Drastic Land Research Articles

Integrating the ordered weighted averaging method to establish an ecological security pattern for the Jianghuai ecological economic zone in China: Synergistic intraregional development

• Considering ecosystem service trade-offs to identify ecological sources. • OWA was used to set up multiple ecological source scenarios. • Circuit theory was used to constructed an ecological security pattern. • Results can provide implications for ecosystem security in fast-growing cities. A well-constructed ecological security pattern (ESP) can promote linkages between ecological sources, mitigate the degradation of ecosystems, and facilitate sustainable urban development. However, when determining the ecological sources for ESPs, previous studies have less frequently or insufficiently considered the ecosystem service trade-offs. Our research aims to fill this research gap to improve the assessment of ESPs. Through a case study in a rapidly urbanizing region—the Jianghuai Ecological Economic Zone in China—we demonstrate the application possibilities of the proposed framework. Ecosystem services in the study area were evaluated using the Integrated Valuation of Ecosystem Services and Tradeoffs model, ecological sources were screened using the ordered weighted averaging method; then, an ESP was constructed using the minimum cumulative resistance model and circuit theory. The results indicated that crop production and water purification were higher in the east and lower in the west, while the water yield showed the opposite trend. Habitat quality and carbon storage were higher in the south and lower in the north. Eleven scenarios were set to determine ecological sources based on ecosystem service trade-offs. By comparing service efficiency, scenario 5 was selected as our optimal scenario, and the service efficiencies of ecological sources for crop production, water yield, habitat quality, carbon storage and water purification were 1.35, 1.15, 1.21, 1.06 and 0.92, respectively. There were no significant ecological sources in the developed eastern and central regions due to rapid urbanization and drastic land use changes in the area. There were 31 major ecological sources located in the western and northwestern parts of the study area, where water bodies and wetlands were well developed. There was a total of 70 ecological corridors in the study area, with 53 key ecological corridors. Based on these results, we proposed three measures to improve the sustainability of ecosystems to cope with the rapid urbanization while providing ecological quality. This study can provide implications for ecosystem security in other fast-growing cities.

Village classification in metropolitan suburbs from the perspective of urban-rural integration and improvement strategies: A case study of Wuhan, central China

Urban-rural integration is an ideal urban-rural relationship that balances and coordinates urban and rural development. Suburbs, as transitional zones between urban and rural areas, are usually treated as part of urban areas and are insufficiently considered in this integration. However, during rapid urbanization, the suburbs of metropolitan cities attract huge populations and industrial agglomeration. Mixed land use types, population structure, industrial construction, and underdeveloped infrastructure cause the suburbs of big cities to face significant spatial differentiation of socioeconomic development and public services, together with an ecological environmental pressure brought about by drastic land use change. The complexity, gradual change, and dynamics of suburbs render it difficult to map them effectively. In addition, due to different conditions such as the development basis, traffic conditions, spatial location, and resource endowments, the type and degree of integration of villages around metropolises are also differentiated, which determines their future development direction. Against this background, this study first maps the suburban boundaries at the village scale using a logistic-geographically weighted regression (GWR) model, which is a localized parameter estimation method. This study classifies the types of suburban villages in metropolitan areas using three dimensions: socioeconomic, spatial, and ecological integration. Finally, improvement suggestions have been proposed for villages with different types of urban-rural integration. Following findings are summarized: 1) The logistic-GWR model identifies 2626 suburban villages in Wuhan; 2) the integration differentiation identifies 370, 564, 216, and 365 suburban villages that exhibit comprehensive, ecological, socioeconomic, and spatial disintegration, respectively; and 3) solutions for promoting urban-rural integration of suburban villages are provided accordingly.

