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Location Pond-breeding amphibian habitat suitability near municipal well fields in southern Rhode Island

  • Student: Michael J. Narcisi
  • Institution: The University of Rhode Island
  • Degree: M.Sc.
  • Posted on: December 28, 2012

Thesis Abstract

I investigated whether seasonal ponds located near municipal wells have shorter
hydroperiods and provide less suitable habitat for pond-breeding amphibians than ponds located far
from such wells. I studied 24 ponds from two well fields, along with 14 control ponds, in the
Pawcatuck River watershed of Rhode Island. In 2008 I compared hydroperiods among the three
pond groups and modeled expected hydroperiods using a multivariate regression equation developed from four years of control pond data. I counted egg masses of the wood frog (Lithobates sylvaticus) and spotted salamander (Ambystoma maculatum) as a measure of reproductive effort, and estimated potential reproductive success as the percentage of ponds in each of the three pond groups that should have been able to support emigration of at least 50% of all metamorphs prior to drying. Well-field ponds generally had shorter observed hydroperiods, a greater discrepancy between observed and expected hydroperiods, lower amphibian reproductive effort, and lower potential for reproductive success than control ponds; results varied, however, between well fields and species. If ongoing hydrologic studies confirm induced groundwater recharge as the primary cause of hydroperiod reduction near wells, regulatory agencies should strongly consider adopting specific guidelines for minimizing the impact of groundwater withdrawal on seasonal ponds and their biota.