The leaf litterfall pattern in an old-growth evergreen broad-leaved forest and its implication for leaf litter mixing studies

Abstract

In natural systems, litter typically undergoes decomposition as species mixtures, with litter species composition and richness affecting decomposition processes and ecosystem functioning. In this study, we collected and measured leaf litter samples from 25 litter traps within a 1 ha permanent forest dynamics plot and 396 litter traps in three forest sites. Our objective was to investigate the temporal and spatial pattern of leaf litterfall in an old-growth evergreen broad-leaved forest. Mean annual leaf litterfall in the study area was 4.31 ± 0.46 Mg/ha. A total of 61 tree species were recorded in the leaf litter mixtures collected in the 1-ha forest plot, and 39, 48, and 37 tree species were found in the three forest sites. We noted that the abundance of the tree species in the leaf litter mixtures was best fitted as the preemption model. We observed a significant difference in litter species composition between the rain season and the dry season, as well as among the three forest sites, caused by the relative abundance of litterfall from evergreen and deciduous tree species in the two seasons, and the varying proportion of litterfall from dominant tree species in three forest sites. The species diversity of leaf litterfall also varied across different levels. Our study highlights the importance of the dominant tree species in producing leaf litters and determining the litter composition, and indicates that the studies on the leaf litter mixing effects in subtropical forests should be conducted at a high level of species richness, taking into account the relative abundance of litter species.

Keywords

• Leaf litter mixture
• Species composition
• Tree species richness
• Evergreen broad-leaved forests
• Preemption model