If you have visited one of HLT’s preserves in the spring, you may have noticed shallow depressions in the ground filled with water, and perhaps even seen tadpoles meandering through the mud. These areas are known as vernal pools, so named because they only hold water for part of the year, often drying up in the summer months. This seasonal drying pattern means that fish, which need water year-round, cannot survive in them.

Vernal pools are therefore a crucial home for many reptiles, amphibians, and invertebrates as a safe place to lay eggs and for young to grow without risk of fish predators.

These pools also serve as a seasonal source of water for a variety of birds, mammals, and other wildlife, and the forests surrounding the pools are crucial habitat during periods when the pools are dry.


In addition to the importance of vernal pools for wildlife, they also benefit our water quality and groundwater recharge, and help to prevent flooding. As with other types of wetlands, vernal pools filter out pollutants from the water that passes through them. By capturing runoff and slowly releasing it to groundwater, vernal pools are a beneficial tool that prevent flooding in significant rain events.

HLT has experienced the benefits of vernal pools firsthand! As part of the restoration of Walnut Brook at the Dvoor Farm last fall, we installed five vernal pools in the floodplain, with the aim that they would help to absorb water and prevent flooding during extreme rain events. This July, Walnut Brook overtopped its banks for the first time since the restoration, and the vernal pools did their job – they took on enough of the overflow to prevent any significant flooding.

If you visit our Idell Preserve in Kingwood Township, you will see many vernal pools along the trail. In the spring and summer, keep an eye out for egg masses and tadpoles, and listen for frog calls.

We invite you to share your observations with us, either through the iNaturalist app or by contacting us directly to share your findings. Gathering more information on the species that call our preserves home will empower us to manage these special places to benefit wildlife.

The benefits of vernal pools also rely heavily on the health of the forests surrounding them! By removing invasive species and fostering a healthy understory, we aim to improve the entire ecosystem’s health.

We welcome your help with these efforts at our monthly Stewardship Saturdays, when we come together to accomplish a variety of stewardship tasks. By supporting HLT, whether through your time or a donation, you are joining our efforts to protect these unique habitats and the many critters that depend on them.

We encourage you to join us on Sunday, October 22 at 8 a.m. for our free fall migratory birding event at the Idell Preserve. Register by emailing dave@hunterdonlandtrust.org.