Fish are top predators in wetlands, but they can’t survive in pools that dry out.. As a result, vernal pools provide key breeding habitat for amphibians whose tadpoles and larvae are especially vulnerable to fish predation: wood frogs, spotted, blue-spotted, and Jefferson’s salamanders. In the spring, these amphibians migrate from nearby woodlands to vernal pools– where they breed and deposit their eggs. Once hatched, tadpoles and larvae develop quickly into young frogs and salamanders that must leave the wetland before it dries up – by early or mid-summer for wood frogs, or by late summer or early autumn for salamanders.
Photo credit: Michael Marchand, NH Fish & Game

Other species besides amphibians use vernal pools as habitat. Fairy shrimp (at right) are small crustaceans that require vernal pools for breeding. Spotted and Blanding’s turtles, great blue herons, raccoons and predatory insects travel to vernal pools to feed on amphibian eggs, tadpoles, insects and crustaceans in the pools.

Photo credit: Timothy Beaulieu

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Threats from
development

The impact of human development on vernal pools is the most significant threat to these habitats and their associated wildlife. Development, road-building and re-grading of land can fill and destroy vernal pools, causing immediate loss of habitat and (for some species) permanent loss of populations. Many amphibians breed in the pools where they hatched, returning to the same pool every year. If one pool is lost, the pool’s returning amphibians may be lost as well. Although many vernal pools meet the state regulatory definition of a wetland, some pools either don’t meet the definition (for example, no vegetation) or are overlooked during wetlands’ mapping due to their small size and isolation. If construction of a new development will affect wetlands, it is often the small pools which are chosen to be filled.

The species listed here are closely associated with vernal pools, but many other wildlife species will use vernal pools at some time of the year for breeding or foraging. Species of conservation concern--those wildlife species identified in the NH Wildlife Action Plan as having the greatest need of conservation--appear in bold typeface with links to their species profile from the Plan.

NH Fish & Game publishes a website about reptiles & amphibians in NH with identification photos for all species. Many of the links below connect to these Fish & Game webpages.

NH Fish & Game

• Work with the New Hampshire Fish and Game Department to identify and map the vernal pools on your land or in your town (contact the Wildlife Division at 603-271-2461 or read more here).
  
• New Hampshire Fish and Game tracks all sightings of rare reptiles and amphibians. Report any sightings you make to the New Hampshire Reptile and Amphibian Reporting Program (links to New Hampshire Fish & Game webpage).
• To conserve the greatest diversity of amphibians, focus conservation efforts on areas containing a variety of wetlands such as vernal pools and others that hold water all year long. Keep in mind:
  

  - Isolated pools (without inlet or outlet) are less likely to have fish. - Small pools can have just as many (or more) breeding amphibians as larger wetlands—size isn’t a good measure of habitat value. - Most amphibians require wetlands that hold water at least four months. - Pools that hold water for four to 11 months (including permanent wetlands) help protect against complete reproductive failures in more seasonal pools during dry years. - Pools that hold water less than four months can still serve as foraging sites, as wood frog breeding sites, as habitat for insects and crustaceans, and as stepping stones for amphibians migrating to new habitats. - Clusters of vernal pools may be more productive for wildlife than single, isolated pools.

• When conducting any work near vernal pools, avoid creating ruts and skid roads that collect or change the flow of water. Through runoff, these disturbances can influence the timing of wet/dry periods in a vernal pool, altering the species that can breed there.
  
• To avoid changing the pool’s ability to hold water, don’t run heavy machinery through vernal pool basins (wet or dry).
  
• Avoid clearcuts in or around vernal pools. Removing the shade of the tree canopy can heat up the air, soil and water in the pool, change the period of time that water remains in the pool, and influence which species can survive there.
  
• In upland areas within 300 feet of a pool, and in corridors between vernal pools, retain ground cover (logs, surface stones, deep leaf-litter) as cover for amphibians, and maintain a moist environment on the forest floor by retaining patches of canopy shade.
  
• Consult a licensed New Hampshire forester before conducting a timber harvest on your property. Understand and follow all laws pertaining to tree harvesting near wetlands and waterbodies. Many vernal pools qualify as wetlands by New Hampshire state regulations.
  
• Follow established Best Management Practices, and harvest timber near vernal pools only when the soils are either frozen (winter) or very dry (summer).
  
• The quality of the uplands that surround vernal pools has a strong impact on the diversity of the vernal pool. When possible, keep development, roads, and driveways at least 300 yards away from vernal pools (and other wetlands).
  
• When planning new roads or upgrades that bisect known amphibian and reptile migration corridors (especially for such species as Blanding’s turtles, marbled or Jefferson salamanders), consider incorporating tunnel crossings under roads with accompanying drift fencing to minimize deaths among these animals during migration.
  
• Zoning ordinances that promote cluster development can help preserve natural lands and and/or wetlands.

• NH Wetlands Regulations related to Vernal Pools - Link to the NH Department of Environmental Services webpage on vernal pools.

• Learn more about Reptiles & Amphibians in New Hampshire - Link to the NH Fish & Game Department's "Reptile & Amphibian Reporting Program," and learn about identifying species, learning frog calls, and how you can help conserve New Hampshire's snakes, frogs, salamanders, and toads.