LAND‐USE DYNAMICS BEYOND THE AMERICAN URBAN FRINGE*

ABSTRACT. A deficiency common to both the historical debates over loss of agricultural land and the current discussions of urbanization and sprawl is a limited understanding of land‐use dynamics beyond the urban fringe. Data aggregated at the county level poorly capture the fine‐grained pattern of land‐use change beyond the dynamic urban‐rural interface. Furthermore, current urban‐based definitions are poorly suited to delineate these areas, and low‐density, exurban land use is difficult to measure using existing land‐cover databases. Urbanization and the conversion of once‐agricultural or other natural resource lands to other uses has traditionally been tracked using urban areas, as delimited in the U.S. census. Urban densities are typically defined as areas with more than 1,000 people per square mile, or 1.6 people per acre (U.S. Census Bureau 2000). Assuming an average of 2.5 people per housing unit, this translates to roughly 0.7 units per acre, or approximately 1 unit per 1.6 acres. The analytical units used in the census, however, both overbound and underbound areas with urban densities. About one‐third of urban areas in 1990 comprised lower‐than‐urban housing density, thanks to overbounding. But, then, one‐third of locations that had urban‐level housing densities failed to be included in urban areas as a result of underbounding, which, if counted, would have constituted another 18 million acres of urban area. An increase over time of the average number of acres required per housing unit in exurban and higher‐density locations occurred in roughly one‐third of U.S. counties from 1960 to 1990 and persisted from 1990 to 2000. In 2000 roughly 38 million acres were settled at urban densities, and nearly ten times that much land was settled at rates from low, exurban density (as low as one house per 40 acres) to higher rates (up to one per 10 acres). This represents a continuing encroachment on land previously given over to other uses—habitat or agriculture. Practitioners of natural resource management need to recognize the ubiquity of exurban development and better incorporate the fine‐scale patterns of land use beyond the urban fringe.     

Multi‐scale correlations between topography and vegetation in a hillside catchment of Honduras

All systems have causes and effects that can be appreciated at different spatial scales. Understanding and representing the complexity of multi‐scale patterns in maps and spatial models are key research objectives. We describe the use of three types of correlation analyses: (1) a standard Pearson correlation coefficient, (2) a ‘global’ multi‐scale correlation, and (3) local geographically weighted correlation. These methods were applied to topographic and vegetation indices in a small catchment in Honduras that is representative of the country's hillsides agro‐ecosystem which suffers from severe environmental degradation due to land‐use decisions that lead to deforestation, overgrazing, and unsustainable agricultural. If the geographical scale at which topography matters for land‐use allocation can be determined, then integration of knowledge systems can be focused. Our preliminary results show that: (1) single‐scale correlations do not adequately represent the relationship between NDVI and topographic indices; (2) peaks in the global multi‐scale correlations in agricultural areas coincided with the median farm size, but there was no evidence of any community or larger‐scale land‐use planning or optimization; and (3) local multi‐scale correlations varied considerably from the global results at all scales, and these variations have a strong spatial structure which may indicate local optimization of land use.     

Recreational Access to Privately Owned Rural Land: A Case Study in Canterbury Hill Country, New Zealand

There is public concern that private ownership restricts public access to land for such uses as recreation and amenity value. There is little systematically collected information about the extent of unfavourable attitudes to public access in New Zealand. This case study analyses the responses of 94 farmers/foresters to a request to operate a series of large‐scale sporting events that traversed privately owned rural land. Issues of concern to landowners included visitor health and safety, disturbance to farm or forest management, and spread of disease. Despite these concerns 90 percent of the landowners who were approached allowed access to their land for recreation. An approach for handling possible landowner requests to charge for access for large‐scale events is suggested.     

Residential perspectives: the value of Floodplain‐ buyout open space

This mixed‐methods case study identifies how floodplain property acquisition—a buyout—impacts an urban environment at the neighborhood scale while considering the role of individual residents in formal and informal land‐use decision making. In floodplain buyouts, the reopening of urban space is enabled by federal structural drivers, primarily Federal Emergency Management Agency (FEMA), but it is repurposed as a cultural landscape constructed and produced by individuals. This research explores how residents perceive and ascribe values to the buyout landscape in Lexington, Kentucky. Enabled by federal funds, but left largely to their own devices, residents in Lexington adopted uses, ascribed values, and produced their own land‐use norms in each buyout neighborhood.     

