Breeding Ponds of the Spotted Salamander 73 



Table 3. Stepwise discriminant function analyses of the importance of elements 

 in the use of breeding ponds by spotted salamanders. 



Element Partial R 2 Wilks' Lambda 3 



Aluminum 0.209 0.808 



Copper 0.232 0.650 



Silicon 0.240 0.589 



Zinc 0.161 0.494 



a Elements and associated statistics are listed in order of entry in the analyses. 

 All Wilks' Lambda values are significant at P< 0.05. 



Dunson 1985a), calcium (Freda and Dunson 1985a), magnesium (Freda 

 and Dunson 1985a), and sodium (Freda and Dunson 1984, 1985a). 

 However, there seem to be few data regarding the ambient levels of 

 cations in temporary ponds, and little information regarding the 

 combined effect of a more complex suite of ions (see Gascon and Planas 

 1986). 



The chemistry of temporary waters on the lower piedmont and 

 coastal plain of Virginia is complex. The chemical composition of the 

 water in these ponds, along with its physical characteristics and local 

 biotic influences, may all vary between ponds even when they are 

 separated by only short distances. Year-to-year variations in water 

 depth, temperature, and duration are important determinants of 

 reproductive success and continued use of ponds by spotted salamanders 

 (see Shoop 1974, Albers and Prouty 1987). The surrounding forest and 

 soil are important influences on levels of biologically significant cations 

 (James and Riha 1986). Coastal plain and lower piedmont soils of 

 Virginia vary widely in composition (Blem and Blem 1989), and it is not 

 surprising that elements detected in temporary ponds are also extremely 

 variable. For example, several of our test ponds had aluminum 

 concentrations of 2-3 ppm; 0.3 ppm is considered extremely high in 

 Virginia waters (C. Lunsford, personal communication). Furthermore, 

 the relationship between pH and aluminum toxicity appears to be 

 complex (Freda et al. 1989). For example, organically bound aluminum 

 may be harmless (Freda 1986) or less harmful (Seip et al. 1984) than 

 free aluminum ions; therefore ponds with large amounts of humic acids 

 could have high concentrations of aluminum without harm to aquatic 

 life. Also, aluminum may ameliorate acid toxicity at intermediate 

 concentrations and low pH values (Freda et al. 1989). 



Only traces of copper were found in many ponds, but others had 

 levels as high as 0.179 ppm. Copper is known to be toxic to amphibians 



