Changing sedimentation patterns due to historical land-use change in Frenchman’s Bay,Pickering, Canada: evidence from high-resolution textural analysis

This study examines the anthropogenic alteration of sedimentation in Frenchman’s Bay in Lake Ontario, using high-resolution particle size analysis in two 200 cm cores. Lithofacies were determined using the particle size data of both the terrigenous sediment and terrigenous sediment + diatom fractions. Terrigenous particle size data from the centre of the lagoon provided the most representative record of anthropogenic impacts. Three distinctive lithofacies were recognized: (1) a Natural Wetland (NW) lithofacies (106–200 cm) had an average mean particle size of 49.4 μm, a mode of 29.4 μm and an average standard deviation of 119.1 μm; (2) an Agricultural and Deforestation (AD) lithofacies (40–105 cm) had a statistically significant lower average mean (30.8 μm), mode (13.5 μm), and standard deviation (48.5) μm; (3) an Urbanized (U) lithofacies (0–40 cm) showed a continued trend towards smaller particle sizes with an average mean of 21.2 μm, a mode of 9.4 μm, and an average standard deviation of 32.7 μm. The lithofacies correlated with previously identified trends in thecamoebian biofacies and magnetic susceptibility data showing post-colonial lagoon eutrophication and increased overland soil erosion. The up-core trend towards finer and less variable particle sizes is attributed to erosion of fine-grained watershed sediments (glacial Lake Iroquois silts and clay) during land-clearance and modification of natural drainage patterns. The influx of silts and clays into the lagoon is also recorded by increased sediment accumulation rates and a reduction in seasonal sediment variability in the wetland. Based on the ²¹⁰Pb dates, sedimentation rates increased at 1850 ±56 AD (AD lithofacies) and suggest an exponentially increasing trend in accumulation rates. Increasing sedimentation rates can be attributed to the progressive loss of native vegetation and intensified erosion of Lake Iroquois deposits via stream and hillslope erosion. Ecologically, the increased input of fine-grained sediments into the wetland has resulted in reduced water clarity and has altered the wetland substrate contributing to wetland loss in Frenchman’s Bay.     

The response of soil erosion and sediment export to land-use change in four areas of Europe: The importance of landscape pattern

The response of erosion and sediment export to past land-use change has been studied in four agricultural areas of Europe. Three of these areas were subject to land abandonment or de-intensification and one to intensification of land-use practices. Erosion and sediment yield were modeled using the WaTEM/SEDEM model, which combines the RUSLE equation with a sediment routing algorithm. Spatial relationships between the RUSLE C-factor (i.e. land-use) and other erosion and sediment export-determining factors (slope, soil erodibility and distance to rivers) were investigated, as these account for non-linearity in the response of erosion and sediment export to land-use change.Erosion and sediment export have decreased enormously in the de-intensified areas, but slightly increased in the intensively cultivated area. The spatial pattern of land-use change in relation to other erosion and sediment export-determining factors appears to have a large impact on the response of soil erosion and sediment export to land-use change. That the drivers of abandonment of arable land and erosion coincide indicates that de-intensification leads to a more favourable landscape pattern with respect to reduction of erosion and sediment export. This mechanism applies not only within the study areas, but also among the European study areas where the process of intensification of some areas and de-intensification of others might result in an overall decrease of erosion and sediment yield through time.     

Projecting land-use change processes in the Sierra Norte of Oaxaca, Mexico

The objective of study was to explore short-term trends of processes that determine land-use change in Sierra Norte of Oaxaca (SNO), Mexico. Land use and land cover changes (LULCC) were estimated in a complex mosaic of vegetation in the SNO from 1980 to 2000, and projected them to 2020 through a Markovian model. SNO is highly vulnerable to climatic change according to a 2050 GCM scenario. However, 3% annual rate of tropical and temperate forest deforestation from agriculture and livestock encroachment, suggest the threat from land-use change is higher than that from climatic change for this study site. Productive land-use strategies are needed to reduce such high deforestation rates for tropical regions. Controlling deforestation would also reduce short-term effects of CO₂ emissions to the atmosphere. Because of the necessity to evaluate anthropogenic ecosystem changes, it is imperative to separate short-term influences such as deforestation, from long-term influences such as climatic change.     

