Knowledge Resource Center for Ecological Environment in Arid Area
| 沙化草地裸斑植被自然恢复中的种子传播制约 | |
| 其他题名 | Seed Dispersal Limitation in the Vegetation Restoration of Bare Patches in the Desertified Grassland |
| 邓徐 | |
| 出版年 | 2011 |
| 学位类型 | 硕士 |
| 导师 | 刘志民 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 我国是世界上受荒漠化危害最严重的国家之一，荒漠化导致草地中形成大量裸斑，如何重建裸地植被是恢复生态学和群落生态学研究重点。已有研究要么缺乏对传播、停留、出苗的比较研究，要么缺乏传播种子数量的调查，并且仅考虑单物种或若干优势物种，或者仅从单因素考虑影响停留的因子。\n 本研究以半干旱区的科尔沁沙化草地裸斑为对象，通过野外监测传播到裸斑的种子、停留种子、传播种子出苗数量，分析传播种子的时空格局，比较种子传播、种子停留、生境条件对植被恢复的相对重要性，分析种子属性（种子重量、形状、附属物、传播媒介）及裸斑属性（面积、形状、海拔、植被盖度）对种子停留的影响。\n 结果表明：（1）5-8月（生长季）传播种子为208-743粒 m-2，停留种子为17-93粒 m-2，9-11月（非生长季）传播种子为120-638粒 m-2，停留种子为15-83粒 m-2，5-8月与9-11月传播或停留种子数量差异不显著（P>0.05）；（2）5-8月和9-11月传播种子的停留率均低于20%；（3）裸斑中沙生植物的出苗数（9.3-22.3株 m-2）高于非沙生植物（0-3.4株 m-2）；沙生植物在裸斑的出苗数（9.3-22.3株 m-2）高于植被区（7.7株 m-2），而非沙生植物在裸斑的出苗数（0-3.4株 m-2）低于植被区（4.5株 m-2）；（4）种子形状和附属物影响种子在裸斑的停留，圆形无附属物种子较扁长具附属物的更易停留；（5）裸斑植被盖度越高，越利于种子停留。\n 传播种子停留率低是裸斑可用种子少的主要制约因素，种子在非生长季传播到裸斑则近一步降低了可用种子的数量，沙生植物在裸斑建植主要受可用种子数量制约，而非沙生植物建植受可用种子数量和出苗共同制约。本研究揭示裸斑植被自然恢复的制约因素，为半干旱草原区的沙漠化防治和植被恢复提供依据。 |
| 英文摘要 | Bare patches are frequently found in the desertified grassland in China which is one of the countries suffering the most serious desertification. The revegetation in bare patches has been the focus of the restoration ecology and the community ecology. However, previous studies do not link seed dispersal, seed retention and seed germination or investigate dispersed seed; in addition, they discuss single or dominant species or single factor that affects seed dispersal and retention.\n In this paper, we investigated dispersed seeds, retained seeds, and seedlings germinated from dispersed seeds in bare patches. Then we analyzed the spatio- temporal pattern of dispersed seeds in bare patches, and compared the relative importance of dispersal, retention and habitat limitation in the revegetation of bare patches. Also, we explored how seed attributes (seed mass, seed shape, appendages and dispersal agent) and bare patches attributes (area, shape, altitude, and plant coverage) affected seed retention. The objective was to find out the factors limiting revegetation of bare patches and their mechanism, and to provide information for vegetation restoration in the desertified grassland in semi-arid regions.\n Our results indicated that (1) from May to August (the germination season), the arrived seeds were from 215 to 743 (grains m-2) of different bare patches; the retained ones were from 17 to 93 (grains m-2); from September to November (part of the non-germination season), the arrived seeds were from 129 to 638 (grains m-2) of different bare patches; the retained ones were from 15 to 83 (grains m-2); there was no significant difference in arrived or retained seeds between two seasons; (2) the retained seed:arrived seed ratio was less than 20% each season; (3) in bare patches, seedling of psammophytes species (9.3-22.3 m-2) were higher than those of non-psammophytes (0-3.4 m-2); 3) seedlings of psammophytes in bare patches (9.3-22.3 m-2) were higher than those in high-cover patches (7.7 m-2) and seedlings of non-psammophytes in bare patches (0-3.4 m-2) were lower than those in high-cover patches (4.5 m-2); (4) seed shape and appendages influenced seed retention ability, round seed without appendages were prone to stay and flat seeds with appendages were likely to move again; (5) plant cover influenced bare patches seed-retained ability, and there was a positive relationship between them. Based on these results, vegetation restoration and management were discussed.\n Our study indicated that bare patches in the desertified grassland lacked seeds because of low seed retention and wrong arriving time of seed. For psammophytes, seed availability is more important in the re-vegetation of bare patches than seedling emergence, but for non-psammophytes, the importance of seed availability is equal to seedling emergence. |
| 中文关键词 | 裸斑 ; 植被恢复 ; 种子传播 ; 种子停留 ; 种子形态 |
| 英文关键词 | Bare patches Vegetation restoration Seed dispersal Seed retention Seed morphology |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院沈阳应用生态研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286968 |
| 推荐引用方式 GB/T 7714 | 邓徐. 沙化草地裸斑植被自然恢复中的种子传播制约[D]. 中国科学院大学,2011. |
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