Interannual and seasonal variations of energy and water vapor fluxes above a tropical seasonal rain forest in Xishuangbanna, SW China

The values and variation characteristics of energy components, their relationship with net radiation and the characteristics of water balance in the forest were analyzed, based on the observation data of energy fluxes, meteorological parameters and biomass in a tropical seasonal rain forest in Xishuangbanna from January 2003 to December 2004. The results show that annual net radiation was 3516.4 MJ/(m² · a) and 3516.6 MJ/(m² · a) in 2003 and 2004, respectively, of which 46% and 44% were used in latent heat flux, and 12% and 11% were lost as sensible heat flux. Annual mean canopy surface conductance was 10.3 mm/s and 10.0 mm/s in 2003 and 2004, respectively. Moreover, canopy surface conductance was lower in dry-hot seasons than in fog-cool and rainy seasons. Canopy surface conductance correlated significantly and positively with leaf area index, but negatively with water vapor pressure deficit. In general, canopy surface conductance was not affected directly by soil water content, but highly depended on soil moisture status when soil water content was below 0.15 m³/m³. Annual total evapotranspiration of this forest ecosystem in dry seasons was lower than that in rainy seasons, which was considered as one of the most important reasons that tropical seasonal rain forest could survive and flourish in Xishuangbanna at limit of water and heat.     

西双版纳热带季节雨林水热通量

利用西双版纳热带季节雨林2003和2004年常规气象、生物量以及水热通量观测资料,对该林地两年内各能量分量的数值大小和变化规律、能量分配以及水量平衡特征等进行了分析研究。结果表明,2003和2004年净辐射总量分别为3516.4MJ/(m.2a)和3516.6MJ/(m.2a)。在能量分配过程中潜热通量占优势,2003年和2004年的总量分别是相应年份净辐射总量的46%和44%,显热通量则分别只有12%和11%。2003年和2004年林冠传导率均值分别为10.3mm/s和10.0mm/s,其中干热季期间的林冠传导率明显低于雾凉季和雨季。林冠传导率与叶面积指数和空气饱和水汽压差值之间分别呈极显著的正、负线性相关关系;它基本上不受土壤含水量的影响,只是当长期无雨或雨量很小导致土壤含水量低于0.15m3/m3时,林冠传导率才与土壤含水量间存在极显著的相关关系。西双版纳热带雨林2003和2004年的蒸散量分别是663mm和634mm,受浓雾和林冠传导率的综合影响,该森林生态系统干季蒸散量低于雨季,这是西双版纳热带季节雨林能够在水热极限条件下生存并良好发育的重要原因。     

西双版纳热带季节雨林的树种组成和群落结构动态

研究了西双版纳热带季节雨林1 hm2(hectare)动态监测样地1993年与2007年之间树种组成和群落结构的变化。对样地中胸径≥5 cm的乔木进行了每木调查。目前其树种组成的热带分布科、属所占比例分别为91%和94%,具有较高比例的热带植物区系性质。在1993年与2007年两次调查之间,树种数量由145种增至179种,仅有1到2个个体的稀有树种所占比例从54%降为51.1%。从森林的垂直结构来看,A、B、C三层的个体死亡率分别为12.8%、12.9%和19.0%,各层树木的增长率分别为-8.5%、-1.4%和44.8%。与此相对应,C层小径级的树木所占比例有较大提高。虽然小径级的树木在种类和数量上比例增大,但个体数量和种类组成相对稳定的A、B层优势树种变化不大,维持了群落结构的稳定性。14 a间,群落中新增加的具有先锋性质的树种不超过5个。1993年时,A、B两层尚有先锋树种存在,2007年已经从A、B两层中退出。因此,从14 a间树种组成和群落结构的变化来看,虽然具有树木的死亡和增补,但其物种成分和群落结构的总体格局没有明显的变化,处于动态平衡过程中。     

