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1.
河北省休闲农业的空间分布及影响机制   总被引：10，自引：5，他引：5  
向雁  陈印军  侯艳林  屈宝香 《地理科学》2019,39(11):1806-1813
以河北省436家休闲农业品牌主体为研究样本,采用最邻近指数、核密度估算、近邻分析等方法,对其空间分布类型、空间结构演化、空间分布特征进行了分析。在此基础上进一步利用地理探测器量化分析了不同因素对休闲农业空间分布的影响作用。结果表明,河北休闲农业品牌总体呈显著的聚集型空间分布,并逐步演化为南部聚集连片、北部环绕京津、局部组团化聚集的高密度空间分布格局;休闲农业品牌呈现“沿路”“傍水”“环城”“近景”“依产”分布特征;休闲农业品牌的空间分布受到多种因素的综合作用影响,旅游市场条件是影响休闲农业空间分布的最主要的影响因素,其次为交通条件和自然资源。针对河北省休闲农业提出发展建议。  相似文献   

2.
This article examines two key aspects of land‐cover change in the south of the Chocó region. First, it assesses and compares the local impact on forest condition of labor‐intensive and capital‐intensive commercial logging. Second, it assesses the regional significance and permanency of these changes. Studies of land‐cover change associated with commercial logging have focused almost exclusively on capital‐intensive extraction and have assumed that after logging, degraded forests are transformed into agricultural cover. This study shows that both capital‐ and labor‐intensive logging result in similar land‐cover changes (i.e., forest degradation) if the timber sought is the same. However, labor‐intensive loggers also seek timber species not sought by capital‐intensive loggers, and this impact is statistically different from the impact of the extraction of the first group of species. Results also show that only a small fraction (20–30 percent) of the area logged is later converted to agricultural cover types. The persistence of logged forests means that up to 20 percent of the remaining forest cover could correspond to forests with significant and lasting levels of degradation. Furthermore, the different production requirements for each group of species also mean that there is a spatial differentiation in the impact of logging in the region. Logged forests are arranged into two consecutive corridors on each side of access routes (e.g., rivers). The first corridor corresponds to a narrow (approximately 1‐km) band of high‐intensity degradation. The second, broader (approximately 2‐km) forest band, with lower levels of degradation, extends inland along first‐tier corridors. A key factor determining the permanency of this land‐cover pattern is the strong control local communities have over the land in the region. This limits the spread of patterns observed in other frontier areas, especially the conversion of logged forests into agricultural cover.  相似文献   

3.
This research assessed the soil erosion threat in the Congo Nile Ridge Region of Rwanda. The study forecasted erosion by applying the Revised Universal Soil Erosion (RUSLE) with five factors (rainfall, soil, topography, cover management, and support practices) and spatial data. About 85.5% of the area under investigation was predisposed to erosion with unsustainable average soil loss rates of > 1 t/ha/yr. The outcomes of the research highlighted that the average rate of estimated soil loss in the region prone to erosion was > 63.62 t/ha/yr, resulting in an overall annual predicted soil loss of approximately 44 × 106 t in 2016. All of the districts studied have steep slope gradients (30.4%–36.1%) and high annual rainfall totals (1199–1484 mm/yr), except Rubavu district. More than 88.8% of croplands had unsustainable average soil loss rates of > 1 t/ha/yr. The analysis indicated that both terracing and strip cropping have the potential to reduce rates of soil loss in the farmland, by 64.4% and 10.4%, respectively. The results of this study will serve as a baseline for soil erosion mitigation and land-use planning in the study area and Rwanda at large.  相似文献   

