退耕还林政策影响下农林生态系统交错带动态变化
发布时间：2019-04-08 17:54
【摘要】：退耕还林工程不仅影响着土地利用方式的改变,还会引起土地覆盖的变化。通过分析退耕还林工程的实施对山地农业生态系统和自然生态系统空间格局的影响,可以为土地的可持续利用和退耕还林工作的开展提供参考价值。 本研究选取云南省维西县退耕年限不同的两块样地为对象,调查这两块样地在不同退耕年限下的植物群落结构、生长型组成及物种多样性和土壤的养分指标,用以测定交错带的位置和宽度,来探讨景观格局水平上生态系统内部的变化及生态过程。这对预测该工程驱动下景观和生态系统恢复及将来的变化趋势有着非常重要的意义。 得到结果如下： (1)2011年到2013年间,2009年退耕撂荒地中的优势种主要为草本群落。期间在撂荒地中逐渐出现零星分布的云南松幼苗；在2003年退耕样地的撂荒地中植物群落出现了明显的乔、灌、草分层结构,随着退耕年限的增加,灌木逐渐替代草本成为优势种,草本植物种类数量有所下降,灌木和乔木物种所占比例有所上升。 (2)2011年到2013年间,两块退耕样地的物种组成,群落结构趋于复杂,物种多样性指数也逐渐增加。同一年份下,2003年退耕样地的各物种多样性指数高于2009年退耕样地。这种变化符合一般的群落演替规律。说明在该研究区,自然恢复是较为有效的植被恢复方式。 (3)2011年到2013年间,沿着撂荒地-云南松林样带序列,两块退耕样地土壤酸性都逐渐增强。不同退耕年的样地pH值均呈现交错带撂荒地云南松林,有机质含量均呈现交错带云南松林撂荒地。且同一块退耕样地,2013年的pH值整体趋势都要低于2011年,有机质含量都要高于2011年,说明林地涵养土壤养分的能力较强,退耕还林政策也促进了土壤质量的改善。 (4)2009年退耕样地基于物种重要值为标准测定的交错带宽度,在2011年到2013年间,增加了7m,以土壤养分为标准测定的交错带宽度,在2011年到2013年间,增加了8m；2003年退耕样地基于物种重要值和土壤养分为标准测定的交错带的宽度变化比较一致,在2011年到2013年间,都增加了15m。期间,2009年退耕样地呈现的交错带波峰较窄且陡峭,表明该处边界明显,具有急变型特征,交错带类型为急变型。2003年退耕样地则由陡峭逐渐变化为平缓,交错带类型由原来的急变型过渡为平缓型。说明交错带的变化是一个动态变化的过程,随着退耕时间的增加,交错带的宽度也在增加,两个异质性较大的相邻斑块最终可能恢复成一个斑块,随着时间进程,撂荒地最终可能演替为以云南松林为主的森林。
[Abstract]:The project of returning farmland to forest not only affects the change of land use mode, but also causes the change of land cover. Through the analysis of the impact of the implementation of the project on the spatial pattern of mountain agro-ecosystem and natural ecosystem, it can provide a reference value for the sustainable use of land and the development of the work of returning farmland to forestry. In this study, the plant community structure, growth type composition, species diversity and soil nutrient indexes of two plots with different years of returning farmland in Weixi County, Yunnan Province, were investigated, and the results were as follows: (1) the structure of plant community, the composition of growth pattern, the diversity of species and the nutrient index of soil were investigated in the two plots. It is used to measure the position and width of the interlaced zone to discuss the changes and ecological processes of the ecosystem at the landscape pattern level. It is of great significance to predict the trend of landscape and ecosystem restoration and future changes driven by the project. The results are as follows: (1) from 2011 to 2013, the dominant species of abandoned land in 2009 were mainly herbaceous communities. The scattered seedlings of Pinus yunnanensis gradually appeared in abandoned land during the period. In 2003, the plant communities in the abandoned land of the recultivated land appeared obvious hierarchical structure of Arbor, Irrigation and Grass. With the increase of the years of returning farmland, shrubs gradually replaced herbs as the dominant species, and the number of herbaceous species decreased. The proportion of shrub and tree species has increased. (2) from 2011 to 2013, the species composition of the two plots tended to be complex and the species diversity index increased gradually. In the same year, the species diversity index in 2003 was higher than that in 2009. This change is in accordance with the general rule of community succession. It shows that natural restoration is an effective vegetation restoration method in this study area. (3) from 2011 to 2013, along the abandoned land-Pinus yunnanensis forest-like zone sequence, the soil acidity of the two plots gradually increased. The pH value and organic matter content of the sample plots were interlaced-zone wasteland and abandoned land of Pinus yunnanensis in different years of returning farmland. And in the same plot, the overall trend of pH value in 2013 was lower than that in 2011, and the content of organic matter was higher than that in 2011. This indicated that the soil nutrient conservation capacity of forest land was stronger, and the policy of returning farmland to forest also promoted the improvement of soil quality. (4) in 2009, the width of interlaced zone based on species importance was increased by 7 m from 2011 to 2013, and by 8 m from 2011 to 2013, using soil nutrients as the standard measure of the interlaced zone, and the interlaced zone width based on species importance value was increased by 7 m in 2009 and 8 m between 2011 and 2013. In 2003, the width of the interlaced zone measured on the basis of species importance and soil nutrients was consistent, increasing by 15 m between 2011 and 2013. During the period of 2009, the peak of the staggered zone was narrow and steep in 2009, indicating that the boundary was obvious and had the characteristics of rapid variation, and the type of interlaced zone was acute type. In 2003, the cropland changed gradually from steep to flat. The type of interlaced zone changes from the original acute type to the flat type. It is indicated that the change of the interlaced zone is a dynamic process, and the width of the interlaced zone increases with the increase of the conversion time, and the two adjacent patches with greater heterogeneity may eventually return to a patch, and with the development of the time, the interlaced zone may eventually return to a patch. Abandoned land may eventually be replaced by forests dominated by Pinus yunnanensis.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S718.55