Assessing urban sprawl by remote sensing and GIS techniques

In the context of mega sustainable urban development projects, this research was commenced with the impartial of assessing urban sprawl (i.e., land use versus land cover variations) during 2000-2016 by remote sensing and GIS techniques, where GCR “Greater Cairo Region” was taken as a case study. Primarily, literature in the field of remote sensing and GIS technologies were assembled and scrutinized. In addition, data regarding build zones, agricultural areas and bare soil regions so as water were assembled from different resources (i.e., Ministry of Agriculture). Remote sensing and GIS techniques were implemented. Results were obtained and analyzed. Finally, conclusions were deduced and recommendations were suggested. The research flagged-out that the GCR designated a drastic agriculture land loss of 10%. In addition, the research confirmed that built-up areas increased by 10% during 2000-2016. On the other hand, the results indicated that Giza and Qalyubia Governorates recorded the largest agriculture land loss by 8.72 and 7.88%, respectively, which is equivalent to 47 and 77 km2, respectively. The research prioritized the importance of defining the most affected zones within Giza and Qalyubia Governorates by correlating GIS data versus governmental files, where a difference of 50% was designated. The research portrayed the priority of modifying the government assessment approach in order to control urban sprawl.

WITHDRAWN: Urbanization and Land-Use change in the hill town of Nainital

Abstract The current study shows the effects of rapid increasing urbanization on land use change / cover by humans due to technological progress in a tourism city situated in the central mountain range (central) of Uttarakhand province (India). This work tried to investigate the land utilization/land cover changes compared with the help of Google Earth from the year 2006 to 2019. Images of a different era are used as a base map to develop land utilization/cover. The study area is classified to 5 different classes as Open space, agriculture-land, Vegetation, Water -bodies & Built-up area for carrying out the study. The results shows that during the last fourteen years there is a significant decrease of Open space, Vegetation, Agricultural Land about 19% (i.e., 0.03 sq.km), 22% (i.e., 1.83 sq.km) and 18% (i.e.,0.03 sq.km) respectively and the built-up area of the Nainital town has been raised for approx 68% (i.e., 1.89 sq.km).This clearly demonstrates the continuous development and drastic land utilization/ land cover changes in the last 14 yrs in the town resulting urbanization which leads to decrease in open space, vegetation and agricultural land.

Study on Hydrologic Effects of Land Use Change Using a Distributed Hydrologic Model in the Dynamic Land Use Mode

It is reasonable to simulate the hydrologic cycle in regions with drastic land use change using a distributed hydrologic model in the dynamic land use mode (dynamic mode). A new dynamic mode is introduced into an object-oriented modularized model for basin-scale water cycle simulation (MODCYCLE), a distributed hydrologic model based on sub-watersheds, and the hydrological response unit (HRU). The new mode can linearly interpolate data for the years without land use data and consistently transfer HRU water storage between two adjacent years after a land use data update. The hydrologic cycle simulation of the Sanjiang Plain in China was carried out from 2000 to 2014 in the dynamic mode using land use maps of 2000, 2005, 2010, and 2014. Through calibration and validation, the performance of the model reached a satisfactory level. Replacing the land use data of the calibrated model using that of the year 2000, a comparison model in the static land use mode (static mode) was built (i.e., land use unchanged since 2000). The hydrologic effects of land use change were analyzed using the two models. If the land use pattern remained unchanged from 2000, despite the average annual runoff increasing by 4% and the average annual evapotranspiration decreasing by 4% in this region only, the groundwater storage of the plain areas in 2014 would increase by 4.6 bil. m3 compared to that in 2000, rather than the actual decrease of 4.7 bil. m3. The results show that the fluxes associated with groundwater are obviously more disturbed by land use change in the Sanjiang Plain. This study suggests that the dynamic mode should be used to simulate the hydrologic cycle in regions with drastic land use change, and the consistent transfer of HRU water storage may be considered in the dynamic mode.