4.
Moose–vehicle collisions (MVCs) pose a serious safety and environmental concern in many regions of Europe and North America. For example, in the state of Vermont, one‐third of all reported MVCs resulted in motorist injury or fatality while collisions have increased from two in 1982 to 164 in 2002. Our work used a MVC dataset from 1983 to 1999 in the Northeastern Highlands of Vermont (four major roads) to perform space, time and spatiotemporal analyses and guide future mitigation strategies. An adapted kernel density estimator was implemented for exploratory analyses to detect high density collision hotspots on roads. The kernel in space showed seven major density peaks which varied in magnitude and spread between roads. The kernel estimator in time for all roads showed an exponentially increasing trend with annual periodicity and a seasonal cyclic component, where the majority of collisions occurred from May to October. Spatiotemporal kernel estimation exhibited discontinuous density hotspots in time and space suggesting changing animal movement patterns across roads. We used an adapted Ripley's K‐function to test the hypothesis that MVCs clustering occurred at multiple scales in space, in time and in space–time combined. Statistically significant spatial clustering was evident on all roads at spatial scales from 2 to 10 km. A more consistent clustering in time occurred on all roads at a scale distance of 5 years. Similar to the kernel estimation, annual periodicity was also evident. Positive space–time clustering was present at small spatial (5 km) and temporal scales (2 years) indicating that where MVCs occur is also influenced by when they occur. In retrospect, using multiple road lengths, and the combined kernel estimation and Ripley's K‐function in time and space, provided a powerful methodology to study varying spatiotemporal patterns of wildlife collisions along roads. This can greatly assist transportation planners in identifying optimal mitigation strategies along specific roads, such as deciding on location and spatial length for permanent and expensive measures (e.g. crossing structures and associated fencing) versus less permanent and inexpensive structures (e.g. wildlife signage and reduced speed limits).  相似文献   

5.
This study developed a spatial dynamic model to examine the coupled natural–human responses in the form of changes in population and associated developed land area in the Lower Mississippi River Basin region. The goal was to identify key socioeconomic factors (utility) and environmental factors (hazard damages, elevation, and subsidence rate) that affected population changes, as well as to examine how population changes affected the local utility and the local environment reciprocally. We first applied areal interpolation techniques with the volume-preserving property to transform all the data at Year 2000 into a unified 3 km by 3 km cellular space. We then built an Elastic Net model to extract 12 variables from a set of 33 for the spatial dynamic model. Afterward, we calibrated the neighborhood effects with a genetic algorithm and use the spatial dynamic model to simulate population and developed land area in 2010. Furthermore, we took a Monte Carlo approach for analyzing the uncertainty of the model outcome. Our accuracy assessment shows that the model on average slightly overpredicts the number of population and the developed land percentage at 2010, as indicated by the low values of mean absolute deviation (MAD) due to quantity. On the other hand, the MADs due to allocation are larger than the MADs due to quantity, with most outliers found in the New Orleans region where population and urban development declined significantly during 2000–2010 after Hurricane Katrina. The proposed model sheds light on the complex relationships between coastal hazards and human responses and provides useful insights to strategic development for coastal sustainability.  相似文献   

6.
This paper provides a positive view of the desert, in terms of the warming effect of deserts on oases and the impact of heat resources and agricultural production. We use data from experimental sites in the Manas River Basin in China to characterize these relationships. We note that the warming effect of the desert was found to be significant but gradually reduced with increased distance of the oasis from the desert. The range of warming effect is about 100 km, and the improvement in temperature is about 1.8 °C. Due to this warming effect, the desert serves as the second heat source for the oasis, which represents one important aspect of the ecologic value of the desert. Our results also show the warming effect has a strong spatial impact on agricultural productivity. Crop productivity fell by about 49 kg/ha with every 10 km increase in distance away from the desert. Our results imply that crop suitability must correspond to the warming effect of the desert. More efficient use of heat resources can contribute towards achieving potential productivity.  相似文献   

7.
This study explores the structure and modulation of the mean diurnal climate of Africa with a focus on satellite rainfall. Solar heating over tropical mountains and land-sea temperature gradients initiate moisture convergence in the afternoon-evening. The diurnal temperature range is from 5 °C along the coast to 20 °C in arid zones with low vegetation fraction. NCEP2 reanalysis reveals the diurnal circulation via continental-scale drainage and seabreeze flows. Factors modulating the diurnal cycle vary across four sub-regions: South Africa, East Congo, Ethiopia, and Guinea. In the Congo and Guinea coast the surface moisture and heat fluxes are important, while in South Africa convective available potential energy and vertical motion are influential. Ethiopia’s evening orographic convection is out of phase with surface fluxes. The diurnal residual calculated from NCEP2 fields exhibits a 2 km depth for thermal gradients and 200 km inland penetration of onshore flow by evening.  相似文献   

