Knowledge Resource Center for Ecological Environment in Arid Area
| 两种荒漠植物种群数量特征及空间分布格局研究 | |
| 其他题名 | Quantitative characteristics and spatial distribution patterns of populations of two desert plants |
| 张永宽 | |
| 出版年 | 2012 |
| 学位类型 | 硕士 |
| 导师 | 张道远 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 在环境恶劣的荒漠中生长着许多克隆植物，它们是荒漠生态系统的重要组分。从种群动态角度了解荒漠克隆植物对环境的响应和适应是一个重要的科学命题。以古尔班通古特沙漠不同生境下准噶尔无叶豆种群和囊果苔草种群为研究对象，通过样地调查，对人工固沙区和自然流沙区准噶尔无叶豆种群数量特征和空间分布格局做了对比；通过定点动态监测，对三个沙丘坡底、坡顶和坡中三种小生境类型下囊果苔草种群数量特征进行了分析，并对囊果苔草种子扩散及种子萌发特征进行了初步研究。主要研究结果如下：\n (1)准噶尔无叶豆种群数量特征和空间分布格局研究结果表明：①人工固沙区内植物的科、属、种数均明显多于流沙区，而且2种生境物种相似性指数仅为0.522，表明人工固沙措施显著改变了群落物种组成与结构。②除植株密度外，人工固沙区准噶尔无叶豆种群的高度，盖度，地上、地下及总生物量密度，单株地上、地下及总生物量等数量特征均显著高于流沙区。人工固沙区的土壤有机质、全氮和有效氮含量显著高于流沙区，且与种群数量特征(植株密度除外)呈显著正相关。③2种生境中准噶尔无叶豆种群空间分布的关联维数均接近2.0，体现了较强的个体空间相关性和空间占据能力。2种尺度(1 m和2 m)下的聚集度分析表明，2种生境中种群基本为随机分布。因而，人工固沙生境并未明显改变种群空间分布格局，这可能是种群的固有特性。\n 总之，与流沙区相比，人工固沙使地表得到固定，提高了土壤有机质和氮素含量，明显改变定居于其中的准噶尔无叶豆种群主要数量特征，增强了种群的生存和适应能力。该结论对荒漠濒危植物的保育具有重要指示意义。\n (2)囊果苔草种群数量特征分析表明：①坡顶、坡底、坡中三种小生境中，坡顶囊果苔草种群的主要特征是平均分株叶片数少，平均分株高度低，平均分株地上生物量、平均分株地下生物量、生物量密度和种群密度均比坡底和坡中的高。在坡底生境植物种类多、植被盖度大、土壤养分高；坡顶生境植物种类少、植被盖度小、沙丘能够形成干沙层。这些环境特征在一定程度上解释了囊果苔草在种群数量特征上的一系列差异。说明囊果苔草种群特征在不同环境下具有可塑性。②五个时期单个分株的叶片数总体均呈负偏态，分株高度总体呈正偏态或正态分布。说明囊果薹草分株的生长策略重点在于叶片的数量，而不注重在高度生长上的投资。\n (3)囊果苔草种子扩散及种子萌发特征研究表明：①异质性小环境对囊果苔草果实结籽率有显著性影响，背风坡最高为86.96%，坡顶最低为64.33%。②完整果实和去皮种子在室内的扩散试验表明，果皮对其风媒、水媒传播均有较大的促进作用。③新采收的囊果苔草种子能够吸收水分，说明新采收的种子不具有物理休眠。新采收的种子在五种温度梯度下均不萌发，说明存在生理休眠，但GA3处理及干藏5个月处理均不能打破其生理休眠。种子野外沙埋处理试验结果表明，囊果苔草种子随着野外埋藏时间的增加萌发率呈下降的趋势，这可能意味着囊果苔草具有深度生理休眠，或者囊果苔草种子自然萌发率本身很低，其主要靠克隆繁殖进行种群更新。 |
| 英文摘要 | Clonal plants grown in the harsh desert environment are an important component of desert ecosystem. To understand the desert clonal plants' responses and adaptations to the environment from the perspective of population dynamics is an important scientific proposition.In this paper, Eremosparton songoricum and Carex physodes population in the Gurbantunggut Desert was taken as the research object. The quantitative characteristics and spatial distribution patterns of E. songoricum population in the sand fixed areas and natural bare sand areas were compared by plot investigation. Dynamic quantitative characteristics of C. physodes populations at the bottom, middle and top of three plots(dunes)were analyzed. A preliminary study on fruit dispersal and seed germination of Carex physodes was conducted. The main results are as follows：\n (1)Results of study on quantitative characteristics and spatial distribution patterns of E. songoricum population showed that: ①The numbers of families, genera and species of E. songoricum communities in the artificial sand fixed habitat were significantly higher than those in the bare sand habitat. The similarity index value between communities in the two habitats was only 0.522, indicating that the artificial sand fixed habitat changed the species composition and structure of the E. songoricum community greatly. ②The quantitative characteristics of height, coverage, above ground, below ground and total biomass densities and above ground, below ground and total biomass per individual were also significantly higher (P <0.05 or P <0.01) in the artificial sand fixed habitat than those in the bare sand habitat. The organic matter, total nitrogen and available nitrogen contents in the artificial sand fixed habitat were significantly (P <0.01) higher than those in the bare sand habitat, and were significantly (P <0.05 or P <0.01) positively correlated with the population quantitative characteristics except for abundance of E. songoricum individuals. ③The correlation dimension values of the population spatial distribution in the two habitats were all close to 2.0, indicating strong spatial relevance and holding space ability for individuals. The aggregation analysis at two scales (1 m and 2 m) indicated that almost all of the populations were randomly distributed; thus the artificial sand fixed habitat had no effect on the degree of spatial aggregation. Random distribution pattern may therefore be part of the intrinsic properties of E. songoricum populations and it is possible that it forms the same way regardless of habitat.