三峡库区乡镇水平乡村道路对森林演化的“通道—阻隔”效应

发布时间：2017-12-28 09:43

本文关键词：三峡库区乡镇水平乡村道路对森林演化的“通道—阻隔”效应　出处：《重庆师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：人为扰动被认为短时空尺度森林景观演化或用途转换的主要驱动力,而干扰的拓展或扩散及其频度的发生常受到道路通道的可达性程度所制约,体现为明显的“通道-阻隔”效应。本文使用遥感影像图、森林调查图、土地利用图、历史统计数据,结合实地踏勘和参与式农村评估收集资料,利用ArcGIS10.2软件进行叠加分析,以石柱县西沱镇为研究区,识别三峡库区社区水平乡村道路对森林景观演化的“通道-阻隔”效应,分析森林景观及结构变化的轨迹,及其与乡村道路“通道-阻隔”效应间的关系,理解其背后的潜在影响因素,揭示乡村道路变化对森林景观的影响,对未来乡镇水平森林景观恢复和经营提供参考依据和理论支撑。结果表明:(1)22年间研究区乡村道路数量和质量发生较大程度的变化,1992~2014年呈先增加后减少的格局,且乡村道路质量得到了大幅提升。道路数量的变化主要表现在生产便道的增减,村级公路和等外公路数量变化并不大,1992~2002年研究区道路由255.92km增加到413.65km,在2002~2014年降低至323.80km;质量上则主要表现在村级公路及高级别道路的拓宽与硬化,水泥路由0km/hm2增加至0.016km/hm2,等外公路、村级公路是主导研究区的对外与对内交通,2m以下的道路是农业生产的重要生产便道。(2)研究区森林景观以原始林和次生林为主,森林景观格局演化在空间分布上资源分布相对应;研究区2002年前森林景观呈退化格局,之后在退耕还林政策、生态工程建设和农户撂荒作用下森林自发恢复;研究区森林景观的类型构成主要有乔木林和其他灌木林,22年间乔木林的变化呈2002年减少和2014年增加的格局。而且,22年间间研究区乔木林和其他灌木林的变化表现出显著的互补格局,其他灌木林的减少主要由乔木林的增加所补充;研究区森林的起源主要以天然实生和萌生为主,但因人为扰动的作用(包括正向和逆向干扰)不同时期差异较大;(3)22年间研究区森林景观演化对乡村道路的响应显著。在等外公路、村级公路等生产大路框架道路贯通下,联合生产便道对“通道”效应延伸的支持下,研究区22年乡村道路对森林景观格局演化的“通道”效应是非常显著的。从景观格局上看,1992~2002和2002~2014年的两时段,乡村道路缓冲区内的森林景观格局演化面积均高于相应时间内非缓冲区总演化面积。研究区前10年森林退化和恢复量均随远离道路而降低,后12年退化量随远离道路降低,临近道路森林扰动强度大,恢复量则表现为先降低后增加。从森林结构上看,无论从森林类型、起源和林龄方面,道路影响域内森林各种结构的破碎度均大于道路影响域外,道路的建设不仅是沿途的破坏,对两侧森林也造成严重影响,明显表现出破碎度的增加。道路对其他灌木林、幼龄林和天然萌生林的退化有“通道”效应;对人工直播等政策性森林生态恢复起到一定的“通道”效应;远离道路通达性不畅的区域,道路“通道”效应不显著,促进森林的恢复,表现出“阻隔”效应。从道路影响看,道路的新增和消失对森林变化的“通道-阻隔”作用最明显,道路质量的提高促进了森林的退化演化;等级公路和村级公路质量的提高以及生产便道的增加致使其他灌木林、幼龄林以及天然萌生林退化显著,研究区森林结构在道路“通道”作用下朝着退化的方向演化,而生产便道的消失“阻隔”效应又促进研究区森林结构朝着恢复的方向发展。因此,在研究区森林景观恢复与保护过程中,要减少人为扰动影响,提高研究区交通通达度,可从改善乡村高等级道路的角度出发(如改善道路宽度、提高路面质量)入手,尽量减少低等级道路分布密度或切断原有低等级道路可达性,同时保持政策性生态保护长期不变。
[Abstract]:Human disturbance is considered to be the main driving force of forest landscape evolution or use conversion in short time and space scale. The expansion or diffusion of disturbance and its frequency are often restricted by the accessibility of the road passageway, which is manifested as an obvious "channel barrier" effect. The use of remote sensing images, forest survey map, land use map, historical data, combined with field survey and participatory rural assessment and data collection, overlay analysis using ArcGIS10.2 software to West meituohu town of Shizhu County as the study area, the "corridor barrier recognition community in the Three Gorges area level of rural road to the forest landscape evolution effect analysis of forest landscape, and changes in the structure of the track, and rural road corridor barrier function relationship between the potential factors of understanding behind it, reveals the rural road changes on forest landscape impact on the future of the township level of forest landscape restoration and management to provide reference and theoretical support. The results showed that: (1) in the 22 years, the quantity and quality of rural roads in the study area changed a lot. The pattern of rural roads increased first and then decreased in 1992~2014, and the quality of rural roads has been greatly improved. Change the quantity of road is mainly manifested in the production course changes, changes in the number of village roads and roads and little road 1992~2002 in the study area increased from 255.92km to 413.65km, reduced to 323.80km in 2002~2014 years; quality is mainly manifested in widening the village roads and high grade road and hardening cement routing 0km/hm2 increased to 0.016km/hm2 roads, village road is the domestic and foreign traffic research area leading, 2m following the path of agricultural production is an important production. (2) the forest landscape in