喀斯特森林植被自然恢复中凋落物现存量 及其碳库特征演化

采用空间代替时间的方法,研究了茂兰退化喀斯特森林自然恢复中凋落物现存量及其碳库特征.结果表明:随群落恢复凋落物现存量呈减少趋势,早期减幅大,中后期减幅小;随群落恢复凋落物现存量演化受地貌因子、群落生活史、土壤微生物的影响较大,受水热条件的影响较小;凋落物现存量生物量与其分解失重率、表层土壤微生物量碳有较强的负相关关系;凋落物分解失重率与表层土壤微生物量碳呈极强的正相关关系;随群落恢复凋落物现存量含碳率变化不显著,凋落物现存量碳密度变化规律与凋落物现存量变化规律一致,单位面积凋落物碳储量表现为碳源效应,且早期碳源效应较强、固碳能力不稳定,中后期碳源效应较弱、固碳能力稳定;凋落物碳密度(Y)与其现存生物量(x)的关系:Y=b.+b1x(b0、b1为常数).

Evolution of Litterfall Accumulation and the Characteristics of Its Carbon Pool in the Process of Natural Restoration of Karst Forest Vegetation

Using the method of taking space instead of time, the evolution of litterfall accumulation and the characteristics of its carbon pool in the process of natural restoration of karst forest vegetation was studied in the Maolan National Nature Reserve of Guizhou. The results are as follows:the litterfall accumulation reduced in the process of natural restoration, and the changes of litterfall accumulation decreased quickly in the early stages, but slowly in the middle and late stages. The litterfall accumulation was affected deeply by geomorphologic factors, life cycle of community and soil microorganism in the process of natural restoration. By contrast, the water and heat conditions had little influence to the litterfall accumulation. The litter accumulation had a strong negative correlation with the lost weight rate and the soil surface microbial biomass carbon. There was a strong positive correlation between the lost weight rate and the soil surface microbial biomass carbon. The litter accumulation carbon content rate had no difference among all stages. The litterfall accumulation carbon density followed the same evolution law with the litterfall accumulation as the positive succession developed. The litterfall accumulation played a role as a sink of atmospheric carbon dioxide along the natural restoration, and the characters of litterfall accumulation carbon pool varied from strong carbon source effect and instable carbon sequestration capacity in the early stage to little carbon source effect and stable carbon sequestration capacity in the middle and late stages. The relation equation between the litterfall carbon density (Y) and the exist litterfall accumulation (x) are:Y=b_o+b₁x(b_o and b₁ are constant). It plays an important role in observing litterfall carbon density in the research region. So it is necessary to enhance the protection of karst forest vegetation, which would be beneficial for the forest succession, create good condition for litterfall accumulation organic carbon being turned into soil organic carbon, and enhance the stability of forest ecosystems.