Thursday, March 25, 2010

Spring Amphibian Migrations

Why did the wood frog cross the road?

NJ Audubon, partners with the NJ Fish and Wildlife Endangered and Non-game Species Program (ENSP)
and Conserve Wildlife Foundation of NJ, to study migratory movements of amphibian populations in the state

There are widespread declines in amphibian populations globally. Studying local populations can help us more effectively protect their habitats.

Amphibians often play important and keystone roles in the natural world as indicators of functioning healthy ecosystems and as part of the predator - prey relationship. Like birds, they often signify a "canary in the coal mine" because widespread declines may indicate far reaching problems in the ecosystem. Herpetologists around the world have initiated research and conservation efforts to identify problems associated with these declines and come up with solutions to counteract them. The incredibly high extinction rate of some species can be attributed to:

* Human disturbance
* Habitat destruction
* Encroachment
* Pollution
* Introduced predators

Why did that frog, toad, or salamander cross the road?  Amphibian populations require habitat with abundant food supplies, breeding areas, and hibernation sites - and they need a safe travel path between these sites.

The always increasing development here in NJ and the entire northeast continues continues to separate hibernation sites from breeding pools with road crossings that amphibians must travel.

There are some amphibians (vernal pond obligates VPOs) that can only reproduce successfully in vernal ponds. Why vernal (spring) pools?  These pools only hold water for several months in the spring, so they are not places for amphibians to "live" but their short existence also ensures that fish can not live there and so will not eat the amphibian's eggs or young.

Most of these species are moving from safer upland forests on the first warm rainy nights to these vernal ponds. There, it is amphibian dating time. They search for mates, breed and lay their eggs for the next generation.

Spring Amphibian Migration 2010 video shows volunteer training and two crossings.

These amphibians might be living in your backyard or a small woodlot near you. You probably wouldn't even notice any "road kill" as nocturnal scavengers do a good job of cleaning up the evidence by morning.

Volunteers learn how to identify amphibian crossing sites (generally historic migratory routes from past years) and conduct night surveys on suitable weather nights to look for frogs and salamanders crossing roads.

They collect amphibian mortality data for the NJ Endangered Species Program. They also act as "crossing guards" to help amphibians negotiate dangerous road crossings during the most stressful time of their life cycle.

Of course, all volunteers also act as ambassadors for the project by educating other people about what they do.

Fowler's toad

To become a volunteer, visit the ENSP website at

For more information on this effort, see

On NJ Vernal Pools
Aquatic Turtles: Sliders, Cooters, Painted, and Map Turtles
NJ Wildlife: An Introduction to Familiar Species of Birds, Mammals, Reptiles, Amphibians, Fish and Butterflies

Obligate Vernal Pool Breeding Amphibians:
Eastern tiger salamander (Ambystoma t. tigrinum) Endangered
Marbled salamander (A. opacum) Special Concern
Spotted salamander (A. maculatum)
Jefferson salamander (A. jeffersonianum) Special Concern
Blue-spotted salamander (A. laterale) Endangered
Wood frog (Rana sylvatica)
Eastern spadefoot toad (Scaphiopus holbrookii)

Facultative Vernal Pool Breeding Amphibians:
Green frog (Rana clamitans melanota)
Bullfrog (R. catesbiana)
Pickerel frog (R. palustris)
Southern leopard frog (R. utricularia)
Carpenter frog (R.virgatipes) Special Concern
Northern cricket frog (Acris crepitans)
Northern spring peeper (Psuedacris crucifer)
New Jersey chorus frog (P. triseriata kalmii)
Upland chorus frog (P. triseriata ferarium)
Northern gray treefrog (Hyla versicolor)
Southern gray treefrog (H. chrysocelis) Endangered
Pine Barrens treefrog (H. andersonii) Threatened
Four-toed salamander (Hemidactylium scutatum)
Long-tailed salamander (Eurycea l. longicauda) Threatened
American toad (Bufo americanus)
Fowler's Toad (B. fowlerii) Special Concern

In addition to amphibians, there are several reptiles that inhabit vernal pools on a seasonal basis, primarily to eat the eggs and larvae of amphibians:
Wood turtle (Glyptemys insculpta) Threatened
Spotted turtle (Clemmys guttata) Special Concern
Mud turtle (Kinosternon subrubrum)
Eastern painted turtle (Chrysemys picta picta)
Common snapping turtle (Chelydra serpentina serpentina)

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