72 Charles R. Blem and Leann B. Blem 



Pearson correlation coefficients (Table 2) indicate that only calcium 

 concentration was correlated significantly with pH (P < 0.001;. A 

 number of other elements were correlated positively with each other and 

 many of these were metals. For example, zinc and copper, calcium and 

 magnesium, strontium and magnesium, and strontium and calcium have 

 correlation coefficients > 0.7. Some of these elements apparently 

 influence one another's abundance. Canonical correlation analyses (Fig. 

 1) indicate that successful ponds are distinctive; 91.8% of the ponds 

 were identified correctly by the analyses. Major loading was on 

 aluminum and sodium (first canonical correlation) and copper and 

 silicon (second canonical correlation). Aluminum, copper, silicon, and 

 zinc are the only significant cations in stepwise discriminant function 

 analyses of successful and failed ponds (Table 3). 



DISCUSSION 



In the 1970s and early 1980s, the spotted salamander was abundant 

 locally in the lower piedmont and coastal plain of Virginia, a zone of 

 relatively high acid deposition from precipitation (Schwartz 1989). 

 Recently we observed severe declines in the number of egg masses of the 

 spotted salamander at some sites (Blem and Blem 1989). For example, 

 one site had more than 500 egg masses in 1984, but the number declined 

 annually, and in 1990 only 15 masses were deposited. At the same time 

 the pH of this pond decreased from > 5.0 to < 4.0. During the same 

 period we detected a general decrease in survivorship of spotted 

 salamander eggs and embryos throughout eastern Virginia (Blem and 

 Blem 1989). In general, there has been a trend for only a few ponds with 

 pH values between 6.0 and 7.0 to support salamanders. However, the 

 increased mortality has not been uniform. Some acidic ponds continue 

 to support substantial numbers of egg masses, which have not declined 

 during that period. 



A correlation between decreased pH of temporary ponds and 

 decreased survival of spotted salamander eggs and larvae has been 

 recognized for more than a decade (e.g. Pough 1976). Mortality seems 

 to increase at a pH below 6.0, although substantial proportions of eggs 

 survive to hatch at pH values from 4.0 to 6.0 (Pough 1976, Pough and 

 Wilson 1977, Saber and Dunson 1978, Ling et al. 1986, Blem and Blem 

 1989). Complete lethality to embryos appears to be in the range of 3.5 

 to 4.5 (Pierce 1985, Freda 1986, Ling et al. 1986, Robb and Toews 

 1987), although this depends upon levels of certain elements in the 

 breeding pond (Pough 1981, Dale et al. 1985, Freda and Dunson 1985a, 

 1986). Recently it was found that mortality may be associated with 

 concentrations of specific elements such as aluminum (Albers and 

 Prouty 1987, Clark and Hall 1985, Clark and LaZerte 1985, Freda and 



