From pastoralism to tourism: The historical impact of changing land use practices in Namaqualand

We use the concept of ecological revolutions to explain the environmental history of Namaqualand, from the advent of pastoralism 2000 years BP, to colonial settlement in the 18th century and finally to the recent trend of de-agrarianization from the middle of the 20th century. Early traveller's records and census data are used to assess changes in the human population of the region and how this affected wildlife and agricultural practices. Pre-colonial indigenous hunter-gatherer (Bushmen) and pastoralist (Khoekhoen) populations in Namaqualand consisted of probably no more than a few thousand individuals. Over the next three centuries, the general population rose steadily to more than 65,000 people but has fallen in recent years. Wildlife appears not to have been abundant in Namaqualand's pre-colonial landscapes and large springbok ‘treks’ were probably a rare event. The number of domestic livestock in Namaqualand peaked in 1957 largely as a result of an increase in the number of sheep which have fallen steadily since this time. Crop production was absent from Namaqualand's pre-colonial landscapes but increased to cover nearly 30,000 ha in the early 1970s. The area under cultivation has declined by nearly two thirds since this time largely as a result of the large-scale abandonment of wheat farming in marginal environments. We touch on differences between the communal areas and private farms, particularly in terms of their human populations and agricultural impact on the land. Repeat landscape photographs support our main findings which suggest that both rocky, upland habitats and rivers have not been transformed substantially by land use practices in Namaqualand. Instead, sandy pediments have borne the brunt of human impacts in the region. Finally, we highlight the beginning of a new ecological revolution in Namaqualand due to changes in the global and national political economy.     

Biodiversity conservation and pastoralism—reducing herd size in a communal livestock production system in Richtersveld National Park

Biodiversity is a critical component of the natural environment and the protection of it often meant the displacement of local communities in developing countries. The Richtersveld National Park (South Africa) is unusual in that it forms part of the Richtersveld communal rangeland and is currently managed for goat and sheep farming as well as biodiversity conservation under a contractual agreement. These two objectives are not regarded as mutually compatible and have created tension between conservation management officials and pastoralists. We set out to examine the consequences of reducing herd size in a communal livestock production system in support of biodiversity conservation in a protected area. Kidding, animal offtake (sales and slaughter), mortality and herd persistence showed no clear incentives for an individual pastoralist to reduce herd size. Reducing herd size is not considered a recommended intervention for the conservation of biodiversity or livelihood improvement of pastoralists in the park. The future of the natural resources of the national park is dependent on a delicate balance between the needs of the pastoralists and the conservation of those very same resources that the pastoralists use.     

Assessing spatial and attribute errors in large national datasets for population distribution models: a case study of Philadelphia county schools

Geospatial technologies and digital data have developed and disseminated rapidly in conjunction with increasing computing efficiency and Internet availability. The ability to store and transmit large datasets has encouraged the development of national infrastructure datasets in geospatial formats. National datasets are used by numerous agencies for analysis and modeling purposes because these datasets are standardized and considered to be of acceptable accuracy for national scale applications. At Oak Ridge National Laboratory a population model has been developed that incorporates national schools data as one of the model inputs. This paper evaluates spatial and attribute inaccuracies present within two national school datasets, Tele Atlas North America and National Center of Education Statistics (NCES). Schools are an important component of the population model, because they are spatially dense clusters of vulnerable populations. It is therefore essential to validate the quality of school input data. Schools were also chosen since a validated schools dataset was produced in geospatial format for Philadelphia County; thereby enabling a comparison between a local dataset and the national datasets. Analyses found the national datasets are not standardized and incomplete, containing 76 to 90 percent of existing schools. The temporal accuracy of updating annual enrollment values resulted in 89 percent inaccuracy for 2003. Spatial rectification was required for 87 percent of NCES points, of which 58 percent of the errors were attributed to the geocoding process. Lastly, it was found that by combining the two national datasets, the resultant dataset provided a more useful and accurate solution.     

Enhanced data and methods for improving open and free global population grids: putting ‘leaving no one behind’ into practice

ABSTRACT

Data on global population distribution are a strategic resource currently in high demand in an age of new Development Agendas that call for universal inclusiveness of people. However, quality, detail, and age of census data varies significantly by country and suffers from shortcomings that propagate to derived population grids and their applications. In this work, the improved capabilities of recent remote sensing-derived global settlement data to detect and mitigate major discrepancies with census data is explored. Open layers mapping built-up presence were used to revise census units deemed as ‘unpopulated’ and to harmonize population distribution along coastlines. Automated procedures to detect and mitigate these anomalies, while minimizing changes to census geometry, preserving the regional distribution of population, and the overall counts were developed, tested, and applied. The two procedures employed for the detection of deficiencies in global census data obtained high rates of true positives, after verification and validation. Results also show that the targeted anomalies were significantly mitigated and are encouraging for further uses of free and open geospatial data derived from remote sensing in complementing and improving conventional sources of fundamental population statistics.     

