黄土高原耕地撂荒后的生态水文效应——以延安市宝塔区羊圈沟小流域为例
文献类型：学位论文
| 作者 | 侯健 |
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 傅伯杰 |
| 关键词 | 黄土高原 撂荒地 土壤侵蚀 植被恢复 Loess Plateau Abandoned farmland Soil erosion Vegetation restoration |
| 其他题名 | Ecological and Hydrological Response of Farmland Abandoned in Loess Plateau, China-A Case from Yangjuangou Catchment, Yan’an City |
| 学位专业 | 生态学 |
| 中文摘要 | 作为一种广泛分布的土地利用类型，撂荒地以其复杂的生态及水文响应成为当今一个研究热点。目前，世界上很多研究都热衷于关注退化过程中的生态水文响应，而对生态系统恢复过程的关注不够。另外，关于生态恢复与水文响应之间相互的关系仍然有待于进一步的研究。 本研究首先在黄土高原腹地羊圈沟小流域，对坡面上不同撂荒年限（4、12、22和50年）撂荒地次生草本植被进行调查，并对土壤样品进行取样分析。在斑块尺度研究了植被对土壤理化因子空间分布的影响。进而，通过分析坡面尺度不同退耕年限撂荒地上径流小区（5×2m）的监测结果，来研究并揭示植被斑块的形成对坡面径流、产沙的影响。最后，在斑块尺度上综合性的分析了各个植被参数覆盖面积、格局和多样性）与土壤侵蚀的耦合作用，探讨了植被次生演替与土壤侵蚀之间的互反馈作用，目的在于揭示撂荒地植被对坡面径流产沙影响的机理。 通过野外实际调查与研究发现，随着撂荒时间的增加，撂荒地群落当中的优势种依次为菊科植物、豆科植物和禾本科植物。随着撂荒年限的增加，菊科植物的重要值从在 4年撂荒地上的0.874降到了在22年撂荒地上的 0.0345，而后升到了在 50年撂荒地上的 0.282。在撂荒 4年的撂荒地上，群落当中菊科植物的重要值较其他物种都要高。随着撂荒年限的增加，豆科植物在群落当中的重要值变化趋势不明显。然而在撂荒 12年的撂荒地上，豆科植物在群落当中占据了主导地位。在退耕 4年的撂荒地上并没有发现禾本科植物，但是随着撂荒时间的增加，禾本科植物的重要值从在 4年撂荒地上的0增长到在22年撂荒地上的0.894。而后退回到在 50年撂荒地上的 0.254。其在 22年撂荒地上占据着群落当中的主要位置。而且在每一演替阶段中，土壤中与植被生长相关的土壤因子也会聚集在这些优势种附近。随着植被演替的进行，肥力岛也在不断的发育并成型，土壤资源格局发生着变化，而这种变化对植被次生演替又具有正向反馈作用，促使植被斑块逐渐形成。耕地撂荒后，植被进行着正向的次生演替。在这个过程当中，虽然维管束植被覆盖面积变化不明显，但是其分布状态却明显由均匀分布转为聚集分布。坡面上包含有植被斑块和斑块间隙的两相斑块格局随着撂荒年限的增加而逐渐形成。随着这种两相斑块的形成，植被斑块间隙中的生物结皮的面积也在逐年增加。伴随着这一过程，在为期两年的坡面径流小区监测中发现，随着撂荒时间的增加，径流小区的平均累计径流量从在 4年撂荒地上的9698.2ml增加到了在 50年撂荒地上的 38605.3ml。而径流小区的平均累计产沙量从在4年撂荒地上的2019.5g减少到在 50年撂荒样地上的 387.7g。撂荒地地表径流量在逐年增加，而产沙量却逐年减少。 为了进一步解释撂荒地植被次生演替对径流产沙影响的细节，我们综合性的研究了植被各因子与土壤侵蚀的耦合作用。研究发现，植被覆盖面积有阻止土壤流失的作用。随着植被逐渐呈现出聚集分布的状态，土壤颗粒逐渐转移到植被斑块中来。植物多样性与土壤流失的关系依赖于植被格局。当植被呈现出相对均一的分布格局时，随着植物多样性的增加，植被覆盖面积减小，故而土壤流失加重;当植被呈现出聚集分布的格局时，植被覆盖面积随多样性的增加而增加，继而土壤流失被抑制；当植被格局出在以上两种分布形式之间时，植物多样性与土壤流失的关系不明朗。植被演替与土壤流失相对独立而又动态统一。随着植被演替，植被各因子协同变化，这种变化使得植被更好的抑制了土壤流失的发生。 |
| 英文摘要 | As a widely distributed land use type, abandoned farmland has become a research focus due to its complex ecological and hydrological responses. Most recent studies have focused on the interactions between the ecological and hydrological responses in degradation processes, whilst little research has focused on the recovery of the ecosystem. Moreover, some in-depth analyses are required to further elucidate their interactive on abandoned farmland. This study first investigated the vegetation and soil composition on farmlands abandoned for different lengths of time (4, 12, 22 and 50 years) on a mountain slope located in the Loess Plateau of China, and studied effects of vegetation on distribution of soil parameters on patch scale. Then, we carried out a 2 years monitoring experiment to monitor the runoff and soil erosion in plots (5×2m) on these different abandoned farmland, in order to research effects of vegetation patch on runoff and soil loss on slope scale. Finally, a comprehensive analysis of relationship between vegetation attributes and soil erosion has been carried out to explain the relationship between vegetation and soil erosion in detail. We determined that the dominant vegetation families on land abandoned from 4 to 50 years were the Compositae, Leguminosae, and Gramineous plants. The importance value of Compositae