Relative Population Growth Research Articles

The Israel and Palestine land settlement problem, 1948–2005: An analytical history

This paper traces the history of the current conflict between Israel and Palestine from 1948–2005 C.E. It focuses on the frontier conflict between Israel and Palestine, a conflict that has resulted in four major wars during the post-Second World War period, and that has left Israel as the occupying power over a large swathe of territory not allocated to it by the United Nations in 1947. It outlines the nature of the refugee problem in Palestine and neighboring Arab states, and defines the political problems posed both by relative Israel-Palestine population growth, and by the `right to return’ claim by ousted Palestinian Arabs. It reviews the political problems posed by religious extremism and theocratic government both in Israel and Palestine. It concludes with a brief discussion of the unpleasant alternatives left as the road map to peace disintegrates and outlines a preferred solution from the perspective of the advanced western nations.

Modelling population dynamics of banana plant-parasitic nematodes: A contribution to the design of sustainable cropping systems

This article describes the biological background, the model-building methodology and some applications of SIMBA-NEM, a new model to simulate the population dynamics of two major plant-parasitic nematode species of banana, Radopholus similis and Pratylenchus coffeae. For each species, each generation is represented by one cohort. Cohorts of the same species form a chain representing the developmental stages of nematodes. A logistic function describes population growth in relation with: (i) an environmental carrying capacity ( K) that depends on available banana root biomass, (ii) an intrinsic growth rate ( c) and (iii) competition between nematode species. Soil water content and the quantity of nematicides used are considered to be the main variables influencing the intrinsic population growth rate of each species. SIMBA-NEM was calibrated and validated using datasets from banana cropping systems in Guadeloupe (French West Indies). By analysing the sensitivity of the model to the main parameters and performing simulations of validation for various cropping systems (banana monoculture with or without nematicide applications use and a banana/sugarcane rotation) we were able to test the ability of the model to predict nematode population dynamics under a range of conditions. SIMBA-NEM is able to predict long-term nematode population size, while taking interspecific competition into account. It also helped to define knowledge gaps in nematology and modelling. SIMBA-NEM was used to optimise the effect of nematicide applications. SIMBA-NEM can already be a very helpful tool for designing sustainable and more environment-friendly banana cropping systems. In the SIMBA global crop-modelling environment, SIMBA-NEM is a key sub-model which provides essential information concerning the sustainability of the simulated system and thus permits planning environmentally friendly cropping systems.

Dynamics of seedling populations and tree species coexistence in a forest: a simulation study

AbstractTheoretically, temporal variation of reproduction promotes species coexistence of sessile and polycarpic organisms when the reproduction is synchronized within species but independent among species. Monopoly of vacant sites and high relative population growth rate of minor species in the absence of propagules of other species is the essence of this mechanism. The mechanism is expected to work in forests, but persistent populations of seedlings may affect the promotion of coexistence. Using a tree‐based simulation model of forest dynamics, it was demonstrated that the number of coexisting tree species was sensitively affected by the seedling establishment rate. The coexistence was not enhanced by temporal variation of reproduction when seedling establishment rate was low. This is because the reproducing minor species fail to monopolize vacant sites and allow the establishment of seedlings of other species in later years. High mortality of established seedlings under shade also suppressed coexistence. This is likely to be the result of a reduced storage effect of the population of seedlings. A forest structure and dynamics pattern that appears when tree species coexistence is promoted by fluctuating reproduction was searched for, and the number of coexisting species was varied by manipulating the seedling establishment rate. No distinct difference other than the species number itself was found between species‐rich and species‐poor forests. For example, the seedling population size varied, reflecting the temporal variation of reproduction, irrespective of the seedling establishment rate. Further strategy development is needed to validate the proposed mechanisms of species coexistence.

Counterurbanization and Its Socioeconomic Effects in High Mountain Areas of the Sierra Nevada (California/Nevada)

Abstract Resettlement of peripheral areas (“counterurbanization”) is driving population growth in the central Sierra Nevada of California and Nevada. The present study analyzes the impact of “urban refugees” on socio-economic conditions in rural high mountain regions (above 1800 m). From 1960 onward, the High Sierra counties have ranked among Californian high mountain regions with the heaviest relative population growth. Tourism provides the most important impulse for the diffusion of metropolitan populations to high altitude areas, and constitutes the major source of employment there. People who migrate to the study areas (Lake Tahoe region and Mammoth Lakes area) tend to be white, well-educated, with considerable household earnings, but do not fall into the senior citizen category. There is no doubt that their demand for vacation or permanent homes has increased housing prices enormously. Planning problems that tend to come with settlement expansion in high mountain regions represent a certain potential...

