Population pressure and areas of potential rural development in Southern Nigeria

The spatial analysis of agricultural development is the necessary precondition for research in the rural landscape and for rural planning. Basic data emerging from field investigation and a systematic interpretation of aerial photographs have resulted in a series of thematic maps of Southern Nigeria and parts of Western Cameroon. This comprehensive research work has been organized within the framework of the Afrika-Kartenwerk of the German Research Society.In this paper our recently published population map of the scale of 1:1 million and the map of rural settlement patterns form the basis for some rather general estimates of agricultural potential. Exact spatial information of simple but non the less most important regional processes, like migration, are caused by population pressure. Not bare statistical figures but their transformation by cartographic means forms a fundament for area studies and hypothetical prospects for regional planning as well as for regional analysis.By larger scale observations agricultural carrying capacity, evaluation of rural potential, migration dynamics and changes of land-use systems have to be analyzed. This calls for meticulous studies of individual areas. The first of three such case studies stresses the process of intensification of land utilization near the Nsukka-Escarpment. Linear settlement patterns and chains of regular individually owned stripfields can be seen as inprints of a dynamic transformation within the cultural landscape. Reception of new agricultural technology has been a way for emigrant farmers to exploit traditionally sparsely utilized zones with rich soils, which had been less attractive, because they were hard to cultivate with the hoe.The second case deals with the well known migratory and agro-economic links between the overpopulated food crop belt of Northern Yoruba Savannah Country and the cocoabelt in the rain forest about 100 km further south.In Central Iboland rural overpopulation of more than 1000 persons per km² and land shortage theoretically could be diminished by opening up uninhabited areas of the Niger flood-plain and the delta for modern agricultural exploitation. But not only the physical obstacles such as there are poor soils, very high rainfall and seasonal floods within the Niger low lands are hindering rural colonization. Social and political factors, like ethnic traditions and historic barriers still seem to be very perserverant. All this hardly allows strangers to get hold of unused land, to exploit valuable natural resources or to introduce modern agricultural technology. But generally speaking, population pressure as well as higher demand for social services and better incomes result in changes in the traditional land-use systems. The impact of growing urban or industrial economic spheres on agriculture acts as accelerating factor in this development. A paradise-landscape for Africa where optimal utilization of all physical resources under best socio-economic conditions may be practiced and where more than ten times of the present population of Africa could exist, as CAROL puts it in one of his scenarios (1973 and 1975), seems to be quite unrealistic and really never will be desirable.     

Rural gentrification in Catalonia, Spain: A case study of migration, social change and conflicts in the Empordanet area

The intensity of rural depopulation in Catalonia has diminished since the 1980s. New population growth patterns are occurring in rural areas, basically due to immigration. Although there has been a certain awareness of the magnitude of this process and its territorial distribution, little is known about the protagonists in this immigration and the impact on rural municipalities. Results are presented from a study of the immigration process in a group of rural inland municipalities close to the Costa Brava, a Mediterranean coastal region with extensive tourism. The great beauty of the landscape and the existence of housing stock that is being abandoned but remains desirable have led to a population influx from Catalonia’s large urban areas, especially Barcelona, purchasing these homes as a primary or secondary residence.This has led to rehabilitation of the housing stock, but also to higher housing prices and the resulting exodus of the young local population that cannot afford them; a potential source of conflict between the local population and the newcomers. The study is based on census data and statistical records, as well as extensive fieldwork, including interviews with local residents, newcomers and key informants.     

Rural settlement change in the Republic of Ireland — a preliminary discussion

One of the notable repercussions of the population stability and growth in Ireland in the past two decades has been the impact on settlement in rural areas. Rural areas in the vicinity of towns and cities especially have experienced this urban-generated settlement expansion. This preliminary examination looks at the changes which have taken place in rural settlement patterns and briefly discusses their implications.     

