Moso Bamboo Invasion Alters Soil Microbial Nutrient Limitation by Modifying Plant Diversity and Soil Nutrient Cycling in Subtropical Forest

Jiannan Wang¹Shihao Wen¹Weiqiang Liu¹Zitian Hao¹Xiuping Wu¹Sili Peng¹Zhiwei Ge¹Xiaoyue Lin²Lingfeng Mao^1*

• ¹Nanjing Forestry University, Nanjing, China
• ²Forestry Bureau of Longyou County, Longyou, China

In recent years, increasing management costs and declining market prices for Moso bamboo (Phyllostachys edulis) have led to the abandonment of many Moso bamboo forests, resulting in their gradual encroachment into neighboring broadleaf forests—a phenomenon that continues to intensify in subtropical regions of China. Moso bamboo invasion has significant impacts on ecosystem processes and functions; however, its effects on soil microbial nutrient limitations remain unclear. Here, we employed a space-for-time substitution by selecting plots representing four stages of Moso bamboo invasion and measuring plant community diversity, soil physicochemical properties, and extracellular enzyme activities related to carbon, nitrogen, and phosphorus cycling. Results showed that bamboo invasion reduced overstory (tree layer) diversity but increased diversity in the shrub and herb layers. Soil total organic carbon (TOC), total nitrogen (TN), available phosphorus (AP), and available potassium (AK) all decreased significantly with increasing invasion intensity. In contrast, soil pH and the activities of β-1,4-glucosidase (BG), N-acetyl-β-glucosaminidase + leucine aminopeptidase (NAG+LAP), and acid phosphatase (ACP) increased along the invasion gradient. Throughout the invasion process, microbial C limitation intensified, whereas P limitation was partially alleviated. These shifts in microbial nutrient limitation were closely related to changes in soil nutrient content and plant diversity. In particular, shrub layer diversity was the main factor associated with microbial C limitation, whereas the degree of invasion primarily influenced microbial P limitation. Thus, Moso bamboo invasion alters soil microbial nutrient acquisition strategies by changing plant diversity and soil nutrient availability, which may have profound effects on nutrient cycling and ecosystem functioning. Our study provides new insights into invasion ecology, deepens understanding of ecosystem responses to Moso bamboo spread, and offers scientific guidance for managing the expansion of Moso bamboo in subtropical forests.