Ephemeral pools, Vernal ponds, Woodland pools, Seasonal pools are essentially one and the same so to speak. These are other names for what I am referring to as a Vernal Pool. These are low lying areas, depressions, that collect and hold rain water for intermittent periods of time but are not permanent. These areas may fill and dry out several times during a single year. Think shallow areas like the one pictured. Usually less than a couple feet in depth and the overall size of the total pool may vary greatly.
The pool pictured was located on my former Cat Spring Texas Ranch and is approximately 18 inches deep in the center. The life span of these pools obviously changes with the seasons. In most years this particular pool would hold water for several months after average rainfall events. If a heavy rainfall event occurred in August, this pool would usually remain about 3-4 weeks.
During these brief, extended or cyclical periods of inundation, Vernal pools provide unique habitat for multiple species of both plants and animals that have adapted their life cycles to these changing conditions. When completely dry on the surface these areas hold the seeds, eggs, and dormant plants and animals patiently awaiting the next accumulation of fresh rain water or runoff.
These are essentially mini wildlife magnets. Vernal pools can be found in forested settings as well as open pastures.
This particular pool pictured is a hybrid between being a naturally occurring pool and a man made pool. I enhanced/enlarged an existing depression with a small tractor and box blade during the dry season. This pool supported crawfish, multiple species of frogs, Mosquito fish and what we call a Texas MudPuppy , a species of "Salamander".
A game camera set in this location revealed multiple species of wading birds and mammals including deer, coyotes, bobcats utilizing the mini Oasis. Fragrant clusters of Texas Spider Lily would appear in early spring. This location on the property was rotationally grazed by cattle during dry periods only with the intent to protect this seasonal habitat.
Many Brenham Texas area properties will have what is sometimes referred to as "marginal or woodland waste" acres. These areas often have Vernal pools and hold great opportunity for the Naturalist at heart!