不同收入水平的城市居民生活消费生态足迹测算与对比——以河南省开封市为例

本文运用生态足迹的理论和方法,以2009年开封市3个不同收入居民消费水平生活小区为例,采用居民生物资源和能源消费调查问卷数据,定量分析了2009年开封市不同收入水平小区居民的生活消费生态足迹。根据板桥小区、康平小区、龙成花园3 个小区的调查资料,分别计算了3个小区的生物资源消费和能源消费的生态足迹。结果表明:① 从3个小区人均生态足迹来看,总体上能源消耗的生态足迹较大;② 从3个小区居民生物消费的生态足迹来看,猪肉的人均生态足迹最大,奶制品次之,肉类食品和奶制品的生产需要较多的土地面积;③ 通过分析3个小区不同类型的人均生态足迹,板桥小区化石燃料用地和建筑用地所占的比重最大,其次是耕地和草地;收入消费水平越高的居民,生态足迹越大,收入消费水平越低的居民,生态足迹越小。证实了高收入水平居民对生态以及资源的占用程度要远远大于低收入水平居民,造成居民生态占用以及碳排放的不公。最后,提出了有针对性的对策建议。     

WHY MONITOR CARBON IN HIGH‐ALPINE STREAMS?

In this short communication, we report on dissolved organic and inorganic carbon concentrations from a summer stream monitoring campaign at the main hydrological catchment of the Tarfala Research Station in northern Sweden. Further, we place these unique high‐alpine observations in the context of a relevant subset of Sweden's national monitoring programme. Our analysis shows that while the monitoring programme (at least for total organic carbon) may have relatively good representativeness across a range of forest coverages, alpine/tundra environments are potentially underrepresented. As for dissolved inorganic carbon, there is currently no national monitoring in Sweden. Since the selection of stream water monitoring locations and monitored constituents at the national scale can be motivated by any number of goals (or limitations), monitoring at the Tarfala Research Station along with other research catchment sites across Fennoscandia becomes increasingly important and can offer potential complementary data necessary for improving process understanding. Research catchment sites (typically not included in national monitoring programmes) can help cover small‐scale landscape features and thus complement national monitoring thereby improving the ability to capture hot spots and hot moments of biogeochemical export. This provides a valuable baseline of current conditions in high‐alpine environments against which to gauge future changes in response to potential climatic and land cover shifts.     

珠三角核心区农田耕层土壤有机碳库储量时空变化特征及其影响因素识别

土壤有机碳库动态变化对区域乃至全球碳平衡具有显著影响,快速城市化地区社会经济迅速发展中土地利用/覆被变化剧烈,其农田耕层土壤有机碳库变化问题倍受关注。选择珠三角核心区为研究区域,基于1980与2015年农田耕层土壤有机碳含量数据,以乡镇为单元分析农田耕层土壤有机碳库储量的时空变化特征,并通过地理探测器定量识别其影响因素的主导因素。结果表明：1）珠三角核心区农田耕层土壤有机碳库储量1980―2015年间损失巨大,损失量达67.16%,同时其空间变化具有典型的城镇集群指向特征,即距离城镇集群越近,损失程度越大;2）珠三角核心区农田耕层土壤有机碳库储量的时空异质性变化受到气候变化、地形状况、水文环境、社会经济发展、土地利用变化和农田景观变化等多种因素的影响,且其影响力存在较大差异,各因素贡献力（q统计量）介于0.004~0.256之间;3）珠三角核心区农田耕层土壤有机碳库时空变化主导影响因素的贡献力表现为农田景观变化＞二三产增长胁迫＞水网密度＞土地结构变化。     

Modeling watershed-scale sequestration of soil organic carbon for carbon credit programs

Impending risks associated with climate change have forced the global community to devise tradable pollution permit or “cap and trade” approaches to control the release of greenhouse gases. In the U.S, soils have the potential to offset about 10 percent of annual CO₂ emissions; however, if carbon credits are to be included in greenhouse gas control programs, soil organic carbon (SOC) sequestration rates associated with agricultural land uses must be computed at a watershed scale. The Soil Water Assessment Tool (SWAT) water quality model, the Water Erosion Prediction Project (WEPP) erosion model, and the CENTURY 4.0 a soil carbon model were used to simulate carbon sequestration rates for 160 crop-tillage rotations in 272 sub-basins of the Big Creek watershed (12,300 hectares). Under annual crops, only no-till in a corn-soybean rotation, on low to moderate slopes results in net gains in SOC. Substantial annual rates of SOC sequestration occur only under perennial crops such as Conservation Reserve Program (CRP; 0.14 t/ha without erosion; 0.08 with erosion), pasture (0.67 t/ha without erosion; 0.58 with erosion), hay (0.88 t/ha without erosion; 0.52 with erosion), and forest (2.66 t/ha without erosion; 2.49 with erosion). Erosion thus has a large effect on the spatial distribution of field-measured SOC by moving it down slope and increasing its spatial variability. Because of this, carbon credit programs should be based on field practices, thus targeting the locations where the sequestration of atmospheric carbon actually occurs and minimizing monitoring costs. Developing model-based estimates of SOC sequestration rates of field practices at many locations would thus greatly serve the needs of carbon crediting programs.     