喀斯特山区土地利用变化的人类驱动机制研究——以贵州省为例

根据土地利用和相关的社会经济状况及其变化特征分析,提出了表征县域土地利用变化及其人类驱动因素的指标,分析了二者的联系以探讨人类驱动因素对土地利用变化的驱动机制,指出了人类驱动因素在解释土地利用变化过程中的贡献,为协调喀斯特地区土地资源和人类活动的关系提供依据,为进一步进行土地利用/土地覆盖变化研究积累方法和经验。     

内蒙古草原NPP时空变化及驱动力

植被净初级生产力(NPP)及驱动力分析是全球变化研究的核心内容.以1982-2015年内蒙古草原为研究对象,基于GIMMS NDVI3g、ERA5气象和草原类型数据,采用CASA模型生成年草原NPP.综合运用趋势分析、偏相关、复相关及残差分析法探讨1982-2015年草原NPP变化趋势,并定量确定气候因子和人类活动对草...     

An interdisciplinary approach to depict landscape change drivers: A case study of the Ticuiz agrarian community in Michoacan, Mexico

Landscape changes are driven by a combination of physical, ecological and socio-cultural factors. Hence, a large amount of information is necessary to monitor these changes and to develop effective strategies for management and conservation. For this, novel strategies for combining social and environmental data need to be developed. The purpose of this study is to demonstrate the value of an innovative interdisciplinary approach to help in explaining landscape change. We integrated three main sources of information: biophysical landscape attributes, land-use/cover change analysis and social perceptions of land-use change, institutional and policy factors and environmental services. Multivariate statistical analysis was used to develop a weight for each variable described or quantified. Finally we identified proximate causes and underlying driving forces of land transformation in the study area. The study was undertaken in a typical community in Mexico.     

1979-2014年长沙市城市功能用地扩展与驱动力研究

基于长沙市中心城区1979年、1989年、2003年、2011年、2014年5个年份的土地利用现状图,借助ArcGIS、SPSS分析工具,提取居住、工业、服务三大功能用地,从方向、圈层、强度、用地间转变及轴带趋向对长沙城市功能用地扩展的时空特征及驱动力进行研究。结果表明：① 用地扩展模式以“圈层式、轴带式”为主,并逐渐向“多组团式”过渡,由单一的向外扩展向内部功能间演替和外部扩展相结合转变。整体扩展方向经历了由“东、南、东南-西北、东、东南、北”的变化,但各类用地的扩展方向有所差异;② 从扩展强度看,居住用地远远高于城市总体扩展强度,造成了城市功能空间失衡的现象,服务配套明显滞后,部分分区在扩展过程中,出现了与规划定位严重不符的矛盾;③ 功能用地间的转变主要集中在城市核心区,表现出以核心-外围明显分异的差距。外围片区的功能较为单一,融合度不够,未来应增强配套服务功能。④ 从经济驱动力、政策调控力、生态制约力与吸引力、社会助推力四个方面分析了功能用地扩展时空差异的驱动因素。⑤ 从“问题导向-现象归纳-本质剖析-策略应对”提出了城市功能用地扩展研究的基本研究框架。     

Spatial and temporal variation of the urban impervious surface and its driving forces in the central city of Harbin