Application of DRASTIC and Modified DRASTIC Models for Modeling Groundwater Vulnerability of Malda District in West Bengal

Groundwater is one of the most important freshwater resources in our daily life. Under the background of global climate change, untreated rate of urbanization, human interferences and policy variations affect the change of global and local groundwater quality which is very common in developing countries like India. Hence, protecting groundwater from different types of contamination is the most accurate and appropriate measures of groundwater conservation. The main objectives of this work are to assess the groundwater vulnerability of Malda district using DRASTIC and modified DRASTIC methods. Seven influencing factors groundwater depth, net recharge, aquifer material, soil media, topography, the impact of vadose zone and hydraulic conductivity were used to complete DRASTIC method, agricultural DRASTIC, land use DRASTIC and AHP land use DRASTIC methods. The multi-model approach has been used to identify the best vulnerability model. For modeling Land use DRASTIC and AHP Land use DRASTIC, the land use layer was added with other layers. The groundwater vulnerability zone has been divided into three categories like high, moderate and low. High-vulnerability zones were found in the northern and southern parts, moderate zones were found in the middle part of the district, and the low-vulnerability zones in the eastern part of the district. The vulnerability model was validated using the ROC curve and Friedman test. The AHP land use DRASTIC shows better performance compared to other vulnerability models.

Mapping 20 Years of Urban Expansion in 45 Urban Areas of Sub-Saharan Africa

By 2050, half of the net increase in the world’s population is expected to reside in sub-Saharan Africa (SSA), driving high urbanization rates and drastic land cover changes. However, the data-scarce environment of SSA limits our understanding of the urban dynamics in the region. In this context, Earth Observation (EO) is an opportunity to gather accurate and up-to-date spatial information on urban extents. During the last decade, the adoption of open-access policies by major EO programs (CBERS, Landsat, Sentinel) has allowed the production of several global high resolution (10–30 m) maps of human settlements. However, mapping accuracies in SSA are usually lower, limited by the lack of reference datasets to support the training and the validation of the classification models. Here we propose a mapping approach based on multi-sensor satellite imagery (Landsat, Sentinel-1, Envisat, ERS) and volunteered geographic information (OpenStreetMap) to solve the challenges of urban remote sensing in SSA. The proposed mapping approach is assessed in 17 case studies for an average F1-score of 0.93, and applied in 45 urban areas of SSA to produce a dataset of urban expansion from 1995 to 2015. Across the case studies, built-up areas averaged a compound annual growth rate of 5.5% between 1995 and 2015. The comparison with local population dynamics reveals the heterogeneity of urban dynamics in SSA. Overall, population densities in built-up areas are decreasing. However, the impact of population growth on urban expansion differs depending on the size of the urban area and its income class.

Recharge mechanism of deep soil water and the response to land use change in the loess deposits

Deep soil water (DSW) is of utmost importance for plant growth and groundwater recharge, but the depletion of DSW has been largely reported due to land use change, especially because of the conversion from shallow- to deep-rooted plants. To answer the question whether DSW can be replenished, it is important to reveal the recharge mechanism of DSW under different vegetation types. China’s Loess Plateau has experienced drastic land use change resulting in soil water depletion in deep vadose zones, which provides a good platform to explore these issues. We collected 380 soil samples from five boreholes up to 18 m deep covered by five plants (grassland, apricot, pine, poplar, and peashrub), and determined the contents, stable and radioactive isotopes (δ2H, δ18O, and 3H) of soil water. DSW, defined as soil water below 3 m in this study, was mainly recharged by the wet events in rainy season, especially those with intensities ≥ 50 mm/day, through piston flow. But they were significantly influenced by land use types. Specifically, the forestland and shrubland had lower evaporation effects and higher precipitation offset, and their soil water was recharged by wet events with higher intensities than those under grassland. Nevertheless, the deep-rooted plants substantially reduced recharge rates due to excessive root water uptake, and thus prevented rainfall from replenishing DSW. This study has implications to groundwater sustainability in those regions with limited water resources, drastic land use change, and thick unsaturated zones.

