Effects of N-deposition on Millipede Survival and Weight Maintenance

Millipedes play an important part in ecosystem function. However, millipede ecology is understudied, with the role of many species of millipedes being entirely unknown. This is especially true for nutrient cycling, decomposition, and other ecosystem-scale processes, where the effect of millipedes has rarely been documented. Quantification of millipedes\u27 ecological roles is important in the context of global change, because impacting millipedes has the potential to impact the way ecosystems function. Nitrogen cycling is one aspect of global change where changes are conspicuous: terrestrial ecosystems are receiving increased nitrogen from fossil fuel combustion as well as from nitrogenous fertilizers. Available nitrogen is likely limiting to millipede populations, and millipedes certainly affect N-mineralization by increasing decomposition rates and preferentially selecting litter and soil sources. However, neither the effects of nitrogen concentrations nor the effects of millipedes on nitrogen transformations are well understood. Preliminary experiments showed millipedes with additional nitrogen introduced as nitrate had a trend towards decreased weight loss rather than those millipedes without added nitrogen. In the updated experiments presented here, we altered experimental design in order to increase the likelihood of detecting a statistically significant change in weight maintenance or weight gain between the two experimental groups. Cherokia georgiana were collected from a mixed forest in Central Georgia and exposed to either ambient or increased nitrogen. Experimental mesocosms were 7.5 cm diameter, 7 cm tall plastic specimen cups with 5 grams of soil and 1.5 grams of fragmented maple (Acer sp.) leaf litter. Soil nitrogen as nitrate was increased from ambient by 10 kg/ha by the addition of sodium nitrate. Nitrate was monitored weekly during the experiments, as well as biomass and survival