不同道路类型对澜沧江流域景观的生态影响

生境破碎化引发一系列潜在的生态效应,定量表达道路建设造成破碎化特征对于道路生态系统管理具有重要意义。针对澜沧江流域,利用GIS和FragStat软件,通过情景分析,分析了不同级别道路建设对景观的影响。结果表明:澜沧江流域一级路所影响面积最大,三级路最小,而影响的斑块数目则为一级路>二级路>三级路>高速路;生态系统影响面积为林地>草地>旱地>灌丛>水田>建设用地,斑块数目以旱地最高,其次为林地。情景分析表明,随着道路的建设和规划方案的实施,影响域内斑块平均面积减少,斑块数目、平均分维数增加,但总体上,高速路建设对生境破碎化的贡献率较小。土壤侵蚀分布结果表明,侵蚀面积为一级路>二级路>高速路>三级路。     

Using kernel density estimation to assess the spatial pattern of road density and its impact on landscape fragmentation

Road density (i.e., km/km²) is a useful broad index of the road network in a landscape and has been linked to several ecological effects of roads. However, previous studies have shown that road density, estimated by grid computing, has weak correlation with landscape fragmentation. In this article, we propose a new measure of road density, namely, kernel density estimation function (KDE) and quantify the relation between road density and landscape fragmentation. The results show that road density estimated by KDE (km/km²) elucidates the spatial pattern of the road network in the region. Areas with higher road density are dominated by a larger proportion of built-up landscape and less possession of forest and vice versa. Road networks segregated the landscape into smaller pieces and a greater number of patches. Furthermore, Spearman rank correlation model indicates that road density (km/km²) is positively related to landscape fragmentation. Our results suggest that road density, estimated by KDE, may be a better correlate with effects of the road on landscape fragmentation. Through KDE, the regional spatial pattern of road density and the prediction of the impact of the road on landscape fragmentation could be effectively acquired.     

黄土高原典型小流域道路特征及影响因素

通过GPS野外实测黄土高原纸坊沟小流域的道路特征,在GIS空间分析等方法支持下研究了流域内各级道路的分布规律。研究表明:黄土高原道路可分为4级,2级以下的土路是小流域的代表路型。各级别道路总长度都随级别增大而增加且累计总长度与道路级别线性相关,道路平均长度和密度则随级别增大而减小。道路网系和流域水系在结构规律上具有一定的相似性。不同级别道路分布范围受地形特征影响不同。爬坡道路坡度与地表坡度之间存在线性回归关系,且次级道路分布受主路控制;典型爬坡路在大于25°坡度范围内多呈"之"字形弯曲,随坡度的减小道路弯曲跨度和与等高线夹角增大。研究结果有助于定量模拟黄土高原地区道路分布特征,并为土壤侵蚀模型中道路影响因子的确定提供参考。     

深圳市道路网络结构特征的成因及其景观格局效应

本文以我国典型快速城市化地区深圳市为例,综合使用GIS技术、道路网络结构特征分析、景观格局分析和相关分析方法研究其道路网络结构特征的成因及其景观生态效应。在确定了24个独立的空间研究单元的基础上,重点分析了深圳市道路网络结构特征的相关关系、城市化水平差异对道路网络结构特征的影响和道路格局特征的景观整体及重要组分的格局效应。结果表明:城市建设用地密度的增加导致交通用地密度、节点和廊道储量增加,道路网络结构复杂程度、格局指数降低;资源条件、环境和生态保护约束是导致道路网络复杂性增加、结构发育水平下降、网络格局指数不断降低的主要原因;深圳市的道路网络格局特征对全市景观整体格局没有表现显著的约束性影响,对建设用地显示出环境保护约束和空间吸引两个方面的综合效应,对于林地则表现出生态保护约束、空间排斥和物理分割三个方面的综合效应。     

