科尔沁沙地樟子松(Pinus sylvestris)人工固沙林演变过程中物种多样性和土壤水分特征

Changes in Species Composition,Diversity and Soil Water Content of Pinus sylvestris Artificial Sand-fixation Forest along An Afforestation Successional Gradient in Horqin

人工固沙植被是干旱、半干旱区荒漠化防治的重要内容,研究人工固沙植被演变过程中物种多样性和土壤水分变化特征对于人工固沙植被的经营与管理有重要意义。对科尔沁沙地营造的5~45a的樟子松(Pinus sylvestris)人工固沙植被林下植被的物种多样性和土壤水分变化特征进行了研究。结果表明:在樟子松固沙林演变过程中,群落中禾本科和菊科植物种始终占主导地位,且随着樟子松栽植年限的增加,禾本科植物所占比例显著增加。物种总数和草本植物数量都随着栽植年限的增加显著降低,呈显著的线性关系。而灌木数量和栽植年限呈抛物线形关系,随着樟子松栽植年限的增加先增大后减小。草本植物盖度和地上生物量与樟子松栽植年限也呈抛物线形关系,在栽植25a后草本植物盖度达到最大值。樟子松人工固沙林演变过程对土壤含水量也有显著影响,土壤平均含水量和樟子松栽植年限呈显著线性关系,栽植45a后,土壤平均含水量由3.5%降至1.4%。土壤水分的急剧下降是樟子松人工林演变后期面临的主要挑战。

Afforestation is a key technique for control of desertification in arid and semi-arid regions. There- fore, study the characteristics of species composition, diversity and soil water content of artificial sand-fixa- tion forest during its successive process is important for the management of artificial vegetation. In this pa- per, we studied characteristics of species composition, diversity and soil water content of Pinus sglvestris artificial sand-fixation forest along an afforestation successional gradient from 5--45 years in Horchin. Our results show that the community was dominated by species in the Poaceae and Compositae during the succes- sive process, and the number of species in the Compositae was significant increased with the increase of plantation age. The number of total species and herbs were decreased with the increase of plantation age fol- lowed a linear functions. However, the relationship between the number of shrubs and plantation age can well described with parabola functions. The biomass and coverage of herbs were first increased and then de- creased with the increase of plantation age, and reached their maximum when the plantation age was 25 years. Soil water content was significant decreased with the increase of plantation age. And the average soil water content was decreased from 3.5 % to 1.4 % after 45 years. The shapely decline of soil water moisture is the mainly challenge of P. syLvestris in the later successive process.