scholarly journals Clustering or Scattering? The Spatial Distribution of Cropland in a Metropolitan Region, 1960–2010

2018 ◽  
Vol 10 (7) ◽  
pp. 2584 ◽  
Author(s):  
Andrea Colantoni ◽  
Ilaria Zambon ◽  
Maria Gras ◽  
Enrico Maria Mosconi ◽  
Alessandra Stefanoni ◽  
...  
Keyword(s):  
Land Use ◽  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Spatial Behavior ◽  
Metropolitan Region ◽  
Time Interval ◽  
Non Linear ◽  
Long Time ◽  
Agricultural Areas

This article presents empirical results of a multivariate analysis run with the aim to identify (apparent and latent) socioeconomic transformations that shape the distribution pattern of cropland in a metropolitan region of southern Europe (Athens, Greece) over a sufficiently long time interval spanning from 1960 to 2010. The study area is representative of monocentric cities expanding in an unregulated fashion and experiencing sequential cycles of economic growth and recession. Percent share of cropland in total municipal area increased moderately over time. A non-linear relationship with the distance from downtown Athens was also observed, indicating that the highest rates of cropland were observed at a distance ranging between 20 and 30 km from the inner city. A multivariate regression was run by decade at each municipality of the study area using 11 predictors with the aim to identify the factors most associated with cropland decline along urban fringes. Distance from downtown Athens, soil and climate quality, population growth rate, and competing land use were the most relevant factors correlated with cropland expansion (or decline) in the study area. Competing land use was particularly important for cropland decline in a first urbanization phase (1960–1980), while population growth rate—and hence an increased human pressure—was positively associated with agricultural areas in a subsequent phase (1990–2010). In these regards, per capita urban land had a non-linear spatial behavior, being correlated negatively with cropland in 1960 and 1970 and positively in 2010, possibly indicating a moderate change from a monocentric model towards a more dispersed metropolitan configuration impacting distribution of agricultural areas. Empirical findings of this study suggest that effective strategies supporting peri-urban agriculture require a comprehensive knowledge of the local socioeconomic context and relevant biophysical conditions—specifically focusing on the dominant soil and climate attributes.

Demography of Machaerium cuspidatum, a shade-tolerant neotropical liana

2004 ◽  
Vol 20 (5) ◽  
pp. 505-516 ◽  
Author(s):  
Jacob Nabe-Nielsen
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Woody Species ◽  
Canopy Openness ◽  
Lower Growth ◽  
Growth And Survival ◽  
Population Growth Rates ◽  
Long Time ◽  
Slow Growing

The population dynamics of the liana Machaerium cuspidatum (Fabaceae) were studied in an Amazonian forest in Ecuador using a stage-classified matrix model. Growth, mortality and number of new seedlings were recorded over two 1.5-y periods in eight 20 × 250-m transects. The population growth rate (λ) was 1.032, which was significantly higher than 1. The dynamics of the species were most influenced by survival of large plants, which is typical for slow-growing woody species. λ varied little among years or transects in spite of the high seedling production in one period. The importance of canopy openness and crown height for population growth was studied using bootstraps on λ for different subsets of the whole population. The results suggest that the population growth rate was lower in tall forest (height > 10 m) than in the population in general. The population growth rates in areas with shaded understorey and in low forest (≤ 20 m) were the same as for the whole population. A life table response experiment (LTRE) revealed that the lower λ in tall forest resulted from lower growth and survival of large plants in tall forest. These results indicate that the species is shade-tolerant but that it is sensitive to variations in forest dynamics. The dominance of the species and the increasing population size suggest that the forest has had a low disturbance rate for a long time.

scholarly journals A METHOD TO ESTIMATE THE LAND USE EFFICIENCY IN THE OLD CITY OF BEIJING

2020 ◽  
Vol XLII-3/W10 ◽  
pp. 1073-1076
Author(s):  
J. X. Zhang ◽  
G. Y. Cai
Keyword(s):  
Land Use ◽  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Rapid Development ◽  
Limited Region ◽  
Land Use Efficiency ◽  
In Situ Investigation ◽  
Old City ◽  
Use Efficiency

Abstract. The old city of Beijing represents the brilliant history and attracts people’s attention worldwide. With the rapid development of urbanization in Beijing, the old city is facing the problem that more and more people are working or living in this limited region. How to estimate the land use efficiency in the old city is crucial for the city planners to perform some policy-making decisions. Based on the Sustainable Development Goal 11 (SDG 11) which is to develop inclusive, safe, resilient and sustainable cities and human settlements, in which indicator SDG 11.3.1 is designed to testify the land use efficiency that is defined as a ratio between land consumption rate to population growth rate(PGR).This paper focus on how to evaluate the land use efficiency in the old city where the land is limited to a region while people are in a continuous growing. Based on the extraction of buildings from high resolution images with sub-meter spatial resolution in the area enclosed by the second-ring road which is mainly consists of Dongcheng and Xicheng districts, this study obtained the 3D building information including building height and floor numbers over years from 2005, 2010 to 2015 with the help of visually interpretation, POI information and the in situ investigation. By calculating the ratio of the building density growth rate(BDGR) to the population growth rate, the land use efficiency in the old city was computed for each year. Our results showed that most of the ratios are greater than 1 over year from 2005 to 2010 and less than 1 during periods from 2010 to 2015. Which means that the land use efficiency tend to lower from 2010 to 2015 than from 2005–2010. The reasons caused this phenomenon has been discussed in the discussion part. The results are helpful for local governors or managers to make a better decision in the protection and conservation of the old city, and to keep a sustainable old city.

scholarly journals Quantifying the links between land use and population growth rate in a declining farmland bird

