A vernal pool. (photo by Maine Department of Environmental Protection)

by Roland D. Hallee

Like an idiot, I decided to stop into the office on my way to camp on Sunday. However, every chore has its rewards. On our way to camp afterwards, I noticed a small vernal pool in its customary spot on the Cross Hill Road, in Vassalboro. It’s always there, but it’s usually dried up during the summer. Vernal pools are a very important occurrence in our ecosystem. Let’s take a look at what actually happens there.

Vernal pools, also called vernal ponds, are temporary pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe development of amphibian and insect species unable to withstand competition or predation by fish.

Despite being dry at times, vernal pools teem with life when filled. The most obvious inhabitants are various species of breeding frogs and toads. Some salamanders also utilize vernal pools for reproduction, but the adults may visit the pool only briefly. Other notable inhabitants are Daphnia and fairy shrimp, the latter often used as an indicator species to decisively define a vernal pool. Other indicator species, at least in New England, are the wood frog, the spadefoot toad, and some species of mole salamanders. Certain plant species are also associated with vernal pools, although the particular species depend upon the region.

Vernal pools are shallow depressions that usually contain water for only part of the year. In the Northeast, vernal pools may fill during the fall and winter as the water table rises. Rain and melting snow also contribute water during the spring. Vernal pools typically dry out by mid to late summer. Although vernal pools may only contain water for a relatively short period of time, they serve as essential breeding habitat for certain species of wildlife, including salamanders and frogs. Since vernal pools dry out on a regular basis, they cannot support permanent populations of fish. The absence of fish provides an important ecological advantage for species that have adapted to vernal pools, because their eggs and young are safe from predation.

Species that must have access to vernal pools in order to survive and reproduce are known as “obligate” vernal pool species. In Maine, obligate vernal pool species include wood frogs, spotted and blue-spotted salamanders (two types of mole salamanders) and fairy shrimp. While wood frogs and mole salamanders live most of their lives in uplands, they must return to vernal pools to mate and lay their eggs. The eggs and young of these amphibians develop in the pools until they are mature enough to migrate to adjacent uplands. Fairy shrimp are small crustaceans which spend their entire life cycle in vernal pools, and have adapted to constantly changing environmental conditions. Fairy shrimp egg cases remain on the pool bottom even after all water has disappeared. The eggs can survive long periods of drying and freezing, but will hatch in late winter or early spring when water returns to the pool.

Not all vernal pool habitats are considered “significant”. In general, a vernal pool habitat is significant if it has a high habitat value, either because a state-listed threatened or endangered species, such as a spotted turtle, or a rare species, such as a ribbon snake, uses it to complete a critical part of its life history, or there is a notable abundance of specific wildlife, such as blue spotted salamander, wood frog, or fairy shrimp.

Do you have a vernal pool on your property and don’t know whether it is significant? The specific criteria describing a significant vernal pool are listed in DEP Rules, Chapter 335, and allow these resources to be identified in the field. Using these criteria, a person who has experience and training in either wetland ecology or wildlife ecology may identify and document a significant vernal pool; or the DEP may provide a written determination concerning whether or not a vernal pool habitat is significant.

“Significant vernal pool habitat” includes the vernal pool itself and the area within a 250-foot radius of the spring or fall high water mark of the pool, which is considered critical terrestrial habitat.

Since September 1, 2007, significant vernal pool habitat is protected by law under the Natural Resources Protection Act (NRPA). An activity in, on, or over these areas must avoid unreasonable impacts on the significant vernal pool habitat and obtain approval from the DEP, through a Permit by Rule or individual NRPA approval.

A permit by rule will be available if certain standards are met, and can be approved within 14 days. The standards do not create a mandatory setback or no-build zone, but do affect what can be done, so it is advisable to plan ahead. For more information on the NRPA, a copy of the rules addressing significant vernal pools, application forms, and related materials, see the NRPA page.

