Thursday, January 31, 2008

Anthropothrow: a feature of urban ponds.

Man-made ponds created in parks as beautifying features and wildlife attractants are not truly natural features, so nature will eventually eliminate them. Infilling will occur through the colonization and spread of aquatic plants, the seasonal deposition of organic matter as they die, and the continual introduction of new plants by various means, until the pond gradually heals over and reverts back to forest or field, whatever it had previously been.

Bufflehead, Great Blue Heron, Mallard, Hooded Merganser.

It takes a while, of course, and the first years of a pond can be very picturesque, after the initial scouring of the edges is masked by emergent vegetation. Once a sizeable invertebrate fauna becomes established, perhaps augmented by the arrival of sticklebacks or other fish via the storm system or other means, larger animals appear: waterfowl, herons, raccoons, etc.

But such paradises must be managed closely in urban settings. The filling in of a pond can be remarkably fast because of the amount of debris that decends onto the surface during winter months. Some may be windthrow from winter storms, but there is another kind of throw, anthropothrow.

Why does this happen?

Because we want to break the ice!

Try pieces of wood. Not heavy enough. Rocks! Try rocks!

Even complete automobile wheels won’t do it. Anybody know where we can get an anvil? A safe?

Urban Pond: Winter vista.

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