摘要
【目的】南亚热带滨海过渡带气候条件恶劣,生态系统极其脆弱,土地沙化和水土流失严重,开展滨海沙地原生天然林和人工林的凋落物量及其分解速率与气候因子的关系研究,揭示滨海脆弱的森林生态系统的养分循环和地力恢复机制,为气候变化下滨海森林生态系统保护与生态安全的研究提供理论参考。【方法】在广西防城港东兴市北仑河口海湾的海岸带沙地区域的高山榕-假苹婆-细枝龙血树-沿阶草(FSDO)、红鳞蒲桃-九节-沿阶草(SPO)两种天然林和马占相思-乌药-沿阶草(ALO)人工纯林中,设置凋落物收集网和分解袋,在一年内每月固定时间收取样品,测定月凋落物量、残留量,计算凋落物的月失重率和月损失量,与5个气候因子的月平均值进行Pearson相关性分析和主成分分析。【结果】1)3种林分类型的年凋落量在8.58~23.40 t·hm^(-2)·a^(-1)之间,大小依次为FSDO>SPO>ALO,仅ALO的凋落物量与FSDO和SPO之间存在显著性差异(P<0.05);在凋落物组分中,凋落叶的占比在84.24%~94.98%之间,凋落叶总量表现为ALO>SPO>FSDO,其他组分表现为FSDO>SPO>ALO。2)在5个气候因子中,仅月平均气温(AT)与FSDO的月凋落物量存在极显著相关性(P<0.01),与ALO的月凋落物量存在显著相关性(P<0.05);第一主成分主要包括FSDO、SPO、ALO、AT四个因子,累计特征贡献值为96.27%。3)一年中3种林分类型凋落物的失重率均随时间呈持续上升趋势,表现为先快先慢的变化规律,三者分解速率快慢为FSDO>SPO>ALO;3种林分类型中仅ALO的凋落物月损失量与月平均降水量(AR)呈极显著相关(P<0.01),与AT和月降水天数(AD)呈显著相关性(P<0.05);第一主成分主要包括SPDO、ALO、AT、AR、AD五个因子,累计贡献值为97.52%。【结论】南亚热带滨海的森林植被具有较高的生产力和年凋落物蓄积量。原生天然林的年凋落物总量和分解速率均优于马占相思纯林;林分类型、平均气温和平均降雨量是凋落物量及分解速率的主导因子。在滨海生态安全保护中,保护现有天然林植被和根据乡土树种的特性营造近自然复层林,更有利于滨海沙地的地力恢复和维持。
【Objective】There are extremely fragile ecosystems,serious desertification,and soil erosion,because of the harsh condition of climate in the south subtropics tropical coastal transition zone.To reveal the nutrient cycle and soil fertility restoration mechanism of the coastal fragile forest ecosystem,the relationship between litterfall and its decomposition rate and climatic factors in natural forests and plantation forests in coastal sandy land was studied,which provided the theoretical reference for the study of coastal forest ecosystem protection and ecological security under climate change.【Method】In the coastal sandy area of Beilun estuary bay,Dongxing city,Fangchenggang,Guangxi,there are two kinds of natural forests:Ficus altissima-Sterculia lanceolata-Dracaena gracilis-Ophiopogon bodinieri(FSDO),Syzygium hancei-Psychotria rubra-Ophiopogon bodinieri(SPO),and an artificial pure forest which was Acacia mangium-Lindera aggregata-Ophiopogon bodinieri(ALO),set up litter collection nets and decomposition bags.Samples were collected at a fixed time every month within a year,and the amount and residue of monthly litter were determined,and the monthly weight loss rate and loss amount of litter were calculated.Pearson correlation analysis and principal component analysis were performed with the monthly average of five climatic factors.【Result】1)The annual litterfall of the three forest types was between 8.58-23.40 t·hm^(-2)·a^(-1),and the order was FSDO>SPO>ALO.Only the litter quantity of ALO is significantly different from that of FSDO and SPO(P<0.05).Among the litter components,the proportion of leaf litter was between 84.24%and 94.98%.The total leaf litter showed ALO>SPO>FSDO,and the other components were represented by FSDO>SPO>ALO.2)Among the five climatic factors,only monthly mean temperature(AT)had an extremely significant correlation with the monthly litter amount of FSDO(P<0.01),and had a significant correlation with ALO monthly litter(P<0.05).The first principal component mainly includes FSDO,SPO,ALO,AT four factors,the cumulative characteristic contribution value is 96.27%.3)The weight loss rate of three forest litters in a year from January to December showed a continuous upward trend with time,showing a change law of fast first slow.The decomposition rate of the three types of forest litter was FSDO>SPO>ALO.Among the three forest types,the monthly litter loss of ALO was in a highly significant correlation with month average rainfall(AR)(P<0.01),and was significantly correlated with AT and Monthly rainfall days(AD)(P<0.05).The first principal component mainly included five factors:SPDO,ALO,AT,AR,and AD,with a cumulative contribution value of 97.52%.【Conclusion】The forest vegetation in south subtropical coastal area has high productivity and annual litter accumulation.The annual litter amount and decomposition rate of natural forests were better than those of artificial pure forests of Acacia mangium.Forest type,average temperature,and average rainfall were the dominant factors of litter amount and decomposition rate.In the protection of coastal ecological security,the protection of existing natural forest vegetation and the construction of near-natural multi-storied forest according to the characteristics of native tree species are more conducive to the soil remediation and maintenance of coastal sandy land.
作者
曹雨虹
刘易
张艺帆
谢伟东
CAO Yuhong;LIU Yi;ZHANG Yifan;XIE Weidong(College of Forestry,Guangxi University,Nanning 530004,Guangxi,China)
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2021年第10期122-130,共9页
Journal of Central South University of Forestry & Technology
基金
国家自然科学基金项目(31260093)
广西自然科学基金项目(2013GXNSFAA019057)
广西创新驱动发展重大专项(AA17204058)。
关键词
南亚热带
滨海
林分类型
凋落物
分解过程
气候因子
south Asian tropics
coastal
forest type
litter
decomposition process
climate factors