Assessment of impacts of land use/land cover changes upstream of a dam in a semi-arid watershed using QSWAT

The study of hydrodynamic responses of the watershed influenced by the changes occurring in the climate and pattern of land use is vital in the management of sustainable water resources. The open-source soil and water assessment tool QSWAT has been adopted in this study to link the meteorological factors with land-surface hydrology and present a complete response of an ungauged watershed in the Krishna basin. The main objective of the present work is to assess the adaptability of the QSWAT model for the selected semi-arid watershed, which has undergone drastic land use/land cover (LULC) changes due to the construction of a dam. The impact of the LULC changes on the hydrodynamic response of the watershed is analysed. For automatic calibration and uncertainty analysis, SUFI-2 algorithm is used. Initially, the model adaptability for the watershed is assessed by simulating for 32 years, of which 27 years (from 1982 to 2008) are used for calibration and 5 years (from 2008 to 2013) for validation. Further, Landsat satellite images along with 14 LULC classifications for the year 1998 and 2009, indicating scenarios of pre- and post-construction of the dam, respectively, are used as input to QSWAT to analyse the influence of LULC changes on the water balance components. The comparison indicates decrease in the agricultural area, barren land and urban built-up area. The annual water yield and surface runoff of the watershed have been reduced by 28.97% and 29.91%, respectively. An increment of 6% evapotranspiration loss with a decreasing trend in rainfall is noted which is alarming. The simulated results indicate that the hydrological responses are influenced by the LULC changes. The basin LULC and hydrological components have been affected by the storage reservoir created due to the dam. The QSWAT seems to be reliable tool as there is a good agreement between the simulated and observed flows. The obtained model performance indices: the NSE and R2 calibration values are 0.89 and 0.96, respectively, and the values for validation are 0.79 and 0.83 respectively, hence indicating a strong and predictive capability of the model to the ungauged watersheds with drastic LULC changes. Apart from establishing sustainable water resources management techniques in the watershed, there is a stressing need for such analysis before any human intervention into the natural system like construction of dams.

Response of Water Quality to Landscape Patterns in an Urbanized Watershed in Hangzhou, China

Intense human activities and drastic land use changes in rapidly urbanized areas may cause serious water quality degradation. In this study, we explored the effects of land use on water quality from a landscape perspective. We took a rapidly urbanized area in Hangzhou City, China, as a case study, and collected stream water quality data and algae biomass in a field campaign. The results showed that built-up lands had negative effects on water quality and were the primary cause of stream water pollution. The concentration of total phosphorus significantly correlated with the areas of residential, industrial, road, and urban greenspace, and the concentration of chlorophyll a also significantly correlated with the areas of these land uses, except residential land. At a landscape level, the correlation analysis showed that the landscape indices, e.g., dominance, shape complexity, fragmentation, aggregation, and diversity, all had significant correlations with water quality parameters. From the perspective of land use, the redundancy analysis results showed that the percentages of variation in water quality explained by the built-up, forest and wetland, cropland, and bareland decreased in turn. The spatial composition of the built-up lands was the main factor causing stream water pollution, while the shape complexities of the forest and wetland patches were negatively correlated with stream water pollution.

Impacts of urbanization on soil organic carbon stocks in the northeast coastal agricultural areas of China

Dynamic changes in soil organic carbon pools have significant impacts on regional and global carbon balance. Due to rapid development in urbanized areas, the land use changes dramatically, impacting soil organic carbon (SOC) stocks in topsoil. This study aimed to document the impacts of urbanization on SOC stocks in a rapidly urbanized area from northeastern China. A total of 12 auxiliary variables were as SOC predictors including elevation, slope aspect, slope gradient, topographic wetness index, Landsat TM band3, Landsat TM band4, Landsat TM5, and normalized difference vegetation index. Urban-specific variables including population (POP), gross domestic product (GDP), distance to the socio-economic center, and distance to the roads are also considered. A set of 523 (in 1990) and 847 (in 2015) top soil samples with SOC measurement were collected. Two random forest (RF) models, one with all auxiliary variables except urban-specific variable (MA) and the other with all auxiliary variables (MB) were used to map the spatial distribution of SOC stocks in the two periods. Ten-fold cross-validation was conducted to evaluate the performance of RF models. We find that the full auxiliary variables model had a better performance for the both periods. POP and GDP were key auxiliary variables affecting spatial variability of SOC stocks in 2015. Over a 25-year period, SOC stocks decreased from 2.77 ± 1.09 kg m−2 to 2.16 ± 0.93 kg m−2, resulting in 3.78 Tg SOC loss in this region. Rapid urbanization led to drastic land- use change, which was the main reason for the decrease of SOC stocks. Additionally, urban-specific variables should be used as the main auxiliary variables when predicting SOC stocks in the areas that experience rapid urbanization. We believe that accurate prediction and mapping of SOC stocks will help manage land use and facilitate soil quality assessment so as to increase soil carbon sequestration in the region.