黄淮海平原耕地转移对植被碳储量的影响

应用GLO-PEM模型和1988年NOAA/AVHRR遥感数据,估算了黄淮海平原植被净初级生产力(NPP),并根据NPP和植被凋落物产生量计算了不同土地利用类型的植被碳密度。通过对1988年与2000年土地利用图的叠置分析,统计了耕地与其他土地利用类型之间的转移量,并估算了耕地转移对植被碳储量的影响。研究发现,耕地转移对植被碳储量变化的影响在不同区域与不同土地利用类型上存在显著差异。1988~2000年间,耕地转移导致全区植被碳储量下降了0.24%,其中耕地转为建设用地是植被碳储量减少的主要原因。这一研究结论为正确把握耕地转移对区域植被碳储量的影响,并据此制订碳汇管理措施具有重要的参考价值。     

A locally-constrained YOLO framework for detecting small and densely-distributed building footprints

ABSTRACT

Building footprints are among the most predominant features in urban areas, and provide valuable information for urban planning, solar energy suitability analysis, etc. We aim to automatically and rapidly identify building footprints by leveraging deep learning techniques and the increased availability of remote sensing datasets at high spatial resolution. The task is computationally challenging due to the use of large training datasets and large number of parameters. In related work, You-Only-Look-Once (YOLO) is a state-of-the-art deep learning framework for object detection. However, YOLO is limited in its capacity to identify small objects that appear in groups, which is the case for building footprints. We propose a LOcally-COnstrained (LOCO) You-Only-Look-Once framework to detect small and densely-distributed building footprints. LOCO is a variant of YOLO. Its layer architecture is determined by the spatial characteristics of building footprints and it uses a constrained regression modeling to improve the robustness of building size predictions. We also present an invariant augmentation based voting scheme to further improve the precision in the prediction phase. Experiments show that LOCO can greatly improve the solution quality of building detection compared to related work.     

Large-scale land cover mapping with the integration of multi-source information based on the Dempster–Shafer theory

Land cover type is a crucial parameter that is required for various land surface models that simulate water and carbon cycles, ecosystem dynamics, and climate change. Many land use/land cover maps used in recent years have been derived from field investigations and remote-sensing observations. However, no land cover map that is derived from a single source (such as satellite observation) properly meets the needs of land surface simulation in China. This article presents a decision-fuse method to produce a higher-accuracy land cover map by combining multi-source local data based on the Dempster–Shafer (D–S) evidence theory. A practical evidence generation scheme was used to integrate multi-source land cover classification information. The basic probability values of the input data were obtained from literature reviews and expert knowledge. A Multi-source Integrated Chinese Land Cover (MICLCover) map was generated by combining multi-source land cover/land use classification maps including a 1:1,000,000 vegetation map, a 1:100,000 land use map for the year 2000, a 1:1,000,000 swamp-wetland map, a glacier map, and a Moderate-Resolution Imaging Spectroradiometer land cover map for China in 2001 (MODIS2001). The merit of this new map is that it uses a common classification system (the International Geosphere-Biosphere Programme (IGBP) land cover classification system), and it has a unified 1 km resolution. The accuracy of the new map was validated by a hybrid procedure. The validation results show great improvement in accuracy for the MICLCover map. The local-scale visual comparison validations for three regions show that the MICLCover map provides more spatial details on land cover at the local scale compared with other popular land cover products. The improvement in accuracy is true for all classes but particularly for cropland, urban, glacier, wetland, and water body classes. Validation by comparison with the China Forestry Scientific Data Center (CFSDC)–Forest Inventory Data (FID) data shows that overall forest accuracies in five provinces increased to between 42.19% and 88.65% for our MICLCover map, while those of the MODIS2001 map increased between 27.77% and 77.89%. The validation all over China shows that the overall accuracy of the MICLCover map is 71%, which is higher than the accuracies of other land cover maps. This map therefore can be used as an important input for land surface models of China. It has the potential to improve the modeling accuracy of land surface processes as well as to support other aspects of scientific land surface investigations in China.     

