长白山苔原植被变化对土壤呼吸影响研究

气候变化导致长白山苔原由灌木苔原向灌草苔原演化，对土壤呼吸及碳循环造成了重要影响。为了明确植被变化对苔原土壤呼吸的影响，该研究选取了长白山苔原典型的群落，测定分析了不同草本植物盖度下的土壤呼吸的季节动态变化及差异。结果表明：(1)在生长季，3个群落下不同变化阶段样地的土壤呼吸速率均有明显的动态变化，均呈单峰型变化特征；草本植物盖度增加没有改变土壤呼吸的季节动态变化趋势。(2)草本植物盖度增加对土壤呼吸速率有显著影响，随着草本植物盖度的增加，土壤呼吸速率也逐渐增大。(3)不同植物群落下土壤呼吸不同，在草本植物盖度相同的条件下土壤呼吸速率依次为：牛皮杜鹃 小叶章群落>牛皮杜鹃 地榆群落>笃斯越桔 苔草群落。(4)不同群落草本植物盖度增加对土壤呼吸的增速效应不同，牛皮杜鹃 小叶章群落的土壤呼吸增速最快，笃斯越桔 苔草群落的次之，牛皮杜鹃 地榆群落最小；草本植物盖度的增加也使3个群落之间土壤呼吸的差值出现明显的变化。

Effects of Tundra Vegetation Change on Soil Respiration in the Tundra of Changbai Mountain

Climate change leads to the evolution of the tundra in Changbai Mountain from shrub tundra to herb shrub tundra, which has an important impact on soil respiration and carbon cycle. In order to study the effect of vegetation change on soil respiration of tundra, we selected typical communities of tundra in Changbai Mountain to measure and compare the seasonal dynamics and differences of soil respiration under different herbaceous coverage. The results showed that: (1) during the growing season, the soil respiration rate varied significantly in different change stages among the three communities, and all showed single peak changes. The seasonal changing trend of soil respiration was not affected by the increase of herbaceous coverage. (2) The increase of herbaceous coverage significantly affected soil respiration. With the increase of herbaceous coverage, soil respiration rate gradually increased. (3) Soil respiration was different in different plant communities. Under the condition of the same herbaceous coverage, the soil respiration rate of Rhododendron aureum Deyeuxia purpurea community > R. aureum Sanguisorba officinalis community> Vaccinium uliginosum Carex siderosticia community. (4) The growth effect of soil respiration in different communities was different. The growth rate of soil respiration was the fastest in the R.aureum D.purpurea community, followed by V.uliginosum C.siderosticia community, and R.aureum S.officinalis community was the slowest. At the same time, the increase of herbaceous coverage significantly altered the gap of soil respiration among the three communities.