国内外道路侵蚀研究回顾与展望

道路引起的径流汇集及道路侵蚀的不断演化常常是沟蚀加剧的诱因,未铺装路面上形成的侵蚀沟及坡面侵蚀来沙在路面上的堆积,也会严重影响正常交通运输。国内外许多学者已从不同角度关注道路侵蚀。文章回顾近20年来国内外有关道路侵蚀的研究工作及所取得的成果,分析目前研究存在的主要问题。针对中国侵蚀环境特征及侵蚀产沙特点,对未来道路侵蚀研究工作开展进行展望。     

西双版纳地区公路两侧土地利用变化格局特征

根据西双版纳地区1976、1988和2003年三期LandsatMSS/TM/ETM影像解译的土地利用数据,运用Arc-G IS软件的缓冲区分析方法,分析该区内主干公路两侧土地利用变化的时空格局。结果如下:27 a间,与整个西双版纳州相比,主干公路两侧的土地利用强度更大、增长速度更快。公路两侧的土地利用转化主要表现为由林地向橡胶园和茶园转变,林地锐减,橡胶园迅速增加,林地是橡胶园的最主要来源。主要地类的面积在一定范围表现出与距公路距离的相关关系,距公路越近,林地面积百分比越小,橡胶园、建筑用地和水田面积百分比越大。土地利用变化也表现出明显的公路效应,距离公路越近,林地减少的速度、橡胶园增加的速度越快;随着距离的增加,林地向橡胶园的转化面积逐渐减小。土地利用变化的公路效应深度表现出不断扩展的趋势:1976年为公路两侧5 km,1988年为7 km,2003年达11 km。     

Road network detection from SPOT imagery for updating geographical information systems in the rural–urban fringe

Abstract

Visual interpretation of high-resolution satellite data has been useful for mapping linear features, such as roads and updating land-use changes. However, it would be beneficial to map new road networks digitally from satellite data to update digital databases using semi-automated techniques. In this paper, an algorithm called Gradient Direction Profile Analysis (GDPA) is used to extract road networks digitally from SPOT High Resolution Visible (HRV) panchromatic data. The roads generated are compared with a visual interpretation of the SPOT HRV multispectral and panchromatic data. The technique is most effective in areas where road development is relatively recent. This is due to the spectral consistency of new road networks. As new road networks are those of most interest to the land manager, this is a useful technique for updating digital road network files within a geographical information system of urban areas.     

Affordance-based categorization of road network data using a grounded theory of channel networks

We propose a grounded ontological theory of channel networks to categorize features, such as junctions, in road network databases. The theory is grounded, because its primitives can be given an unambiguous interpretation into directly observable qualities of physical road networks, such as supported movements and their medium, connectedness of such media, and turnoff restrictions. The theory provides a very general approach to automatically annotate and integrate road network data from heterogeneous sources, because it rests on application-independent observation principles. We suggest that road network categories such as junctions and roads are based on locomotion affordances. Road network databases can be mapped into our channel network theory, so that instances of roads and junctions can be automatically categorized or checked for consistency by what they afford. In this paper, we introduce affordance-based definitions of a road network and a junction, and show that the definition of latter is satisfied by some of the most common junction types.     

暴雨内涝影响下的城市道路交通拥挤特征识别

近年来,暴雨内涝频繁发生,常引发严重的城市交通拥堵问题。本文利用自主开发的宏观交通模拟工具,模拟了上海市中心城区50年一遇和100年一遇暴雨强度情景下每条路段的小时交通量,通过计算道路饱和度,研究了不同强度暴雨内涝对中心城区高架出入口和重要道路拥挤程度的影响。结果表明：①100年一遇暴雨内涝对上海市中心城区道路交通服务能力影响显著,可导致7个高架道路出入口关闭,部分出入口严重拥堵;②暴雨内涝对道路拥堵状况影响的差异性明显,变拥挤路段占道路总里程的13.35%,其中一级道路的拥挤程度变化最为明显,如：大连路、武宁路,周家嘴路和长寿路等主要路段服务水平下降。     

The New South Wales Travelling Stock Route and Reserve (TSR) network: historical extent,spatial distribution and drivers of loss 1884–2017