8.
艾比湖流域绿洲乡村聚落空间格局及其驱动力分析   总被引：1，自引：0，他引：1       下载免费PDF全文
通过把握绿洲乡村聚落空间规律,揭示其影响机制,以期为西北边陲绿洲美丽乡村建设过程中的聚落管理和规划提供依据。基于GIS技术、计量统计方法和实地考察调查对新疆艾比湖流域绿洲乡村聚落空间格局及影响因素进行了分析。结果表明：（1）艾比湖流域绿洲乡村聚落整体为小规模-低密度-高核破碎化状态,呈现冲洪积扇平原-中低密度扇射型、河流两侧-低密度线状型和中高密度条带型及精河盆地-高密度团块型分布特色。（2）聚落局部规模分异明显,冷点区多为兵团团场连队,热点多为地方乡镇村庄。（3）聚落主要分布在海拔800 m以下、距河流2 km以内、距道路1 km以内区域,并深受政策制度影响。乡村聚落的发展更多地受制于人类的行为,然而,在艾比湖流域绿洲特殊的地形地貌、较大的海拔高程差以及博河、精河贯穿全区的自然条件下,乡村聚落格局及进一步发展受到限制。  相似文献   

9.
Abstract

This article examines two key aspects of land-cover change in the south of the Chocó region. First, it assesses and compares the local impact on forest condition of labor-intensive and capital-intensive commercial logging. Second, it assesses the regional significance and permanency of these changes. Studies of land-cover change associated with commercial logging have focused almost exclusively on capital-intensive extraction and have assumed that after logging, degraded forests are transformed into agricultural cover. This study shows that both capital- and labor-intensive logging result in similar land-cover changes (i.e., forest degradation) if the timber sought is the same. However, labor-intensive loggers also seek timber species not sought by capital-intensive loggers, and this impact is statistically different from the impact of the extraction of the first group of species. Results also show that only a small fraction (20–30 percent) of the area logged is later converted to agricultural cover types. The persistence of logged forests means that up to 20 percent of the remaining forest cover could correspond to forests with significant and lasting levels of degradation. Furthermore, the different production requirements for each group of species also mean that there is a spatial differentiation in the impact of logging in the region. Logged forests are arranged into two consecutive corridors on each side of access routes (e.g., rivers). The first corridor corresponds to a narrow (approximately 1-km) band of high-intensity degradation. The second, broader (approximately 2-km) forest band, with lower levels of degradation, extends inland along first-tier corridors. A key factor determining the permanency of this land-cover pattern is the strong control local communities have over the land in the region. This limits the spread of patterns observed in other frontier areas, especially the conversion of logged forests into agricultural cover.  相似文献   

10.
In this study, two sampling protocols using a model-based and a design-based framework were juxtaposed to evaluate their precision in the estimation of C stock in the Ludikhola watershed, Nepal. The model-based approach exploits the spatial dependencies in the sampled variable and may therefore be attractive over the design-based approach as it reduces the substantial costs of survey and effort required in the latter. Scales of spatial variability for C stock which resulted in a grid resolution of 10,000 m2 were determined using a reconnaissance variogram. Akaike information criterion was used for the selection of the best linear model of feature space for use in kriging with external drift (KED). Among the five tested covariates, distance, elevation, and aspect were statistically significant, with the best model of feature space accounting for 87.7% variability of C stock. An ANOVA established significance differences in mean C stocks (P = 0.00017). KED using the best model of feature space was found to be more precise, (9.89 ± 0.17) sqrt mg C/ha, than a pure-based approach of ordinary kriging and the design-based approach, (9.91 ± 0.8) sqrt mg C/ha. The confidence bounds of the two estimators showed that their confidence intervals will overlap 99.7% of the time, with both confidence intervals falling within the 95% confidence bounds of each other. There is less uncertainty around the mean C stock estimated using the model-based approach than the mean C stock estimated using the design-based approach. The model-based approach is a prospective option for the REDD framework.  相似文献   

