- July 7, 2015
Sometimes called ephemeral wetlands, vernal pools are seasonal collections of water that form in depressions, usually in late winter or early spring due to snow melt, heavy rains, and subsequent rising water table. These pools are isolated from other open bodies of water. They have no above-ground outlet and tend to dry out during the summer months making them absent of breeding fish populations. Without fish as predators, vernal pools provide essential reproductive habitat for many reptiles, amphibians and invertebrates.
Vernal pools come in various shapes and sizes across the landscape. They can be found almost anywhere including low areas in forests, within a floodplain along a river or stream, in an undulating prairie or open field, in natural rock formations, and any other area where water might seasonally collect.
Small but effective pools can even be formed by deep ruts or scrapes from forestry or agriculture equipment. This variability provides numerous ephemeral wetlands of different sizes throughout the local terrain. In New Jersey alone there are an estimated 3000-5000 natural or man-made depressions holding water for at least two consecutive months of the year 1. The distribution and proximity of vernal pools deliver important habitat connectivity, making it possible for many plant and animal species to migrate and disperse across the landscape while the pools are wet.
Add a Vernal Pool to Your Map
Those lucky enough to have large properties may find they include vernal pools. If you aren’t sure, make a plan to walk your property during your next wet season. For many this will be Spring, but for others in more moderate climates (like on the West Coast), this might be during a winter rainy season.
Use the water habitat type to map vernal pools ().
Set the characteristics for this object
Once you’ve added the pool to your map make sure to set the characteristics. Click on the object, and open the infowindow to access these settings under “characteristics.”
First set “running water” to “standing” water.
2nd, set seasonality to “seasonal.”