depressions also occur in Rhode Island and throughout the Northeast.
Though the name vernal pool/ pond has long been adopted, the terminology
may not be totally appropriate for southern New England, as some
ponds fill up with water in the late fall (actually 'autumnal'
ponds). Furthermore, in the northeast, the geologic factors that
determine where on the landscape seasonally-flooded pools occur
is poorly understood.
Nevertheless, the term
'vernal pool' has stuck and the definition remains inconsistent
across the country, as well as, from state to state throughout
the region. This webpage addresses this issue by listing some
of the various definitions.
Two vernal pool studies
currently underway at the university - one led by Dr. Peter Paton
and another by Dr. Frank Golet (URI Dept. of Natural Resources
Science) - are looking at vernal pools in Rhode Island and their
relationship to geology, hydrology, vegetation, and other landscape
aspects. The focus of Paton's research however is amphibians.
Vernal pools can be
rich amphibian breeding areas. In Rhode Island wood frogs,
spotted salamanders, marbled salamanders, and, to a lesser degree,
gray treefrogs, spring peepers, American toads, and red-spotted
newts rely heavily on vernal pools to complete their breeding
cycle. What appears to be one of the most important factors determining
which species are found in a given pond is the length of time
that surface water inundates the pond (termed "hydroperiod").
Fewer species are able to exist in ponds that dry up relatively
rapidly and many species of amphibians avoid ponds that are flooded
throughout the year. Permanent ponds tend to have fish populations,
which are major predators of young amphibians. When you
look at the accompanying life histories,
one of the most important figures to study is the relationship
between hydroperiod and the probability of detecting a species.
Species such as wood frog prefer pools that dry up each year,
whereas bullfrog can only breed successfully in ponds with water