11.
Using Landsat TM data from 1995 and 2000, changes in the landscape erosion pattern of the Yellow River Basin, China were analysed. The aim was to improve our understanding of soil‐erosion change so that sustainable land use could be established. First, a soil‐erosion intensity index model was developed to study soil‐erosion intensity change in the study area. Over the 5 years, the areas of weak erosion, moderate erosion, severe erosion, and very severe erosion all increased. The area of weak erosion increased dramatically by 7.94×105 ha, and areas of slight erosion and acute erosion decreased by 1.93×106 ha and 4.50×104 ha, respectively. The results show that while the intensity of soil erosion has gradually been decreasing as a whole, in some regions the soil erosion is becoming more severe. Based on landscape indices, the pattern of changes in soil erosion over the past 5 years was analysed. The changes in landscape pattern of soil erosion resulted from human activities. Analysis showed that human impact increases fragmentation, having three major effects on landscape pattern, reduction in patch area, variations in patch shape, and changes in spatial pattern. In the study area, population growth, farming, governmental policy and forest degradation are the major factors causing soil erosion change over a 5‐year period.  相似文献   

12.
Colombo port and Hambantota port in Sri Lanka play a key role in transiting and supporting the shipping trade of "the 21 st-Century Maritime Silk Road". In recent years, Chinese enterprises have made huge investments in the infrastructure construction of Colombo port and Hambantota port. The construction progress and development trend of Colombo port and Hambantota port have been attracting the attention of Chinese investment enterprises and the society. In this paper, multi-temporal high spatial resolution remote sensing images are used to monitor the infrastructure construction condition of Colombo port and Hambantota port from 2010 to 2017. According to the interpreted infrastructure information of the two ports, the international container terminal of Colombo and Hambantota port have completed their constructions. By the end of 2017, the international container terminal of Colombo built the container yards with 28.8 ha and roads with 32.6 ha. At the south of the international container terminal of Colombo, the 62.2 ha of reclamation area were built for the planned port city. In Hambantota port, 77 ha of container yards, 48 ha of roads and 2.9 ha of oil storage areas were constructed during this period. Meanwhile, the analysis of potential storage capacity of Colombo port and Hambantota port shows that the throughput of Colombo port may increase by 3 million tons per year while the throughput of Hambantota port will be over its designed 2.5 million tons per year. These analysis results are able to provide a useful reference for Chinese investment enterprises and the related research of "the Belt and Road".  相似文献   

13.
Colombo port and Hambantota port in Sri Lanka play a key role in transiting and supporting the shipping trade of “the 21st-Century Maritime Silk Road”. In recent years, Chinese enterprises have made huge investments in the infrastructure construction of Colombo port and Hambantota port. The construction progress and development trend of Colombo port and Hambantota port have been attracting the attention of Chinese investment enterprises and the society. In this paper, multi-temporal high spatial resolution remote sensing images are used to monitor the infrastructure construction condition of Colombo port and Hambantota port from 2010 to 2017. According to the interpreted infrastructure information of the two ports, the international container terminal of Colombo and Hambantota port have completed their constructions. By the end of 2017, the international container terminal of Colombo built the container yards with 28.8 ha and roads with 32.6 ha. At the south of the international container terminal of Colombo, the 62.2 ha of reclamation area were built for the planned port city. In Hambantota port, 77 ha of container yards, 48 ha of roads and 2.9 ha of oil storage areas were constructed during this period. Meanwhile, the analysis of potential storage capacity of Colombo port and Hambantota port shows that the throughput of Colombo port may increase by 3 million tons per year while the throughput of Hambantota port will be over its designed 2.5 million tons per year. These analysis results are able to provide a useful reference for Chinese investment enterprises and the related research of “the Belt and Road”.  相似文献   

14.
Spatial distribution changes in major crops can reveal important information about cropping systems. Here, a new centroid method that applies physics and mathematics to spatial pattern analysis in agriculture is proposed to quantitatively describe the historical centroids of rice, maize and wheat in China from 1949 to 2014. The geographical centroids of the rice area moved 413.39 km in a 34.32° northeasterly (latitude 3.08°N, longitude 2.10°E) direction at a speed of 6.36 km/year from central Hunan province to Hubei province, while the geographical centroids of rice production moved 509.26 km in the direction of 45.44° northeasterly (latitude 3.22°N, longitude 3.27°E) at a speed of 7.83 km/year from central Hunan province to Henan province. The geographical centroids of the maize area and production moved 307.15 km in the direction of 34.33° northeasterly (latitude 2.29°N, longitude 1.56°E) and 308.16 km in the direction of 30.79° northeasterly (latitude 2.39°N, longitude 1.42°E), respectively. However, the geographical centroids of the wheat area and production were randomly distributed along the border of Shanxi and Henan provinces. We divided the wheat into spring wheat and winter wheat and found that the geographical centroids of the spring wheat area and production were distributed within Inner Mongolia, while the geographical centroids of winter wheat were distributed in Shanxi and Henan provinces. We found that the hotspots of crop cultivation area and production do not always change concordantly at a larger, regional scale, suggesting that the changing amplitude and rate of each crops’ yield differ between different regions in China. Thus, relevant adaptation measures should be taken at a regional level to prevent production damage in those with increasing area but decreasing production.  相似文献   