Biotic homogenization of the California flora in urban and urbanizing regions

Biotic homogenization, driven by native species losses and invasive species gains was investigated for the flora of California. Data from a variety of available databases were aggregated at the county level to examine patterns in county population density and growth in relation to floristic change. Based on population, California was divided into three zones: high ( n = 9; 257–1320 people/km 2), medium ( n = 25; 28–177 people/km 2), and low ( n = 24; 1–24 people/km 2) density counties. Examining patterns of rare plant occurrences among these counties revealed that high and medium density counties contained, on average, as many or more rare and endemic species than low density counties. The largest pool of these species, 48 percent of the 962 highly threatened taxa in California, is restricted to high and medium density counties. Thus, urban and urbanizing counties play a strategic role in maintaining a part of California’s flora that is both globally significant and threatened with extinction. Examining species losses and noxious weed additions across high density counties, reveals a consistent pattern of low similarity among species that have been extirpated from high density counties and a high similarity among noxious weeds that these counties now share. The consequence is that California’s urban county floras appear to be homogenizing. Examining homogenization using the entire flora for urban counties demonstrates that less similar counties become more similar. The effect of loss of rare species could outweigh the gain in exotics, under an assumption of strong extinction. Finally, a strong negative relationship between population density and the proportion of county land in public ownership suggests that high and medium density counties are in a poor position to protect rare plant populations on a localized basis.

Urban comprehensive planning – identifying barriers for the maintenance of functional habitat networks

Maintaining biodiversity requires a wise combination of protection, management and recreation of habitats to secure representative and functional habitat networks. As urbanisation is increasing worldwide, town and cities are becoming the most common habitat for humankind. Accordingly, the urban landscape is becoming increasingly important for maintaining biodiversity on site, as well as for understanding the concept of biodiversity in general, and its maintenance in urban landscapes. We evaluated the extent to which Swedish urban planners experience barriers when using comprehensive planning as a tool for the maintenance of biodiversity through the provision of sufficient quantity and quality of green space. All of the six large Swedish cities, having had constant relative population growth since the beginning of the 19th century were chosen as case studies. We first defined a normative model for planning urban biodiversity and operationalised this concept by using landscape ecological principles. Structured in-depth interviews were then carried out with three planners in each city. The respondents were asked about their interest, ability, and knowledge concerning planning for functional networks of green spaces in relation to the normative model. The in-depth interviews with 18 urban planners indicated that legislation was an important driver for green space planning, that they paid attention to new knowledge concerning recreation values and public health, but that biodiversity maintenance was not a high priority. There was a general agreement that local governments lack necessary resources to plan for biodiversity. A majority of the respondents mentioned geographical information systems (GIS) as an important tool to integrate knowledge about biodiversity in the planning process, and to evaluate likely consequences caused by deviations from current structure plans related to an efficient use of urban green spaces to maintain biodiversity. However, an evaluation of the answers revealed that the respondents had actually overestimated their capacity to implement the normative model. To conclude, the unanimous view was that planners were interested in the maintenance of biodiversity, but were limited by knowledge and by personnel lacking suitable qualifications, as well as by inadequate organisations. Only a minority of the respondents thought that local governments should have resources for biodiversity conservation planning. Finally, we discuss how the implementation of biodiversity policies could be improved by better integration of natural and social sciences in education and policy implementation.

SMALL-SCALE PATCH SELECTION AND CONSUMER-RESOURCE DYNAMICS OF EASTERN GREY KANGAROOS

Models of kangaroo populations have primarily focused on the prediction of population growth and distribution in relation to environmental variation at broad geographic scales. Current understanding of small-scale patterns in distribution, habitat breadth, and niche occupation is less complete. A powerful model of dispersion is ideal free distribution (IFD) theory. In plant-herbivore grazing systems, the most appropriate IFD models are those that allow for the incorporation of a standing crop of resources. Using eastern grey kangaroos (Macropus giganteus), we test the predictions of a previously described standing-crop IFD model where the number of consumers on a patch is proportional to the resource input rate, the standing crop of resources on all patches at equilibrium are equal (in the absence of interference), and the resource mortality rate is directly equivalent to the resource input rate, and is independent of the resource density (in the absence of interference). We make these comparisons at both the habitat and patch scale. At the habitat scale, we observed significant departures from these predictions that are consistent with the commonly reported occurrence of undermatching, whereas at the patch scale, little concordance with the predictions was observed. These results suggest that eastern grey kangaroos select for resources at the habitat scale but not at the level of the patch.

