Rapid Population Growth Rates Research Articles

The Impact of Commodity Terms of Trade in Africa

The sharp increase in commodity prices that began in the early 2000s resulted in a marked improvement in terms of trade for Africa. Since then, commodity exporters’ terms of trade have declined despite a very moderate recovery in mid-2016. Terms of trade still remain higher than they were at the turn of the century, giving the false impression that conditions still favor Africa. The evidence, however, suggests that the commodity-driven prosperity has ended or, at best, has been interrupted for a long time to come. Some of these losses have not been realized fully because of unsustainable macroeconomic and foreign borrowing policies. These policies cannot be sustained, and the actual losses will catch up even if terms of trade do not deteriorate further. The complacency engendered by the relatively high gross domestic product (GDP) growth rates is misplaced, given the very rapid rate of population growth in Africa both in absolute terms and as compared to most other regions of the world. On the basis of the analysis presented in this article, a further decline or even stable terms of trade can be expected to have a significant negative effect on African economies. Many policymakers believe they are choosing between continued growth on the basis of present policies, or painful adjustment, usually imposed from outside. However, adjustment is inevitable. The real choice is between orderly and internationally supported correction and disorderly and disruptive crisis if current policies continue. It is imperative for the African countries, both highly concentrated exporters and more diversified economies, to focus on macroeconomic sustainability. In today’s adverse circumstances, and particularly given the fragile fiscal positions and mounting debts of many African countries, these policies are only possible if the economy adjusts to a sustainable path. Time is of the essence, and a conscious break with a policy of short-sighted comfort is required.

Initial genetic diversity enhances population establishment and alters genetic structuring of a newly establishedDaphniametapopulation

When newly created habitats are initially colonized by genotypes with rapid population growth rates, later arriving colonists may be prevented from establishing. Although these priority effects have been documented in multiple systems, their duration may be influenced by the diversity of the founding population. We conducted a large-scale field manipulation to investigate how initial clonal diversity influences temporal and landscape patterns of genetic structure in a developing metapopulation. Six genotypes of obligately asexual Daphnia pulex were stocked alone (no clonal diversity) or in combination ('high' clonal diversity) into newly created experimental woodland ponds. We also measured the population growth rate of all clones in the laboratory when raised on higher-quality and lower-quality resources. Our predictions were that in the 3years following stocking, clonally diverse populations would be more likely to persist than nonclonally diverse populations and exhibit evidence for persistent founder effects. We expected that faster growing clones would be found in more pools and comprise a greater proportion of individuals genotyped from the landscape. Genetic composition, both locally and regionally, changed significantly following stocking. Six of 27 populations exhibited evidence for persistent founder effects, and populations stocked with 'high' clonal diversity were more likely to exhibit these effects than nonclonally diverse populations. Performance in the laboratory was not predictive of clonal persistence or overall dominance in the field. Hence, we conclude that although laboratory estimates of fitness did not fully explain metapopulation genetic structure, initial clonal diversity did enhance D.pulex population establishment and persistence in this system.

A feasibility study for the locations of waste transfer stations in urban centers: a case study on the city of Nashik, India

Rapid population growth and high rate of urbanization make municipal solid waste management a challenging task for municipalities due to the inadequacy of infrastructural services. Taking this into consideration, this paper proposes an approach for finding economically optimal locations and feasibility demonstration of a municipal solid waste management infrastructure unit, i.e. waste transfer stations. This analytical approach consists of two basic elements: (i) a mathematical model to optimize overall cost for municipal solid waste management; and (ii) geographical information system tools to create a data inventory for the mathematical model. The novelty of the proposed model includes heterogeneity in data compilation, on-road measurements of distances and strategic allocation of transfer stations. Also, to assess waste load estimation more precisely, analyzing the impacts of heterogeneity in data and on-road distances on model, three distinct cases have been considered. Further, the developed approach has been demonstrated on the city of Nashik, India. The mathematical model for Nashik city is written in a mathematical programming language AMPL and the solutions have been obtained using KNITRO solver. Optimization model selects three best locations out of eight potential locations with the optimum capacity of 200 TPD. Furthermore, the assessment of model's behavior under uncertainty has been performed with a comprehensive sensitivity analysis for further improvements. The integrity of all components in this study produces a generic framework for helping municipal officials and researchers for development of a municipal solid waste management system with transfer stations in an economically optimal manner.