西双版纳热带季节雨林林冠截留雾水和土壤水的关系

利用2002年1月-2003年12月在西双版纳热带季节雨林观测样地收集的林冠截留滴落雾水、雨水、浅层土壤水和地下水水样,对其氢、氧稳定性同位素比率δD和δ^18O的测定结果进行了分析,研究了林冠截留雾水对土壤水和地下水的影响。干季（11-翌年4月份）,热带雨林林冠截留雾水的稳定性同位素比率、过量氘（d-excess）值明显高于雨水的相应值,表明雾水水汽中包含了区域森林植被蒸发、蒸腾的再循环水汽。林下地表浅层土壤水的稳定性同位素比率介于雾水和雨水的同位索比率之间,表明浅层土壤水来源于雾水和雨水的补给,但是干季浅层土壤水包含更多的雾水。在降雨稀少的干季,浅层土壤水主要来自雾水的补给,表明了林冠滴落的雾水是林下幼树和耐阴树种生长和生存的重要环境因子。干季和雨季（5-10月份）地下水的稳定性同位素比率与雨水的均没有显著差别,表明雾水对地下水的补给没有贡献,其水分补给仅仅来自雨水。     

热带季节雨林和人工橡胶林林冠截留雾水的比较研究

利用 4a( 1 999～ 2 0 0 2 )的雾水截留观测资料 ,对西双版纳热带季节雨林和人工橡胶林林冠截留雾水进行了研究。热带季节雨林和人工橡胶林全年由林冠截留的雾水分别达 89.4± 1 3.5 mm和 1 8.6± 2 .5 mm(平均值±标准差 ) (雾季各占 62 .9%± 4.8%和 91 .9%± 6.3% ) ,分别占全年降水量的 4.9%± 1 .7%和1 .1 %± 0 .2 %。年雾水截留量与年降雨量呈负相关关系。月雾水截留量与月均最低气温呈显著的负相关 ,与月均相对湿度、月均 0∶ 0 0～ 1 0∶ 0 0风速呈显著的正相关。热带季节雨林全年 68%± 5 %、人工橡胶林40 %± 4%的有雾天气里可以收集到雾水 (分别为 0 .38± 0 .2 7mm/ d和 0 .2 4± 0 .1 2 mm/ d) ,且日雾水截留量与气温和风速呈显著的相关 ,即 :气温越低、风速越大 ,日雾水截留量越多。对本地区热带季节雨林生态系统的健康生长和维持而言 ,雾及雾水极大的弥补了降雨量的不足 ,雾的这种作用在降雨量少的年份似乎更为重要     

西双版纳热带山地雨林生物量研究

观测了西双版纳山地气候,建立了山地雨林生物量回归方程,调查了海拔1 100~1 820 m范围5块样地(面积0.16~0.25 hm2)的热带山地雨林生物量。结果表明,海拔1 105和1 610 m的年平均温度分别为20.1和16.6℃,年降雨量分别为1 659和2 011 mm,旱季(11~4月)降雨量分别为295和283mm,年平均相对湿度分别为81%和84%;5块样地生物量变化为256.4~368.6 t.hm-2,平均为312.6t.hm-2,其中乔木占97.1%、木质藤本占1.2%、幼树和灌木占1.3%、草本和幼苗占0.4%;采用热带季节雨林生物量回归方程估计山地雨林生物量,会使得总生物量以及树干和树根生物量高估38.3%~61.5%,树枝生物量低估7.6%~30.8%。可见,西双版纳山地海拔增加导致雨季降雨量增加,山地雨林生物量较热带季节雨林降低32.6%,季节雨林生物量方程不适用于山地雨林。     

Estimation of evaporation rate from soil surface using stable isotopic composition of throughfall and stream water in a tropical seasonal rain forest of Xishuangbanna, Southwest China

Xishuangbanna is located at the northern edge of the distribution of tropical forests in Southeast Asia, and it has a very high frequency of radiation fog, especially during the dry season (November-April). In this study, rainwater, throughfall, intercepted fog water (fog drip) by forest canopy, and stream water were collected in January 2002 and December 2003 for stable isotopic analysis at a tropical seasonal rain forest site in Xishuangbanna, Southwest China. The objective of the study is to estimate the evaporation rate from the forest floor. The stable hydrogen (δD) and oxygen isotope composition (δ¹⁸O) of rainwater, throughfall, fog drip, and stream water was determined using an isotope ratio mass spectrometer. Stream water during the non-storm runoff period was considered to reflect the effect of evaporation from the forest floor. The evaporation rates from the forest floor were estimated using isotope composition values in stream water and the total throughfall was estimated using the Rayleigh distillation equation under equilibrium conditions. The results indicated that the annual weighted means of δD and δ¹⁸O in fog drip were consistently more enriched than those of rainwater and stream water, and the fog drip was thought to contain water that had evaporated and recycled. The weighted means of δD and δ¹⁸O in stream water during the non-storm runoff period were 5.69% and 0.39% more enriched than those of the total throughfall (rain throughfall + fog drip) in 2002, while in 2003 these were 5.05% and 0.28%, respectively. Evapotranspiration in the humid year 2002 and the dry year 2003, computed from the water balance, was 1186 mm and 987 mm, respectively, which was quite low when compared with the values reported in some humid tropical forests. Consequently, the evaporation rate from the forest floor was 5.1% of the evapotranspiration in 2002, and 3.1% in 2003. The lower evaporation rate was thought to be mainly a result of the influence of the high frequency of heavy radiation fog on the rain forest during the night in the dry season (November-April).     