Temporal changes in key factors and key age groups influencing the population dynamics of female red deer

Summary 1. We use structured demographic accounting to decompose the contribution to the variance in relative population growth between 1971 and 1997 in female red deer on Rum, Scotland, in terms of different fitness components and age categories. 2. During the first 10 years (1971–80) the variance in relative population growth was small (0·00246) as the population grew from 58 to 148 having been culled previously. After this the relative variance in population growth increased to 0·00575 between 1981 and 1989, and increased again to 0·00848 between 1990 and 1997. 3. In the first phase of population growth (1971–80) changes in the birth rate contributed most to the variance in relative population growth (30%), then adult winter survival (23%), with calf summer and calf winter survival contributing less than 10%. Birth rate tended to covary strongly with adult winter survival, and to a lesser extent with calf winter survival. 4. The contribution of birth rate to the variance in relative population growth diminished to less than 5% in both the periods 1981–89 and 1990–97. In contrast, the contribution of adult winter survival increased to 36% in 1980s and 40% in 1990s. At the same time, the covariation of adult winter survival with calf winter survival increased successively to reach 40% in 1990–97. 5. Changes in population age structure were small and contributed little to the variance in relative population growth (≈ 1% over the entire study). In the 1970s the 5–7‐year‐old group contributed most (23%) to the variance in relative population growth, though this covaried with 8–12‐year‐olds. In the 1980s the 8–12‐year‐olds contributed most (27%) and now the covariation was with older animals (> 12‐year‐olds). This pattern persisted in the 1990s, though there was covariation with 5–7‐year‐olds too. 6. Birth rate, calf winter survival and adult winter survival were all density‐dependent. The strength of density dependence within each vital rate did not differ between the 1970s, 1980s and 1990s; however, there were differences in the means of these vital rates relative to population size between the three periods. 7. The implications of temporal changes in the most important vital rates, the ‘key factors’, contributing to the variance in relative population growth rate are discussed.

Population and environment by 2000AD – a social manifesto

Considers the consequences of population growth in relation to space, resources and conflict. Covers environmental issues such as water and pollution. Uses India in the year 2000 as a case study, looking at areas such as housing, agriculture, transport, water, food and environment. Discusses the plans of the country and concludes that an integrated plan for population with development is needed to optimize the use of natural resources. Cites four phases of human development: primitive, active, uncontrolled and aware.

Residential expansion as a continental threat to U.S. coastal ecosystems

Spatially extensive analysis of satellite, climate, and census data reveals human-environment interactions of regional or continental concern in the United States. A grid-based principal components analysis of Bureau of Census variables revealed two independent demographic phenomena, α-settlement reflecting traditional human settlement patterns and β-settlement describing relative population growth correlated with recent construction in non-agricultural areas, notably in coastal, desert, and “recreational” counties and around expanding metropolitan areas. Regression tree analysis showed that β-settlement was differentially associated with five distinct combinations of seasonality, summer heat or cool, intensity of agriculture, and extent of “barren” land. Beta-settlement was greatest in coastal and desert areas, and coincided with national concentrations of threatened and endangered species.

World population and energy demand growth: the potential role of fusion energy in an efficient world

The fertility rate for women and the related population growth rate for numerous developing (transitional) countries show a downward trend with increasing annual per capita energy use. On the assum...

Population Growth and Development Prospects for Pakistan

Since its founding Pakistan has exhibited a continuously high rate of population growth. When measured by population size it has moved from the thirteenth largest country in 1950 to the seventh largest country in 1996 (Table 1). Today Pakistan exhibits the highest rate of growth among the world's largest countries, and according to some projections will become the third most populated country in the world by the year 2050 [United Nations (1998)]. Given the country's present resources, this magnitude of population growth has serious implications for the social and economic well-being of the people of Pakistan. A staggering statistic shows that the area now constituting Pakistan which had only 16.6 million people at the turn of the century, will surpass the 150 million mark by the new millennium (less than a year away). Among the projected top ten contributors to world population growth during 1995-2000, Pakistan ranks third in absolute numbers (Table 2), and number one in rate of growth. Based on the population of 1996 (Table 1) and the projected absolute population increase (Table 2), the population of Pakistan is projected absolute population increase (Table 2), the population of Pakistan is projected to grow at a rate more than 300 percent faster than China and 170 percent faster than India. In absolute and relative terms Pakistan's population growth is unusually high.

