西双版纳热带植物园引种植物个体适应性研究

本研究通过比较引种植物和本土植物的生长状况,主要是果熟现象,讨论了引种植物对引种目的地的适应性。中国科学院西双版纳热带植物园,引种和保存了国内外万种以上的热带和亚热带植物,并对多种引种植物进行了长期连续生长监测。本文统计分析了其中观测4年以上的569个编号的引种植物生长适应状况。结果表明：1）引种植物基本适应植物园的环境,但是不同气候区来源的植物适应性表现不同,不同地区来源植物适应性顺序为：热带亚洲植物〉亚热带和热带北缘植物／热带非洲植物〉热带澳洲植物〉热带美洲植物;2）不同科属植物个体适应表现也有差别,无患子科,蝶形花科,楝科和紫葳科等的植物个体适应性和本土植物比较相似,而大戟科植物个体适应性和本土植物差异最大;3）分析表明引种植物对植物园的适应受到来源地气候和区系起源两个因素的影响;4）紫蒇科,桃金娘科和含羞草科的一些引种植物个体果熟年比高于本土植物,其入侵性有待于进一步入评估。     

Household Differentiation and On-farm Conservation of Biodiversity by Indigenous Households in Xishuangbanna, China

With diversification of field type among households in same eco-environment and social situation, even in the same ecosystem, merging household socio-economics with biodiversity initiative values to determine incentives and optimum strategy of on-farm conservation of biodiversity. Botany survey of agroecosystems at landscape level in Daka and Baka, Xishuangbanna, Yunnan, China, as well as household differentiation of biodiversity in agroecosystem and on-farm conservation strategy merging household socio-economic characters were studied. There were 73 families 179 species distributed in 0.1 ha of different agroecosystems in Daka, and 70 families 166 species distributed in 0.08 ha different agroecosystems of Baka respectively. The cosmopolitan families, such as Gramineae and Compositae decreased the percentage of tropical families and subtropical families. Botany survey among 12 random selected households from Daka in 46 sampling plots of different agroecosystems showed significant differentiation of the species richness indices of natural biodiversity and agrobiodiversity as there were differences of cognition and utilization of plant species besides management practices among households. Dengrogram using the Ward method of hierarchical cluster analysis based on annual questionnaire interview of 60% household from 1998 to 2001 in Daka showed disparity among different households’ socio-economics which underpins management diversity. There were significant correlation coefficients between household socio-economics and species richness indices of different agroecosystems. Fallow size had significant positive correlation coefficients with species richness index of rubber plantation. By contraries, production input had negative correlation coefficients with species richness index of upland rice field. Meanwhile, cereal crop income had significant positive correlation coefficient with agro-species richness index of rubber plantation. By contraries, other income such as off-farm income had negative correlation coefficients with agro-species richness index of rubber plantation. Innovations of the expert farmer on agrobiodiversity on farm conservation were admiration.     

西双版纳热带植物园引种植物物候特征比较

迁地保护是生物多样性保护的重要手段之一,前期的植物引种研究呵为迁地保护提供必要的理论支持。通过对西双版纳热带植物园内不同来源的引种植物和本地植物的4个物候期（萌叶期、落叶期、开花期和果熟期）分布格局及其气候影响因子进行对比,阐明引种植物对环境的适应性和对策。结果表明,引种植物比本地植物萌叶生长盛期更长,但对低温和干旱更加敏感的引种植物,在旱季其落叶比例明显高于本地植物,而3、4月由于气温的回升,使引种植物和本地植物在雨季之前就进入了萌叶盛期。而在繁殖物候方面,由于受气候因子影响较小,引种植物和本地植物的开花期和果熟期格局季节性表现都不明显。且规律性不强。总体上,各来源地的引种植物能根据环境的改变形成相应的生长与繁殖适应对策,可较好地适应西双版纳的环境。     

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。     

西双版纳热带雨林凋落叶分解的生态过程I.凋落叶分解动态

 通过野外试验和室内模拟相结合,系统研究了西双版纳热带雨林生态系统混合凋落叶分解的生态过程。野 外试验采用网袋法,即1 mm和100μm网眼网袋,分别限制大型土壤动物和螨类的进入,从而分别观测小型 土壤动物（螨类）、线虫的分解作用;室内试验则通过控制温、湿度条件,采用灭菌_接种法分别观测微 生物和线虫对凋落叶的分解。研究结果表明,凋落叶的分解是一个先快后慢的过程,在这个过程中存在分 解“滞留”阶段,分解速率变化发生波动,且波动的程度与食物链的复杂程度有关,食物链越复杂,波动 程度越强烈。利用单指数衰减模型xt/xo=exp(-kt)和双指数模型xt/xo=a×exp(-k1t)+b×exp(-k2t) 对凋 落叶分解过程进行模拟,后者将凋落叶前欺的快速分解和后期的慢速分解两个过程分别拟合,不但弥补了 分解前期单指数衰减模型与观测值之间不能吻合的缺陷,而且消除了单指数模型对长期分解进程的过高预 测,因此能更好地反映实际分解进程。利用双指数生物模型研究生物和非生物因子对凋落叶分解速率的贡 献表明,土壤动物是影响分解进程的最重要因子,占影响因子总量的78.1%,非生物因素的作用为14.1%, 微生物对分解速率的贡献只有7.8%。在热带森林生态系统中,土壤动物是最重要的分解者。     

