Abstract:
Larval anurans may constitute the primary biomass of animals in geographically isolated wetlands (GIWs), but few studies have attempted to identify factors that influence larval body stoichiometry or their role in nutrient storage within GIWs. I measured body stoichiometry across larval developmental stages of 11 anuran species within GIWs in Southwest Georgia, USA. I also examined how life-history traits, such as body size, developmental period, and breeding season, affected larval body stoichiometry. Lastly, I used larval stoichiometry data to estimate the magnitude of areal nutrient storage in larval anurans at four GIWs. I found that %C and %N body content decreased throughout larval development in nearly all species, but %P increased. In addition, C:N ratios increased, while C:P and N:P ratios decreased throughout development. Percent C and C:N ratios were higher in larger-bodied and slower-developing anuran species. For the majority of species, %N and %P were lower in larger-bodied and slower-developing anuran species. N:P ratios were higher in some larger-bodied and slower-developing anuran species but there was no effect of body size or developmental rate on C:P ratios. Trends in C:N ratios suggest a switch from N-rich protein storage to C-rich lipid storage, while trends in %P, C:P, and N:P ratios indicate an increased demand for P, likely as a result of P-rich bone growth. Within our study GIWs, the magnitude of larval anuran areal nutrient storage varied among species, wetlands, and across the hydroperiod. For example, in one wetland, larval anurans stored 0.6 mg P/m2 in March 2018, but stored 151.9 mg P/m2 in May 2018. The magnitudes and variability in nutrient storage that I observed suggest that larval anuran assemblages may effectively create temporally variable biogeochemical hotspots.