Estimation of evaporation rate from soil surface using stable isotopic composition of throughfall and stream water in a tropical seasonal rain forest of Xishuangbanna, Southwest China

Xishuangbanna is located at the northern edge of the distribution of tropical forests in Southeast Asia, and it has a very high frequency of radiation fog, especially during the dry season (November-April). In this study, rainwater, throughfall, intercepted fog water (fog drip) by forest canopy, and stream water were collected in January 2002 and December 2003 for stable isotopic analysis at a tropical seasonal rain forest site in Xishuangbanna, Southwest China. The objective of the study is to estimate the evaporation rate from the forest floor. The stable hydrogen (δD) and oxygen isotope composition (δ¹⁸O) of rainwater, throughfall, fog drip, and stream water was determined using an isotope ratio mass spectrometer. Stream water during the non-storm runoff period was considered to reflect the effect of evaporation from the forest floor. The evaporation rates from the forest floor were estimated using isotope composition values in stream water and the total throughfall was estimated using the Rayleigh distillation equation under equilibrium conditions. The results indicated that the annual weighted means of δD and δ¹⁸O in fog drip were consistently more enriched than those of rainwater and stream water, and the fog drip was thought to contain water that had evaporated and recycled. The weighted means of δD and δ¹⁸O in stream water during the non-storm runoff period were 5.69% and 0.39% more enriched than those of the total throughfall (rain throughfall fog drip) in 2002, while in 2003 these were 5.05% and 0.28%, respectively. Evapotranspiration in the humid year 2002 and the dry year 2003, computed from the water balance, was 1186 mm and 987 mm, respectively, which was quite low when compared with the values reported in some humid tropical forests. Consequently, the evaporation rate from the forest floor was 5.1% of the evapotranspiration in 2002, and 3.1% in 2003. The lower evaporation rate was thought to be mainly a result of the influence of the high frequency of heavy radiation fog on the rain forest during the night in the dry season (November-April).     

砂仁种植对季节雨林土壤节肢动物群落结构影响的初步研究

为了探讨砂仁种植对热带季节雨林土壤节肢动物群落的影响,采用样地调查法对西双版纳勐仑自然保护区热带季节雨林及林下砂仁种植地土壤节肢动物群落进行了调查,2种生境、不同季节3次取样共获得土壤节肢动物3772个,隶属6纲23目,其中砂仁地中膜翅目(蚂蚁)、蜱螨目、半翅目为优势类群,占全捕获量的73．329％,而季节雨林中膜翅目(蚁类)、蜱螨目、鞘趔目和弹尾目为优势类群,占全捕量89．778％。2样地土壤节肢动物类群数、个体数和多样性指数的水平分布差异显示为季节雨林高于砂仁地,垂直分布显示季节雨林为土壤表层多于下层,表聚现象明显,砂仁地因受人为活动影响,其土壤节肢动物的垂直分布具有较大变化,出现下层高于表层的逆向分布;2样地土壤节肢动物群落季节变化趋势相近,均表现为干季高于雨季,其中砂仁地土壤节肢动物个体数在干热季最多,季节雨林个体数则在雾凉季最高。     

