The structure of plant communities at local scales depends on both the spatial heterogeneity of abiotic environmental factors and the biotic interactions within the community.However,although environmental filtering d...The structure of plant communities at local scales depends on both the spatial heterogeneity of abiotic environmental factors and the biotic interactions within the community.However,although environmental filtering due to microtopographic heterogeneity and resource competition among plants caused by spatial variation in tree density and size are considered to be very important in explaining the mechanisms of community assembly,their effects on the processes of individual mortality and recruitment in natural forest regeneration,as well as their relative contributions,are still poorly understood.To address this,we established a 12-ha permanent plot in a subtropical evergreen broad-leaved forest area and measured microtopographic variables such as elevation,slope,aspect,and terrain position index(TPI)using a total station.We monitored the individual mortality and recruitment in forest natural regeneration through repeated surveys at 5-year intervals.We fitted spatial covariance models to jointly use multiple factors from three groups of variables(microtopographic effect,neighborhood density effects,neighborhood size effects)as explanatory variables to analyze their roles in driving the mortality and recruitment of all individual and 12 dominant species in forest natural regeneration at the neighborhood scale.Our results show that:(1)In the crucial early stages of secondary forest restoration,natural regeneration is influenced by a synergy of environmental filtering,due to microtopographic heterogeneity,and resource competition among plants.(2)For distinct species responses,evergreen dominant species'mortality is largely explained by neighborhood effects,while deciduous species are more affected by topographic factors.Furthermore,the adverse effects of larger conspecific trees on younger trees indicate a pattern of competitive pressure leading to mortality among regenerating trees,such pattern emphasis the influence of parent trees on natural regeneration.(3)As trees grow,their interaction with these stressors evolv展开更多
In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic chara...In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic characteristics of recruits during the natural recruitment. Both plot survey and the spatial point-pattern analysis were performed. Five developmental stages of natural recruitment were selected and studied, including 1 year before and 2, 5, 8, and 11 years after clear-cutting. Different slope aspects were also included. Natural recruitment was always dominated by Chinese pine with a proportion of higher than 90%. For plots of 1 year before clear-cutting on east-and north-facing slopes, recruit densities were 7886 and 5036 stems/hm2, the average heights were 0.78（±0.85） and 1.06（±1.15） m, and the average diameters at breast height（DBH） were 3.21（±1.38） and 2.91（±1.38） cm, respectively. After clear-cutting, recruit density was initially increased, then it was gradually declined with time; however, the variation of average DBH was contrary to that of recruit density. Both of them were no longer varied between 8 and 11 years after clear-cutting. The average height of recruits continued to increase after clear-cutting. For the plots of 11 years after clear-cutting on east-and north-facing slopes, average heights of recruits reached 2.00（±1.14） and 2.24（±1.20） m, respectively. The statuses of recruits on north-facing slopes were better than those on east-facing slopes after clear-cutting. Meanwhile, recruits on east-facing slopes were always aggregated at small scales, while spatial pattern of recruits varied with time on north-facing slopes. Moreover, forest was recovered more quickly by natural recruitment than by artificial afforestation after clear-cutting. The structural diversity was higher in naturally regenerated forests than in plantations of the same age. Our results demonstrated that clear-cutting of Chinese pine plantations recovered by natural recruitment has th展开更多
【目的】研究蒙古栎天然林的进界模型，为其合理经营提供依据。【方法】以蒙古栎天然林为研究对象，基于吉林省汪清林业局195块固定样地的2期复测数据，采用两阶段条件法建立蒙古栎天然林分的进界生长模型：首先使用二分类的Logistic回...【目的】研究蒙古栎天然林的进界模型，为其合理经营提供依据。【方法】以蒙古栎天然林为研究对象，基于吉林省汪清林业局195块固定样地的2期复测数据，采用两阶段条件法建立蒙古栎天然林分的进界生长模型：首先使用二分类的Logistic回归方法建立进界概率模型，其次使用普通线性逐步回归建立蒙古栎林的进界株数模型，2个模型的自变量均包括海拔、地位级指数、林分每公顷断面积、林分每公顷株数。【结果】最终确定的蒙古栎天然林的进界概率模型χ2检验结果显示，样地实测进界数和预测进界数无显著差异；ROC（Receiver operating characteristic）曲线显示，AUC（Area under curve）值为0.755。进界株数模型的残差大部分为-1.5～1.5，预测株数与实测株数无显著差异，残差未表现出显著的异质性。【结论】检验结果及ROC曲线均显示，所建立的蒙古栎天然林进界概率模型具有较好的解释性和预测性；进界株数模型的检验结果也表明该模型比较合理。因此，所建立模型可用于吉林省汪清地区蒙古栎天然林的进界生长预测。展开更多