IMPLICATIONS OF HIGHWAY CAPACITY MANUAL ON FREEWAY MEASURE OF EFFECTIVENESS: A CASE STUDY

The Fargo-Moorhead Metropolitan Area’s rapid population and employment annual growth rate of 2.5 percent leading an opportunity for transportation infrastructure development. The forecasted growth will add demand, new number of trips, persons, vehicles, and vehicle hour travel, vehicle miles travel in the two principal Interstates (I-29 and I-94) in the Fargo-Moorhead Metropolitan Area. Consequentially, due to the increasing demand, interstates planning performance could be affected significantly in this area and will increase congestion, and thus, require a study with measuring of effectiveness in planning context. Therefore, a study of interstate within the Fargo-Moorhead metro area will be performed with measuring the deficiencies of several parameters such as volume, capacity, and level of service. The study will identify and provide guidance on congested areas incurred due to the forecasted/induced travel demand.

English

The Ngorongoro Conservation Area (NCA) is a World’s Heritage site and Biosphere Reserve in Tanzania. It is the only protected area with multiple land use where both wildlife conservation and limited human activities are allowed. Despite such an important status, the area is experiencing ecosystem changes resulting from increasing human population, diversified livelihoods and tourism activities. This study was conducted to determine the trends and challenges of livelihood activities of the local Maasai and tourism in NCA and their implications on the ecology of the area. Household questionnaire interviews, key informant interviews, focus group discussions, direct field observations and secondary data reviews were applied. A total of 145 people from Enduleni, Oloirobi villages and the NCA Authority (NCAA) were involved in the study. To complement the socio-economic data, landsat MSS satellite images of 1990, 2000 and 2013 blocks were analysed to assess land use/cover changes occurring in the study area. Results indicate rapid human population growth rate of 5.6% and an increment of 1.1% of livestock population per annum. It is also noted that about 46% of cropland has increased in the studied villages. Furthermore, the Maasai who were historically pastoralists are changing to agro-pastoralists. The grasslands and other natural forests showed a decreasing trend. The decreasing trends in wildlife are being associated with the changing vegetation characteristics among other factors. Despite the ecological changes, the Maasai have remained uncomfortable with the restrictions over land use so far implemented by the NCAA. In addition, there has been an increasing number of tourists and facility development within the NCA. There were also differing views between the Maasai and NCAA, which might put the NCA ecosystem under serious threats questioning its future. Whether or not the NCA will remain a world heritage site depends on management measures taken, otherwise the disappearance of the NCA ecosystem is imminent.   Key words: NCA, NCAA, world heritage site, tourism, ecosystem change, human population, diversified livelihoods.

Constraints to Achieving Household Food Security in North Central Nigeria

This study identified constraints militating against the attainment of household food security among three ethnic groups in North Central Nigeria in 2011. A sample of 340 households was interviewed using structured questionnaires. Factor analysis was used to isolate and name the critical factors influencing the attainment of household food security in the region. Findings revealed that economic, governance, institutional and technological constraints hindered the achievement of household food security in the study area. While the economic factors included climatic change and variability (0.57), shortage of farm labour (0.55), limited access to farm land (0.57); the institutional factors were poor market access (0.56), weak support services (0.48), poor nutrition education (0.48) and poor sanitation (0.44). The governance factors included political problems (0.51), rapid population growth rate (0.43) and low crop yield (0.43) while the technological factors were lack of access to clean water (0.43), inadequacy and lack of access to improved agricultural inputs (0.42) and lack of access to labour saving devices (0.41). Attaining household food security in North Central Nigeria is still a mirage. Therefore, governments at the local and state levels should design and implement short term and long term programmes in agriculture value chain to boost food production and productivity and enhance family income for improved household food security. Short Research Article

Dispersal behavior of Tetranychus evansi and T. urticae on tomato at several spatial scales and densities: implications for integrated pest management.