2019 ◽  
Vol 9 (2) ◽  
pp. 868-879 ◽  
Author(s):  
Matthieu Paquet ◽  
Debora Arlt ◽  
Jonas Knape ◽  
Matthew Low ◽  
Pär Forslund ◽  
...  
Keyword(s):  
Land Use ◽  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Farmland Bird

scholarly journals Ratio of Land Consumption Rate to Population Growth Rate—Analysis of Different Formulations Applied to Mainland Portugal

2018 ◽  
Vol 8 (1) ◽  
pp. 10 ◽  
Author(s):  
Rita Nicolau ◽  
João David ◽  
Mário Caetano ◽  
José Pereira
Keyword(s):  
Land Use ◽  
Growth Rate ◽  
Land Cover ◽  
Population Growth ◽  
Urban Area ◽  
Population Growth Rate ◽  
Consumption Rate ◽  
Mapping Technique ◽  
Mainland Portugal ◽  
Land Consumption

This paper presents a methodological approach for the assessment of the indicator 11.3.1: “Ratio of Land Consumption Rate to Population Growth Rate” proposed by the United Nations (UN), discussing the definitions and assumptions that support the indicator quantification, and analysing the results provided by different formulations applied to mainland Portugal, at the municipality level. Due to specific limitations related to the actual formula proposed by the UN (LCRPGR) for the computation of the indicator, an alternative formulation derived from Land Use Efficiency (LUE) was explored. Considering that the land to which the indicator refers may be described by specific classes represented in Land Cover Land Use (LCLU) maps, in the estimation of the land consumption rate we tested two LCLU datasets: Corine Land Cover and COS—the Portuguese LCLU reference map. For the estimation of the population growth rate, prior allocation of inhabitants to the areas where people are most likely to reside was deemed necessary, using a dasymetric mapping technique based on LCLU information. The results obtained for 2007–2011 and 2011–2015 showed, in most municipalities, an increase in the urban area and a decrease in urban population, leading to negative values both in LCRPGR and LUE in most of the territory. Clearly, LUE performed better than LCRPGR in what urban development monitoring and urban area dynamics trends are concerned. Furthermore, LUE was much easier to interpret.

scholarly journals Biological scaling in green algae: the role of cell size and geometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helena Bestová ◽  
Jules Segrestin ◽  
Klaus von Schwartzenberg ◽  
Pavel Škaloud ◽  
Thomas Lenormand ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Internal Diffusion ◽  
Scaling Exponent ◽  
Power Scaling ◽  
Nutrient Distribution ◽  
Metabolic Scaling ◽  
Key Factor ◽  
Size And Morphology

AbstractThe Metabolic Scaling Theory (MST), hypothesizes limitations of resource-transport networks in organisms and predicts their optimization into fractal-like structures. As a result, the relationship between population growth rate and body size should follow a cross-species universal quarter-power scaling. However, the universality of metabolic scaling has been challenged, particularly across transitions from bacteria to protists to multicellulars. The population growth rate of unicellulars should be constrained by external diffusion, ruling nutrient uptake, and internal diffusion, operating nutrient distribution. Both constraints intensify with increasing size possibly leading to shifting in the scaling exponent. We focused on unicellular algae Micrasterias. Large size and fractal-like morphology make this species a transitional group between unicellular and multicellular organisms in the evolution of allometry. We tested MST predictions using measurements of growth rate, size, and morphology-related traits. We showed that growth scaling of Micrasterias follows MST predictions, reflecting constraints by internal diffusion transport. Cell fractality and density decrease led to a proportional increase in surface area with body mass relaxing external constraints. Complex allometric optimization enables to maintain quarter-power scaling of population growth rate even with a large unicellular plan. Overall, our findings support fractality as a key factor in the evolution of biological scaling.

scholarly journals Optimal Perturbations of an Oceanic Vortex Lens

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Thomas Meunier ◽  
Claire Ménesguen ◽  
Xavier Carton ◽  
Sylvie Le Gentil ◽  
Richard Schopp
Keyword(s):  
Normal Mode ◽  
Growth Rates ◽  
Time Interval ◽  
Time Intervals ◽  
Horizontal Structure ◽  
Azimuthal Wave ◽  
Wave Numbers ◽  
Non Linear ◽  
Long Time ◽  
Short Time

The stability properties of a vortex lens are studied in the quasi geostrophic (QG) framework using the generalized stability theory. Optimal perturbations are obtained using a tangent linear QG model and its adjoint. Their fine-scale spatial structures are studied in details. Growth rates of optimal perturbations are shown to be extremely sensitive to the time interval of optimization: The most unstable perturbations are found for time intervals of about 3 days, while the growth rates continuously decrease towards the most unstable normal mode, which is reached after about 170 days. The horizontal structure of the optimal perturbations consists of an intense counter-shear spiralling. It is also extremely sensitive to time interval: for short time intervals, the optimal perturbations are made of a broad spectrum of high azimuthal wave numbers. As the time interval increases, only low azimuthal wave numbers are found. The vertical structures of optimal perturbations exhibit strong layering associated with high vertical wave numbers whatever the time interval. However, the latter parameter plays an important role in the width of the vertical spectrum of the perturbation: short time interval perturbations have a narrow vertical spectrum while long time interval perturbations show a broad range of vertical scales. Optimal perturbations were set as initial perturbations of the vortex lens in a fully non linear QG model. It appears that for short time intervals, the perturbations decay after an initial transient growth, while for longer time intervals, the optimal perturbation keeps on growing, quickly leading to a non-linear regime or exciting lower azimuthal modes, consistent with normal mode instability. Very long time intervals simply behave like the most unstable normal mode. The possible impact of optimal perturbations on layering is also discussed.

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