World Population and Energy Demand Growth: The Potential Role of Nuclear Energy in an Efficient World

The fertility rate for women and the related population growth rate, for numerous developing (transitional) countries, show a downward trend with increasing annual per capita energy use. On the assumption that such trends will continue, estimates are made for some simple cases of the energy demands required to stabilize the world's population in the period 2100 to 2150.An assessment is made of how these energy demands might be met, capitalizing as much as possible on the indigenous energy resources for each of the ten major regions of the world – North America, Latin America, Europe OECD, Former Soviet Union and Central and Eastern Europe, China, Pacific OECD, East Asia, South Asia, Africa, and the Middle East. Consideration is also given to the potential need to limit carbon emissions because of global warming concerns.The study highlights the crucial nature of energy efficiency improvements and the need to utilize all energy sources, including nuclear energy, if the world is to find a sustainable future with a much improved standard of living in the developing world.The deployment of more fission power can build upon the existing successes. The availability of fusion power will depend upon the pace of the development program and, in principle, fusion power deployment might start around the middle of the twenty first century.

Endogenous Growth when Unskilled Labour is Abundant

This paper examines how relative factor endowments and population growth rates affect growth rates in less developed countries. To answer these questions an extension of the Uzawa-Lucas endogenous growth model is used. The paper proves the existence and uniqueness and of the modified model and illustrates the local stability properties. Significantly the results reverse the conclusions of the only previous attempt to address these issues in the UzawaLucas framework, by Mulligan and Sala-i-Martin (1993), and Barro and Sala-i-Martin (1995). They argue that developing economies will follow a low growth transition path due to a scarcity of human capital. It is shown to the contrary that a standard convergence result applies for economies that have a scarcity of human and physical capital relative to labour. It is also shown that higher unanticipated population growth is consistent with slow transitional growth rates and increases the human capital resources devoted to human capital investments.

Predicting Demographic Change in Response to Herbivory: A Model of the Effects of Grazing and Annual Variation on the Population Dynamics of Anthyllis Vulneraria

1 Documenting the impact of herbivores on perennial plants is a particularly acute problem due to the difficulties of quantifying their effects on lifetime reproductive success and survival. 2 Our purpose here is to extend our previous short-term empirical results that two contrasting sheep grazing regimes have a significant effect on seed output but no effect on the establishment and survival of seedlings in a natural population of Anthyllis vulneraria by combining them with stochastic long-term stage-transition models in which the life history stages were classified according to age and developmental state. Our objectives were to predict how: (a) variation in fecundity, rate of germination and seed survival, and (b) the frequency of years with either high or low seed production, may regulate population growth in relation to sheep grazing either as 'one-off' instantaneous effects of high-intensity grazing or via effects due to repeated low intensity grazing. 3 The results of the simulations predict that periods of decline in population growth can be followed by an increase in the rate of population growth with the pattern depending on the sequence of poor and favourable years since these determine annual variation in seed output. The occurrence of consecutive poor years caused a shift in age structure towards a population biased towards older aged plants. As a result, seed output was greatly improved by a subsequent favourable year due to the high reproductive capacity of older plants. 4 The limit that variation in seed output may impose on population growth, which is more severe under repeated free grazing than under a single episode of controlled high intensity grazing, will thus depend on how the population is regulated by the succession of poor and favourable years for seed production. This indicates that the demographic characteristics of natural plant populations may be markedly influenced by an interaction between environmental conditions and herbivory.