基金the Innovative Team Project of Nanjing Institute of Environmental Sciences MEE(ZX2023QT022)Sino-German Environmental Partnership PhaseⅢ:Strengthening Chinese environmental and nature conservation policy through dialogue+2 种基金The Central Public Welfare Scientific Institution Basal Research Fund,MEE(GYZX210302)Biodiversity Survey,Observation and Assessment Program of Ministry of Ecology and Environment of ChinaThe National Environmental Protection Public Welfare Industry Targeted Research Fund:Research and demonstration of key technologies for dynamic supervision of nature reserves(201509042)。
文摘The structure of plant communities at local scales depends on both the spatial heterogeneity of abiotic environmental factors and the biotic interactions within the community.However,although environmental filtering due to microtopographic heterogeneity and resource competition among plants caused by spatial variation in tree density and size are considered to be very important in explaining the mechanisms of community assembly,their effects on the processes of individual mortality and recruitment in natural forest regeneration,as well as their relative contributions,are still poorly understood.To address this,we established a 12-ha permanent plot in a subtropical evergreen broad-leaved forest area and measured microtopographic variables such as elevation,slope,aspect,and terrain position index(TPI)using a total station.We monitored the individual mortality and recruitment in forest natural regeneration through repeated surveys at 5-year intervals.We fitted spatial covariance models to jointly use multiple factors from three groups of variables(microtopographic effect,neighborhood density effects,neighborhood size effects)as explanatory variables to analyze their roles in driving the mortality and recruitment of all individual and 12 dominant species in forest natural regeneration at the neighborhood scale.Our results show that:(1)In the crucial early stages of secondary forest restoration,natural regeneration is influenced by a synergy of environmental filtering,due to microtopographic heterogeneity,and resource competition among plants.(2)For distinct species responses,evergreen dominant species'mortality is largely explained by neighborhood effects,while deciduous species are more affected by topographic factors.Furthermore,the adverse effects of larger conspecific trees on younger trees indicate a pattern of competitive pressure leading to mortality among regenerating trees,such pattern emphasis the influence of parent trees on natural regeneration.(3)As trees grow,their interaction with these stressors evolv
基金supported by the National Key R&D Program of China (2017YFD0600501)the Fundamental Research Funds for the Central Universities of China (TD2011-08)
文摘In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic characteristics of recruits during the natural recruitment. Both plot survey and the spatial point-pattern analysis were performed. Five developmental stages of natural recruitment were selected and studied, including 1 year before and 2, 5, 8, and 11 years after clear-cutting. Different slope aspects were also included. Natural recruitment was always dominated by Chinese pine with a proportion of higher than 90%. For plots of 1 year before clear-cutting on east-and north-facing slopes, recruit densities were 7886 and 5036 stems/hm2, the average heights were 0.78（±0.85） and 1.06（±1.15） m, and the average diameters at breast height（DBH） were 3.21（±1.38） and 2.91（±1.38） cm, respectively. After clear-cutting, recruit density was initially increased, then it was gradually declined with time; however, the variation of average DBH was contrary to that of recruit density. Both of them were no longer varied between 8 and 11 years after clear-cutting. The average height of recruits continued to increase after clear-cutting. For the plots of 11 years after clear-cutting on east-and north-facing slopes, average heights of recruits reached 2.00（±1.14） and 2.24（±1.20） m, respectively. The statuses of recruits on north-facing slopes were better than those on east-facing slopes after clear-cutting. Meanwhile, recruits on east-facing slopes were always aggregated at small scales, while spatial pattern of recruits varied with time on north-facing slopes. Moreover, forest was recovered more quickly by natural recruitment than by artificial afforestation after clear-cutting. The structural diversity was higher in naturally regenerated forests than in plantations of the same age. Our results demonstrated that clear-cutting of Chinese pine plantations recovered by natural recruitment has th
文摘【目的】研究蒙古栎天然林的进界模型，为其合理经营提供依据。【方法】以蒙古栎天然林为研究对象，基于吉林省汪清林业局195块固定样地的2期复测数据，采用两阶段条件法建立蒙古栎天然林分的进界生长模型：首先使用二分类的Logistic回归方法建立进界概率模型，其次使用普通线性逐步回归建立蒙古栎林的进界株数模型，2个模型的自变量均包括海拔、地位级指数、林分每公顷断面积、林分每公顷株数。【结果】最终确定的蒙古栎天然林的进界概率模型χ2检验结果显示，样地实测进界数和预测进界数无显著差异；ROC（Receiver operating characteristic）曲线显示，AUC（Area under curve）值为0.755。进界株数模型的残差大部分为-1.5～1.5，预测株数与实测株数无显著差异，残差未表现出显著的异质性。【结论】检验结果及ROC曲线均显示，所建立的蒙古栎天然林进界概率模型具有较好的解释性和预测性；进界株数模型的检验结果也表明该模型比较合理。因此，所建立模型可用于吉林省汪清地区蒙古栎天然林的进界生长预测。
