After 529 Releases, Zoo New England Stopped. The Salamanders Stayed.

Marbled Salamanders Reappear in Massachusetts After Multi-Decade Disappearance

Marbled salamanders were once common in Middlesex Fells, Massachusetts. Unfortunately, as the region expanded and became more urbanized, the salamanders suffered. By the 1930s, the marbled salamander was locally extinct in the Fells.

Thanks to conservation efforts spurred by Zoo New England, marbled salamanders are now once again found in Middlesex Fells and appear to be reproducing successfully.

Recently, staff from Zoo New England traveled to Middlesex Fells after an afternoon rain, hoping to see a few marbled salamanders near vernal pools. If the salamanders were near the pools, they might lay eggs, since it is breeding season.

What the staff found far exceeded their expectations. There were 15 marbled salamanders near vernal pools, including a vernal pool never before used by the salamanders. According to Matthew Kamm, Zoo New England Associate Director of Field Conservation, seeing these salamanders is proof that conservation efforts have paid off.

“The recent sightings show us that our reintroduction efforts have worked, and that salamanders are persisting at this site even though we have not released salamanders here since 2024,” Kamm explained to Zoo New England. “This is a conservation success story showing that rare species can be brought back given sufficient protected habitat and a collaborative approach.”

How Conservationists Helped Marbled Salamanders Reclaim Middlesex Fells

By the 2010s, Middlesex Fells was determined to be marbled salamander-friendly. However, fragmentation prevented the salamanders from returning to their native habitat. To help the salamanders, Zoo New England began a multi-year, multi-agency project in 2016 to help marbled salamanders become self-sustaining in the region again.

With help from MassWildlife, Friends of the Fells, and local schoolchildren, Zoo New England began collecting newly hatched marbled salamander larvae from vernal pools in western Massachusetts. This helped ensure the salamanders survived to become juveniles.

As the juveniles were released, each step was carefully planned and monitored. Juveniles with similar genetic backgrounds were placed in separate locations to reduce the risk of inbreeding. Conservationists placed juveniles near predator-free vernal pools to help eggs and, later, larvae survive.

In total, 529 marbled salamanders were released in Middlesex Fells between 2016 and 2024. After several years, researchers finally found marbled salamander larvae alive and thriving in vernal pools at Middlesex Fells.

Marbled Salamanders Had Not Been Released in Middlesex Fells for Two Years

For nearly a decade, conservationists at Zoo New England have worked with local schools, Friends of the Fells, and MassWildlife to bring marbled salamanders back to Middlesex Fells. However, this work ended in 2024, and no salamanders have been released since then.

Marbled salamanders have not been released since 2024. This is because the work that began in 2016 to help them reestablish their presence in Middlesex Fells paid off. In 2023, marbled salamander larvae hatched in vernal pools for the first time in over nine decades. This meant the salamander population was sustaining itself. Human intervention was no longer needed.

While conservationists continue to monitor the marbled salamander population in Middlesex Fells, the salamanders have demonstrated that they can thrive when their habitat is restored.

Why Did the Marbled Salamander Go Locally Extinct?

Up until the 1930s, marbled salamanders were commonplace in Middlesex Fells, according to Zoo New England. Unfortunately, as urbanization increased, people did not consider the salamanders’ needs. This led to the marbled salamander’s localized extinction for nearly a century.

Urbanization in Middlesex Fells began in the 19th century. As more people moved into the marbled salamanders’ environment, there was no space for the salamanders to survive. Because of habitat fragmentation and the destruction of vernal pools, marbled salamanders could not survive in the area.

Even after the Middlesex Fells Reservation was established in 1893, the damage had already been done. Deforestation and industrial development had removed the trees and ground cover that salamanders needed.

Even as the forest began to recover, marbled salamanders could not return to their native habitat because it remained too fragmented. Their habitat was too fragmented. There were no habitat corridors to allow salamanders to move between suitable areas. Consequently, populations remained isolated from one another for decades.

Threats Marbled Salamanders Face Today

Although marbled salamanders are considered a species of least concern globally, populations are declining or threatened in some regions, and threats still exist. If these threats are not addressed, salamander populations could face further declines.

The current threats that marbled salamanders face today include:

• Climate change
• Drought
• Habitat loss
• Disease
• Predation

It may not be possible to protect marbled salamanders from every threat they face. But as has been proven with the marbled salamanders in Middlesex Fells, when given suitable habitat, salamanders can recover and reproduce.