No Fish Allowed

Snow melts into spring puddles, but not all puddles are equal. Some will awaken or draw in a rich diversity of wildlife. With diversity comes some unique creatures, from salamanders to small crustaceans, like the fairy shrimp, which depend on these specialized puddles to live. These pools of water can be small in size, as a puddle, or large, like a pond. They are generally temporary, drying up by mid- to late summer, and do not have an inlet or outlet—the snowmelt and/or rainwater are the keys to starting up this annual, temporal ecological community. This annual cycle starts in the spring; hence these pools of water and life are commonly referred to as vernal pools (vernal meaning spring, new). This amazing fairy shrimp photo was taken by Ken-ichi Ueda.

Fairy Shrimp by Ken-ichi Ueda

While they are fresh and new each spring, vernal pools “reappear” on the same ground year after year. They occupy low spots in the field or forest having an impermeable soil layer to hold water long enough for insects and amphibians to transition quickly from eggs, to juveniles, to adults. While not drying out too quick is crucial, equally as crucial is that fish are not a part of the community. A vernal pool's unique creatures would not survive a fish predator's appetite.  

Vernal pools are wonderful places to explore and observe nature. Do you have one on your property? It’s worth knowing, and they’re worth protecting, as they are a big boost to your land’s biodiversity value. Make a note of spring puddles and pools and track them through the year; do they dry out by summer’s start, are they never really dry and part of a flowing wetland marsh/wet meadow system, or do they just slowly shrink in size so there is only a little water or just some water stained leaves left by summer’s end? Here is a more technical document to help you better understand how to identify a vernal pool. If you can document vernal pool loving creatures, say finding egg masses from wood frogs or salamanders, then there is a very good chance that you have a vernal pool.

No vernal pool? You could create one and create habitat for a rare species like a Copperbelly Water Snake. Creating a vernal pool can be accomplished using hand tools, but larger pools require heavy machinery. Don’t tear up an existing wetland, but site it someplace where the soils are compacted or have a clay layer or else you’ll need to use a liner. As with most habitat improvement projects, if you are really motivated it can be DIY. If that is you, here is a resource, and—of course—check your local regulations before you dig. Make sure it won't dry out too quickly (see this resource)! For the rest of us, please reach out to a RML consultant that offers herpetological services or your state’s natural resource department to get their assistance. Some foresters may be able to help you, too; a logging operation may be a good time to create a vernal pool.

Fairy Shrimp by Ken-ichi Ueda

Photo at left: a vernal pool my family has started monitoring for the Michigan Natural Features Inventory.

One more thing about vernal pools is that they are diverse and far ranging; from Californians who can watch plants growing in winter, to me in northern Michigan with snow still falling in April, we all have vernal pools to explore. Do explore, but please take these precautions due to the sensitive animal life:

-  Limit the amount of time in a vernal pool and try not to make big ruts, a.k.a. footprints in the soft soils around the pools.

-  Scrub boots, preferably with disinfectant, (rinsed off away from the pool!) before entering a vernal pool to prevent spreading disease to the pool’s amphibian inhabitants.

-  Wash hands of lotions and bug spray before handling any eggs or frogs if needed for making an observation.

Fairy Shrimp at vernal pool in Ohio - photo by Doug Berube

Salamander egg mass at a vernal pool in Michigan