ABSTRACT

The Travelling Stock Route and Reserve (TSR) network is an historical grazing reserve network under threat, where public alarm has continued over the potential sale of reserves. Present debate on the future of the TSRs is often hindered by a lack of data, as knowledge of the historical extent of TSRs is deficient. This paper documents the original extent of the New South Wales TSR network and changes during 1884–2017, and discusses the key drivers of reserve loss since the late nineteenth century. Research using archived literature showed that, in 1884, the New South Wales TSR network comprised 4,414,690?ha. Comparisons of TSR acreage from that time with present estimates revealed that the reserve network has declined by 54% since its inception. Most reductions in TSR area during 1884–2017 have occurred in the Eastern (83%) and Central (82%) regions of the state, where competing land demands are greatest. Technological changes in transport, environmental pressures and economic changes in the grazing industry were identified as key drivers of TSR loss. These findings support concerns over the efficacy of the TSR reserve network, where the extent and impacts of past government decisions to sell off TSRs has been grossly under-estimated.     

道路网络生态干扰测度指数的改进及其空间分异特征——以闽江上游为例

以闽江上游地区为例,在传统指数的基础上,提出并采用改进后的道路网络线密度和道路网络影响域面密度指数,结合空间自相关分析方法,从线上和面上综合探索道路网络对生态干扰的空间分异格局;并分析指数间的相关性。结果表明：① 道路干扰程度具有明显的地区差异,在研究区中部、东部和南部存在空间集聚效应;② 考虑到坡度影响,同等级的道路缓冲带宽度并不是一个固定值;③ 所有指数均呈显著正相关,同类指数相关性大,不同类指数相关性小。若仅采用单一的线密度或面密度指数,则将导致信息不全;虽然同类指数间相关性很大,相互印证,但改进后的指数更加符合客观事实,建议采用。     

历史交通地理视角下的南岭古通道

基于历史文献资料,从历史交通地理的视角探讨南岭五岭是哪五岭,并对其地理位置及成名进行考证,探讨南岭五岭通道的形成及其在历史交通上所发挥的作用,以及这种作用随着朝代更迭的历史性变化。分析结果认为：1）五岭因其驿道而著名,因此五岭更多是指5条重要古驿道,今天的五岭通常指：大庾岭、骑田岭、都庞岭、萌渚岭、越城岭;2）有学者认为南岭最东端的筠门岭驿道也很重要,它是联系赣南和粤东的重要通道。因此,我们认为,南岭古称“五岭”,改称为“六岭”也是未尝不可;3）南岭古驿道的历史功能更多的是商道,由商道而带来了更深的经济文化交往和人口迁移;4）五岭的交通重心随着政治经济的更迭变化和大庾岭通道的开通而发生了由西到东偏移。     

世界遗产预备项目“丝绸之路-海路-中国段”研究

中国海上丝绸之路申遗于2016年正式启动,迄今尚无有关中国海上丝绸之路申遗专题的综合研究成果。首先建议申遗项目的中英文名称：丝绸之路-海路-中国段（Silk Road-Maritime Route in China）,然后探讨“丝绸之路”申遗的国际背景（除1项“丝绸之路：长安-天山廊道路网”系列跨国世界遗产外,另有8国递交9项“丝绸之路”预备项目）与“丝绸之路-海路-中国”项目的申报意义（主动性、创新性、唯一性、均衡性、政治性、世界性）。并就申报项目的遗产内容提出具体建议：遗产地从31处扩展至141处,遗产类型在文物遗产的基础上增加了聚落遗产（历史文化名镇、名村、街区）。最后提出在UNESCO世界遗产委员会建立“丝绸之路-海路”申遗专项基金。     

Symbolic ecclesiastical representations in the High Middle Ages landscape: A single-case study in northern Scandinavia

A regional examination of representations of geographical ecclesiastical features (boundaries, churches, and land use) in northern Scandinavia during the High Middle Ages was performed, using a peripheral parish as a single case. The analysis was based on historical maps, processed using microhistory and retrogressive approaches, and guided by theories of territoriality and landscape. The results showed that some churches were built on outfields, that landownership and prehistoric burials were clustered in two different areas, and that parish boundaries were often located in uninhabited forests between settlements and were sometimes moved. These results are discussed within the context of symbols, relations, and identity, which are complementary to explanations of centrality such as minimum travel distance. The author concludes that this indicates that, based on kinship networks, farmers from the settlement areas built the churches on jointly owned or managed land, which symbolises their collective effort – their sense of ours. Furthermore, settlement desertion during the agrarian crisis is probably the reason behind later changes in parish boundaries.     