Comparing three transition potential modeling for identifying suitable sites for REDD+ projects

In recent decades, rapid population growth and human improper activities accelerated deforestation. Reducing Emissions from deforestation and forest degradation (REDD+) has been introduced as a strategy for reducing deforestation in developing countries. Thus, identifying areas with high-deforestation is important for site selection of the REDD+ projects. Transition potential modeling is applied as a tool for deforestation simulation. Drastic land use changes in the Central Hyrcanian forests caused a substantial reduction in forests cover. In this research, forest cover changes of the Central Hyrcanian forests were examined. Then, transition potential modeling using of three empirical procedures included: multi-layer perceptron (MLP) neural network, logistic regression, and similarity weighted instance-based learning were performed. Model validation was examined using relative operating characteristic and figure of merit. Using multi-criteria evaluation, suitable areas for REDD+ projects were identified and site selection using zonal land suitability method was performed. The results showed that the Central Hyrcanian forest decreased about 188,607 ha during 1984–2014 and the MLP model obtained the best accuracy. This study provides a general framework for site selection of REDD+ projects and also showed that sites with different suitability were found for REDD+ projects.

Exploring the impacts of biofuel expansion on land use change and food security based on a land explicit CGE model: A case study of China

Biofuel plays an important role in the transition to low-carbon energy systems. However, the large-scale expansion of biofuels may cause drastic land use change (LUC) due to feedstock cultivation and further result in other sustainability impacts (e.g., food supply), which are the key concerns for policy makers when designing bioenergy policies. However, biophysical models omit the indirect LUC from interactions of economic agents, whereas economic models lack the depiction of heterogeneous land use types. Thus, through either technique, it has formidable challenges to simulate land conversions among alternative uses driven by socioeconomic activities, especially policy mandates. To bridge the gap between these models by simultaneously considering land heterogeneity and market mechanisms and to gain better insights into specific national/regional cases to supplement previous global biofuel and LUC analyses, in this study, we develop a national computable general equilibrium (CGE) model augmented with an explicit land allocation module and design a scenario approach to simulate different patterns of land use management. Food grains and dedicated energy crops are considered feedstock sources and marginal land is incorporated as a potential land supply. Using this model, the case study of China quantifies the direct and indirect LUC driven by the bioethanol (one of the main biofuels) expansion of the new nationwide E10 mandate (gasoline containing 10% ethanol) in 2020, as well as the further impacts on food security. The results show that a slight land reallocation occurs with decreases in the land supply for rice (−0.016%), other non-feedstock grains and crops, as well as forest and grassland (−0.023%). The land competition among existing croplands would be intense in the non-deforestation scenario. If marginal land is reclaimed for feedstock cultivation, the cropland competition could be softened. The results of sensitivity analysis indicate that the total LUC scale would be 4.0–5.9% with no corn stockpile serving as feedstock. Additionally, the bioethanol expansion would trigger higher food prices (around +0.1%). To alleviate the negative impacts on land resources and food security, planting energy crops on marginal land could increase non-grain feedstocks by 10% and save 0.217% of croplands; therefore, it may be one of the promising pathways for sustainable biofuel development in China. This study can lay a common foundation for further integrated impact assessments of biofuel expansion.

