Decomposition of Forest Litter and Feces of Armadillidium vulgare (Isopoda: Oniscidea) Produced from the Same Litter Affected by Temperature and Litter Quality

Abstract

To explore the question how litter and macrofauna feces respond to temperature and how respiration differs for litter with a different CN ratio, we compared the decomposition rates of leaf litter (Alnus glutinosa, Salix caprea, and Acer campestre) and isopod (Armadillidium vulgare) feces produced from the same litter in response to three constant (8, 16, and 24 °C) and one fluctuating (first week 8 °C, the other week 24 °C) temperatures in a 50 week laboratory experiment and in a field trial. Microbial respiration of litter with lower CN ratio (alder and willow) was significantly higher than respiration of feces, no significant difference was found for maple litter with higher CN ratio. This was supported by field litter bag experiments where alder and willow litter decomposed faster than feces but the opposite was true for maple litter. Litter respiration was significantly affected by temperature but feces respiration was not. Fluctuating temperature caused either lower or equal respiration as compared to mean constant temperature. The content of phenolics was significantly higher in intact litter in comparison with decomposed litter and feces, either fresh or decomposed. The CN ratio decreased as litter turned to feces in maple and alder litter but increased in willow litter. In conclusion, microbial respiration of both litter and feces were substantially affected by litter quality; the litter was more sensitive to temperature than feces.