\n In a word, in comparison with the bare sand habitat, the surface of the artificial sand fixed habitat was stable and the soil organic matter and nitrogen contents were higher. This meant that the coverage, height, biomass densities and biomass per individual of the E. songoricum population were markedly different and that the survival and adaptation ability of E. songoricum is stronger in these plots. This conclusion is important for the protection and conservation of this and other endangered desert species.\n (2) Results of study on quantitative characteristics of C. physodes indicated that: ①In comparison with the bottom and middle micro-habitat of each plot, mean ramet number of leaf and mean ramet height in top micro-habitat were lower, however, above-ground, below-ground biomass per individual, biomass density and density of ramet population were significantly higher (P <0.05) in the top micro-habitat. Number of plant species was bigger, vegetation cover bigger and soil nutrient content higher in the bottom micro-habitat than in the top. Soil in the top micro-habitat could form dried sand layer. These environmental factors explained the differences of population characteristics to some extent. These findings indicated that the ramet population of C. physodes had morphological plasticity under different conditions. ②Frequency distribution of C. physodes ramet leaf number of three plots at every period was negatively skewed, and height positively skewed or normal distribution. Based on the frequency distribution, one might concluded that development of C. physodes was concentrated more in leaf number rather than height.\n (3) Results of study on seed dispersal and germination of C. physodes showed that:①The heterogeneity of micro-habitat have significant effects on the rate of seed-setting, 86.96% in the leeward slope and 64.33% in the top micro-habitat. ②Indoor experiments of dispersal showed that the peel not only had enhanced the dispersal ability of fruit by wind, but also promote the dispersal by water.③Fresh seeds can absorb water suggests that fresh seeds do not have physical dormancy. Fresh seeds didn’t germinate under five temperature gradient with light and dark treatment, indicated that the seeds had physiological dormancy. GA3 treatments and 5 month dry storage also couldn’t break dormancy. Experiments of wild sand buried were conducted and results showed that seed germination decreased with the time of sand buried. These findings might mean that the seeds of C. physodes had deep physiological dormancy, or natural seed germination rate was very low, C. physodes rely mainly on clonal reproduction for population regeneration. |
| 中文关键词 | 种群数量特征 ; 空间分布格局 ; 准噶尔无叶豆 ; 囊果苔草 ; 扩散 ; 种子萌发 |
| 英文关键词 | Quantitative characteristics of population Spatial distribution pattern Eremosparton songoricum Carex physodes Dispersal Seed germination |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 植物学 |
| 来源机构 | 中国科学院新疆生态与地理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287129 |
| 推荐引用方式 GB/T 7714 | 张永宽. 两种荒漠植物种群数量特征及空间分布格局研究[D]. 中国科学院大学,2012. |
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