Analysis of forty years long changes in coastal land use and land cover of the Yellow Sea: The gains or losses in ecosystem services

The drastic land cover change and its impacts in the Yellow Sea have long been significant issues in terms of coastal vulnerabilities, but holistic data analysis is limited. The present study first reports 40 years long geographical changes of the Yellow Sea coasts including all three neighboring countries of China, North Korea, and South Korea. We delineated tidal flats by analysis of Landsat series satellite imageries (662 scenes) between 1981 and 2016. A total area of the Yellow Sea tidal flats has been considerably reducing for the past 36 years, from ∼10,500 km2 (1980s) to ∼6700 km2 (2010s), say ∼1% annual loss. A majority loss of tidal flats was mainly due to the grand reclamations that conducted in almost entire coast of the Yellow Sea, particularly concentrated in the 1990s-2000s. Coastal reclaimed area during the past four decades reached ∼9700 km2, including ongoing and planned projects, which corresponds to over half the area of precedent natural tidal flats of the Yellow Sea. The potential carbon stocks in the eight representative regions with large scale reclamation indicated significant loss in carbon sink capacity in the South Korea's coast (∼99%), while evidenced a lesser loss from the China's coast (∼31%). It was noteworthy that the progradation of tidal flats after the reclamation in China's coast significantly reduced the loss of carbon sequestration. According to the ecosystem services valuation for the Yellow Sea, a total loss was estimated as ∼8 billion USD yr−1 with relatively high proportional loss (up to 25%) of climate regulating services (viz., carbon sequestration). Overall, huge losses in ecosystem services being provided by the Yellow Sea natural tidal flats need immediate action to prevent or at least alleviate accelerating ecological deteriorations. Finally, future conservative policy direction on coastal wetlands management has been proposed towards enhancement of marine ecosystem services.

Agricultural land use change and associated driving forces over the past 180 years in two municipalities of the Brazilian Cerrado

This paper aims to test the hypothesis that a single driving force from the local, national, or global level is capable of triggering land use changes, including large scale deforestation, within a historical context. To reach this goal we describe and explain the driving forces from the global to farm level that have shaped agricultural land uses, as a case study, over 180 years in the municipalities of Quirinopolis and Gouvelândia in the Brazilian Cerrado. Through secondary data, field surveys, and interviews with farmers and other stakeholders involved with agricultural production, we identified four distinct periods in which drastic or little land use occurred. The evidence found supports our hypothesis. Two drastic land use changes occurred in Quirinopolis and Gouvelândia. The first one was the replacement of about 400,000 ha of original vegetation by pastures and crops between 1965 and 1985 triggered by the availability of abundant subsidized rural credits for farmers; the second one was initiated in 2005 with the replacement of 100,000 ha of pastures and cropping area by sugarcane, which was driven by the sudden domestic and world demand for sugar and ethanol.

China integrating conservation areas into red lines for stricter and unified management

In response to drastic land use changes and inefficient management, in 2015 the Chinese government launched a strategic project entitled the Delineation and Defense of Ecological Protection Red Lines (EPRLs). The purpose of EPRLs was to integrate all conservation areas into a system of unified and strict management. This report introduces the background, content, and management policies of the EPRLs system. EPRLs are either those natural spaces with the greatest importance or the most vulnerability and sensitivity, and they are the minimum area needed for the maintenance of national ecological security. The Guidance for Delineation of EPRLs identified the scope of development prohibited zones and other areas under protection, and assessed areas with important ecological functions, vulnerability or sensitivity. Provincial governments are currently carrying out the delineation of EPRLs and will eventually issue and execute the scheme of EPRLs, while the central government is drafting a complete set of management policies including permitted industrial activity, monitoring and regulation, and ecological compensation.

