景观生态风险研究进展及基于生态系统服务的评价框架: ESRISK

在快速城市化过程中,高强度人为活动对生态系统结构和服务功能造成极大扰动,进而产生一定生态风险。近年来,景观生态风险评价的兴起为景观格局—生态过程互馈研究提供了新的视角,可有效支持生态系统管理。本文在探讨生态风险、区域生态风险与景观生态风险联系与区别的基础上,重点评述了景观指数法和风险“源—汇”法等主要景观生态风险评价方法,归纳了基于生态系统服务的景观生态风险研究进展。进一步地,以生态系统服务退化为损失表征,从地形、人为胁迫、生态恢复力、景观脆弱性等维度构建概率表征指标体系,提出了基于生态系统服务的景观生态风险评价（ESRISK）框架,以期为景观生态风险研究提供一个更为完善、综合的评价方法参考,并辅助支持风险减缓策略制定和有限资源的高效分配。最后,从生态系统服务权衡与协同关系、评价结果不确定性分析、景观生态风险与景观格局多尺度关联关系、脆弱性研究深化等方面做出展望。     

赤水河流域中上游坡地景观特征对河流水质的影响

在喀斯特地区,较大的地表坡降和坡地开发强度导致承载在地表景观上的污染物因地势和降水加倍迁移到河水中。以赤水河流域中上游为研究区,分别在全子流域、子流域坡地、子流域陡坡地三个层面上提取景观结构、景观开发强度和景观格局指数,研究各级坡地景观特征对水质的影响。结果表明：① 与总林地相比坡林地对水质潜在的“汇”作用更加显著;占总耕地面积不足1/7的陡坡耕地、却对河水中总磷（TP）和氨氮（NH₃-N）浓度大小贡献显著（相关系数为0.608和0.614）。② 景观开发强度与各水质污染物指标呈现显著而稳定的正相关性,相关系数最高达0.960,它比单个景观对水质指标更具解释能力。③ 斑块形状复杂度、景观多样性、景观分离度均与水质污染物指标呈高度或显著正相关,且随着地形坡度的增大,水质污染物指标对景观散布与并列指数（IJI）和农香多样性指数（SHDI）越来越敏感。故减少对坡地尤其是陡坡地景观的不当人为干扰,对喀斯特地区流域水质保护有重要意义。     

气候变化和人类活动对南方红壤丘陵区森林生态系统影响模拟研究——以江西泰和县为例

在全球气候变化和人类活动的影响下,森林生态系统结构、功能以及空间格局都将发生不同程度的变化。明晰景观尺度上未来森林的动态变化,对森林可持续发展具有重要意义。选择江西省泰和县为研究区,综合利用土地利用模型（CA-Markov）和森林景观动态模型（LANDIS-II）,并结合生态系统过程模型（PnET-II）,模拟气候变化、土地利用、采伐以及综合情景下未来40年（2010-2050年）阔叶林、针叶林的面积及生物量变化。结果表明：① 气候变化对森林面积影响较小,采伐使森林面积显著减少,土地利用变化使森林面积的变化更加剧烈;② 针叶林和阔叶林对不同干扰方式的响应表现出较强差异,针叶林对采伐的响应更加剧烈;③ 多模型综合模拟方法有助于区域森林管理,为南方红壤丘陵区森林结构优化和功能提升提供科学建议。     

基于无人机航摄影像的喀斯特地区裸岩信息提取及景观格局分析

喀斯特地区不同石漠化等级的结构和格局是实现区域石漠化治理的重要基础信息,受技术手段的限制,目前这方面的研究进展仍非常缓慢。随着无人机技术的快速发展,高精度的地表信息获取越来越方便、且成本较低。本研究利用无人机影像,对比了基于像元的非监督和监督分类方法以及面向对象的分类方法在裸岩信息提取中的表现,发现面向对象分类结果具有更高精度。基于获得的裸岩分布信息的研究结果表明：① 岩石平均斑块面积与裸岩率呈负相关的关系,岩石斑块个数与裸岩率呈正相关关系;② 通过对比不同裸岩率（11%、20%、29%和48%）基质的景观斑块指数、景观形状指数和景观破碎度指数对不同裸岩率的景观分布的影响,从而表明了在不同的石漠化地区随着裸岩率的增加,岩石形状指数与岩石破碎度指数均逐渐增加,进而表明石漠化程度越严重;③ 裸岩率不同的地区表现不同的分布形态和斑块特征,裸岩率越高,岩石越破碎,斑块分布较为分散。小尺度斑块景观格局与区域的生态过程有着重要关系,开展小尺度景观格局的研究会深化区域尺度石漠化发展过程的理解。石漠化地区的小尺度斑块景观格局变化影响区域的生态过程,对以后的石漠化过程以及未来石漠化演变的发展有重要的启示作用。     

禹城市农村居民点空间分布模式和景观格局

以禹城市农村居民点为研究对象,基于禹城市2000和2017年遥感影像解译数据,综合运用GIS、景观生态学及统计学理论与方法,分析了2000年与2017年禹城市乡村聚落的景观格局指数和空间演变特征。结果表明:禹城市两个时期农村居民点在空间分布特征上存在显著差异,与2000年相比,2017年禹城市农村居民点分布更加聚集;从聚集程度来看,禹城市农村居民点聚集的态势不够显著,这与禹城市当地的自然环境有密切的关系;禹城市农村居民点总体用地规模和数量虽然在减少,但部分居民点用地规模增加明显,居民点有集聚发展的态势,同时禹城市农村居民点斑块形态由复杂化向规则化转变。     