INCIDENTS OF TERRORISM IN THE UNITED STATES, 1997–2005

ABSTRACT. The geography of terrorism remains underexplored. By focusing on the spatial patterns of terrorist attacks, the settings and land uses in which attacks occur, and the methods used to perpetrate violence, this analysis helps build a theory of terrorism geography. Between 1 January 1997 and 11 September 2005, 178 terrorist incidents occurred in the United States. Analysis of these incidents suggests three insights. At the national scale, terrorism in the United States clustered in large urban areas, with regional differentiation of terrorist motives and targets. At the scale of individual attack sites, terrorist motivations pinpointed offices, clinics, and public spaces; right‐wing violence, military, government, and infrastructural targets; and religious terrorism, commercial and special land uses. At the scale of individual interactions, terrorists crossed paths with victims in various ways. For example, the 2001 anthrax‐attack letters and lone‐wolf terrorism created alternative intersections of perpetrators with victims.     

Land Use Diversification in the Elite Residential Sector of Quito,Ecuador*

It is generally assumed that older mansions in the elite residential sector of Latin American cities filter down to the middle classes once their residents migrate to modern suburban homes. Five land use maps compiled between 1975 and 1999 show that the elite residential sector of Quito (Mariscal Sucre) experienced a much more complex fate. Diffusion of nonresidential land uses from the city center and its associated spine transformed the residential neighborhood into a vibrant upper‐scale business district. Sophisticated businesses subsequently moved on to modern suburban facilities, but Mariscal Sucre became a major hub for business, nocturnal entertainment, and tourism. Diversification of land use in Mariscal Sucre confirms the Crowley hypothesis of complexity in Latin American urban land use patterns ( Crowley 1995 ).     

生态平衡与农业地理研究——生态平衡、生态系统与自然资源、环境系统

本文第一节主要针对生态平衡或自然界平衡概念的一些误解作简单的说明。说这一概念重要,乃由于许多重要问题的认识和解决需要在此概念的指导之下,根据物质不灭,能量不灭等规律,进行具体、深入的研究。否则这一概念、这一名词就没有什么意义。     

黄土丘陵小流域土地利用格局对径流与土壤养分流失的影响--土壤侵蚀控制的意义

Serious soil erosion is one of the major issues threatening sustainable land use in semiarid areas, especially in the Loess Plateau of China. Understanding the effects of land use on soil and water loss is important for sustainable land use strategy. Two sub-catchments: catchment A (CA) and catchment B (CB) with distinct land uses were selected to measure soil moisture, runoff and soil nutrient loss in Da Nangou catchment of the Loess Plateau of China. The effects of land use patterns on runoff and nutrient losses were analyzed based on soil moisture pattern by kriging and soil nutrients using multiple regression model. The results indicated that there were significant differences in runoff yield and soil nutrient losses between the two sub-catchments. With similar land uses, the CA produced an average sediment yield of 49 kg ha-1 and 22.27 kg ha-1 during two storm events.Meanwhile, there was almost no runoff in the CB with dissimilar land uses during the same events.Buffer zones should be established to re-absorb runoff and to trap sediments in catchment with similar land use structure such as the CA. Moreover, land use management strategy aiming to increase the infiltration threshold of hydrological response units could decrease the frequency of runoff occurrence on a slope and catchment scale.     

The effects of land use on runoff and soil nutrient losses in a gully catchment of the hilly areas: implications for erosion control

Serious soil erosion is one of the major issues threatening sustainable land use in semiarid areas, especially in the Loess Plateau of China. Understanding the effects of land use on soil and water loss is important for sustainable land use strategy. Two sub-catchments: catchment A (CA) and catchment B (CB) with distinct land uses were selected to measure soil moisture, runoff and soil nutrient loss in Da Nangou catchment of the Loess Plateau of China. The effects of land use patterns on runoff and nutrient losses were analyzed based on soil moisture pattern by kriging and soil nutrients using multiple regression model. The results indicated that there were significant differences in runoff yield and soil nutrient losses between the two sub-catchments. With similar land uses, the CA produced an average sediment yield of 49 kg ha-1 and 22.27 kg ha-1 during two storm events. Meanwhile, there was almost no runoff in the CB with dissimilar land uses during the same events. Buffer zones should be established to re-absorb runoff and to trap sediments in catchment with similar land use structure such as the CA. Moreover, land use management strategy aiming to increase the infiltration threshold of hydrological response units could decrease the frequency of runoff occurrence on a slope and catchment scale.     

