PROGRAM | Entomology and Wildlife Ecology

By: Nathan Nazdrowicz Chair: Jacob Bowman

ABSTRACT

I investigated the natural history, ecology, and distribution of eastern long-tailed salamanders (Eurycea longicauda longicauda) because biological information for developing conservation strategies is lacking. On the piedmont of the Delaware Valley in New Castle County, Delaware, and Chester and Delaware Counties, Pennsylvania, populations of eastern long-tailed salamanders may be found associated with springhouses.  Eastern long-tailed salamanders utilize the spring within springhouses for reproduction and to overwinter, and their activity cycle occurs as a regular migration between terrestrial and subterranean habitats.  Adults begin movements into springhouses in August with males arriving before females, while immature individuals remain active in terrestrial habitats until November.  Within springhouses, mating occurs prior to moving deeper within the spring to overwinter.  Eggs are laid singly underwater usually in November and December and females do not exhibit parental care of the eggs.  Rather, females scatter eggs and choose oviposition sites to maximize survival.  Subsurface spring habitats have few predators and sites are selected that maximize surface area of the egg exposed to water to allow for gas exchange.  Adults emerge from overwintering in late April and migrate to surface habitats.  Eggs hatch after approximately 7-9 weeks and larvae migrate to surface streams in March.  Larvae metamorphose from May to August, although on rare occasions overwintering of larvae occurs.  Population estimates per springhouse ranged from 40-49 to 1216-1456 adult salamanders per year, with three study sites showing stable populations, one population declining, and one population increasing during the time of the study.  Sex ratio was even to male biased and juveniles comprised 11% to 35% of the total population per year on average.  The majority (90%) of adult males and females in the population were captured inside springhouses and during the breeding season (15 July to 30 November).  Recapture rate for males and females ≥ 4.5 cm ranged from 0.19 to 0.48; however, recapture rate for unknown sex of this size was ≤ 0.10, suggesting the dispersal cohort arises from this group.  Occupancy of springhouses was related to landscape scale factors such as forest area, distance to nearest forest, total stream length, and total road length suggesting that habitat quantity and connectivity are an important components influencing eastern long-tailed salamander distributions.  Species conservation might best be achieved by maintaining forest tract corridors between and near springheads.  If springhouses are present, I suggest maintaining or restoring these structures in a manner that minimizes drafts and reduces or eliminates light.  I suggest managers or researchers interested in quantifying eastern long-tailed salamander population abundances to concentrate capture effort inside springhouses during the breeding season.

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