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| Karen Crook Matthews © 2023 |
| 2023-05-12 182 Pond; Barnes Arboretum, Merion PA |
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What lives in this pond? Although historically there was small spring nearby, this pond is now a concrete-lined, recirculating, shallow pool. We strive to maintain the pond as an example of a functional local aquatic ecosystem within the constraints of this artificial structure. The aquatic plants in this pond are mostly native to the mid-Atlantic region, and include Pickerel Rush (Pontederia cordata), Lizard's Tail (Saururus cernuus), Water Pennywort (Hydrocotyle umbellata), Floating Heart (Nymphoides peltata), Graceful Cattail (Typha laxmannii), and Sweetflag (Acorus calamus). In the spring, frogs and toads spawn in the pond, and ramps are constructed to facilitate their exit. One of the native duckweeds (Lemna minor) - often mistakenly identified as an algae - also has a presence. Duckweed is an important source of food for a wide variety of fish, reptiles, fowl, and insects. It is also harvested commercially for use as livestock feed and biofuel and grown in contaminated waters as a phytoremediation strategy. However, because of the lack of foraging pressure from naturally occurring aquatic life, the duckweed became too prevalent in this pond, limiting the growth of the other plants and organisms. This past summer, we introduced fish that feed on duckweed: Ornamental Tilapia (Oreochromis sp.). While the tilapia have been successful in controlling the duckweed, they've also drawn the attention of a magnificent local predator: the Great Blue Heron! |