可持续性评价的 ImPACTS等式

可持续发展要求必须在一个地球的约束下,最大限度地满足人类的发展需求。通过分析生态足迹与人类社会发展的关系,从可更新和不可更新资源利用效益角度来看,在发展的可持续性上发达国家比发展中国家在利用地球容纳环境和社会期望方面具有明显的优势。同时,气候变暖的事实说明,人类对不可更新化石燃料的开采和利用速率已经超过地球上生态系统吸收CO₂的能力。各国要取得社会发展并使之具有可持续性,应该在地球的可持续性尺度范围内增加自己的全球足迹份额,而不是简单的减少足迹。以中国的南水北调、北粮南运,粮食安全及世界石油消费利用为例说明了社会资源在缓解和减轻环境影响方面的作用。在剖析经典的IPAT等式及其变种等式ImPACT分析框架的基础上,提出了一个新的可持续性评价研究框架--ImPACTS等式,并讨论了新等式的政策含义。在ImPACTS等式中,新增项S代表社会资源的状态 (社会发展状态),m代表管理,用来强调人类采用协调的方式来解决超过可持续性尺度这一问题的重要性,I因此变成了集成的影响评价--对环境的影响和社会发展的损益评价。     

滨海滩涂土壤有机碳演变驱动因子框架

通过归纳、总结前人大量的研究成果,从土壤有机碳演变的尺度约束框架、滩涂土壤有机碳的核心控制因子以及演变的驱动因素3个方面进行总结。结果表明：①目前形成的监测技术约束下的碳库研究体系,其研究的结果忽视了机理性认识的未来需要,这对于应对未来气候变化条件下的滩涂湿地碳库变化风险稍显不足; ② 滩涂土壤有机碳演变的核心控制因子有泥沙、地貌与埋藏速率、植被与农业活动。滩涂围垦后的农业活动类型与方式是滩涂开发后影响土壤有机碳演变的核心要素,远远高于自然滩涂中的自然主导因子; ③ 不同因素在不同时空尺度上会对滩涂有机碳演变起到重要影响,其中,土地利用/覆被对于有机碳的影响机制是需要重点关注的核心命题; ④ 小尺度、长时间尺度有机碳循环机制的研究需要加强,同时,综合考量要素的时空尺度特性及其技术手段的提升,更加注重过程研究对于指导未来滩涂土壤有机碳研究更具有现实意义。     

Mid‐ and Large‐Scale Geodiversity Calculation in Fuentes Carrionas (NW Spain) and Serra do Cadeado (Paraná, Brazil): Methodology and Application for Land Management

A state‐of‐the‐art geodiversity concept, its use and scientific development are presented. Methodologies for geodiversity calculation are assessed, as well as their aim and problems. Geodiversity calculation methodology based on biodiversity richness index is explained and applied to two different areas: Fuentes Carrionas, a high mountain mid‐latitude environment in northern Spain, and Serra do Cadeado, a tropical mid‐mountain environment in southern Brasil. A geodiversity map of Fuentes Carrionas proves that glacial cirques over 2000 m a.s.l. keep a high geodiversity related to a periglacial and glacial environment, whereas a geodiversity map of Serra do Cadeado shows that high geodiversity areas are situated at its main structural scarp. Geodiversity calculation needs to take scale and hierarchy issues into account, which makes comparison only possible if the same scale is used. Geodiversity calculation is a useful tool for land management as it defines areas subject to protection due to the richness of abiotic elements. It is also useful in terms of environmental impact assessment and geotourism evaluation at remote areas.     

THE DRIVING FORCES OF LAND CHANGE IN THE NORTHERN PIEDMONT OF THE UNITED STATES

Driving forces facilitate or inhibit land‐use / land‐cover change. Human driving forces include political, economic, cultural, and social attributes that often change across time and space. Remotely sensed imagery provides regional land‐change data for the Northern Piedmont, an ecoregion of the United States that continued to urbanize after 1970 through conversion of agricultural and forest land covers to developed uses. Eight major driving forces facilitated most of the land conversion; other drivers inhibited or slowed change. A synergistic web of drivers may be more important in understanding land change than individual drivers by themselves.