Stellar models for very low-mass main-sequence stars: the role of model atmospheres

We present very low-mass stellar models as computed using non-grey model atmospheres for selected assumptions about the stellar metallicities. The role of atmospheres is discussed and the models are compared with models based on the Eddington approximation, and with similar models that have appeared in the recent literature. Theoretical predictions concerning both the HR diagram location and the mass–luminosity relation are presented and discussed in terms of expectations in selected photometric bands. Comparison with available observational data concerning both galactic globular clusters and dwarfs in the solar neighbourhood reveals a satisfactory agreement together with the existence of some residual mismatches.     

HST colour–magnitude diagrams of six old globular clusters in the LMC

We report on HST observations of six candidate old globular clusters in the Large Magellanic Cloud (LMC): NGC 1754, 1835, 1898, 1916, 2005 and 2019. Deep exposures with the F555W and F814W filters provide us with colour–magnitude diagrams that reach to an apparent magnitude in V of ∼25, well below the main-sequence turn-off. These particular clusters are associated with significantly high LMC field star densities and care was taken to subtract the field stars from the cluster colour–magnitude diagrams accurately. In two cases there is significant variable reddening across at least part of the image, but only for NGC 1916 does the differential reddening preclude accurate measurements of the CMD characteristics. The morphologies of the colour–magnitude diagrams match well those of Galactic globular clusters of similar metallicity. All six have well-developed horizontal branches, while four clearly have stars on both sides of the RR Lyrae gap. The abundances obtained from measurements of the height of the red giant branch above the level of the horizontal branch are 0.3 dex higher, on average, than previously measured spectroscopic abundances. Detailed comparisons with Galactic globular cluster fiducials show that all six clusters are old objects, very similar in age to classical Galactic globulars such as M5, with little age spread among the clusters. This result is consistent with ages derived by measuring the magnitude difference between the horizontal branch and main-sequence turn-off. We also find a similar chronology by comparing the horizontal branch morphologies and abundances with the horizontal branch evolutionary tracks of Lee, Demarque &38; Zinn. Our results imply that the LMC formed at the same time as the Milky Way Galaxy.     

不同群体团头鲂生长性能分析

用随机区组试验方法,比较四种不同的选育群体团头鲂的后代和一个对照群体团头鲂的生长性能。结果表明：在同一环境条件下,远交群体比近交群体生长优势明显（|xi-xj|＞D0.01）;亲本年龄大（3足龄）的群体后代生长性能优于亲本年龄小（2足龄）的群体后代（|xi-xj|＞D0.05）;对照群体团头鲂与近交群体后代生长性能相当。     

人口移动与区域经济格局变动

人口移动是我国近几年发生的重要社会经济现象之一,其机制是东部地区人多地少的推力与西部地区产业结构性空缺的吸力,以及国家对后者特定的工资与粮食政策。它对地域分工格局的变动产生着重大影响。     

Socio-economic drivers of deforestation in Roghani Valley,Hindu-Raj Mountains,Northern Pakistan

Deforestation and associated ecological disturbances are the issues of global concern.Researchers have investigated a number of driving forces which accelerate the rate of deforestation at local and regional levels.These include poverty,population growth,market demand and prices,political instability,agricultural expansion and changes in property right and ownership regimes.This paper seeks to explore the impacts of population growth,changing tenure system and other socioeconomic factors on the forest cover of Roghani Valley,located in Hindu Raj Mountains,Northern Pakistan.The present study is mainly based on information collected through participatory observation,selfadministered interviews and questionnaire survey.Geographical Information System（GIS） database is also used for mapping and quantification.The results reveal that in the past three to four decades the study area has been subjected to severe deforestation and about half of the forest area has been converted into barren land.Thus,the area under natural forests decreased from 2099 to 1444 hectares in four decades.This large-scale deforestation is attributed to both proximate and under lying causes particularly traditional land tenure system and demographic development.Consequently,forest resources have been degraded and a number of plant species have disappeared from the forests of the study area while several others are in the process of disappearance.     

济南市人口城镇化与土地城镇化协调发展研究

人口城镇化与土地城镇化协调发展是推进新型城镇化的重点所在。通过构建指标评价体系和评价模型,从"人口—土地"协调的视角分析演算1995—2013年济南市的城镇化水平与协调发展状态。研究结果表明,济南市城镇化整体协调发展度从1995年的严重失调衰退阶段发展到2013年的优质协调发展阶段,但是从2008开始,人口城镇化滞后于土地城镇化发展,表现出一定的失调现象。研究结果可以为制定地区城镇化发展策略提供科学依据。