Assessment of Land-Cover/Land-Use Change and Landscape Patterns in the Two National Nature Reserves of Ebinur Lake Watershed, Xinjiang, China

Land-cover and land-use change (LCLUC) alters landscape patterns and affects regional ecosystems. The objective of this study was to examine LCLUC and landscape patterns in Ebinur Lake Wetland National Nature Reserve (ELWNNR) and Ganjia Lake Haloxylon Forest National Nature Reserve (GLHFNNR), two biodiversity-rich national nature reserves in the Ebinur Lake Watershed (ELW), Xinjiang, China. Landsat satellite images from 1972, 1998, 2007 and 2013 were used to calculate the dynamics of a land-cover and land-use (LCLU) transition matrix and landscape pattern index using ENVI 5.1 and FRAGSTATS 3.3. The results showed drastic land use modifications have occurred in ELWNNR during the past four decades. Between 1972 and 1998, 1998 and 2007, and 2007 and 2013, approximately 251.50 km2 (7.93%), 122.70 km2 (3.87%), and 195.40 km2 (6.16%) of wetland were turned into salinized land. In GLHFNNR both low and medium density Haloxylon forest area declined while high density Haloxylon forest area increased. This contribution presents a method for characterizing LCLUC using one or more cross-tabulation matrices based on Sankey diagrams, demonstrating the depiction of flows of energy or materials through ecosystem network. The ecological landscape index displayed that a unique landscape patches have shrunk in size, scattered, and fragmented. It becomes a more diverse landscape. Human activities like farming were negatively correlated with the landscape diversity of wetlands. Furthermore, evidence of degraded wetlands caused by air temperature and annual precipitation, was also observed. We conclude that national and regional policies related to agriculture and water use have significantly contributed to the extensive changes; the ELWNNR and GLHFNNR are highly susceptible to LCLUC in the surrounding Ebinur Lake Watershed.

Projecting population growth as a dynamic measure of regional urban warming

Urban development is characterized by drastic land use and land cover changes, rooted in urban population growth, with concomitant anthropogenic stressors contributing to global climate changes. While there is extensive literature on predicting future urban climate using biogeophysical models, the direct link between emergent meteorological patterns and the population dynamics remains obscure. In this study, we propose an operative model for predicting regional urban warming using a population growth model based on different scaling laws. We choose the annual average air temperature as the climatic indicator and relate the historical temperature data to demographic data for 10 megapolitan areas in the United States. Linear regression analysis shows that the coefficients of determination range from 0.164 to 0.563 for the study areas, indicating a significant correlation between urban population and climate dynamics. Specifically, the Phoenix Metropolitan Area is selected as a testbed where the regression is applied for correlating the population growth and trend of urban warming. Based on the predicted population dynamics, the annual average temperature in Phoenix is projected to increase by 0.65–3.40°C in the next 35 years.

Reservas extractivas ¿Alternativa para la conservación de especies forestales?

Las reservas extractivas constituyen un tipo de estrategia recientemente creada para la protección de áreas de selva dedicadas a la extracción de productos forestales no maderables. Este tipo de área protegida se originó en Brasil debido a las necesidades de los recolectores de caucho de evitar la pérdida continua y acelerada de grandes áreas forestales de la selva amazónica y al mismo tiempo poder seguir recolectando el caucho de Pará (Hevea brasiliensis [ Willd. Ex Adr. Juss.] M. Arg.), las nueces de Brasil (Bertholletia excelsa Humb. & Bonpl.) y otros productos forestales. El gobierno brasileño reconoció en 1990, en la legislación de Brasil, las reservas extractivas las cuales han evitado la reducción de las tasas de deforestación. En México en 1910 este concepto de reserva ya había sido manejada como tal, aunque no con ese nombre, en la zona maya del Estado de Quintana Roo. Debido a que el mercado del chicle decayó, esta reserva ha favorecido también la explotación moderada y comunitaria de otros productos forestales y al mismo tiempo ha logrado conservar importantes áreas de selva tropical. Se concluye que este tipo de reserva tiene sus limitaciones y debe ser considerada sólo como una alternativa para extraer productos forestales no maderables en cantidades moderadas y al mismo tiempo contener la deforestación de los ecosistemas tropicales húmedos.

