Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.
World Agroforestry Centre, East and Central Asia, Kunming, Yunnan, China.
Appl Environ Microbiol. 2019 May 30;85(12). doi: 10.1128/AEM.00080-19. Print 2019 Jun 15.
Deforestation has a substantial impact on aboveground biodiversity, but the response of belowground soil fungi remains poorly understood. In a tropical montane rainforest in southwestern China, plots were established along a forest degradation gradient ranging from mature and regenerated forests to open land to examine the impacts of forest degradation and deforestation on ecosystem diversity and function. Here, we evaluated the changes in belowground fungal diversity and community composition using a metabarcoding approach. Soil saprotrophic fungal richness declined with increasing forest disturbance. For example, spp. (phosphorus [P]-solubilizing fungi) dominated in mature forest but were less abundant in regenerating forests and showed the lowest abundance in open land sites. Conversely, the abundance of facultative pathogenic fungi increased along the disturbance gradient. The decline in soil saprophytic fungi may be a direct result of forest disturbance or it may be associated with increased availability of soil phosphorus indirectly through an increase in soil pH. The increase in abundance of facultative pathogenic fungi may be related to reduced competition with saprotrophic fungi, changes in microclimate, or increased spore rain. These results demonstrate a loss of dominant P-solubilizing saprotrophic fungi along the disturbance gradient, indicating a change from soil P limitation in mature tropical forests to soil C limitation in deforested sites. The increased prevalence of pathogenic fungi may inhibit plant succession following deforestation. Overall, this research demonstrates that soil fungi can be used as a sensitive indicator for soil health to evaluate the consequences of forest disturbance. The soil fungal functional group changes in response to forest disturbance and indicates a close interaction between the aboveground plant community and the belowground soil biological community. Soil saprotrophic fungi declined in relative abundance with increasing forest disturbance. At the same time, the relative abundance of facultative pathogenic fungi increased. The loss of saprotrophic fungal richness and abundance may have been a direct result of forest disturbance or an indirect result of changes in soil pH and soil P. Furthermore, the dominant P-solubilizing saprotrophic fungi were replaced by diverse facultative pathogenic fungi, which have weaker C decomposition ability. These changes potentially indicate a shift from soil phosphate limitation to carbon limitation following deforestation. This study suggests that changes in fungal functional group composition can be used as an indicator of the effects of forest disturbance on soil carbon and nutrients.
森林砍伐对地上生物多样性有重大影响，但地下土壤真菌的响应仍知之甚少。在中国西南部的一个热带山地雨林中，我们沿着从成熟和再生森林到开阔地的森林退化梯度设立了样地，以研究森林退化和砍伐对生态系统多样性和功能的影响。在这里，我们使用代谢条形码方法评估了地下真菌多样性和群落组成的变化。土壤腐生真菌丰富度随着森林干扰的增加而下降。例如， spp.（解磷真菌）在成熟森林中占优势，但在再生森林中较少，在开阔地中丰度最低。相反，兼性病原真菌的丰度沿干扰梯度增加。土壤腐生真菌的减少可能是森林干扰的直接结果，也可能与土壤 pH 值升高间接导致土壤磷的可用性增加有关。兼性病原真菌丰度的增加可能与腐生真菌竞争减少、微气候变化或孢子雨增加有关。这些结果表明，在干扰梯度上，占优势的解磷腐生真菌减少，表明从成熟热带森林中的土壤磷限制到砍伐地中的土壤碳限制的变化。病原真菌的增加可能会抑制森林砍伐后的植物演替。总的来说，这项研究表明，土壤真菌可以作为土壤健康的敏感指标，用于评估森林干扰的后果。土壤真菌功能群的变化对森林干扰有响应，并表明地上植物群落与地下土壤生物群落之间存在密切的相互作用。随着森林干扰的增加，土壤腐生真菌的相对丰度下降。与此同时，兼性病原真菌的相对丰度增加。腐生真菌丰富度和丰度的减少可能是森林干扰的直接结果，也可能是土壤 pH 值和土壤磷变化的间接结果。此外，占优势的解磷腐生真菌被具有较弱 C 分解能力的多样兼性病原真菌所取代。这些变化可能表明，森林砍伐后，从土壤磷酸盐限制转变为碳限制。本研究表明，真菌功能群组成的变化可以作为森林干扰对土壤碳和养分影响的指标。