Distribution of nitrifying activity in the Seine River (France) from Paris to the estuary

The distribution of nitrification has been measured with the H¹⁴CO₃ ⁻ incorporation method in the Seine River and its estuary during summer conditions. The Seine River below Paris receives large amounts of ammonium through wastewater discharge. In the river itself, this ammonium is only slowly nitrified, while in the estuary nitrification is rapid and complete. We show that this contrasting behavior is related to the different hydrosedimentary conditions of the two systems, as nitrifying bacteria are associated with suspended particles. In the river, particles and their attached bacteria either rapidly settle or have a sestonic behavior. Because of the short residence times of the water masses, the slow growing nitrifying population has no time to develop sufficiently to nitrify the available ammonium. The estuary is characterized by strong tidal dynamics. Particles settle and are resuspended continuously with the strong current inversions of ebb and flood. As a result of these dynamics, particles and their attached nitrifying bacteria experience longer residence times in a temporary suspended state than the water masses themselves, providing to slow growing nitrifying bacteria the opportunity to develop a large population capable of nitrifying all the available ammonium.     

Impacts of hydrological changes on phytoplankton succession in the Swan River, Western Australia

The Swan River estuary, Western Australia, has undergone substantial hydrological modifications since pre-European settlement. Land clearing has increased discharge from some major tributaries roughly 5-fold, while weirs and reservoirs for water supply have mitigated this increase and reduced the duration of discharge to the estuary. Nutrient loads have increased disproportionately with flow and are now approximately 20-times higher than pre-European levels. We explore the individual and collective impacts of these hydrological changes on the Swan River estuary using a coupled hydrodynamic-ecological numerical model. The simulation results indicate that despite increased hydraulic flushing and reduced residence times, increases in nutrient loads are the dominant perturbation producing increases in the incidence and peak biomass of blooms of both estuarine and freshwater phytoplankton. Changes in salinity associated with altered seasonal freshwater discharge have a limited impact on phytoplankton dynamics.     

Coupling sentiment and human mobility in natural disasters: a Twitter-based study of the 2014 South Napa Earthquake

Understanding population dynamics during natural disasters is important to build urban resilience in preparation for extreme events. Social media has emerged as an important source for disaster managers to identify dynamic polarity of sentiments over the course of disasters, to understand human mobility patterns, and to enhance decision making and disaster recovery efforts. Although there is a growing body of literature on sentiment and human mobility in disaster contexts, the spatiotemporal characteristics of sentiment and the relationship between sentiment and mobility over time have not been investigated in detail. This study therefore addresses this research gap and proposes a new lens to evaluate population dynamics during disasters by coupling sentiment and mobility. We collected 3.74 million geotagged tweets over 8 weeks to examine individuals’ sentiment and mobility before, during and after the M6.0 South Napa, California Earthquake in 2014. Our research results reveal that the average sentiment level decreases with the increasing intensity of the earthquake. We found that similar levels of sentiment tended to cluster in geographical space, and this spatial autocorrelation was significant over areas of different earthquake intensities. Moreover, we investigated the relationship between temporal dynamics of sentiment and mobility. We examined the trend and seasonality of the time series and found cointegration between the series. We included effects of the earthquake and built a segmented regression model to describe the time series finding that day-to-day changes in sentiment can either lead or lag daily changed mobility patterns. This study contributes a new lens to assess the dynamic process of disaster resilience unfolding over large spatial scales.     

On the questions of migration in India: Challenges and opportunities

This is an exploratory study made on the basis of migration data of two censuses of 1971 and 1981. It tries to compare some of the important variables of mobility in terms of POB (place of birth) and POLR (place of last residence) which have reacted into the change of usual residence of people causing thereby shift of population. The subject being complex and vast, it may be difficult to project all possible situations at one place. However, the readers may try to test some of the findings more fruitfully by field oriented investigations specially leading to establish various social-economic fall outs. Migration study is processional in the evaluation of population problems which has folded into its orbit, in real sense of the term — idealised migration policies. In the country, like ours, it is essential to really spell out some policy to check urban swelling of population and to strengthen the rural space to reduce regional imbalances at the individual level so that real development is achieved. Some of these questions on migration have been posed in this paper to take up further to promote policy formations and to organise the migrant manpower for a better India.Views expressed in this paper are personal and have no relations with Government and the organisation of author's affiliation in any way.     