plants decreased from 0.874 on the 4-year abandoned land to 0.0345 on the 22-year abandoned land and then slightly increased to 0.282 on the 50-year abandoned land. The importance value of Compositae plants was significantly higher than that of the other groups at the 4-year time point. The trend of importance values for Leguminosae plants was not obvious from the 4- to 50-year time points. However, this group occupied the primary position within the plant community at the 12-year time point. Gramineous plants were not found at the 4-year time point, but this species increased in frequency from 0 to 0.894 on land abandoned for 22 years, and returned to 0.254 at the 50-year time point. This group occupied the main position on land abandoned for 22 years. Correspondingly, on land abandoned for 4 to 50 years, most soil resources accumulated around Compositae, Leguminosae, and Gramineous plants. Therefore, the dominant family of plants during a particular succession stage will play a primary role in the formation of resource islands in that stage. Over the course of vegetative succession, resource islands will develop and mature. It is found that after farmland abandonment, vegetation holds a positive succession. During this process, although the vascular plant coverage is unchanged,increasing vascular plants grow in aggregation. A two phase mosaic structure with plant patches and inter-plant patches forms. And the moss coverage increases on the inter-vascular plant. With this process, the average accumulated runoff within one plot significantly increased from 9698.2 ml in farmland abandoned for 4 years to 38,605.3ml in farmland abandoned for 50 years. In comparison, the average accumulated sediment loss within one plot significantly decreased from 2019.5 g in farmland abandoned for 4 years to 387.7 g in farmland abandoned for 50 years. From 4 to 50 years in abandoned farmland, the average accumulated runoff increases, while the average accumulated sediment loss decreases. After carried out a comprehensive analysis of relationship between vegetation attributes and soil erosion, we found that, Vegetation cover has a negative effect on soil erosion. With the increasing degree of vegetation aggregation, increasing soil particles transport from surrounding areas to vegetation patches. During this period of study, plant diversity can have different relationships with soil erosion according to the vegetation pattern. When vegetation distribution is relatively homogeneous, plant cover decreases with increasing diversity, and the soil loss increases. When vegetation pattern distributes between homogeneous and heterogeneous, the relationship between vegetation diversity and soil erosion is not obvious. When vegetation distribution is in a heterogeneous pattern, cover increases with increasing diversity, and soil loss decreases. |
| 公开日期 | 2015-06-16 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/13476]  |
| 专题 | 生态环境研究中心_城市与区域生态国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 侯健. 黄土高原耕地撂荒后的生态水文效应——以延安市宝塔区羊圈沟小流域为例[D]. 北京. 中国科学院研究生院. 2014. |
入库方式： OAI收割
来源：生态环境研究中心
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