Vernon's Vernal Pools

 Wayne and I went on an egg hunt this week. I suppose that doesn't seem like such an odd thing the first full week of April; but what I was hoping to find was a few vernal pools filled with the sort of creatures that lay eggs in the water.

Vernal pools are an affirmation of spring here in Vernon. It's not all that unusual, once the late March snow turns to mud, for children and adults alike to be drawn to these seasonal pools in forest and field to search for amphibians. With last year's extended drought and upon noticing that in March, the vernal pool across the street appeared empty, I decided to pay a visit to the pool adjacent to the eastern shore of Lily pond. Though the pond looked to be at a good July 4th level, the pool seemed oddly small. I began to wonder what happens in years when depressions in the spring earth fail to fill with snow melt. Thoroughly stumped, I decided to "phone a friend" and ask. Taylor, a university student who has a special interest in and has worked with amphibians, said that adults will return to the same pools each year so dryer years are stressful. If there is another pool in better condition close by, some may hop on over to it but the entire population may be lost when an area is especially dry. 

"The average distance that a Spotted Salamander moves from a pool into the surrounding forest is 386 feet. Jefferson Salamanders may travel 471 feet..."*

Sometime ago along my nature journeys, I learned one of the most curious facts that I know about the inhabitants of vernal pools. Salamander nymphs, tadpoles and the like, somehow know when their pool is going to dry up. If the pool dries up earlier the amphibians will speed up development and emerge as a smaller adult. In years where the pools remain longer, development is slower and larger adults emerge. I think it's the same thing with long winters and me too.

As if I wasn't already concerned enough, Vernon's Fire Warden John E Wheeldon posted on our Vernon Facebook site, that a burn ban was in effect. With the odds seemingly stacking up against a bountiful season, we decided late in the afternoon to check out the situation again.

Why are vernal pools important anyway? Couldn't a Four Toed Salamander just as easily lay its eggs in the pond as in an adjacent vernal pool? Well, as anyone who has ever caught a pickerel ice fishing in the pond knows, a fish has got to eat! Since vernal pools are seasonal and don't have a tributary or distributary, fish can't access them nor can they survive in them . This creates the ideal nursery because without a way in, there aren't any fish to eat the amphibian's eggs.** Of course other threats exist to and within the pools and I can just hear Wayne in my head right now quipping, "It's a numbers game!"  While I have been focused on amphibians, NH Extension  lists twenty two species of insects, reptiles, amphibians, and crustaceans found in vernal pools. Additionally VT  Government wetlands document Seeps and Vernal Pools states it as a habitat for mollusk and copepod populations as well. 

One more confession before moving on, though I always associate vernal pools with the spring melt, the depressions fill in both the spring and the fall. I have kept you in suspense long enough. Our first indication that we were on the right path was this man made drainage system. 

Surely this is the sign I have been waiting for!

We quickly found the first vernal pool after walking on a slightly squishy part of the trail. Vernal Pools have plenty of fauna, but the general lack of presence of flora in the cup shaped basin with thick organic matter is one way to identify a vernal pool in the dry season. If flora is present within the basin, it is typically scattered. ****

The second area with standing water was elongated looking more like several pools joined together.  The soil around it was very wet. I'm unsure if this low wet land remains wet all year or dries up in the summer months. I have been concerned about this area as it has been re designated for a snowmobile trail. I don't think this is a problem in the winter with frozen ground, but four wheelers in this area is another matter.  As noted on page 308 in Seeps and Vernal Pools, "alteration of the depression substrate may affect its ability to hold water and disrupts the eggs and other drought resistant stages of Invertebrate life that form the base of the vernal pool food chain."* Additionally, compression on wet soil creates impassable ridges for small migrating wildlife as well as introduction of silt through erosion.*

Ruts from a four wheeler impacts not only the the food chain within vernal pools and wetlands, but they also inhibit movement within them as well as to and from them. 

This dry leaf and twig filled downward slope was dry even when I removed a few inches of cover

To the right of the above path was a third pool

 About 50 percent of plastics manufactured each year reaches the landfill and around ten percent of plastic is recycled. Micro plastic is in our food chain and found in over 300 aquatic organisms.***

A single use plastic bag floats in the small brook that flows through the area.

It's easy to see how wildlife can become ensnared in plastic or sickened from consuming it. Wayne also found a length of fishing line on the ground which is particularly problematic due to the ease in which it entangles wildlife. 

A critter found this egg before Wayne and I did!

In all we found nine eggs and parts of eggs. Wayne even found one still filled with candy.

One last vernal pool

One last piece of plastic

And a nearby trash can 

I'm not too worried about this area being picked up this spring as I know the caretakers and I know that they will be focusing on maintenance soon. The disappointment of finding trash on the trail was measured by my relief in confirming that this area of Vernon looks to have filled pools in spite of the condition of others in town. There is also new development near this area and that can be devastating to the wetlands if conservation measures are not taken to prevent negatively impacting them and this includes safeguards when clearing the land **** Responsible use of wetlands and land near to wetlands,  including seasonally dry ones like vernal pools, will help ensure that our wildlife both common and those of special concern will have a place to live and breed for years to come. 

So is "Wetland Season" a real thing? In my estimation no. While we may be more aware of wetlands when the Spring Peepers are serenading, our work of ensuring that these vital habitats remain healthy is a year round commitment to thoughtful stewardship. -Norma Manning 

Addendum; We found an egg filled pool in the RBWMA while hiking from Miller Farm to the town forest. Pictures of the poos and eggs are included in my subsequent blog 

Resources:

*Vermont Government Wetlands, Seeps and Vernal Pools

 ** UNH Extension, Vernal Pools

*** VPR Tiny Plastics Could Cause Big Problems in Vermont's Waters

****Good Forestry in the Granite State, Vernal Pools and the Surrounding Forest

 Bio Kids, Spring Peepers

Lang Elliott Music of Nature, Calls of Frogs and Toads of the Northeast.

*****WCS, Conserving Pool Breeding Amphibians in residential and commercial Developments in the Northeastern United States

Further consideration, "It is important to note....vernal pool is only one type of significant amphibian breeding habitat. Many types of wetland including forested swamps, marshes, margins of VT ponds, lakes and even man made farm ponds" *****

A Spring Peeper calls out in a Vernon wetland