We observed only two predators: a few half-inch leeches, and one very thin, red, worm-like insect larva of the Chironomid midge. These midges prey on other tiny invertebrates and plankton and feed on plant detritus. They later hatch in large swarms of non-biting mosquito-like insects that are a rich food source for swallows and probably bats, and thus help cycle nutrients out of the pool into the rest of the forest ecosystem.
As it continues to warm up, many other species can likely be found in the pools. Things to look for are beetles (such as predaceous diving beetles, backswimmers, and water boatman), water stiders, mayflies, caddisflies, dragonflies, water mites, and snails. Very soon, wood frogs may breed in the pools, leaving round, jelly-covered egg masses.
Chris explained that some of the animals in vernal pools are so well adapted to their wet-and-dry cycles that they cannot survive without them. Such obligate (or indicator) species, as they’re known, include Sligo animals like wood frogs and spotted salamanders. Many other animals — called facultative species — use vernal pools as one of many habitat options. Such species in Sligo might include spring peepers, tree frogs, and American and Fowler’s toads. Other wildlife use vernal pools for water and food, including snakes, turtles, mammals, and birds.
For further information, Chris recommends An Introduction to Mid-Atlantic Seasonal Pools, published on line by the EPA ( also available in hard copy).
Report by Michael Wilpers – Natural History Committee Chair
Photos by Bruce Sidwell and Albert Hartley