Growth and Development of Spotted Salamander, Ambystoma maculatum Larvae in Relation to Vernal Pool Size and Hydroperiod

Matthew Hanbury

Biology

Rebecca Hale

Vernal pools are seasonal wetlands that provide important habitat for regional biodiversity and are an essential reproductive environment for many amphibians. Importantly, these ephemeral wetlands are increasingly susceptible to drought and flooding events, which may be influenced by the hydrological impacts of urbanization and climate change. Yet, little is known about how fluctuation in the hydroperiod of these pools could affect the development and survival of the species that depend on this habitat. Vernal pools typically dry up in mid-summer and refill by late winter; however, if these habitats dry up too early, during the aquatic phase of developing amphibian larvae, this could impact the developmental rate and survival of larvae and metamorphs. In this study we investigated whether the rate of larval development differs among breeding pools experiencing different hydroperiods. Four isolated vernal pools were selected differing in size and depth. Each pool served as a breeding site evidenced by the presence of spotted salamander egg masses. We measured the length, width, and depth of each pool in weekly intervals. Each week, we collected three random cylinder trap samples from each pool, identified animals sampled, and noted developmental stage and size of the salamander larvae collected. Results showed no significant difference in larval growth or development among pools, although all pools had dried temporarily in mid-May for several weeks, potentially impacting development rate and our sample size. Larvae from all pools presumably never fully metamorphosed, suggesting all four ponds were population sinks due to their short hydroperiod this year.

Jan-9-2024