西双版纳片断山地雨林蚁科昆虫群落研究

西双版纳是中国具有热带雨林的３个地区之一。采用样地调查法对西双版纳自然保护区山地雨林和３块山地雨林片断的蚂蚁群落作了比较研究。目的是揭示保护区与各片断间距离对蚂各落的影响。在４种样地中共计采集蚂蚁６亚科３５属７４种。与保护区距离不等的片断各有自己的特有种（１０－１１种）,各片断的特圾种少于自然保护区（１５种）。随着片断与自然保护区的距离增加,片断与保护区共有物种数减少（从５种、３种至２种）;最重要     

西双版纳热带雨林蚂蚁区系的起源与演化

从早寒武纪至早侏罗纪,西双版纳古陆一直与其南面的缅甸古陆连为一体,并具有相同的物种起源和演化历史,但西双版纳古陆分别于晚石炭纪和中,晚侏罗纪两次沦为海洋,其物种起源与演化成果前功尽弃,蚂蚁起源于白垩纪中后期或更早,大量分化于第三纪,至白垩纪早期,西双版纳古陆同时与南面的缅甸古陆和北面的中国古陆 为一体,从此再未沦陷,因此西双版纳的物种是此时开始从缅甸古陆和中国古陆同时移入的,至第三纪喜马拉雅造山运     

西双版纳热带雨林蚂蚁群落生物量和生态功能研究

采用样地调查法对西双版纳自然保护区和整个西双版纳地区的蚂蚁数量,生物量,每天和每年搬运土壤和有机质的数量进行了测定和推算,在勐腊县橡胶园内,黄ｊｉｎ蚁Ｏｅｃｏｐｈｙｌｌａｓｍａｒａｇｄｉｎａ（Ｆａｂｒｉｃｉｕｓ）在４５．５％的树冠上做巢,并很好地保护了这些橡胶树。西双版纳地区总面积１９６９０ｋｍ＾２,其中保护区占１２．７％蚂蚁的数量相当可观,经测定,西双版纳自然保护区的蚂蚁数量为５．２×１０＾１２     

西双版纳次生林火烧前后土壤养分变化的研究

研究了火烧对西双版纳热带次生林下土壤养分的影响。火烧后０～１０ｃｍ土层的ｐＨ、有机质、全Ｎ、Ｐ、Ｋ和有效Ｎ、Ｐ、Ｋ都显著提高,ｐＨ、有机质、全Ｎ、Ｋ和有效Ｎ、Ｋ达０．１％显著水平,有效Ｐ达１％水平,全Ｐ达５％水平。但１０～３０ｃｍ土层的上述各指标均无显著变化。火烧前后各土层的Ｃ／Ｎ比率变化均不显著。     

Estimating predation pressure in ecological studies: controlling bias imposed by using sentinel plasticine prey

Sentinel plasticine prey has been increasingly used to estimate predation pressure. The use of plasticine prey may, however, bias the results, as this method was originally designed to account for predation by organisms that can visually recognize the shapes and colors of their prey. To evaluate the limitations of using sentinel plasticine prey, we compared predator attack rates between real prey – dead and live mealworms, Tenebrio molitor L. (Coleoptera: Tenebrionidae) – and plasticine models in a monsoonal tropical rainforest of southeastern China. The attack rates by invertebrates were highest on dead prey followed by live prey and plasticine models, whereas the attack rates by vertebrates were lowest on dead prey, and did not differ between live prey and plasticine models. These results confirm that bias imposed by using the plasticine models is affected by the type of predators. In addition, we tested the validity and generality of the premise that predators can distinguish the shapes of plasticine model prey and preferentially attack a caterpillar-like shape over other shapes. To test this hypothesis, we conducted three independent experiments in China, Papua New Guinea, and Finland. In the two latter localities, predation rates on plasticine caterpillars were higher than on models of other shapes, whereas in China, these differences were not significant. Taken together, our study suggests that plasticine models may underestimate the predation by invertebrates to a greater extent than predation by vertebrates, and the preference of model shape by predators may be locality-specific, presumably due to differences in the composition of the predator community. We propose that predation be estimated on both live and plasticine prey in future studies to measure the potential bias imposed by using plasticine models and its variation among various habitats and predator groups.