Studying distribution is necessary to understand and manage the dynamics of species with spatially structured populations. Here we studied the distribution in Tetranychus evansi and T. urticae, two mite pests of tomato, in the scope of evaluating factors that can influence the effectiveness of Integrated Pest Management strategies. We found greater positive density-dependent distribution with T. evansi than T. urticae when assayed on single, detached tomato leaves. Indeed, T. evansi distribution among leaflets increased with initial population density while it was high even at low T. urticae densities. Intensity and rate of damage to whole plants was higher with T. evansi than T. urticae. We further studied the circadian migration of T. evansi within plant. When T. evansi density was high the distribution behavior peaked between 8 am and 3 pm and between 8 pm and 3 am local time of Kenya. Over 24 h the total number of mites ascending and descending was always similar and close to the total population size. The gregarious behavior of T. evansi combined with its rapid population growth rate, may explain why few tomato plants can be severely damaged by T. evansi and how suddenly all the crop can be highly infested. However the localisation and elimination of the first infested plants damaged by T. evansi could reduce the risk of outbreaks in the entire crop. These findings suggest also that an acaricide treated net placed on the first infested plants could be very effective to control T. evansi. Moreover circadian migration would therefore accentuate the efficiency of an acaricide treated net covering the infested plants.

Light brown apple moth (Epiphyas postvittana) (Lepidoptera: Tortricidae) colonization of California

In response to the confirmed detection of the light brown apple moth, Epiphyas postvittana, in California, approximately 53,000 pheromone-baited Jackson traps were deployed and more than 246,000 males were caught (February 2007–February 2010). Approximately 46,000 manually entered catch records were corrected for errors and converted into catch per trap per day. As empty trap data (zeros) were not recorded, we added zeros between first and last catch for each trap based on the stated servicing period (~30,000), before analyzing for trends. Residual data error rate was estimated as 1.5 %. San Francisco and Santa Cruz counties had relatively high trap catches immediately upon trap set, and remained the leading population centers, while most other counties showed a more general trend of a slow build-up in catch over time (12 counties). An exponential increase in trap catch was observed in four counties with sufficient data. The pattern of spread indicated natural, as well as anthropogenic-assisted spread rates, with populations appearing well ahead of the invasion front. This jump dispersal is probably due to movement of host plants, unsurprising since eggs of this polyphagous moth are readily laid on foliage. There was evidence of seasonality in spread, probably linked to the phenology of the insect. There was a positive relationship between catch and known host tree preference, suggesting that trap placement in preferred hosts could add sensitivity to future surveys. Recommendations include the improved provision of data acquisition by telecommunications, standardization of data input, more archiving, and frequent analysis of trap catches. The rapid rate of population growth demonstrated in two counties and spread across many others supports the hypothesis of the recent arrival of E. postvittana in California.

Malthusian Population theory and the Nigerian Economy: A Political Economy Approach

Malthusian population theory was developed as a result of the rapid population growth rate and diminishing return in agricultural sector. Malthus observed geometric ratio growth in population vis-a-vis arithmetic ratio growth in food production and envisaged world “misery” or “vice” if not checked. Subsequent development in the world however, proved the theory wrong. But this work discovers that the predicted doom of population theory is manifesting in Nigeria - rapid population growth rate, food crises, large scale poverty, ethnic and religious conflict, HIV/AIDS epidemics, etc. Although, the aforementioned are in line with the theory’s predictions, Nigerian government operational modus favors these manifestations over the years. The work therefore, recommended that the judicial arm of government be made more efficient at law-enforcement, education sector be given appropriate budgetary attention to subdue poverty, diseases and health care predicaments. Thus, conclude that although, the theory is looked upon as primitive and wrong, the forecasted melancholies still exist in the 21st century Nigeria. Keywords: Population, Political Economy, Economic Growth

