Breeding Ponds of the Spotted Salamander 



71 



RESULTS 



Only 71 of 218 potential breeding ponds that we checked in 1988, 

 1989, and 1990 contained egg masses. The incidence of egg laying by 

 spotted salamanders in those ponds declined between 1988 and 1990 by 

 23.9% (649 egg masses in 1988, 494 masses in 1989, 450 masses in 1990). 

 By 1990, nearly 75% of all egg masses were in only 20 of the original 71 

 study ponds. The pH of the 71 ponds was 5.64 ± 0.07 SE in 1988, 5.30 

 ± 0.08 in 1989, and 5.54 ± 0.08 in 1990. The pH of ponds with no 

 evidence of salamander breeding activity during the 3-year period was 

 significantly lower in all 3 years (5.32 ± 0.07, 5.01 ± 0.06, and 5.12 ± 

 0.08, respectively). Acidity varied from year to year, depending upon the 

 amount and possibly the pH of rainfall; acidity increased as ponds dried 

 up in late spring. 



In the 48 ponds in which we studied water chemistry (25 successful, 

 23 failed), no significant difference was detected in the pH of successful 

 versus failed ponds (Table 1). Of the 20 elements measured, 18 were 

 found at detectable levels. Cobalt and molybdenum were absent or were 

 at concentrations below detectable levels. Aluminum, copper, and lead 

 were at significantly higher concentrations in failed ponds than in 

 successful ones (Table 1). Silicon concentrations were significantly 

 higher in successful ponds. There was no statistical difference in pond 

 depth or in pond surface area between successful and failed ponds 

 (Table 1). Because some ponds were near roads, we were concerned 

 about the effects of vehicular emissions and of chemical treatment of 

 highways on element levels. Comparison by /-tests of the 16 ponds near 

 roads (100 m or less) with 32 remote ponds did not reveal any 

 significant difference in pH or in concentration of an element. 



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Fig. I. Canonical correlation analyses of the effect of cations in successful 

 breeding ponds (closed circles) and failed ponds (open circles). 



