ASSESSING CARBON AND NITROGEN ISOTOPE FRACTIONATION BETWEEN LAND SNAIL TISSUES AND DIET UNDER LABORATORY CONDITIONS

Climate change drives ecological shifts that are difficult to predict due to the complexity of interacting systems and the limited data available for most species. A few recent publications have reported that some animals respond to increasingly warming conditions by modifying their diet. Other studies have shown that rising temperatures can lead to decreased nitrogen fractionation in some species. However, it is unclear if these responses are taxon-specific, or a general pattern across animal groups. Land snails play important roles in the ecosystem through their diet as they break down organic matter and contribute to the calcium cycle. However, little is known about if and how changing temperatures impact snail dietary patterns and isotope fractionation. This research investigates the isotopic fractionation among diet, snail soft tissues, and shell carbonate in the snail Anguispira alternata under laboratory conditions. The selected species is native to North America and while historically abundant and commonly preserved in Quaternary sediments, appears to have declined in recent years. Approximately 200 specimens of A. alternata were fed a consistent C₃ plant diet (i.e., fresh lettuce) for a period of 8 months at two constant temperatures, ~22°C and ~17°C. This presentation shows the first results on the effects of temperature in carbon and nitrogen isotope fractionation of snail tissues and diet, which should improve interpretations of isotope data extracted from fossil shells.