Changing settlement patterns in the German Democratic Republic: 1945–1976

The settlement pattern in the German Democratic Republic has undergone dramatic changes since 1945, largely as a consequence of the socialist government's aim of concentrating population into fewer but larger central places. The impact of this policy has been greatest in rural areas, most especially in the northern part of the country. This paper examines the character of the changes experienced by both urban and rural areas in northern G.D.R. since 1945.     

Magnesium in well water and the spatial variation of acute myocardial infarction incidence in rural Finland

The protective role of water hardness and Mg in cardiovascular illness has been suggested in several epidemiological studies. In the present ecological study, the association of Ca, Mg, Al, Cu, F, Fe, Zn and NO₃ in local ground water and spatial variation of acute myocardial infarction (AMI) incidence among men and women 35–74 years of age in rural Finland in 1991–2003 were examined. Data on AMI cases, 67,755 men and 25,450 women, were obtained from the Finnish Cardiovascular Disease Register. The statistical analysis was carried out using Bayesian modeling. 10 × 10 km grid cells were used instead of administrative boundaries to partition the study area. On average, 1 mg/L increment in Mg level in local ground water was associated with 2% (95% HDR −0.0391, −0.0028) decrease in incidence of AMI in the rural population. In conclusion, high AMI incidence in eastern Finland is associated with soft ground water, low in Mg.     

Environmental change and human mobility in the digital age

This intervention argues for the need of research to examine how information and communication technologies (ICTs) shape human mobility in the context of environmental change. ICTs are becoming increasingly central in the daily lives of migrants and communities at risk of environmental events. There is a lack of research, however, exploring how access to and the use of ICTs influences practices and dynamics of human mobility in the face of environmental change. I will outline this research gap and highlight areas for further research. I will do so by bringing together literature from human geography and environmental studies on migration and social resilience, and from sociology on the influence of our mobile and network society. In conceptualizing the role that ICTs play, I argue that the use of ICTs shapes human mobility through its impact on social network activities and relations. In this manner, this intervention builds on a growing body of research conceptualizing social networks – and related dynamics of power, access, in/exclusion – as shaping migration trajectories and abilities to cope with environmental events.     

The fifth edition of the Atlas of Finland —thematic and methodological guidelines

Finland has a most extraordinary experience in the field of thematic and expecially atlas cartography. The traditions of national atlases go almost 100 years back through five extensive editions (1899, 1910, 1920, 1960 and the fifth 1977–1991). Thematically these atlases have acted as thruthful mirrors of the rather dramatic changes Finland has lived through both from the point of environment (including political boundaries), economy, settlement and cultural features. Methodologically the series of Finnish atlases show many interesting aspects of development, in many respects important new approaches have been introduced and also the fifth edition has in international reviews been described as “innovative”. Finally one can stress the purposeful geographical emphasis in the content of these atlases; they are no mechanistic interpretations of e.g. statistical data. The presently-day work in the field of national atlases faces many new demands. Automation has enhanced the cartographic processing of data, there is a much extended information base concerning all the aspects of the modern societies which must be taken into account and there is also a number of new outlets for the ready product (printed and numerical). The greater scope and diversity must not, however, restrict the scientific unbiased editorial work of analyzing and synthetizing the data for cartographic expression; a clearcut geographical philosophy must be the guideline. In the future the thematic and atlas cartography must also be dealt increasingly in problem-oriented and international frames.     

Urbanization and spatial structure in Hungary

The last four decades have brought fundamental changes in Hungarian urbanization. The number of towns has increased from 54 to 166 and the number of settlements with a population over 100 000 has grown from 3 to 8, and the number of small towns with a population just over 30 000 has increased four times compared to the situation at the beginning of the century. While urban concentration has been growing, there has been a degradation of rural settlements, especially in the category of less than 500 inhabitants. This study deals with the spatial structure of Hungarian settlements, categorizing the towns according to their regional roles, population and dynamics of growth. The changes of their social and economic spheres influence their internal structures. The study attempts to summarize all the territorial, regional consequences of the recent social and economic changes that have been defining or modifying the urban development in Hungarian settlements.     

