Abstract: Vernal pools are temporary, depressional wetlands associated with a unique and specialized flora and fauna. Because of their small size and temporary hydrology, vernal pools are vulnerable to loss and degradation due to urbanization, agriculture, invasive species, and climate change. This has led to mitigation efforts that often rely on vernal pool creation or restoration. However, much uncertainty remains about whether created and restored pools replace function lost in the destruction of natural pools. The fact that several vernal pool restoration and creation attempts in eastern Pennsylvania and New Jersey have been paired with conservation of natural pools in the same area provided a valuable research opportunity to compare amphibian habitat quality between project sites and natural, reference pools. Monitoring of five natural, four restored, and six created pools distributed over four sites in eastern Pennsylvania and New Jersey began in 2017 and is ongoing. The 15 vernal pools vary not only in terms of type (created, restored, and natural), hydroperiod, and depression characteristics but also in terms of extent of surrounding habitat fragmentation by roads. The initial goal of this research was to compare various within-pool and upland characteristics among pool types and evaluate correlations between these parameters and reproductive success of the wood frog and spotted salamander (Ambystoma maculatum), both obligate vernal pool-breeding amphibians. More recently, microsatellite DNA markers were used to examine the correlation between habitat features in the upland area surrounding vernal pools (e.g., road density and proximity, canopy cover) and wood frog genetic differentiation. Although many previous studies indicate that restored and created pools rarely replace function lost in the destruction of natural pools, success of vernal pool indicator species was not necessarily related to pool type in this study. Pool depth, volume, hydroperiod, and predator abundance were among the best predictors of amphibian reproductive success, regardless of pool type. Population genetic diversity of wood frogs was high, and there was a comparable degree of population differentiation at sites with high and low road density, suggesting high connectivity among populations. Applications of this research include isolation of environmental factors that are most important for native species success and evaluation of different vernal pool creation and restoration strategies to guide future projects. Longer-term goals of this project include establishing partnerships with park managers at these sites and engaging citizen scientists to participate in active restoration and post-restoration monitoring of vernal pools.