基于地理国情普查的奉化市建成区绿地景观格局研究

以奉化市建成区为研究区域,结合奉化市建成区绿地率和绿化覆盖率调查,在Arc GIS支持下,对奉化市建成区绿地景观格局进行研究。研究结果表明:奉化市建成区绿地现状面积为387.12 hm2,绿化率13.32%,绿化覆盖面积542.43 hm2,绿化覆盖率18.65%;绿地斑块大小组成比较合理,城市边缘地区缺乏大中型和大型绿地斑块;绿地平均形状指数相对较高,绿地景观形状指数,公园绿地防护绿地其他绿地生产绿地附属绿地;各类型绿地景观平均斑块分维数基本都处于1.3~1.6之间,分维数较高,斑块边界较复杂。此外,本研究还对奉化市建成区各街区绿地景观指数做了比较分析。     

The topological viewshed: embedding topological pointers into digital terrain models to improve GIS capability for visual landscape analysis

The effort to develop a Digital Earth has made dramatic progress in terms of visualisation and visual data integration for use-cases which demand semantically rich analysis. To provide this analysis and ensure legitimate representations of the spatial data from which visualisation are derived, it is necessary to provide more comprehensive analytical capabilities of the view. Questions of aesthetic valuation of landscape require a richer analytical response than simply ‘whether and possibly how much of’ an object or area of land can be seen. It requires interrogation of the scene as it appears and to distinguish between transient visual effects and those locally invariant to view point change. This paper explores a data structure to support scene analytics. As such, it first reviews the existing techniques from the fields of GIS and computer graphics as to their potential and limitations in providing a qualitatively more nuanced visual analysis. It then introduces a new method of encoding visually apparent relationships into terrain models. A prototype implementation is presented based on the Quad-Edge Triangular Irregular Network, though it is believed that raster or vector implementation would be possible. Although developed primarily with landscape analysis in mind, the method could have wider applicability.     

Spatial pattern of urban functional landscapes along an urban–rural gradient: A case study in Xiamen City,China

Since there is an increasing demand for integrating landscape ecology and urban planning theories to study complex urban ecosystems and establish rational and ecological urban planning, we introduced a new concept-urban functional landscapes which can be reclassified based on detailed land use data to fulfill the various urban functions, such as residential, commercial, industrial, and infrastructure purposes. In this paper, urban functional landscapes were defined based on urban land use data produced from Pleiades images, and then landscape metrics and population density were combined to identify the urban functional zones along an urban–rural gradient. The features of urban functional landscape patterns and population density were also analyzed, and their relationship has been explored. The results showed that the pattern of urban functional landscapes and population density in the urban functional zones (Urban center, Urban peripheral area, Landscape barrier, Satellite city and Far-suburb) along the urban–rural gradient in Xiamen doesn't totally conform to the classical theories in spatial and social aspects. Urban functional landscapes is potential of acting as bridges between the landscape ecology and urban planning theories, providing scientific support for rational urban landscape planning and urban land use policy making.     

Spatial variation of wetlands and flux of dissolved organic carbon in boreal headwater streams

In order to investigate the relation between water chemistry and functional landscape elements, spatial data sets of characteristics for 68 small (0·2–1·5 km²) boreal forest catchments in western central Sweden were analysed in a geographical information system (GIS). The geographic data used were extracted from official topographic maps. Water sampled four times at different flow situations was analysed chemically. This paper focuses on one phenomenon that has an important influence on headwater quality in boreal, coniferous forest streams: generation and export of dissolved organic carbon (DOC). It is known that wetland cover (bogs and fens) in the catchment is a major source of DOC. In this study, a comparison was made between a large number of headwater catchments with varying spatial locations and areas of wetlands. How this variation, together with a number of other spatial variables, influences the DOC flux in the streamwater was analysed by statistical methods. There were significant, but not strong, correlations between the total percentages of wetland area and DOC flux measured at a medium flow situation, but not at high flow. Neither were there any significant correlations between the percentage of wetland area connected to streams, nor the percentage of wetland area within a zone 50 m from the stream and the DOC flux. There were, however, correlations between catchment mean slope and the DOC flux in all but one flow situations. This study showed that, considering geographical data retrieved from official sources, the topography of a catchment better explains the variation in DOC flux than the percentage and locations of distinct wetland areas. This emphasizes the need for high‐resolution elevation models accurate enough to reveal the sources of DOC found in headwater streams. Copyright © 2007 John Wiley & Sons, Ltd.     

县域生态景观要素信息图谱的图像分析

“数字福建”、“数字厦门”正在建设中。本文以永泰县为例,在RS技术支持下,对生态景观要素信息图谱进行初步研究。利用影像光谱信息统计分析、特征变换等进行生态景观要素(生态水、生态能和生态元)的遥感监测,对山区水热状况、山区植被类型作了分析。