The demography of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) on kibbled wheat

Finite rates of population increase (λ) of a pesticide susceptible strain of Oryzaephilus surinamensis (L.) living in kibbled wheat were determined at 20, 22.5, 25, 30, 32.5 and 35°C at 30, 50 and 70% relative humidity (r.h.) using survivorship and fertility schedules, i.e. observed numbers of adult offspring produced by cohorts of insects over a physiological time frame of twice the immature development period at each condition. Population growth rate increased with temperature up to 30°C at 30% r.h. and up to 32.5% at 50 and 70% r.h. Populations subjected to drier conditions grew slower than those subjected to moister conditions. The greatest value of λ (2.4122) was observed at 32.5° C 70% r.h. The rate of population increase declined rapidly after a maximum value was reached and at 35° C 30% r.h. a negative rate of increase was observed. The value of λ at low temperatures was little affected by relative humidity with a minimum theoretical population growth threshold varying from 19.0 to 19.4°C between 30 and 70% r.h. Egg to adult development and immature age-specific mortality were examined in detail at 20, 30 and 35°C at 30, 50 and 70% r.h. Minimum mortality occurred at 30 and 35°C at 70% r.h. and maximum mortality occurred at 20 and 35°C at 30% r.h. Maximum mortality accounted for almost complete extinction of the immature population and occurred mainly during the egg stage. At increasingly suboptimum conditions, a larger proportion of surviving immatures required an extra instar before pupation. Demographic data for O. surinamensis were compared with other available data for the species, as well as with similar data for Sitophilus oryzae and Rhyzopertha dominica. Concerns were raised about relating estimates of population growth of O. surinamensis to wet bulb temperature. It was considered that relating population growth to dry bulb temperature and relative humidity or equilibrium grain moisture content, in the conventional manner, was more appropriate for this insect.

A nonautonomous model of population growth.

With x = population size, the nonautonomous equation x = xf(t, x) provides a very general description of population growth in which any of the many factors that influence the growth rate may vary through time. If there is some fixed length of time (usually long) such that during any interval of this length the population experiences environmental variability representative of the variation that occurs in all time, then definite conclusions about the population's long-term behavior apply. Specifically, conditions that produce population persistence can be distinguished from conditions that cause extinction, and the difference between any pair of solutions eventually converges to zero. These attributes resemble corresponding features of the related autonomous population growth model x = xf(x).

Growth patterns of the eight regions in the People's Republic of China (1980-1985).

The objective of this brief paper is very specific: to test with data from the People's Republic of China an earlier model by the author on regional relative dynamics. Originally, that model was used to replicate the regional relative population and income growth of 9 divisions in the US for the period 1929-1979. Due to data limitations, only 1 component of the original model is replicated in the case of the People's Republic of China. Although the full regional dynamics model contains a system of 2 simultaneous differential equations, with a linear and a non-linear isocline respectively, here only the equation with the linear isocline is confirmed. This particular component of the model has also been independently verified for the case of Japan's regional growth.

Population Pressures, Saving, and Investment in the Third World: Some Puzzles

For over 25 years economists and population specialists have generally embraced the plausible notion that rapid rates of population growth exert a quantitatively significant adverse impact on the pace of economic growth through the effects of age dependency capital shallowing and investment diversion. However empirical research has not sustained these hypotheses individually or collectively. One general factor appears to account for this variance between theory and facts--the tendency to develop analyses with simplifying assumptions that are not then subjected to adequate empirical tests. At its most fundamental level economics is about making choices in the face of scarcity. In the literature relating population growth savings and investment and modeling of choices has been amazingly narrow--indeed almost a-economic. At the household level population pressures are usually modeled by engineering-like fixed-coefficient formulae. In contrast trade-offs between quantities or qualities of consumption are seldom admitted parents work force behavior is usually taken to be uninfluenced by family size and children are typically assumed to contribute nothing productively. Similarly at the government level population pressures are modeled to show population-sensitive expenditures taking priority and crowding out more productive spending. In reality governments respond with more flexibility than the models suggest and some of the population-sensitive expenditures may be growth-enhancing. More elaborate analyses reveal 2nd-order effects: economizing on scarce resources and an expansion in supply.

Population growth and land subdivision in rural Pennsylvania, 1950–1982

Summary The purpose of this study was to examine the subdivision of rural land from 1950 to 1982 under differing rates of population growth. Data from nine townships in rural Pennsylvania, reflecting a diversity of rural land uses, provided information on the extent to which land had been subdivided, the size of the new subdivisions, ownership characteristics, land values, and the kind of land from which the new parcels were subdivided. Time series data since 1950 related population growth to the extent of land subdivision. Implications are drawn about the future of our rural land resources, particularly for agricultural uses and aesthetic purposes. Rural landowners need a strong land conservation ethic; otherwise, the continual chipping away of the land resource through the uncontrolled development process as recorded by the data in this study will ultimately lead to its irreversible loss.