How Long Will South Africa Survive? The Looming Crisis, R.W. Johnson

Reviewed by: How Long Will South Africa Survive? The Looming Crisis by R. W. Johnson Damien Ejigiri Johnson, R. W. 2015. HOW LONG WILL SOUTH AFRICA SURVIVE? THE LOOMING CRISIS. London: Hurst & Company. 266 pp. With visionary South African president Nelson Mandela at the helm of his country’s affairs, every citizen saw a rosy picture and a bright future. Since his death, burial, and departure from the political landscape, there have been negative feelings. Therefore, R. W. Johnson’s book and its subtheme, How Long Will South Africa Survive? The Looming Crisis, are not accidental. The author, an emeritus fellow of Magdalen College at University of Oxford, was supposed to be the only South African Rhodes scholar who returned to the country after the fall of the apartheid regime; one wonders if there was a survey on that. The publication being reviewed is one of a dozen or more books and many scholarly articles and popular articles that Johnson has authored. Since South African president Jacob Zuma once sat in his classroom, he writes that “it feels strange for me to be writing about South Africa in the era of Jacob Zuma” (p. ix). Yet he goes on to complete his book, in which Zuma plays a central role. In his estimation, Zuma “never expected to be president” (p. ix). He goes on to give a brief anecdote of Zuma’s biography: that he migrated “to Durban from a bone-poor rural background (his mother a domestic, his father a policeman, who died young)” (p. ix). Describing Zuma’s relationship with the African National Congress (ANC), he sees him as being full of a bounce and life, and says it was natural that he joined the ANC out of enthusiasm: “Albert Luthuli, a Zulu chief, was its leader and, for Zuma, with his rural Zulu background, that mattered a lot” (p. x). Johnson recalls an early Mandela rally on Commercial Street in Durban in the early 1960s, when, as a result of a whisper in Mandela’s ear, [End Page 105] Mandela bolted from the platform and “the meeting broke up in disorder as the police arrived in force to close the meeting down” (pp. x–xi). This book, apart from the fact that it is divided into ten main chapters, provides a list of abbreviations and acronyms, a preface, copious notes, and a useful subject index. Johnson discusses such topical themes as KwaZulu-Natal, the world of Jacob Zuma (chapter two); the ANC under Zuma (chapter three); the new class structure (chapter five); culture wars (chapter six); state repression of economic activity (chapter seven); the view from the International Monetary Fund (chapter eight); the BRICS countries as an alternative model (chapter nine); and what he calls the impossibility of autarchy (chapter ten). In the final chapter, where autarchy is handsomely discussed, the Zimbabwe is invoked in variety of subheadings, including “The Zimbabwean Example” (pp. 223–24); “Why South Africa Can’t Be like Zimbabwe” (pp. 224–28); and “Going for the Mugabe Option” (pp. 230–32). In the final chapter, Johnson’s references to Zimbabwe lead to a question: why could South Africa not be like Zimbabwe? Johnson answers that if South Africa were to follow Mugabe’s example, it would have to undertake drastic land reform, which the ANC leaders are not ready to authorize; and that turning to a Mugabe option or “direction on its own would soon find itself [South Africa] trying to implement a wholly impossible and, indeed, ruinous set of policies” (pp. 233–34). It is, however, not that South Africa—like Zimbabwe—did not implement policies that were similar to Mugabe’s policies in Zimbabwe, including the fact that the “ANC has on its own embraced a series of policies (expropriation without compensation, the 50 per cent seizure of commercial farmland, the NHI, forced demographic representivity in the workforce, etc.) which are already far down the road—and the ANC official policy is now for a much more radical ‘second transition’” (p. 234). Surely, this book is worth perusal by Africanists and general readers, especially those who want to know about post-Mandela South Africa. Damien Ejigiri Southern University and A & M...