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The Rideau River Biodiversity Project


Research Methods

Researcher in the field.
In the field, Francis Cook's "office" is his truck. Here, he measures, weighs and identifies the amphibians he captures.

In the course of the Rideau River Biodiversity Project, nine elements were examined in order to evaluate the health of the River: water quality, algae, aquatic plants, aquatic invertebrates, freshwater mussels, fish, amphibians, reptiles and birds.

For each biological element, scientists recorded the distribution, diversity and relative abundance of each species. They also identified biodiversity havens along the Rideau River between Smiths Falls and the Rideau Falls.

During three summers of research, samples were taken every two weeks from 20 sites that were located between Smiths Falls and the Rideau Falls. Samples were also taken irregularly from 54 additional sites. Phycologists (scientists who study algae) collected algae by towing a very fine meshed net through the water behind a boat. The algae were captured in the net, and then they were rinsed off the mesh into collecting jars. Back at the laboratory, scientists used a microscope to identify, count, measure and photograph the specimens.

Amphibians and Reptiles

Amphibians and reptiles were sampled along the length of the Rideau River between Smiths Falls and the Rideau Falls. Herpetologists (scientists who study amphibians and reptiles) and volunteers tracked these animals by catching, counting, measuring and marking them. Amphibians were marked by clipping one of their toenails. Turtles were marked with tiny notches filed into the edge of the shell. Once the specimens were measured and marked, they were returned to the water. The area was sampled again several days later because scientists can get an idea of the population size, growth and distance travelled by the number of marked animals they recapture.

Auditory surveys were used to determine the number of male frogs, which are vocal. Scientists also studied reptiles by canoeing the entire length of the River in order to count the turtles and snakes seen basking. Traps and hand nets were used to trap turtles, frogs and salamanders. Emphasis was placed on bullfrogs, mudpuppies, painted turtles and musk turtles because they are representative indicator species. The community greatly helped the turtle census through calls to the Turtle Hot Line that reported sightings.

Aquatic Birds
Fifteen sampling sites were located along the length of the Rideau River between Smiths Falls and the Rideau Falls. Ornithologists (scientists who study birds) conducted aerial surveys throughout the spring and summer to determine which species of aquatic birds are found along the Rideau River. Three surveys were conducted from an airplane during the migration periods (spring: mid-March to mid-May; fall: mid-August to mid-December) and in the winter (early January). Seven surveys were conducted by helicopter during the nesting and brood-rearing periods. Ground surveys were also conducted along certain sectors of the river in order to gather information about daily use of the River at various times of the year.

Aquatic Plants
Person sampling aquatic plants.
Sampling aquatic plants.
Twenty-five sampling sites were located along the length of the Rideau River between Smiths Falls and the Rideau Falls. Scientists and community volunteers estimated the density of aquatic plants by counting all of the specimens growing in 1m2 quadrates, outlined by square metal frames placed temporarily on the bottom of the River for this purpose. Surveys were made to evaluate and map the extent to which submerged aquatic plants grow along the shorelines of the River. Surveys began in July when the weed beds were well developed and continued until they disappeared in mid-September.

Greater redhorse, Moxostoma valenciennesi.
Measuring a greater redhorse, Moxostoma valenciennesi.
Ichthyologists (scientists who study fish) and volunteers determined the abundance and diversity of the fish community by sampling 14 sites in the length of the Rideau River and three sites in each of five tributaries. A variety of gear was used at each site because each type of gear catches a different size of fish. Small fish were captured by trapping them in seines, which are like large mesh curtains and are pulled through the water. Larger fish were captured using trap nets, which are mesh boxes with funnels inside that prevent the fish from escaping. Electrofishing was used to capture fish that were not easily captured in nets, such as bottom-dwellers that live in the cracks between rocks. This technique temporarily stuns fish so they float to the surface. If the scientists' reflexes are quick enough, they can scoop the fish into a dip net before the animals recover and dart away. Before being released, the captured fish were identified, measured and weighed.

Invertebrate samples were taken at 11 sites along the Rideau River between Smiths Falls and the Rideau Falls. Entomologists (scientists who study insects) and volunteers collected invertebrates by sweeping finely meshed nets through the water column and through plant beds. Specimens were brought back to the laboratory because a microscope was needed to identify and photograph them. A multimedia database of Rideau River specimens was created using digital photos and video.

Scientists focused on the identification of caddisflies, dragonflies and damselflies, and water mites because these groups are among the most diverse in the River and include a variety of plant feeders, predators and parasites.

A person counting mussels.
Counting mussels is time-consuming and exacting work.
Twenty-three sampling sites were located along the length of the Rideau River between Smiths Falls and the Rideau Falls. With snorkelling and scuba gear, malacologists (scientists who study molluscs) and volunteers collected native freshwater mussels from rapids and from the by-passes where some of the River's water skirts the locks at Smiths Falls, Andrewsville, Long Island and Ottawa. The divers raced to collect as many live and dead native mussels as possible within a predetermined time in order to calculate a standard measure of abundance. The mussels were collected and carried to shore in mesh bags. Once on land, the mussels were quickly sorted and counted before being returned to the River.

A person sampling zebra mussels.
Sampling zebra mussels (Dreissena polymorpha) from the door of a lock.
The density of exotic zebra mussels was estimated during late autumn, when the walls of the locks were exposed. The water level is lowered in the autumn in order to prevent ice damage to the locks. Scientists were able to climb down into each lock to count the zebra mussels stuck to the walls. In many of the downstream locks there were too many zebra mussels to count, so scientists counted all of the zebra mussels within several quadrates, then extrapolated the results in order to calculate a quantity for the entire lock.

Water Quality
Limnologists (scientists who study fresh water) took hundreds of water samples from 18 sites along the Rideau River and from three additional sites in the headwater lakes near Smiths Falls. These samples were analysed in a laboratory to determine the concentrations of nutrients (fertilizer), bacteria (faecal coliforms and E. coli), metals and chlorophyll. The sampling was conducted twice a month over three years, starting in early May and finishing at the end of October. Samples were collected from both the navigational channel and the shoreline.


A Project of the Canadian Museum of Nature
 Images: Thomas Cook, Fiona Currie, Lynn Gillespie, Anne Phelps, Judy Redpath