|fwg is a long-term project of the ottawa field-naturalists' club|
THE POND WAS CREATED in 1991 by building a small dam near the top of the ravine. It receives runoff from the Experimental Farm through a system of weeping tiles and conduits as well as directly from the surrrounding slopes. Cattails grow thickly along the edge and Elodea oxygenates the water.
The habitat has attracted American toads, wood frogs, green frogs, grey tree frogs, Blandings, painted, and snapping turtles, red-winged blackbirds, mallards and black ducks, green and great blue herons, and spotted sandpipers. A plentiful supply of flying insects feeds the tree swallows that nest in bird boxes nearby, and the variety of water-based insects is rapidly increasing. In 1996, the pond was deepened at one end to allow snapping turtles to overwinter in its depths.
In 1998, we made a special effort to identify the frogs using our pond. Wood frogs appeared first in early April, calling for about a week. By the third week of April, we could hear a number of American toads, and green frogs had also put in an appearance. In mid-May we could see large tadpoles, which had overwintered at that stage, along with tiny American toad tadpoles and this year's green frog tadpoles.
In 1999, the water level remained relatively high all summer and well into the fall. Cattail growth seemed less robust than in previous years, but the number of flowering rush (Butomus umbellatus) plants increased significantly. We're planning to cull this non-native, somewhat invasive species in the spring. Our Blandings turtle was sighted again this year as were at least 4 small painted turtles. A good variety of damsel and dragonflies can be seen over and around the pond all season.
For the last several years, we've been contending with invasive species in our pond as well as elsewhere in the garden. Flowering rush grew exponentially until it covered all open water. Frog-bit also became a problem. It and Duckweed covered the surface by July, preventing sunlight from getting to the underwater plants that keep the water oxygenated.
Since 2001, we've been removing these species from the pond. Work does not start until mid- to late July, when the many Red-winged Blackbirds have finished nesting. This year, our Green Herons used the pond heavily; we saw up to 5 birds at once during early June.
The number of dragonflies, backswimmers, water striders, etc., has decreased from 5 years ago. However, this year's residents of the pond included a large Blandings Turtle, at least one Painted Turtle, a muskrat, Wood Frogs, Green Frogs, American Toads, Grey Treefrogs, backswimmers, spiders, a giant waterbug, lots of aphids followed by lots of ladybeetles, especially Coleomagilla maculata, a native species.
There were fewer Red-winged Blackbird nests this year as we have disturbed their nesting sites simply by being in the pond last summer. However, there were at least 7 nests. Goldfinches could be seen in August fetching cattail fluff for their nests. The Green Herons were regular visitors. In September, a few pairs of Mallards and Black Ducks spent some time in the pond. Below the dam in the ravine, hummingbirds were a big attraction as they zoomed from one Jewelweed flower to another, perching only briefly on a raspberry cane every now and then.
As noted above, invasive species such as flowering rush and frog-bit have dramatically decreased the number of species of amphibian, reptiles, birds, and insects using our pond. Drastic action is needed and a project to restore this important habitat has finally been approved.
Work is scheduled for this fall. Please watch for signs on site. The bridge and the area surrounding the pond will be closed to the public until the restoration is completed. We believe this inconvenience will be rewarded, as our rejuvenated pond promises to be quite wonderful.