Food insecurity: challenges of agricultural extension in developing countries

The emphasis on accelerated agricultural development by developing countries was meant to achieve food security. However, food insecurity has remained a problem throughout much of the developing world and is the result of such factors as slow (as well as highly variable) growth in domestic food production, rapid population growth rates, limited financial capacity to import food and inadequate external assistance. Agricultural extension, on the other hand, plays an important role in development by assuring adequate and timely access by farmers to relevant advice, with appropriate incentives to adopt new technologies if it suits their socio-economic and agroecological circumstances. This paper discusses: the concepts of food security and food insecurity; the causes and consequences of food insecurity; the short-run and long-run measures for alleviating food insecurity; the strengths and weaknesses of some extension modalities; and the modifications to existing extension systems for the achievement of food security. The conclusions drawn are that: (a) improvements in nutritional standards and food security will involve not just a certain rate of agricultural growth, but reduction in population growth rates; and (b) modifications to extension services have the potential to improve agricultural productivity, increase farmers’ incomes, and improve food security. Key words: Food insecurity, food security, agricultural extension, developing countries

Food Insecurity: Challenges of Agricultural Extension in Developing Countries

The emphasis on accelerated agricultural development by developing countries was meant to achieve food security. However, food insecurity has remained a problem throughout much of the developing world and is the result of such factors as slow (as well as highly variable) growth in domestic food production, rapid population growth rates, limited financial capacity to import food and inadequate external assistance. Agricultural extension, on the other hand, plays an important role in development by assuring adequate and timely access by farmers to relevant advice, with appropriate incentives to adopt new technologies if it suits their socio-economic and agroecological circumstances. This paper discusses: the concepts of food security and food insecurity; the causes and consequences of food insecurity; the short-run and long-run measures for alleviating food insecurity; the strengths and weaknesses of some extension modalities; and the modifications to existing extension systems for the achievement of food security. The conclusions drawn are that: (a) improvements in nutritional standards and food security will involve not just a certain rate of agricultural growth, but reduction in population growth rates; and (b) modifications to extension services have the potential to improve agricultural productivity, increase farmers’ incomes, and improve food security.

Effect of main-stem dams on zooplankton communities of the Missouri River (USA)

The persistence of plankton in flowing water presents an enigma, i.e., how can populations be sustained while constantly losing individuals downriver? We examined the distribution and abundance of zooplankton from 146 sites on the Missouri River (USA) and found large shifts in the dominance of major taxa between management zones of this regulated river. Crustacean zooplankton were dominant in the inter-reservoir zone of the river, and their taxonomic composition was similar to regional lakes and reservoirs. The exponential decline of cladocerans and copepods with distance from main-stem dams suggests that conditions within the river are adverse to population growth and that reservoirs are the main source of these crustaceans in the river. Rotifers dominated in the channelized zone of the river. High algal biomass and rapid population growth rates likely allow persistence of rotifers in segments of the river that do not receive direct reservoir inputs. Rotifers were less abundant in the inter-reservoir zone, suggesting that their numbers are limited by internal processes, such as food or predators. Since zooplankton are known to be an important food for larval fishes in rivers, this shift of major taxa in regulated rivers has implications for river food webs.

Sustaining economic expansion in Pakistan in an era of energy shortfalls: growth options to 20351

AbstractPakistan's recent economic acceleration together with rapid rates of population growth is having a significant impact on the country's energy supply/demand balances. Energy supplies in turn affect the pace and pattern of the country's economic expansion. Drawing on the empirically‐based complex links between energy and the economy, several alternative scenarios of growth and energy needs are developed in an attempt to answer several key questions. In particular, what are some of the key interrelationships between sources of energy demand and supply? What are the economic growth consequences of alternative energy availabilities and, in turn, how do these growth patterns affect the subsequent energy supply and demand patterns? What energy strategies are suggested by the interconnection between the country growth requirements and energy needs? Are these significantly modified under rising or falling energy prices? Based on this analysis, several guidelines are drawn for the country's future energy policy.

