Intraspecific Differences in Responses of Marsh Frog (Pelophylax ridibundus) Tadpoles Exposed to Environmentally Relevant and Acute Levels of Ammonium Nitrate Fertilizer

ABSTRACT

Marsh frog (Pelophylax ridibundus) tadpoles from two different ponds in the same region were exposed to acute (0 to 500 mg/L) and chronic (0 to 25 mg/L) levels of ammonium nitrate to assess lethal and sublethal effects (growth, duration of larval development, occurrence and frequency of abnormalities, level of tadpole activity, and mortality). Both acute and chronic toxicity experiments indicated that there was a difference in the level of innate resistance of tadpoles taken from the two different sites. Elevated levels of ammonium nitrate caused prolonged larval development, decreased growth rate, increased number of abnormalities, decreased duration time for abnormalities to occur, increased mortality, and decreased activity. Our results suggest that different exposure regimes of ammonium nitrate in the natural habitats may drive adaptation mechanisms to increase resistance to ammonium nitrate, creating intraspecific variations among the populations of Pelophylax ridibundus