The effects of canopy gaps on soil nutrient properties: a meta-analysis

Canopy gaps are a prevalent disturbance form in forest ecosystems that promote forest regeneration and succession by modifying the heterogeneity of the microenvironment. However, a significant knowledge gap exists in comprehending the global-scale impact of canopy gaps on soil nutrient properties, which is related to forest management and conservation tactics. In this study, 518 paired observations derived from 31 peer-reviewed articles were meta-analyzed to evaluate the overall response of soil nutrient properties to canopy gaps. The results showed that canopy gaps increased NO3--N (+ 22.20%) and MBP (+ 194.17%). The canopy gap decreased the content of TN, MBC, and C:P ratio by 9.27%, 19.58%, and 19.25%, respectively. The size of canopy gaps significantly reduced SOC (-14.37%), MBC (-27.45%), TN (-11.98%), NH4+-N (-65.26%), C:N (-15.77%, -16.02%) and C:P ratio (-28.92%), but significantly increases NO3--N (+ 37.25%). Hence, it is advisable to establish a critical gap size that caters to the specific soil fertility requirements of various regions for the optimal release of soil nutrients. These findings hold substantial significance for optimizing canopy gap management, comprehensively understanding the impact of canopy gaps on soil nutrient properties, and facilitating decision-making to assess soil fertility following canopy gap disturbances.