NATIVE AND EXOTIC PLANT SPECIES EXHIBIT SIMILAR POPULATION DYNAMICS DURING SUCCESSION

A growing body of literature has led to the debate in invasion biology whether exotic species perform within communities differently than native taxa due to inherent advantages. To address this issue, the population dynamics of native and exotic plant species were assessed from a 48-year record of permanent plot data from the Hutcheson Memorial Forest Center (New Jersey, USA) to determine rate of increase, lag time, maximum frequency, and the year of peak frequency. Overall, native and exotic species exhibited very similar population dynamics. Rates of increase and length of lag times were similar between native and exotic taxa but were strongly influenced by plant life form. Short-lived species were characterized by rapid population growth rates and short lag times. Growth rates decreased and lag times increased with species longevity. Overall, correlations between population metrics were the same in native and exotic taxa, suggesting similar trade-offs in life history patterns. The one difference observed was that, in native species, peak frequency was negatively associated with the year of peak frequency (i.e., early-successional species tended to become more abundant), while there was no relationship in exotic species. These analyses show that exotic species behave in essentially the same way as native taxa within dynamic communities. This suggests that abundant native and exotic plant species are exploiting the same range of ecological strategies resulting in similar roles within communities.

Extremely Rapid Spread of Human Immunodeficiency Virus Type 1 BF Recombinants in Argentina

The epidemic of human immunodeficiency virus type 1 (HIV-1) in Argentina is distinctive in that many infections are caused by subtype BF recombinant viruses. To determine their demographic history, we estimated the evolutionary rate, mode of population growth, and age of genetic diversity among 40 BF vpu sequences. This revealed one of the highest substitution rates reported for HIV-1, at 10.793 x 10(-3) substitutions per site per year, and a very rapid rate of population growth, with an initial mean epidemic doubling time of 3.72 months. This rapid population growth is compatible with an elevated fitness for subtype BF compared to that for "pure" B and F viruses.

Invasion and Maintenance of Dengue Virus Type 2 and Type 4 in the Americas

Dengue virus type 4 (DENV-4) was first reported in the Americas in 1981, where it caused epidemics of dengue fever throughout the region. In the same year, the region's first epidemic of dengue hemorrhagic fever was reported, caused by an Asian strain of dengue virus type 2 (DENV-2) that was distinct from the American subtype circulating previously. Despite the importance of these epidemics, little is known about the rates or determinants of viral spread among island and mainland populations or their directions of movement. We employed a Bayesian coalescent approach to investigate the transmission histories of DENV-2 and DENV-4 since their introduction in 1981 and a parsimony method to assess patterns of strain migration. For both viruses there was an initial invasion phase characterized by an exponential increase in the number of DENV lineages, after which levels of genetic diversity remained constant despite reported fluctuations in DENV-2 and DENV-4 activity. Strikingly, viral lineage numbers increased far more rapidly for DENV-4 than DENV-2, indicative of a more rapid rate of exponential population growth in DENV-4 or a higher rate of geographic dispersal, allowing this virus to move more effectively among localities. We propose that these contrasting dynamics may reflect underlying differences in patterns of host immunity. Despite continued gene flow along particular transmission routes, the overall extent of viral traffic was less than expected under panmixis. Hence, DENV in the Americas has a clear geographic structure that maintains viral diversity between outbreaks.

The Water Crisis in the Gaza Strip: Prospects for Resolution

Israel and the Palestinian Authority share the southern Mediterranean coastal aquifer. Long-term overexploitation in the Gaza Strip has resulted in a decreasing water table, accompanied by the degradation of its water quality. Due to high levels of salinity and nitrate and boron pollution, most of the ground water is inadequate for both domestic and agricultural consumption. The rapid rate of population growth in the Gaza Strip and dependence upon ground water as a single water source present a serious challenge for future political stability and economic development. Here, we integrate the results of geochemical studies and numerical modeling to postulate different management scenarios for joint management between Israel and the Palestinian Authority. The chemical and isotopic data show that most of the salinity phenomena in the Gaza Strip are derived from the natural flow of saline ground water from Israel toward the Gaza Strip. As a result, the southern coastal aquifer does not resemble a classic "upstream-downstream" dispute because Israel's pumping of the saline ground water reduces the salinization rates of ground water in the Gaza Strip. Simulation of different pumping scenarios using a monolayer, hydrodynamic, two-dimensional model (MARTHE) confirms the hypothesis that increasing pumping along the Gaza Strip border combined with a moderate reduction of pumping within the Gaza Strip would improve ground water quality within the Gaza Strip. We find that pumping the saline ground water for a source of reverse-osmosis desalination and then supplying the desalinated water to the Gaza Strip should be an essential component of a future joint management strategy between Israel and the Palestinian Authority.

