The removal of litterfall in the Eucalyptus plantations in South China affected the plant biodiversity in these ecosystems was found based on the field observation and lab analysis. The protection times of species di...The removal of litterfall in the Eucalyptus plantations in South China affected the plant biodiversity in these ecosystems was found based on the field observation and lab analysis. The protection times of species diversity of three Eucalyptus communities were different (Community Ⅰ with no protection, Community Ⅱ with 7-year-protection, Community Ⅲ with 35-year-protection). The total numbers of species in these communities (from Community Ⅰ to Ⅱ to Ⅲ) are 1, 6, and 17, respectively. The results showed that the protection of litterfall from being taken out of the ecosystem is important and can increase plant species diversity. This study combined biomass data, the chemical and physical properties of the soil, and the diversity of microbes in the communities. It is concluded that the mechanism of the effects of litter removal on biodiversity includes three factors: removing the suitable habitat of microbe and animal, decreasing the soil nutrient, and changing the special habitat for the germination and growth of invading plants. These results should have important implications for managing these Eucalyptus forest ecosystems in South China.展开更多
凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,...凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,0 gN m^(-2)a^(-1))、低氮(LN,15 gN m^(-2)a^(-1))、中氮(MN,30 gN m^(-2)a^(-1))和高氮(HN,60 gN m^(-2)a^(-1)),并在每种氮添加处理下设置去除凋落物和保留凋落物两种处理,于2021年3月—2022年2月利用LI⁃8100测定土壤呼吸速率,并分析氮添加及凋落物处理对土壤呼吸速率影响,确定影响土壤呼吸速率变化的主要因子。结果表明:氮添加和去除凋落物处理没有改变土壤呼吸速率的时间变化,土壤呼吸速率月均最大值出现在7月,月均最小值出现在2月。氮添加对土壤呼吸速率无显著影响(P>0.05),除CK外,去除凋落物处理会显著降低土壤呼吸速率(P<0.05)。凋落物对土壤总呼吸速率的贡献率为8.6%—28.5%,且LN处理下凋落物对土壤呼吸速率的贡献率最大。土壤呼吸速率与5 m土壤温度呈显著指数相关(P<0.01),与5 cm土壤湿度呈显著负线性相关(P<0.01)。土壤温度解释了土壤呼吸速率变异的58.5%—79.5%,土壤湿度解释了土壤呼吸速率变异的26.4%—39.5%,以土壤温度和湿度构建的双变量模型拟合效果均好于单因子模型,土壤温湿度共同解释土壤呼吸速率变异的59.1%—85.8%。结论表明在大气氮沉降增加的背景下,温度是影响土壤呼吸的主要因素,凋落物管理是调控土壤呼吸的关键过程。展开更多
文摘The removal of litterfall in the Eucalyptus plantations in South China affected the plant biodiversity in these ecosystems was found based on the field observation and lab analysis. The protection times of species diversity of three Eucalyptus communities were different (Community Ⅰ with no protection, Community Ⅱ with 7-year-protection, Community Ⅲ with 35-year-protection). The total numbers of species in these communities (from Community Ⅰ to Ⅱ to Ⅲ) are 1, 6, and 17, respectively. The results showed that the protection of litterfall from being taken out of the ecosystem is important and can increase plant species diversity. This study combined biomass data, the chemical and physical properties of the soil, and the diversity of microbes in the communities. It is concluded that the mechanism of the effects of litter removal on biodiversity includes three factors: removing the suitable habitat of microbe and animal, decreasing the soil nutrient, and changing the special habitat for the germination and growth of invading plants. These results should have important implications for managing these Eucalyptus forest ecosystems in South China.
文摘凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,0 gN m^(-2)a^(-1))、低氮(LN,15 gN m^(-2)a^(-1))、中氮(MN,30 gN m^(-2)a^(-1))和高氮(HN,60 gN m^(-2)a^(-1)),并在每种氮添加处理下设置去除凋落物和保留凋落物两种处理,于2021年3月—2022年2月利用LI⁃8100测定土壤呼吸速率,并分析氮添加及凋落物处理对土壤呼吸速率影响,确定影响土壤呼吸速率变化的主要因子。结果表明:氮添加和去除凋落物处理没有改变土壤呼吸速率的时间变化,土壤呼吸速率月均最大值出现在7月,月均最小值出现在2月。氮添加对土壤呼吸速率无显著影响(P>0.05),除CK外,去除凋落物处理会显著降低土壤呼吸速率(P<0.05)。凋落物对土壤总呼吸速率的贡献率为8.6%—28.5%,且LN处理下凋落物对土壤呼吸速率的贡献率最大。土壤呼吸速率与5 m土壤温度呈显著指数相关(P<0.01),与5 cm土壤湿度呈显著负线性相关(P<0.01)。土壤温度解释了土壤呼吸速率变异的58.5%—79.5%,土壤湿度解释了土壤呼吸速率变异的26.4%—39.5%,以土壤温度和湿度构建的双变量模型拟合效果均好于单因子模型,土壤温湿度共同解释土壤呼吸速率变异的59.1%—85.8%。结论表明在大气氮沉降增加的背景下,温度是影响土壤呼吸的主要因素,凋落物管理是调控土壤呼吸的关键过程。
