学术
地形对森林群落年龄及其空间格局的影响
胡志伟[1] 沈泽昊[1] 吕楠[1] 赵俊[1] 李道兴[2] 陈华[3] 王功芳[2]
[1]北京大学环境学院生态学系,地表过程分析与模拟教育部重点实验室,北京100871 [2]湖北省宜昌市大老岭国家森林公园,湖北宜昌443000 [3]湖北省宜昌市林业勘测设计院,湖北宜昌443000
摘 要:
地形已被广泛认为是植被环境时空异质性的重要来源，但其对山地森林群落动态的影响及其机理仍不清楚。作者在三峡大老岭选取一块200m×100m的常绿落叶阔叶林样地，在样地植物群落调查的同时，建立了1：500的数字高程模型，并利用树木年轮数据和分种的胸径-年龄幂函数模型，推算了全部10m×10m单元样方的群落年龄。统计了样地群落的年龄结构及其代表种的构成特征，并利用多元回归结合方差分析方法分析了地形和生物因子对群落年龄结构的影响与途径。结果表明：1）幂函数模型很好地拟合了16个树种的胸径-年龄数量关系；2）样地内群落斑块的年龄介于14～179年，平均值在95年左右；3）代表样方群落年龄的树种共有24个，而前5种即在68．5％的样方中决定群落的年龄；4）回归分析表明群落年龄受到溪流影响指数、坡位、坡度、样方内受干扰木胸面积和树种生长指数等因素的显著影响。显示沟谷地表径流冲击和表土侵蚀等坡面过程带来的干扰明显影响群落发育过程的空间格局，具有不同生态习性树种的潜在年龄也限制了群落的现实年龄；5）地形主要通过控制地表干扰体系的时空分布和不同物种的选择性分布两方面而对群落动态与年龄产生影响。但由于生态格局自身的复杂性与随机性和分析方法带来的误差，使基于地形的群落年龄格局预测结果还存在较大的不确定性。[著者文摘]
文章出处:
《植物生态学报》-2007年31卷5期 -814-824页
栏目信息:
分 类 号:
IMPACTS OF TOPOGRAPHY ON THE SPATIAL PATTERN OF THE AGE OF FOREST COMMUNITY
HU Zhi-Wei, SHEN Ze-Hao, LU Nan, ZHAO Jun, LI Dao-Xing, CHEN Hua, WANG Gong- Fang（ 1.Department of Ecology＇, College of Envirobnental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China; 2.Dalaoling National Forest Park, Yichang , Hubei 443000, China;3.Yichang Forest Inventory and Design Institute, Yichang , Hubei 443000, China）
Abstract:
Aims Our objective is to assess the impacts of topography, a main source of spatial and temporal environmental heterogeneity, on the dynamics of mountain forest communities. Methods We sampled a 200 m × 100 m plot of mixed evergreen broad-leaved and deciduous forest at Mt. Dalaoling in the Three Gorges Region of China using a 10 m ×10 m grid. We measured the topography and set up a digitalized elevation model with resolution of 1：500. We then took tree ring samples of 16 common tree species, fitted species specific diameter-age models and estimated community age in each of the 200 grids. Multivariate linear regression and ANOVA were applied to analyze the relationship between community age and habitat variables. Important findings Power model successfully describes the quantitative relationship between DBH and age in all species. Community ages of the grids range from 14 to 179 years old, with a mean of 95 years old. The oldest individuals in the grids include 24 tree species, but the top 5 species make up the oldest individuals in 68.5 % of the grids. Significant correlations exist between estimated community age and stream impact index, position, slope, sum of basal area of disturbed trees, and growth rate index, implying that soil erosion critically impacts community development, although species-specific potential age is a constraint of community age. We suggest that topography impacts on community age by controlling the spatial pattern of disturbance regime （by surface erosion）, and habitat choice of species with diversified ecological strategies. However, our quantitative estimate of community age has considerable uncertainty due to the complexity of the object studied and the method applied.[著者文摘]
Key words:
topography, mixed evergreen broad-leaved and deciduous forests, community age, spatial pattern, disturbance, Mt. Dalaoling
基金资助:
国家自然科学基金项目（30000024和30470313）本文工作的树木年轮分析部分得到中国科学院植物研究所张齐兵研究员的大力帮助;野外工作得到宜昌市大老岭国家森林公园管理部门的大力支持
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