Population growth and savings rates: Some new cross‐country estimates

It is widely recognised that population growth can have two conflicting effects on savings. It reduces savings as it leads to more dependent children, but if balanced it can also increase savings by increasing the number entering the working part of the life cycle and hence the number of potential savers. However, this positive effect has largely been ignored in the empirical literature. Based on the population growth rate as its measure and an augmented cross‐country life cycle regression model evidence for its existence is confirmed. Confidence in the estimates is undermined by tests indicating that in many countries over the relevant period population growth was not in steady state balance. This is ameliorated by the high regression R2s and by comparable labour force growth rate estimates, but it was also found that the estimates could not be interpreted as evidence that countries with more rapid population growth rates actually save more. This is because the negative impact of larger families was found to outweigh any increase in savings because of more families. The net elasticity effect was calculated to be − 0.08. The paper concludes that savings continues to be a cost of rapid population growth, but perhaps not quite as debilitating as some might have presumed.

More Options Offered for Long-Term Energy Solutions

The debate on energy resources and population clearly includes thoughtful and concerned people on all sides. Responses appear to be based on one of two different models. In one model, population growth is slowing and will soon stabilize at a level at which both birth rate and death rate are low. Technological innovation and resource substitution will ensure that the Malthusian scenario of food and energy shortages, and their resultant malnutrition, disease, and wars need not occur.The error in this model is that it only applies to countries where women have access to education and employment and need not depend on childbearing for status and security. But much of the developing world has a rapid population growth rate, due to the application of medical technology that limits infant mortality, without the application of contraceptive technology that limits the birth rate. Rapid population growth limits the use of resources to those needed for survival, with little left for education and job training, especially for women. They have no alternative to childbearing as a way of ensuring for themselves a respectable place in society.In the other model, a high level of education and participation of women in the work force has stabilized the population in the developed countries. They have a low birth rate that balances a low death rate. But that is not happening in underdeveloped countries. In fact the frequent news reports of famines and local wars imply that unsustainable growth is occurring that will result in the Malthusian scenario in which population stability is achieved only with a high death rate to balance the high birth rate.The error in the second model is that the present situation need not perpetuate itself. Provided globalization continues and productive capacity and resource control shift from the minority to the majority, the Malthusian scenario for the majority could be avoided. This option would also require that women worldwide be given access to family planning technology. It is also essential that women receive education and job training so that they have an attractive alternative in life to that of continual childbearing.© 2005 American Institute of Physics.

The impact of land use on soil carbon in Miombo Woodlands of Malawi

In the Miombo Woodlands Region of south-central Africa, it is estimated 50–80% of the total system's carbon stock is found in the top 1.5 m belowground. Deforestation and rapid population growth rates have led to reduced fallow periods and widespread land degradation in the south-central Africa area of the Miombo Woodlands. The impact of this land use conversion on belowground carbon and nitrogen stocks within the Miombo Woodlands has not been examined extensively in the past. We addressed how the soil carbon profile reacts to conversion to agriculture, the continuation of agriculture, and the ability of the soil carbon budget to recover following abandonment within the Chimaliro Forest Reserve and surrounding villages in Kasungu, Malawi. Protected natural Miombo Woodlands sites, agricultural fields of increasing ages, and fallow fields of increasing ages were sampled. Surface carbon levels in Miombo soils varied from 1.2 to 3.7%. Agricultural soil carbon was significantly depressed with surface layers ranging from 0.35 to 1.2% carbon. Unexpectedly, fallow carbon and nitrogen levels continued to be significantly repressed (surface soils 0.65–2.3% C), pointing out the possible unsustainability of the current agricultural management cycle dominant in the area. On average, agricultural soils contain 40% less soil carbon than the natural Miombo Woodlands. Soil carbon declined logarithmically with depth within all land use types. Clay content was significantly positively correlated with soil carbon in the top 40 cm and therefore areas of higher clay content contained elevated carbon levels. Although a common attribute to many agricultural systems, bulk densities were not significantly altered by land use changes.