.

For its habitat, beavers build a dam to control the flow of water surrounding their home, a lodge that is a mastery of aquatic engineering. The lodge, dome-shaped, up to 91 cm high and 1.5 m wide is built of logs, bark, sticks and mud. There are two underwater entrances for security. Interior ramps lead up to the drying off floor of the lodge and then to the living space, built above water level and covered in woodchips to deter the humidity. A vent lets in fresh air for the single beaver family in each lodge.

The beaver is considered a keystone species designating it as a major influence on the surrounding ecosystem. The beaver dam and lodge induce water, temperature and chemical changes.

The positive aspects of the beavers *The beaver naturally replaces its cuttings. and cattails and cambium, the soft tissue presence are: Mature trees are lost at the shoreline due of hardwood trees, including birch, aspen, to flooding and tree loss can be recorded willow, cottonwood, and alder. *There are less flooding problems with some distance from the water. But beavers nearby as the beaver’s thinning tree volume warms the forest *Beaver dams can cause problems. Low landscaping raises water levels, floor and increases the plant biomass to lying areas can be flooded, the slow flow accumulates water around the shoreline greater than the timber mass decrease. of water can cause the build up of silt, and and banks, resulting in an eco-drainage Aquatic plants will sprout up when the some species can lose their habitat. The system. beaver abandons the lodge to build a new flooding caused by the dam can upset the one, and eventually, with shrubs and other infrastructure involved in modern water *The raised water levels, necessary to plants, the area will become a meadow. dispersion : drained marshes, tunnels, maintain a safe habitat for the beaver, The shrubs in the meadow will provide the ditches, drains and pipes controlling the also impact the surrounding terrestrial shade for trees to grow and the land will direction of water, extensions of farmland environment. This shallow warm water, become woodland again. and gardens. The dams change the the perfect climate for wetland vegetation, course of streams, water flow and create revitalizes the shoreline with rich and *The beaver dam increases biodiversity in ponds, streams, brooks and marshes. diverse aquatic vegetation and fauna and the complexity of the ecosystem by forms a wide, swampy transition zone creating natural shelter, food and nesting *Recent studies of stagnant water in the between water and land slowing erosion. conditions for a large variety of small Laurentian lakes presented by the Society mammals, bird species and water of Limnolog, are pointing to a new threat *The beaver contributes to the purification invertebrates that become the food for from the beaver population. Phosphorus, of the surrounding water as the dam slows fish, reptiles and birds. The fish attract the a major cause of water pollution, usually down the flow, functioning like a water otter, mink, herons and storks. Moose, associated with the resident lifestyle, is treatment plant, filtering environment deer and wild hogs become frequent now linked to that of the beaver. The sediments and other chemical visitors. dams that flood the forest and rot the cut substances. Drifting to the bottom, these trees are the culprit; producing a major substances create a perfect environment source of phosphorus.Professor Richard for the development of aquatic vegetation. The negative aspects of the Carignan says that the impact of the This stabilizes the waterbed and creates a beaver’s presence are: beaver is major in some lakes. “If a private further filter for incoming debris of organic business had this environmental balance substances, changing the chemistry and *The beaver and the impact of its lifestyle sheet, they would be closed immediately”, the hydration of the soil. The pollutants in are positive from an ecological stance, but he stated. the water can be decomposed by micro- in terms of forest, agricultural production, organisms supported by the new and landscaped towns, the beavers' effect So, is the beaver a problem or a solution? vegetation. Also, the beaver’s constant on their surroundings such as felling trees Google for interesting sites filled with facts foraging for food unclogs weeds and and flooding crops is negative. The beaver and ongoing research about this keeps the water flowing freely. razes our landscape with his diet of ingenuous little mammal. aquatic plants: pond weeds, water-lilies, . SOURCES www.gouv.qc.ca/portaiol/quebec

Agriculture and Agri-Food Canada Research Brand; A review of the environmental impacts of the microbial insecticide Bacillus thuriensis Technical Bulletin No. 29 www.hww.ca www.nature.ca/notebooks/english/beaver www.members.shaw.ca/kcicl/beaver www.fishbc.com/adventure/wilderness/animals/beaver