西双版纳热带季节雨林干热季林冠上小气候特征及CO2通量的观测

热带森林在陆地生态系统中起着重要的作用,但是人们对它在碳循环中的作用却了解不多;近年来,为了对其进行深入研究,热带森林的CO2通量成为了研究的热点。应用微气象法中的开路系统涡度相关法,使用设置在西双版纳一片成熟的热带季节雨林中观测铁塔上的观测仪器所得的干热季7个晴好天气的CO2通量及小气候观测数据,对冠层的CO2通量及小气候特征进行了分析研究。研究结果表明:(1)热带季节雨林林冠上风速及摩擦风速在中午和上半夜较大,而后半夜和上午较小;风向有显著的昼、夜交替特征,昼间多为偏东风(45~135°),而夜间多为偏西风(250~280)°;(2)林冠上方气温和树冠面表温具有显著的日变化特征,树冠表温日变化幅度大于气温,热量由空气传向树冠中,在观测的7d中,气温有着较明显的升高趋势;(3)干热季林冠上湿度变化范围为26.5%~97.2%,饱和水汽压差数值大小介于0.3~30.5 hPa之间;(4)CO2浓度在364.5~408.5m l/m3之间变化,夜间浓度升高,而昼间CO2浓度降低;(5)地下5cm土壤温度与气温一样日变化规律明显,土壤含水量的变化幅度很小,在7d内其变化幅度维持在19.9%~23.3%之间,日变化幅度更小;(6)总体上讲林冠上方显热通量小于潜热通量,上午显热通量和潜热通量的数值基本相同,但是在中午和下午,潜热通量远大于显热通量,充分显示了西双版纳干热季热带雨林森林的热量支出主要是蒸腾耗热;(7)观测期间,生态系统净CO2交换(NEE)在-20.9~17.6μm o l/(m2.s)之间浮动,每天最大净CO2吸收速率在-20.9~-12.9μm o l/(m2.s)范围内。从生态系统净CO2交换的平均日变化看,昼间最大的净CO2吸收速率为-12.4μm o l/(m2.s),夜间最大的净释放速率为6.6μm o l/(m2.s)。净CO2交换的日累积量在-0.0665~0.0448m o l/m2范围内变化,7d的累积量为-0.0140 m o l/m2,表明在西双版纳干热季的7 d观测时间段里,热带季节雨林呈现弱的碳汇效应。     

热带季节雨林林窗边缘不同热力作用面热力效应的季节变化特征

通过对热带季节雨林雾凉季和湿热季昼间林窗区域不同热力作用面的热力效应初步分析,指出在西双版纳,不论是雾凉季还是湿热季,热带季节雨林林窗边缘壁面均具有不可忽视的热力作用,且由于受林缘树木的影响,热力效应较强的东侧,北侧林缘壁面最大区域出现位置高于次生林林窗,而强度小于次生林林窗,显示了林窗边缘壁面的热力效应除与太阳高度角,太阳辐射的时间长短和强度有关之外,林窗边缘树木高度也是不可忽视的因子,其结果可为进一步研究林窗小气候形成机制提供研究基础,为研究林窗更新及生物多样性问题提供科学参考。     

西双版纳热带季节雨林林下土壤蒸发的稳定性同位素分析

利用2002年1月～2003年12月在西双版纳热带季节雨林样地测定的大气降雨、林冠穿透雨、林冠滴落雾水、溪流水水量及其氢、氧稳定性同位素比率δD和δ18O的测定结果,分析了热带季节雨林林下土壤的蒸发率.结果表明,热带雨林在雨水偏多的2002年和雨水偏少的2003年的蒸发散分别为1186 mm和987 mm,明显低于世界其它湿润热带雨林的蒸发散值;雾水的稳定性同位素比值明显重于雨水,表明雾水中包含区域再循环的蒸发水汽;由于森林林冠和林下土壤的蒸发作用,穿透雨水和溪水的稳定性同位素值又明显重于雨水的相应值.根据溪流水和穿透水（穿透雨水＋滴落雾水）的同位素差值,利用平衡状态下的瑞利蒸馏方程计算的森林土壤蒸发率表明,这两年的森林总蒸发散中分别有5.1%和3.1%来自林下土壤的蒸发.分析认为,持久、浓重的辐射雾是导致西双版纳地区热带雨林蒸发散和土壤蒸发率较低的重要因子.     

