鼎湖山区域大气降水特征和物质元素输入对森林生态系统存在和发育的影响  

The influences of regional atmospheric precipitation characteristics and its element inputs on the existence and development of Dinghushan forest ecosystems

作　　者：周国逸[1] 闫俊华[1] 

机构地区：[1]中国科学院华南植物研究所,广州510650

出　　处：《生态学报》2001年第12期2002-2012,共11页Acta Ecologica Sinica

基　　金：国家基金 3970 0 1 1 2 ;3992 80 0 7项目;中日合作 990 2 83项目的;CERN运动费资助

摘　　要：通过对鼎湖山区域大气降水特征及降水的物质元素输入的观测分析 ,得到如下一些主要结果 :1本区域年内降水分配不均 ,而热量输入却相对均匀 ,使整个区域湿季水土流失和干季水分亏匮的可能性加大。区域内的对比研究发现 ,无论从降水的季节差异 ,全年的暴雨降水量 ,多年的降水变率等方面 ,鼎湖山都比鹤山偏小 ,这对鼎湖山森林景观的形成起到了重要的作用。 2该区的年降水量主要是湿季降水量存在着显著的 7a周期性振荡现象。 3大气降水中氮的含量偏高 ,浓度为 1 .92 mg· L- 1,总含 N量为 38.4 kg· hm- 2·a- 1;而钠、镁的含量偏低 ,浓度分别为 0 .1 0 5 mg· L- 1和 0 .0 6 1 mg· L- 1,总含量分别为 2 .1 0 kg· hm- 2· a- 1和 1 .2 2 kg·hm- 2·a- 1。年内降水的集中使得生态系统的养分输入主要在湿季 ,与高温多雨处于同一时期 ,有利于森林植被的形成和森林生态系统生产力的提高。从水热角度出发 ,鼎湖山地带性森林的存在不仅是季风气候的结果 ,和同区域的其它地方相比 ,也是这里的降水季节性差异 ,降水变率和暴雨降水量较小的结果 ;根据区域性水热特性的分析 ,认为 。The region near tropic of cancer is dominated by semi-desert or desert.Dinhushan,being at 23°10′N,112°34′,is located in the region,but is covered by regional monsoon evergreen broad-leaved vegetation.This is undoubtedly resulted from the large rainfall due to monsoon climate,but other facts may complicate this explanation.Some regions near Dinghushan,desertification is unavoidable if the degraded ecosystem is not restored timely.For those kinds of degraded ecosystems,high rainfall will accelerate degradation.This study will examine the characteristics of rainfall,mineral input and their influences on the existence and development of forest ecosystems,and identify the major causes for formation of its typical vegetation. 34 years'rainfall data for the periods 1959 to 1965 and 1973 to 1999 were checked for accuracy using double cumulative rainfall curves with data from Gaoyao and Zhaoqing meteorological observatories as reference.The regression analysis was used to estimate the missing rainfall data of Dinghusha for the periods of 1956 to 1958 and 1966 to 1972. Two rainfall samples over the canopy of forest were taken monthly between 1998 and 1999.Concentrations of ammonia and nitrate were measured using Miniatnvized Kjeldahl and Phenoldisulphonic Acid methods respectively,content of phosphorus was measured using Molybdenum Blue method,and these of potassium,sodium and magnesium were measured using atomic absorption(model Zee man 180-80). More than 80% of annual rainfall falls in wet season(April to September),over which the air temperature is high,and that period coincides with active plant growth.The combination of water and heat inputs influences the development and restoration of ecosystems in this way:(1)Heavy rain in wet season often results in soil erosion and nutrient loss.Sufficient heat input in dry season will loose the washed surface soil,which makes it easy to be flushed in next wet season;and (2)Because of moderate solar radiation input in dry season,the plant growth potential still keeps hig

关 键 词：鼎湖山区域 大气降水 养分 脆弱生态系统 森林 物质元素输入 广东 

分 类 号：S718.5[农业科学—林学]