Associated with the rapid economic development of China, the level of urbanization is becoming a serious concern. Harbin, the capital city of Heilongjiang Province, China and one of the political, economic, cultural, and transportation centers of the northeastern region of China, has experienced rapid urbanization recently. To examine the spatial patterns of long-term urbanization and explore its driving forces, we employed the impervious surface fraction derived from remote sensing image as a primary indicator. Specifically, urban impervious surface information for the central city of Harbin in 1984, 1993, 2002, and 2010 was extracted from Landsat Thematic Mapper image using a Linear Spectral Mixture Analysis (LMSA). Then, the spatial and temporal variation characteristics and the driving factors of percent impervious surface area (ISA) changes were analyzed throughout this 26-year period (1984 to 2010). Analysis of results suggests that: (1) ISAs in the central city of Harbin constantly increased, particularly from 1993 to 2010, a rapid urbanization period; (2) the gravity center of impervious surface area in the central city was located in Nangang District in 1984, moving southeast from 1984 to 1993, northwest from 1993 to 2002, and continuing toward the southeast from 2002 to 2010; and (3) the urban growth of the central city can be characterized as edge-type growth.     

Spatially explicit changes of forestland in Taiwan Province from 1910 to 2010

Journal of Geographical Sciences - Reconstructing long-term changes of forest cover (FC) can provide reliable underlying data for carbon source/sink accounting and simulation of the effects of land...     

2001-2015年间我国陆地植被覆盖度时空变化及驱动力分析

本文基于MODIS-NDVI遥感数据反演计算了我国陆地2001—2015年地表植被覆盖度的空间分布,讨论了植被覆盖度的时空变化规律,分析了影响植被覆盖度近十几年来动态变化的主要驱动因素。研究结果表明：我国陆地植被覆盖度从2001—2015年,植被覆盖度总体上呈增加趋势,其中淮河流域、华北平原地区、以及黄土高原地区增加趋势显著。根据植被覆盖度在时间序列上的变化特征,可将其变化类型分为持续增长型、先减小后增长等六种类型,其中农业种植区基本为一直增长型,而主要森林覆盖区,特别是西南地区的植被覆盖度在研究时段内表现出波动性的变化特征。降水是驱动华北平原北部,内蒙古,以及西北大部分区域植被覆盖度动态变化的重要因素,东北、青藏高原等地区植被覆盖度受温度的影响较大,而在中国东南沿海地区,光照条件是影响该区域植被覆盖度的主要因素。     

Arcellaceans (thecamoebians) as indicators of land-use change: settlement history of the Swan Lake area, Ontario as a case study

Arcellaceans have been used as indicators of a variety of paleolimnological conditions including pH, eutrophication, oxygen level, and heavy metal contamination, but there has only been limited application of the group to climate and land-use change research. The limnological evolution of Swan Lake in southwestern Ontario was documented using arcellaceans as proxies, and compared to the results of a palynological analysis, with which it closely correlated. The palynological record documents the rapid disappearance of forest by around 1850 as the area was cleared for agriculture and settlements. The change was characterized by a shift in the palynological record from the Woodland to High Diversity assemblages. Similarly the arcellacean fauna changed from the Pre-European Settlement Assemblage to the distinctive low diversity, stressed environment European Deforestation Assemblage. The introduction of high-yield chemical fertilizers in the post World War II era, and the resultant eutrophication of the lake, was clearly recognizable in the palynological record as indicated by the dramatic increase in the algae Pediastrum (High Nutrient Assemblage). This change in farming practice was also identifiable with arcellacean proxies, as indicated by the appearance of the algalphilic Eutrophication Assemblage. The arcellacean Ecologically Destabilized Assemblage dominated the lake for short intervals during the transition between the Pre-European Settlement and European Deforestation assemblages and again at the transition between the European Deforestation and Eutrophication Assemblages, indicative of periods of ecological destabilization as the lake adjusted to new trophic inputs. A stressed environment arcellacean Ecologically Destabilized Assemblage found in a portion of the core estimated to have been deposited between AD 1350 and AD 1700 may provide evidence of an earlier phase of deforestation associated with Huron Indian agricultural practices. The close correlation between the palynological and arcellacean proxy data clearly demonstrates the potential of arcellaceans as land-use change proxies, and indicates that changes in land-use had an almost immediate impact on the Swan Lake ecosystem. This observation raises concerns about the impact that rapid urbanization is having on the environmentally sensitive Oak Ridges Moraine watershed, of which Swan Lake is a part.     