西双版纳热带雨林干季林冠层雾露形成的小气候特征研究

对西双版纳热带雨林干季林冠层雾露形成的小气候特征进行了观测研究。结果表明,雾露首先形成于最上林冠层,林下露水的形成迟于林上3～4h,林下雾是由上层雾变浓、下沉而来。夜间,雾形成前,气温高于叶表温;雾形成后,气温则低于叶表温,且气温及叶表温均有回升。雾露的形成不仅凝结了水汽进入森林,同时也对森林起到了一定的保温作用,这对热带雨林的生存和发展具有致关重要的作用。     

热带季节雨林林窗辐射特征研究

利用不同季节热带季节雨林林窗、林内及旷地不同波长太阳辐射的实测资料,探讨了热带季节雨林林窗不同波长辐射特征。结果表明,热带季节雨林林窗中央和北侧林冠下的不同波长太阳辐射存在“突跃现象”,中午前后各辐射量值迅速达到最大后又急速下降;林窗内不同波长太阳辐射日总量值均大于林内,却小于旷地;林窗中央和北侧林冠下比较可见,在干热季、雨季和雨季后期,林窗中央的各辐射要素总量值高于北侧林冠下,但雾凉季时受浓雾和太阳高度以及方位的影响,各辐射要素总量值较北侧林冠下低;林窗中央的总辐射日总量在雨季太阳高度角最大时最高,雨季后期和干热季其次,雾凉季时最小;林窗中央和北侧林冠下的红外辐射及可见光在总辐射中所占份额随季节的变化而不同,充分显示了林窗辐射环境的异质性;与旷地和林内相比,林窗内各测点的红外辐射在总辐射中所占份额介于旷地和林内之间．高于旷地却低于林内;而可见光占总辐射的比值情况正好相反．另外,林窗可见光分配率的季节变化都大于红外辐射;热带季节雨林林窗育增加红外辐射、减少可见光的特征．     

西双版纳热带山地雨林枯落物及其土壤水文功能

研究了云南西双版纳热带不同海拔梯度山地雨林枯落物层及土壤层水文功能.结果表明: 土壤容重随着海拔的增加而降低,土壤总孔隙度、非毛管孔隙度、毛管孔隙度、土壤最大持水率、最大持水量、有效持水量和土壤含水量随海拔的增加而增加,局部有所波动;雨季前期含水量、饱和含水量和有效调蓄水空间随海拔的增加而增加,其中,饱和含水量和土壤有效调蓄水空间在不同海拔区差异均显著(P<0.05).土壤渗透性能与总孔隙度和非毛管孔隙度均呈极显著正相关关系(P<0.01),其中,非毛管孔隙对土壤渗透性的影响更为显著.不同海拔枯落物未分解层厚度均占总厚度的一半以上,枯落物厚度均表现为未分解层＞半分解层;枯落物总蓄积量和半分解层蓄积量占枯落物总蓄积量的比例均随海拔的增加而增加,说明低海拔枯落物分解速度较慢,高海拔枯落物分解速度较快.不同海拔枯落物半分解层和未分解层最大持水量、最大持水率、自然含水率、有效拦蓄率和有效拦蓄量均随海拔的增加而增加,并且各海拔未分解层均高于半分解层,而有效拦蓄量深度随海拔的增加而降低,局部有所波动.综合未分解层和半分解层的变化规律可知,高海拔拦蓄能力较强,低海拔较弱.不同海拔枯落物持水量随着浸泡时间增加而增加;枯落物吸水速率随着浸泡时间增加而降低,12 h后枯落物吸水速率逐渐趋于饱和.不同海拔枯落物持水量与浸水时间可用对数方程表示;吸水速率与浸泡时间可用冥函数方程表示.综合分析各项因子,低海拔热带山地雨林水源涵养能力普遍低于高海拔.     

西双版纳热带季节雨林粗木质物残体储量及其空间分布

粗木质物残体(CWD)在森林生态系统的物质循环和碳动态中发挥着重要作用,但目前国内对热带地区CWD储量与其空间分布关系上的研究还处于起步阶段。对西双版纳1hm2热带季节雨林样地调查发现,≥10cm的粗木质物残体占森林总凋落物量的68.02%,其中45.72%的CWD处于腐解中后期。由于多数大径级的CWD分布于15°～25°的坡地上,且其饱和持水力随腐解等级的增加而上升,因此,CWD将有助于改善坡地生境下的水肥条件。CWD的分布受风向和本地湿热环境的影响,但掉落指向则更倾向于随机过程。CWD产生和分布上的普遍性有可能对森林生境异质性和生物多样性产生重大影响。     

