Prairie Works

Ephemeral - Existing only briefly

Spring is a great (and the only) time of year to view epehemeral ponds that lay scattered in our woodlands. Ephemeral ponds, sometimes called vernal pools, are a small but important ecosystem as they harbor many different amphibians, birds and plants. They increase the local biodiversity greatly when present and are a dynamic part of woodland ecosystems.

These ponds are depressions with obstructed drainage that hold water for a short period of time following snowmelt and spring rains but typically dry out by mid-summer. Common plants of these habitats include: Yellow water crowfoot (Ranunculus flabellaris), bluejoint grass (Calamagrostis canadensis), fowl manna grass (Glyceria striata), spotted cowbane (Cicuta maculata), smartweeds (Polygonum spp.), orange jewelweed (Impatiens capensis), and sedges (Carex spp.). During their existence these plants provide critical breeding habitat for many amphibians such as frogs and salamanders.

Ephemeral ponds also provide feeding, resting and breeding habitat for songbirds and a source of food and water for many mammals. They contribute to the biodiversity of a woodland in many ways. Ephemeral ponds fit into an eco-community context by the following attributes: their placement in woodlands, isolation, small size, hydrology and length of time they hold water. Trees adjacent to ephemeral ponds provide a variety of benefits such as maintaining cool water temperatures, preventing premature drying, and adding organic matter each fall. The annual input of leaves from trees around the pool support a detritus-based food web and a support a variety of invertebrates that are part of the food web.

Here, in the Driftless Area, ephemeral ponds are not as common as they are in flatter regions and are usually found in floodplains where the land is not sloped. I have noticed that old mining holes can behave similar to an ephemeral pond, but cannot hold water for very long. These little depressions are fun to watch over the year and should be enjoyed by any birder, animal lover or plant observer. 

http://watermonitoring.uwex.edu/level3/WIephemeral.htm SE Wisconsin’s Ephemeral Pond Project

http://www.vernalpool.org/ Great Learning Resource (get a t-shirt)

http://www.epa.gov/r5water/ephemeralwetlands/ The E.P.A.’s information