本文编号：2454787
[Abstract]:The project of returning farmland to forest not only affects the change of land use mode, but also causes the change of land cover. Through the analysis of the impact of the implementation of the project on the spatial pattern of mountain agro-ecosystem and natural ecosystem, it can provide a reference value for the sustainable use of land and the development of the work of returning farmland to forestry. In this study, the plant community structure, growth type composition, species diversity and soil nutrient indexes of two plots with different years of returning farmland in Weixi County, Yunnan Province, were investigated, and the results were as follows: (1) the structure of plant community, the composition of growth pattern, the diversity of species and the nutrient index of soil were investigated in the two plots. It is used to measure the position and width of the interlaced zone to discuss the changes and ecological processes of the ecosystem at the landscape pattern level. It is of great significance to predict the trend of landscape and ecosystem restoration and future changes driven by the project. The results are as follows: (1) from 2011 to 2013, the dominant species of abandoned land in 2009 were mainly herbaceous communities. The scattered seedlings of Pinus yunnanensis gradually appeared in abandoned land during the period. In 2003, the plant communities in the abandoned land of the recultivated land appeared obvious hierarchical structure of Arbor, Irrigation and Grass. With the increase of the years of returning farmland, shrubs gradually replaced herbs as the dominant species, and the number of herbaceous species decreased. The proportion of shrub and tree species has increased. (2) from 2011 to 2013, the species composition of the two plots tended to be complex and the species diversity index increased gradually. In the same year, the species diversity index in 2003 was higher than that in 2009. This change is in accordance with the general rule of community succession. It shows that natural restoration is an effective vegetation restoration method in this study area. (3) from 2011 to 2013, along the abandoned land-Pinus yunnanensis forest-like zone sequence, the soil acidity of the two plots gradually increased. The pH value and organic matter content of the sample plots were interlaced-zone wasteland and abandoned land of Pinus yunnanensis in different years of returning farmland. And in the same plot, the overall trend of pH value in 2013 was lower than that in 2011, and the content of organic matter was higher than that in 2011. This indicated that the soil nutrient conservation capacity of forest land was stronger, and the policy of returning farmland to forest also promoted the improvement of soil quality. (4) in 2009, the width of interlaced zone based on species importance was increased by 7 m from 2011 to 2013, and by 8 m from 2011 to 2013, using soil nutrients as the standard measure of the interlaced zone, and the interlaced zone width based on species importance value was increased by 7 m in 2009 and 8 m between 2011 and 2013. In 2003, the width of the interlaced zone measured on the basis of species importance and soil nutrients was consistent, increasing by 15 m between 2011 and 2013. During the period of 2009, the peak of the staggered zone was narrow and steep in 2009, indicating that the boundary was obvious and had the characteristics of rapid variation, and the type of interlaced zone was acute type. In 2003, the cropland changed gradually from steep to flat. The type of interlaced zone changes from the original acute type to the flat type. It is indicated that the change of the interlaced zone is a dynamic process, and the width of the interlaced zone increases with the increase of the conversion time, and the two adjacent patches with greater heterogeneity may eventually return to a patch, and with the development of the time, the interlaced zone may eventually return to a patch. Abandoned land may eventually be replaced by forests dominated by Pinus yunnanensis.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S718.55
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