【摘要】 为探讨木麻黄Casuarina equisetifolia作为先锋树种对广东岩质基干林带困难立地的生态修复作用,该研究选择惠州市惠东县黑排角和海龟岛2个岩质海岸带退化地,选取5个耐瘠薄、抗风木麻黄无性系进行植被重建,植被修复2.5 a后测定木麻黄成活率、乔木层生长量、林下植物多样性、土壤养分、林分碳储量等指标。结果表明,5个木麻黄无性系在岩质海岸带困难立地均具有较好的适应性,2.5 a可基本成林;黑排角平均树高6.3 m,海龟岛平均树高4.5 m,平均成活率85%左右,其中以“X19”“海口”2个无性系表现最佳。木麻黄造林2.5 a后,两地点的植物物种数、植被覆盖度及物种丰富度均显著（P<0.05）高于自然恢复的原生态退化地;黑排角物种数量、植被覆盖度及物种丰富度显著（P<0.05）高于海龟岛,分别是海龟岛的2.0倍、3.4倍、1.6倍。造林2.5 a后,2地点土壤有机碳含量及有效钾含量均高于原生态退化地,但总氮、总磷、总钾、速效氮、有效磷含量变化不显著（P>0.05）。经测算,黑排角原生态退化地林分碳储量可达36.9 t·hm^-2,造林后提高至87.3 t·hm^-2;海龟岛原生态退化林地碳储量5.43 t·hm^-2,造林后提高至27.9 t·hm^-2。植被重建前,2地点林分碳储量以土壤层碳储量占绝对优势;木麻黄造林后,形成了以乔木层碳储量占比最高,其次是土壤层碳储量的分配格局。各试验点乔木层碳储量增加幅度最大(海龟岛从0 t·hm^-2增加到22.07 t·hm^-2,黑排角从0 t·hm^-2增加到44.83 t·hm^-2),其次是凋落物层,土壤层变化最小(海龟岛从5.39 t·hm^-2增加到5.61 t·hm^-2,黑排角从27.48 t·hm^-2增加到28.67 t·hm^-2)。相关分析表明,土壤有机碳含量高的区域,其土壤总钾、速效氮、有效磷含量也比较高,并具有较高的林下植物层碳储量及土壤层碳储量。更多还原

【Abstract】 To explore the role of Casuarina equisetifolia as a pioneer tree species in the ecological restoration of harsh sites in the rocky coastal areas of Guangdong Province,five barren-resistant and wind-resistant clones of C.equisetifolia were selected for vegetation resconstruction in two degraded rocky coastal areas（Heipaijiao and Turtle Island,Huidong County）.After 2.5 years of vegetation restoration,the survival rate of C.equisetifolia,growth of the tree layer,understory plant diversity,soil nutrients,and forest carbon stocks were measured.The results showed that all five clones of C.equisetifolia had good adaptability to harsh sites in the rocky coastal areas,and could basically form forests within 2.5 years.The average tree height of C.equisetifolia in Heipaijiao was 6.3 m,and the average tree height in Turtle Island was 4.5 m,with an average survival rate of about 85%.Among them,the two clones "X19" and "Haikou" performed the best.After 2.5 years of afforestation with C.equisetifolia,the number of understory plant species,vegetation coverage,and species richness in two locations were significantly（P<0.05） higher than those in the naturally restored degraded areas.The number of plant species,vegetation coverage,and species richness in Heipaijiao were significantly（P<0.05） higher than those of Turtle Island,being 2.0 times, 3.4 times,and 1.6 times those of Turtle Island,respectively.After 2.5 years of afforestation,soil organic carbon content and available potassium content in both sites were higher than those in the original degraded land,but total nitrogen,total phosphorus,total potassium,available nitrogen,and available phosphorus content did not change significantly（P>0.05）.The carbon stocks of the original degraded land in Heipaijiao were 36.9 t·hm^-2,and increased to 87.3 t·hm^-2 after afforestation.The carbon stocks of the original degraded land in Turtle Island were 5.43 t·hm^-2,and increased to 27.9 t·hm^-2 after afforestation.Before vegetation reconstruction,the forest carbon stocks in two locations were dominated by soil layer carbon stocks.After afforestation with C.equisetifolia,the distribution pattern was changed,where the proportion of carbon stocks in the tree layer was the highest,followed by the soil layer.The tree layer showed the greatest increase in carbon storage across all study sites,rising from 0 to 22.07 t·hm^-2 at Turtle Island and from 0 to 44.83 t·hm^-2 at Heipaijiao.The litter layer showed the second-largest increase,while the soil layer showed the smallest change.On Turtle Island,the soil density increased from 5.39 to 5.61 t·hm^-2 while at Heipaijiao,it increased from 27.48 to 28.67 t·hm^-2.Correlation analysis indicates that areas with high soil organic carbon content also tend to have higher levels of total potassium,available nitrogen,and available phosphorus,as well as higher carbon stocks in the understory vegetation and soil layers.更多还原