从新构造应力场论公路水毁问题——兼论地貌发育的对抗性原理

根据沙依德格尔的对抗性原理，研究了新构造应力场对公路水毁的影响问题，发现在高应力区，如果公路走向平行于新构造应力场的剪切面或垂直于这个应力场的主压应力方向，公路的稳定性即将变坏。     

Relationships of Agricultural Land Use to an Expanded Road Network within Tropical Forest Landscapes of Cameroon and Republic of the Congo

Road building in Congo Basin forests has increased due to expansion of commercial logging, with potential to expose intact forests to greater establishment of agriculture. We developed new knowledge of agriculture clearing sizes, spatial patterns, and relationships with roads in seven case study sites comprising 7,529 km². Using very high spatial resolution satellite imagery, we mapped roads and rivers, plus clearings for agriculture, settlements, and logging. Mapped clearings (N = 1,781) ranged in size from 0.008 ha to more than 300 ha; most were smallholder agriculture, with 64 percent ≤ 1 ha. Statistical tests of spatial pattern confirmed that agriculture occurred in an inhomogeneous-aggregated pattern, suggesting interactions with other landscape elements. Proximity analyses showed that 76 percent of clearings were within 1 km of a road or river. Thirty-five percent of agriculture clearings were within 1 km of main public roads built before 1990, compared to 17 percent for logging roads built after 2000. Less than 6 percent of agriculture clearings were within 1 km of logging roads with overgrown canopies, suggesting transient relationships. Results based on fine-scale data provide new empirical support for understanding the interactions between agriculture and roads in one of the remaining relatively intact forest areas of the Congo Basin.     

山地林道网对林地环境的影响

山地林道网对林地环境影响的定量研究是一个重要的却一直未被重视的领域。采用定点观测与面上调查相结合的方法。定量研究山地林道网对林地土壤性质、土壤侵蚀量和植被的影响，分析其成因．揭示山地林道网对林地环境影响的机理。其研究结果可为定量评价森林作业系统对林地环境所产生的负面影响提供依据。     

Assessing the impact of Celaque National Park on forest fragmentation in western Honduras

The effectiveness of parks as management regimes is much in debate. This study examines the effect of establishment of the Celaque National Park, Honduras, in 1987, on limiting deforestation through a comparison with the surrounding landscape using remote sensing, GIS and landscape pattern analysis. Pressure on the park region is found to relate spatially to the locations of towns and roads, with increasing deforestation in the landscape surrounding the park. In contrast, the park has been largely successful in maintaining forest cover. Although the extent of change within the park is not pronounced, the pattern of change is. Expansion of agriculture and coffee production have led to increasing pressure on the park boundaries, with as much as 25% of the landscape surrounding the park experiencing land cover change between 1996 and 2000. This has significant implications for the future of the park.     

高速公路建设对山地景观格局的影响--以云南省澜沧江流域为例

以云南省土地利用图为基本图件,借助地理信息系统软件,运用景观生态学原理和方法研究云南省国际大通道建设对山地景观格局的影响,选择了澜沧江流域中下游两个典型区公路段,通过计算不同缓冲区景观格局指数的变化来定量化研究公路建设对景观格局影响规律。结果表明,道路修建直接导致景观格局改变,斑块数目、斑块密度、边缘密度和分维数增加,景观异质性增加;进一步研究表明,道路建设对缓冲区200 m内的景观格局直接影响最大,200 m外的影响趋于缓和;而多样性指数和均匀度指数在不同缓冲区变化不是很大;分析结果也表明,澜沧江中下游土地利用的空间分异和地貌差异也导致道路建设对景观格局影响不同。