If you have questions, need hard copies of materials, or would like to request a field determination, contact your nearest DEP regional office, and ask to speak to the “on-call” person in the Land & Water Bureau, Division of Land Resource Regulation.

The Central Maine Regional Office is located at 17 State House Station, Augusta, ME 04333-0017; Phone: 207-287-7688 or 1-800-452-1942.

Roland’s trivia question of the week:

Which pitcher, who started for the Red Sox in the 1986 World Series, later enjoyed success coaching the Chinese national team?

Answer can be found here.

Left, the pumpkin bug or squash bug. Right, the brown marmorated stink bug.

by Roland D. Hallee

I have seen this bug around my house recently – like two in the last couple of weeks – and I was wondering what it was. I’ve seen it many times before, and merely dealt with it. But this time, my curiosity was peaked, and it was time to find out who these little critters are. Turns out they are called pumpkin bugs, or squash bugs.

The pumpkin bug, or squash bug, are also called stink bugs, but are not the traditional stink bug. Although some pumpkin bugs are called stink bugs, not all stink bugs are pumpkin bugs. If you ever spot a sizable green stink bug, there’s a good chance that it’s a pumpkin bug. They are similar in appearance to stink bugs because they both have a foul odor when squashed. However, stink bugs are wider and rounder.

The squash bug, Anasa tristis, is common throughout the United States. It primarily attacks squash and pumpkins but can also attack other cucurbits, such as cucumbers.

They are the bane of a gardener. They are difficult to kill and can cause a lot of havoc.

The adult bugs are somewhat flat, large insects, measuring 5/8 inch long and 1/3 inch wide. They are usually dark gray to dark brown. The edges of the abdomens protrude beyond their wings and typically have alternating orangish and brown stripes. They are able to fly, however they often simply walk around on plants.

These bugs overwinter as adults in sheltered places, such as under plant debris, around buildings, or under rocks. When adults emerge in the spring, they fly to growing cucurbit plants to feed and mate. Females lay eggs individually in small clusters of about 20 commonly on the undersides of the leaves, especially between the veins where they form a V. The females usually begin to appear in gardens in early June, and continue to lay eggs through mid-summer.

These bugs have piercing-sucking mouthparts they use to suck the sap out of leaves. This process produces yellow spots that eventually turn brown, and disrupts the flow of water and nutrients, which can cause wilting. Young plants are more susceptible to extensive damage. Larger, more vigorous plants are more tolerant of feeding damage, although they can also be injured or killed if they are severely attacked.

These bugs inject a toxin into the plant and suck the sap right out of it with their sharp mouthparts. This causes yellow spots that eventually turn brown. The leaves will wilt because the damage prevents the flow of nutrients to the leaves, and then they will dry up and turn black.

The most important times to control squash bugs are when the plants are young seedlings and when they are flowering. Early detection is important because adult squash bugs are difficult to kill.

Remove or knock off and kill nymphs and adults by dropping them into a bucket of soapy water. This can be challenging because the bugs hide under leaves and move quickly when disturbed.

Crush the eggs that are attached to the undersides and stems of leaves.

Trap the bugs by laying out boards or pieces of newspaper. The bugs will congregate under the boards at night, and then can be collected and destroyed in the morning.

Check your plants daily. If there are no more than a few vines infected, keep collecting and destroying the bugs and crushing the egg clusters that you find.

Insecticides are not generally needed to control these bugs. They can be used if cucurbits are found wilting early in the season. Carbaryl/Sevin, is most effective if applied when eggs are hatching. Consult your local garden center for controls that are locally approved. When using an insecticide, make sure to read the instructions well.

Planting time is approaching. Make sure your garden is free of these little pests. There is no worse feeling than seeing your plants being destroyed and you have no idea what is causing it. Check under the leaves.

Roland’s trivia question of the week:

In addition to pitching a one-hitter in game two of the 1967 World Series, who became the first Red Sox pitcher to win the AL Cy Young Award in 1967?

Answer can be found here.