西双版纳地区热带季节雨林与橡胶林林冠水文效应比较研究

季节雨林和橡胶林是西双版纳热带森林系统中可以代表原始林和大面积种植的人工林两种林型,采用水量平衡法,利用对以上两种林分林冠水文各分量1996～2001年的观测结果,初步分析其林冠水文效应,结果表明：一年内,季节雨林林冠截留量660．6mm,树干径流量80．7mm,穿透降雨量,853．2mm,分别占同期降雨总量的41．43％、5．24％、53．74％;橡胶林林冠截留量393．5mm,树干径流量104．1mm,穿透降雨量1096．8mm,分别占同期降雨总量的24．68％、6．68％、67．85％;两种林分森林水文各分量干、雨季差异显著,在研究中还发现,季节雨林中树干径流量随径级的增大而减小,干季出现密林(季节雨林)的穿透降雨量大于疏林(橡胶林)的反常现象;与我国其他地区相比,季节雨林和橡胶林有较大的林冠截留率及干流率。     

Tree species diversity of tropical forest vegetation in Xishuangbanna, SW China

Tree species diversity of four tropical forest vegetation types was investigated in Xishuangbanna, southwestern China. These are: tropical seasonal rain forest, tropical montane rain forest, evergreen broad-leaved forest and monsoon forest over limestone. A total of 17 samples were taken and four species diversity indices were calculated: Shannon-Wiener's H, the complement of Simpson's index, d, Fisher's and evenness index E. The results reveal the long-tailed rank/abundance diagrams of these forests. However, this feature is greatly reduced in the samples of monsoon forest over limestone. Tropical seasonal rain forest shows the highest tree species diversity of all four vegetation types. Owing to the variation of microenvironment, diversity values within the same vegetation type vary between the samples from different patches. The tree species diversity of single-dominant rain forest is not significantly lower than that of mixed rain forest, because the dominant species of some single-dominant rain forests are principally in the emergent layer. This is composed of sparse and huge trees of one species and, consequently, creates a unique canopy architecture and more heterogeneous microenvironments for the more diversified species composition under the emergent layer. The occurrence of tree species with small population sizes, particularly of species represented by only one individual, is highly correlated with the tree species diversity of the local forest vegetation. They are crucial elements in the richness of local biodiversity.     

海南尖峰岭热带林土壤动物群落——群落结构的季节变化及其气候因素

对土壤原生动物、线虫和其它大中型土壤动物等3个部分,分别描述群落的季节变化,然后,综合分析气候因素对群落的影响。①原生动物群落的季节化表现为：种数在1、2月份最高,达43、44种;个体数量则在8月份和12月份（14万多和12万多/g.干土）。②线早的种数也在1月份最高,达67种;个体数则在9月份（88.3万/m^2）;DG指数显示出有9月份的大高峰（19.9）和1月份的小高峰（19.7）。③大中型土壤动物群落的季节变化幅度很大：类群数的大高峰在7月份（31个）,小高峰在12月份（17种）;个体数量则在6月份和11月份（5.8万个和1.05万个/m^2）。④气温与地表温度对群落变化的影响较小：对线虫的种数变化有显著负相关;对原生动物、大中型土壤动物种数变化也只有阶段性的相关。⑤土壤含水量对群落变化的影响较大：与原生动物丰度呈非常显著的相关（r=0.896,d?=10,r0.01=0.708）;与其它大中型土壤动物的类群数、总个体数及DG指数的影响则具有季节性差异,即在湿季呈显著的负相关。⑥降水量年内和年间的变化均具很大的不稳定性,暴雨又是土壤动物（除原生动物外）灾难性的因素。因此降水量的变化是造成群落跳跃式波动和大起大落的主要因素。     

瑞丽莫里热带雨林种子植物区系的初步研究

初步分析了鲜为人知的滇西南瑞丽莫里的热带雨林植物区系组成与地理成分。该植物区系中热带和主产热带的科占总科数的80%以上,热带分布属占总属数的84.1%;典型热带分布种占总种数的82.1%,该区系在科、属和种水平上均以热带成分占优势,明显属于热带性质的植物区系。在其热带分布属中,又以热带亚洲分布属最多,占总属数的26.5%;典型热带分布种中也以热带亚洲分布及其变型的种占绝对优势,占总种数的72.9%,反映了该植物区系具有热带亚洲植物区系的性质特点。在其热带亚洲成分中,又具体以南亚—大陆东南亚成分比例最高,反映了滇西南的热带雨林植物区系由于地域邻接关系,受印度(喜马拉雅)—缅甸植物区系的强烈影响。