锡林郭勒盟草原沙化动态变化及驱动力分析——以正蓝旗为例

以地处浑善达克沙地腹地的正蓝旗为研究区,以TM／ETM＋影像数据为基础,利用动态度、栅格运算等方法,对该区1980年代以来四个时期的草原沙化状况及其空间动态变化进行了监测分析,并探讨了正蓝旗草原沙化变化与降雨、温度、人口和牲畜等数据的关系。结果表明：（1）三级沙化草地及未沙化草地间的相互转换主导着草原沙化发展或是逆转的...     

改革开放以来中国行政区划格局演变与驱动力分析

行政区划变更与社会经济发展密切相关,也影响着社会经济的健康发展。主要分析了1978年以来35年间中国县级以上各类型行政区的数量变化,根据变化特征和规律划分出四个发展阶段,阐述了各个阶段行政区划空间格局的发展变化,总结了中国行政区划演变的五种主要模式:建制变更、行政区拆分、行政区合并、建制升格以及新设立行政区。行政区划格局的演变受多种因素的影响,城镇化进程、中心城市的空间拓展、人口的集聚与增长、交通和通讯条件的改善以及政策因素都是行政区划格局演变的重要驱动力。在新型城镇化背景下,应该加强中国行政区划时空格局演变和驱动力分析,以期为中国未来的行政区划调整和城镇化的健康发展提供一些指导与借鉴。     

Satellite based long-term assessment of rangeland condition in semi-arid areas: An example from Botswana

A methodology was devised for comparison of generalised range condition over time, irrespective of the nature of original imagery used. It was applied for range condition change mapping throughout Botswana through 1984-2000. Results showed that range degradation was most widespread during the 1980s drought when 25% of the country was affected, decreased to 6.5% in 1994 and increased to 9.8% in 2000. This suggests that these semi-arid rangelands are fairly resilient and can withstand “normal” droughts even under conditions of heavy grazing pressure. However, degradation that persists during normal or above average rainfall years is related to increasing livestock and other pressures on rangelands and may represent areas with severe range recovery problems. This application meets some requirements of a semi-arid developing country looking to improve range condition monitoring over relatively remote areas.     

Linking hydrological, infinite slope stability and land-use change models through GIS for assessing the impact of deforestation on slope stability in high Andean watersheds

In the Ecuadorian Andes, episodic slope movements comprising shallow rotational and translational slides and rapid flows of debris and soil material are common. Consequently, not only considerable financial costs are experienced, but also major ecological and environmental problems arise in a larger geographical area. Sediment production by slope movement on hillslopes directly affects sediment transport and deposition in downstream rivers and dams and morphological changes in the stream channels. In developing countries world-wide, slope movement hazards are growing: increasing population pressure and economic development force more people to move to potentially hazardous areas, which are less suitable for agriculture and rangelands.This paper describes the methods used to determine the controlling factors of slope failure and to build upon the results of the statistical analysis a process-based slope stability model, which includes a dynamic soil wetness index using a simple subsurface flow model. The model provides a time-varying estimate of slope movement susceptibility, by linking land-use data with spatially varying hydrologic (soil conductivity, evapotranspiration, soil wetness) and soil strength properties. The slope stability model was applied to a high Andean watershed (Gordeleg Catchment, 250 ha, southern Ecuadorian Andes) and was validated by calculating the association coefficients between the slope movement susceptibility map of 2000 and the spatial pattern of active slope movements, as measured in the field with GPS. The proposed methodology allows assessment of the effects of past and future land-use change on slope stability. A realistic deforestation scenario was presented: past land-use change includes a gradual fragmentation and clear cut of the secondary forests, as observed over the last four decades (1963–2000), future land-use change is simulated based on a binary logistic deforestation model, whereby it was assumed that future land-use change would continue at the same rate and style as over the last 37 years (1963–2000).     

