Ecology and Vulnerability

Marbled Salamander

Background
Marbled salamanders are distributed across the eastern US from New Hampshire to northern Florida, and west to Lake Michigan in the north and Texas in the south¹. The species generally inhabits deciduous forest and prairie and is absent from much of the Appalachian Mountains^1,2. In Massachusetts, it is present at relatively low abundances, (partially due to being at the extreme northern limit of its range), and is listed as "threatened" in Massachusetts³. Marbled salamanders breed in vernal pools, which are temporary, fishless ponds². Unlike other vernal pool breeding salamanders, marbled salamanders migrate to pools in late summer and early fall when pools are dry or nearly dry. Eggs are deposited in dry portions of the pool and guarded by females until pools fill with the onset of autumn rains. Eggs hatch soon after they are flooded and larvae will overwinter beneath the ice in the pool⁴. Adults are terrestrial and retreat to higher ground surrounding breeding ponds for most of the year³. Marbled salamanders exhibit a high degree of philopatry, meaning they return to the ponds where they were born to breed⁶. However, a small percentage will disperse to different ponds, creating connections between different pond populations. Dispersal appears to be more frequent in contiguous forest habitats. Increasing development leads to isolation of populations⁷.

Climate Impacts
The species is at the northern end of its range in Massachusetts, and it is likely that a warming climate will result in expansion of the range northward⁵. High winter pond temperatures were found to significantly increase overwinter survival of larvae in southern New Hampshire. In addition, larvae are absent from ponds that freeze solid, suggesting that warmer temperatures could enhance available winter habitat as well as overwinter survival⁵.

However, higher temperatures and changes in precipitation patterns have the potential to reduce reproductive success and population sizes, and may affect the distribution of marbled salamanders in Massachusetts. Marbled salamanders are dependent on very specific pool hydrology for reproduction. Climate projections for the Northeast suggest that higher temperatures and a longer growing season will lead to increases in evapotranspiration (evaporation and transpiration from plants)⁸. These changes are expected to increase the frequency of short-term drought conditions, which is likely to reduce the amount of time vernal pools hold water.  Changes in precipitation patterns that affect the timing of when pools fill with water or the volume of water in the pools over winter could negatively affect breeding success for this species.