LB 7-72 - CANCELLED - Litter quality and soil fauna effects on litter decomposition of Moso bamboo organs

Thursday, August 18, 2022

5:00 PM – 6:30 PM EDT

Located in: ESA Exhibit Hall

Presenting Author(s)

MO

Marly Orrego

Kyushu University, Japan

Coauthor(s)

AK

Ayumi Katayama

Kyushu University, Japan
MH

Motohiro Hasegawa

Doshisha University, Japan
TE

Tsutomu Enoki

Kyushu University, Japan

Background/Question/Methods:

Bamboo forests occupy large areas in many tropical and subtropical ecosystems and can have significant impacts on biogeochemical cycles through the input of senescent material. The variation in litter quality can influence the contribution of soil decomposers to decomposition. However, little is known about the potential interaction between soil fauna presence and litter quality from different plant organs. We evaluated the effect of litter quality and soil mesofauna on the mass loss, nutrient release and litter respiration rates of five types of Moso bamboo (Phyllostachys edulis) organs (leaf, branch, culm, rhizome and fine roots). We used litterbags of different mesh sizes (1 mm and 42 μm) to control the access of soil mesofauna to the bamboo litter. Initial chemical and physical traits of litter were measured to determine their relationship with litter decomposability. Bamboo organs in the 1 mm mesh litterbags were exposed to heat for 5-7 days and soil microarthropods were collected and identified to order level and suborder level in the case of the Acari group. A permutational multivariate analysis of variance (PERMANOVA) was performed to test whether the soil fauna community composition differed significantly among bamboo organs.

Results/Conclusions:

After 2 years of decomposition, the mass loss followed the order of leaf > fine root = rhizome > branch > culm litter. At each retrieval time, organ identity had a significant effect on litter respiration rates. Individual chemical traits, such as nitrogen, ash concentration and C/N ratio, explained consistently the variation in decomposability of the organs. Among the physical traits, three-dimensionality and water holding capacity were correlated with the mass loss of the organs. Soil mesofauna had no overall contribution to bamboo litter decomposition. Further, the variation in litter quality did not modulate the effect of soil fauna on litter mass loss or nutrient loss. Litter fauna density and order richness were comparatively higher in leaf litter than in the other organs. In addition, differences in soil fauna assemblage among bamboo organs depended on the incubation period. Overall, our results show that the intraspecific variation of chemical and physical traits is an important driver of litter decomposition in bamboo organs. Although soil fauna had a limited contribution to decomposition, the abundance and diversity of soil mesofauna responded to the litter quality, which holds further implications for the importance of litter properties on the diversity of soil organisms.