Importance of climate,forest fires and human population size in the Holocene boreal forest composition change in northern Europe

The relative importance of climate, forest fires and human population size on long‐term boreal forest composition were statistically investigated at regional and local scales in Fennoscandia. We employ pollen data from lakes, reflecting regional vegetation, and small forest hollows, reflecting local vegetation, from Russia, Finland and Sweden to reconstruct the long‐term forest composition. As potential drivers of the Holocene forest dynamics we consider climate, generated from a climate model and oxygen isotope data, past forest fires generated from sedimentary charcoal data and human population size derived from radiocarbon dated archaeological findings. We apply the statistical method of variation partitioning to assess the relative importance of these environmental variables on long‐term boreal forest composition. The results show that climate is the main driver of the changes in Holocene boreal forest composition at the regional scale. However, at the local scale the role of climate is relatively small. In general, the importance of forest fires is low both at regional and local scales. The fact that both climate and forest fires explain relatively small proportions of variation in long‐term boreal vegetation in small forest hollow records demonstrates the complexity of factors affecting stand‐scale forest dynamics. The relative importance of human population size was low in both the prehistorical and the historical time periods. However, this is the first time that this type of data has been used to statistically assess the importance of human population size on boreal vegetation and the spatial representativeness of the data may cause bias to the analysis.     

Geochemical and flow modelling as tools in monitoring managed aquifer recharge

Due to a growing world population and the effects of anthropogenic climate change, access to clean water is a growing global concern. Managed aquifer recharge (MAR) is a method that can help society's response to this increasing demand for pure water. In MAR, the groundwater resources are replenished and the quality of the recharged surface water is improved through effects such as the removal of organic matter. This removal occurs through mechanisms such as microbial decomposition, which can be monitored by studying the isotopic composition of dissolved inorganic carbon (DIC). Nevertheless, the monitoring can be difficult when there are other factors, like dissolving calcite, affecting the isotopic composition of DIC.The aims of this study were to establish a method for monitoring the decomposition of organic matter (dissolved organic carbon – DOC) in cases where calcite dissolution adds another component to the DIC pool, and to use this method to monitor the beginning and amount of DOC decomposition on a MAR site at Virttaankangas, southwestern Finland. To achieve this, we calculated the mean residence times of infiltrated water in the aquifer and the fractions of this water reaching observation wells. We conducted geochemical modelling, using PHREEQC, to estimate the amount of DOC decomposition and the mineral reactions affecting the quality of the water.     

Rural settlements,mission settlements and rehabilitation in Transkei

During the 19th century the predominant form of rural settlement in Transkei was that of dispersed homesteads. The form of the homesteads tended to differ from tribe to tribe, while the homesteads of various tribal groups were separated from each other by uninhabitated areas, or buffer zones. During the 19th century mission settlements were introduced to Transkei, some of which developed into towns.In the 20th century, mainly as a result of government action, homesteads have been nucleated into rural settlements and villages and much of the land has been fenced. A few peri-urban and industrial villages also exist in Transkei. Over 95% of the population of Transkei in 1980 were still rural dwellers.     

‘White cranes fly over black cranes’: The longue durée of rural–urban migration in Vietnam

The changing nature of rural–urban migration, in the context of transition economies of East and Southeast Asia, is usually interpreted as an outcome of structural transformation, while the longue durée of these migration flows tends to be neglected. Adopting a historical perspective, supported by the ’migration as resistance’ approach, this paper examines the changes in rural–urban migration dynamics in Vietnam from the 1950s to 2010 in relation to the country’s political and economic reforms (Ð?i M?i). Drawing on a case study of female migration between Phu Khe and Hanoi, it analyses how migrants resist and undermine state control over population mobility in order to pursue their movement and migration, and how they develop their migration networks over time. By doing so, the paper highlights a gradual process of the changing nature of rural–urban migration in which migrants themselves, through their resistance to governance of mobility and their establishment of migration networks prior to Ð?i M?i, play an important role.     