东北地区唐代渤海古城遗址空间格局及影响因素分析

运用ArcGIS软件及空间分析等方法,研究了东北地区234座唐朝渤海国古城遗址分布特征,探讨了古城遗址空间格局与自然条件的关系。通过对234座古城址进行分析,发现唐朝渤海国古城址主要集中在4个集聚区,即图们江?鸭绿江流域集聚区（A）、牡丹江流域集聚区（B）、松花江?辽河流域集聚区（C）、穆棱河流域集聚区（D）。其中图们江?鸭绿江流域集聚区是最主要的遗址分布区,位于研究区的南部,占遗址总量的47.43%。研究区渤海国古代城址呈北疏南密的分布特征,形成明显的“空间组群”格局。在当时的气候环境之下,水热条件等自然因素成为影响城址的主要因素,而政治、经济、军事和交通区位等人文因素则对古城遗址的数量和分布起重要导向作用。     

1980—2018年银川市生态系统服务价值评价及驱动力分析

生态系统服务价值(Ecosystem service values,ESV)的准确评估及其驱动力分析,关乎区域生态安全和经济发展。基于1980—2018年银川市各区县的土地利用数据,结合变化率、动态度、敏感性和相关性核算了银川市的生态系统服务价值,并利用地理探测器分析了驱动因子。结果表明:1980—2018年不同生态服务类型总的ESV在减小,减少了0.753×10⁹元。绝大部分生态服务类型的生态系统服务价值变化幅度较小,水文调节的价值最高且变化显著。水资源供给的变化动态度最大,并且呈增长趋势;草地和水体生态系统服务价值的敏感性较强,水体与总的生态系统服务价值关联性最强。从分布来看,灵武市生态系统服务价值最高,金凤县最小。单因子主要驱动因子为国内生产总值(Gross domestic product,GDP)和数字高程模型(Digital elevation model,DEM),多因子交互驱动中GDP∩气温和GDP∩DEM对银川市ESV分布的贡献最大,银川市生态系统服务价值分布主要受人为因素和自然因素的交互作用影响。     

北京丰台区土地利用变化及其经济驱动力分析

采用GIS技术和统计分析技术,基于1984、1992和1995～2001年土地利用图件和数据,分析了1984年以来北京丰台区土地利用变化历史过程及其空间分异特征。土地利用变化的基本特点是农业用地面积大幅度下降,非农用地面积快速增加,且随着时间的推移,变化高峰地域在由内向外传递。对1999年土地利用类型数据与经济产值数据匹配结果表明:土地经济产出效益巨大差异的存在是驱动丰台区土地利用从农业用地,尤其是耕地向非农业用地转化的最大动力所在。利用1992～2001年的非农业用地与固定资产投资、人口,二、三产业增加值进行的相关分析显示,固定资产投资、人口增长和第二产业的发展对非农业用地扩展有着显著的作用。     

1999-2018年重庆市主城区住宅用地空间演变特征及驱动因素研究

以典型山地城市重庆市主城区为研究对象,基于住宅小区空间矢量数据和多源兴趣点(Point of Interest,POD数据,采用标准差椭圆、圈层缓冲区分析、扩展强度指数、景观格局分析和地理加权回归(GWR,Geographic-ally Weighted Regression)方法,对近20 a重庆市主城区住宅小区的空...     

企业合作模式及其对区域经济发展的影响——以江苏省通州市企业为例

随着竞争日益复杂化,企业之间纷纷从对立型竞争转向合作型竞争,并由此对企业的空间行为、空间结构及区域经济发展产生了重要影响。相对于在实践中不断推进的企业合作活动,这方面的理论研究落后很多,特别是有关企业合作与区域经济发展关系方面的研究更少。企业合作可以分为研发合作、生产合作、营销合作、资金合作等不同模式,他们对于区域经济发展有如一柄双刃剑,既可以加快区域生产要素的流动,通过蛙跳效应、涓滴效应、网络化效应等加快落后地区的发展,也可造成落后地区在合作过程中对发达地区的过度依赖,并承接来自发达地区的污染转移,影响落后地区的可持续发展和产业升级。