the study area primary and secondary forests, forest landscape pattern evolution in the spatial distribution of resources distribution corresponding to the study area in 2002; before the forest landscape pattern was degraded, after the effect of the policy of returning farmland to forest, ecological construction and farmers abandoned forest types in the area of spontaneous recovery; the composition of the main forest landscape there are trees and other shrubs, trees showed a change in the 22 years of 2002 and 2014 to reduce the increase pattern. Also, change in the 22 years between the study area of arbor and other shrubs showed a complementary pattern significantly reduced, mainly by increasing the arbor to supplement other shrub; the origin of the forest area is mainly natural seedling and sprouting, but due to human disturbances (including positive and negative interference) different time difference; (3) 22 years of forest landscape evolution in response to rural roads significantly. Under the support of "channel" effect extension under the support of the "road" effect extension of the combined production roads, the "channel effect" of the rural roads on the forest landscape pattern evolution is very significant in the past 22 years. From the view of landscape pattern, the evolution area of forest landscape pattern in rural road buffer area is higher than that in the corresponding time within the two time period of 1992~2002 and 2002~2014. In the first 10 years of the study area, the amount of forest degradation and restoration decreased with the distance away from the road, and the degradation amount decreased with the distance away from the road in the first 12 years. From the forest structure, both forest types, origin and age, effects of road broken domain forest structure were more than the road impact outside the road, along the way construction is not only the destruction, and also have a serious impact on both sides of the forest, showed significant increase of fragmentation. The road to the other shrub forest, young forest and natural forest degradation initiation "channel" effect; broadcasting policy of artificial forest ecological restoration to play a "channel" effect; away from the regional road accessibility is not smooth, the road "channel" effect is not significant, promote the restoration of forests showed a "barrier" effect. The impact from the road, the road of new and disappearing "corridor barrier of forest change the most obvious effect of road quality promotes the evolution of forest degradation; highway and improve the quality of rural highway pavement and increasing the production result of other shrub forest, young forest and natural coppice forest structure of degraded significantly. In the Road" channel "role towards the direction of degradation evolution, and production of sidewalks disappear" blocking "effect and promote the forest structure in this area towards the direction of recovery. Therefore, in the study area of forest landscape restoration and protection process, to reduce the influence of artificial disturbance, improve the traffic research area, starting from the improvement of rural high grade road angle (such as improving road width, improve the quality of pavement) of reducing traffic distribution density of low grade or cut off the original low grade road accessibility. While maintaining the ecological protection policy will remain unchanged for a long time.
【学位授予单位】：重庆师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S718.5

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