Possibilities of agricultural settlements in the northern coastal area of Kenya —an analysis of relevant climatic factors

Kenya is one of those African countries with a very high population pressure. In cultivatable areas we find up to 650 rural inhabitants per sq km. The search for new possibilities of agricultural settlement is an indispensable task. Many sciences are involved, also the geography of climates. Probably the largest potential settlement area from the climatic point of view is the Northern coastal zone. It has been settled in medieval times much more densely than today. War-like invasions of nomads have decreased the population since the 16th century. The average density of the cultivatable strip has been less than 5 inhabitants per sqkm in the last census year 1969. New settlement schemes have been developed since 1970, but they face the difficulty to choose the right varieties of crops. Careful climatic investigations are necessary for the further selection of areas and for the agricultural extension service. Here, only a first approach has been made. The main emphasis was laid on the effective rainfall in the so-called agrohumid period of the year and its probability. A new system of climatic classification was applied to give a frame for further, more specialised studies.     

The community morphology of skilled migration: the changing role of voluntary and community organisations (VCOs) in the grounding of British migrant identities in Paris (France)

Research into skilled migrant communities tends to emphasize the grounding of identities through transnationalism and mobility. Less research has been conducted into how skilled migrants actually ground their identities within the city through everyday social networks. The paper addresses this imbalance by examining the changing significance of British voluntary and community organisations (VCOs) in Paris, France. Combining qualitative and quantitative data, findings show local migrant networks to be important focal points for the British even though migrants’ lives may increasingly be transnational in orientation. The research also shows that in situ social networks are evolving. Specifically, traditional forms of elite expatriate communality are not as omnipotent as they once were, with the popularity of some high-profile British VCOs in Paris declining over recent decades. The paper argues that the link between social dynamism and communal morphology helps explain this shift: as British middle-class lifestyles have fragmented, and as the British migrant population in Paris has grown in scale and scope, so the range of VCOs and associated informal networks has grown. Whilst some skilled migrants still embed within traditional expatriate organisations, Britishness is increasingly grounded elsewhere; both within the city through alternative social networks, and located beyond the city through transnational ties.     

Intra-city migration to squatter settlements in Mexico City

The paper describes spatially the zonal movements of residents to three squatter settlements established at different time periods in Mexico City. In addition, moves are related to the dynamics of the low income housing system and previous theories of intra-city squatter migration behaviour are evaluated. The data corroborate the concept that the traditionally accepted pattern of centre to periphery, tenement to squatter settlement movements has altered. Direct movement into the periphery on the part of incoming migrants is increasingly important, and older established squatter areas are the most important suppliers of population in recent invasions. The implications for the distribution and structure of housing opportunities for future low-income populations in Mexico City are discussed.     

Growth and urban differentiation on the urban periphery: A case study from Szeged, Hungary

In late nineteenth century Hungarian cities there were strong contrasts between the inner ‘urban’ core and the rural periphery in terms of housing conditions, accessibility and lifestyle. Rural-urban fringe zones in the Great Plain were quite distinctive because the Turkish period was followed by an outflow of population which resulted in scattered settlement around the urban centres. The fringe could be regarded simply as a zone of transition, but the differences between urban centres and their immediate surroundings were gradually reduced through the industrialisation of the larger towns in the communist period. A study of Szeged examines the expansion of the fringe zone and its gradual urbanisation through the growth of housing as people have moved out from the centre to live among the rural population which increasingly turned from agriculture to commuting. Villages on either side of Szeged's administrative boundary accommodated more migrants from the city during the 1980s and experienced a gradual positive change in the quality of life as people escaped from the decaying residential blocs in the centre. During the years since 1989 there has been further migration, coupled with a growth of small businesses and a big improvement in services (shopping, running water, sewage and telecommunications). Further change may be expected in line with the forces of counterurbanisation. This revised version was published online in July 2006 with corrections to the Cover Date.