15.
Three hundred and sixty three landslides in three watersheds that totaled 382 km2 were identified from air photographs, beginning at a date that preceded logging to the present. The three watersheds all lie on Vancouver Island; however, they have different precipitation regimes, topography, and amounts logged. Landslide areas in the watersheds varied in size from 200 m2 to more than 1 ha. Nearly 80% of the landslides were debris slides; 15% were debris flows, and the remainder primarily rock falls. Following logging, the number of landslides increased substantially in all watersheds although the amount of increase was variable: approximately 11, 3, and 16 times in Macktush Creek, Artlish River, and Nahwitti River, respectively. Other analyses of changes in landslide density also produced highly variable results, with the number of landslides increasing between 2.4 and 24 times. Further, 2–12 times more landslides reached streams following logging activities. Densities for landslides impacting streams increased for the period of record from 1.5 to 10 times following logging activities. The densities were substantially greater where only landslides that reached streams since development began in a watershed were considered. Roads had the greatest spatial impact in the watersheds (compared to their total area), with frequencies determined to have increased by 27, 12, and 94 times for Macktush, Artlish, and Nahwitti, respectively. The results highlight the relative impact of roads and their role in slope stability.  相似文献   

16.
As the major component of terrestrial ecosystems, forests play an irreplaceable role in providing ecosystem services and products (e.g. biodiversity, carbon sequestration, water yield and timber). Spatially quantifying ecosystem services and interactions will shed light on sustainable forest management. Main forest ecosystem services including carbon storage, water yield, soil retention and wood volume in the Ganjiang River Basin (GRB) were evaluated and mapped through the integrated use of InVEST3.1.0, CASA modeling and ArcGIS10.2, and relationships between forest ecosystem services and natural or social-economic factors were quantified and discussed based on ArcGIS10.2 and SPSS19.0. Results showed that the spatial pattern of the four ecosystem services is heterogeneous. Forests dominated by broad-leaved forest and bamboo forest in mountainous regions around the GRB provided the largest carbon storage and wood volume services, while forests dominated by Masson pine plantations or Chinese fir plantations in the northeast provided the largest water yield service. The spatial pattern of the soil retention service is more discrete than others, and forests in the southwestern regions showed larger soil erosion modulus than in the northeastern regions. Ecosystem services are closely related to the environmental process and human activities. With altitude or slope increases, the carbon storage and wood volume of forests increased and water yield depth and soil retention decreased. When the regional total population decreased or GDP per capita increased, carbon storage and wood volume increased. Further research into the interactions between environmental factors and ecosystem services is needed in order to understand environmental constraints when dealing with ecological problems.  相似文献   

17.
The thick (>1 km) Neoproterozoic Otavi Group of Namibia accumulated after ca. 760 Ma along >700 km of the faulted margin of the Congo Craton. The margin shows a north to south, downbasin transition from a shallow‐water carbonate shelf (Otavi Platform) to offshore deepwater slope (Outjo Basin). Within the latter, the Abenab and Tsumeb Subgroups contain large volumes of poorly sorted breccias, conglomerates and diamictites composed principally of locally derived carbonate. Diamictite facies were reported in the 1930s as tillites left by an ice sheet (although the absence of striated clasts and other key glacial indicators was viewed as problematic). Later workers rejected a glacial origin concluding that Outjo basin facies were deposited as parts of prograding submarine wedges built by mass flows during active rifting. Recently, the Snowball Earth hypothesis has returned to the earlier glacial interpretation; arguing that these strata represent a record of extraordinary late Neoproterozoic glacial and interglacial climates when global temperatures fluctuated by up to 100°C. Facies analysis of breccias, diamictites, conglomerates and sandstone strata of the Otavi Group identifies them as genetically related, subaqueously deposited sediment gravity flows. They lack diagnostic indicators of any one specific climate in source areas. These facies were all deposited in deepwater at the foot of landslide‐prone scarp blocks where debris flows and turbidity currents moved large volumes of coarse, freshly broken carbonate debris produced by faulting. Breccias, diamictites, conglomerates and sandstones occur in composite fining‐ and thinning‐upward bundles that are directly analogous to those reported from many other faulted margins in the Phanerozoic stratigraphic record. These rocks provide no clear sedimentological signature of a glacial source or catastrophic Snowball Earth‐type temperature fluctuations. Instead, they point to a dominant tectonic control on sedimentation related to faulting along the margin of the Congo Craton.  相似文献   

18.
翟佳豪  刘影  肖池伟 《热带地理》2022,42(8):1376-1385
基于1987—2018年西双版纳30 m分辨率橡胶林数据集,利用叠置、缓冲区等GIS空间分析方法,对比分析了过去32年橡胶林沿道路、河流和边境线的空间变化特征与区域差异。结果表明：1) 1987—2018年,西双版纳橡胶种植面积在道路、河流沿线5 km以内分别增加了1 874.6和1 484.6 km2,在边境地区(国境线20km缓冲带)增加了1 393.1 km2。2)从道路沿线看,受橡胶种植可达性和交通运输影响,过去32年道路5 km缓冲带内的橡胶林平均占比超过九成。3)从河流沿线看,因灌溉和水源等需求,过去32年河流沿线5 km缓冲带内橡胶林平均占比69.7%。值得注意的是,受天然橡胶价格持续低迷、城镇化与生态环境保护等影响,2010年河流沿线橡胶林种植面积开始下降,沿线2 km内表现尤为显著。4)从边境地区看,西双版纳橡胶林种植呈明显趋边性特征,跨境种植频繁。过去32年边境沿线地区橡胶林平均占比55.6%,且由1987年的35.4%上升到2018年的66.2%,其中,在中缅边境的扩张面积和速率高于中老边境。  相似文献   

19.
起伏地形下黄河流域太阳直接辐射分布式模拟   总被引：1，自引：0，他引：1  
1 Introduction Directsolarradiation (DSR)isthe key com ponentofthe globalradiation reaching the Earth.For the influence of terrain factors,calculation of DSR quantity of rugged terrain is considerably com plex (Oliphantetal.,2003). The solarradiation quan…  相似文献   

20.
民国时期广州市建成区主体建筑立体形态的恢复及其特征   总被引：1，自引：0，他引：1  
基于1928年1﹕10 000的地形图,解译土地利用类型,确定建成区边界与建筑用地的空间范围。将建筑用地分为单体建筑、线状道路两侧的骑楼和面状同类建筑区3类。根据史料与现场调查,分别为点、线、面3类建筑的高度赋值,恢复不考虑海拔的建成区主体建筑立体形态。基于所建模型,从平面形态、平均高度、空间格局、宽高比、高度轴、天际线以及形态组合几方面对民国时期建成区立体形态特征进行分析归纳,得出如下结论：１）民国时期广州城市沿珠江发展使得城区轮廓呈狭长的带状;２）城市平均高度仅为6.07 ｍ,建筑物普遍低矮;３）建筑物在平面上为多级的棋盘网组合,而骑楼街构成的宽浅网格,成为当时空间尺度最大的建筑单元组合形态;４）道路宽度与两侧建筑物高度形成的宽高比大,城市具有较好的通透性;５）沿江西路与当时的城市中轴线中山纪念堂―市府合署大楼构成了倒“T”型城市空间高度轴,并在单体建筑高度空间分布与天际线的变化上得到很好的反映;６）城市立体形态主要由盆地、格网、谷地、台地等4种宽浅的单元组成。立体形态深层次上反映了当时生产力技术条件下政府与市场力量的综合作用,以及城市功能区分化在立体形态上的表现,从而也成为该时期华南地区依山傍水城市立体形态的重要标志。  相似文献   

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