A review on historical trajectories and spatially explicit scenarios of land-use and land-cover changes in China

ABSTRACT

Land use in China has changed remarkably over the past centuries with manifold implications for sustainable development. Investigation and projection of the land-use and land-cover changes (LUCC) have therefore become critical to promote the understanding of the LUCC process and the interactions with human societies. Scientists had devoted great efforts to create, process, and interpret comprehensive historical land-use/cover datasets, and to simulate future land-use systems under different scenarios. We synthesize the literature on the historical trajectories of LUCC in China, and summarize existing efforts of scenario developments for the projection of spatially explicit LUCC. Our review therefore provides salient suggestions for future land-use change analysis.     

Tools for Groundwater Protection Planning: An Example from McHenry County, Illinois, USA

/ This paper presents an approach for producing aquifer sensitivity maps from three-dimensional geologic maps, called stack-unit maps. Stack-unit maps depict the succession of geologic materials to a given depth, and aquifer sensitivity maps interpret the successions according totheir ability to transmit potential contaminants. Using McHenry County, Illinois, as a case study, stack-unit maps and an aquifer sensitivity assessment were made to help land-use planners, public health officials, consultants, developers, and the public make informed decisions regarding land use. A map of aquifer sensitivity is important for planning because the county is one of the fastest growing counties in the nation, and highly vulnerable sand and gravel aquifers occur within 6 m of ground surface over 75% of its area. The aquifer sensitivity map can provide guidance to regulators seeking optimal protection of groundwater resources where these resources are particularly vulnerable. In addition, the map can be used to help officials direct waste-disposal and industrial facilities and other sensitive land-use practices to areas where the least damage is likely to occur, thereby reducing potential future liabilities. KEY WORDS: Geologic mapping; Groundwater; Aquifers; Aquifer sensitivity; Land-use planning     

Relationships Between Landscape Characteristics and Nonpoint Source Pollution Inputs to Coastal Estuaries

The model can help in examining the relative sensitivity of water-quality variables to alterations in land use made at varying distances from the stream channel. The model also shows the importance of streamside management zones, which are key to maintenance of stream water quality. The linkage model can be considered a first step in the integration of GIS and ecological models. The model can then be used by local and regional land managers in the formulation of plans for watershed-level management.     

Effects of experimental nitrogen additions on plant diversity in tropical forests of contrasting disturbance regimes in southern China

Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (with harvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha⁻¹ yr⁻¹, and 100 kg N ha⁻¹ yr⁻¹. Nitrogen additions did not significantly affect understory plant richness, density, and cover in the disturbed forest. Similarly, no significant response was found for canopy closure in this forest. In the rehabilitated forest, species richness and density showed no significant response to N additions; however, understory cover decreased significantly in the N-treated plots, largely a function of a significant increase in canopy closure. Our results suggest that responses of plant diversity to N deposition may vary with different land-use history, and rehabilitated forests may be more sensitive to N deposition.     

Assessing the effects of land use changes on soil sensitivity to erosion in a highland ecosystem of semi-arid Turkey

There has been increasing concern in highlands of semiarid Turkey that conversion of these systems results in excessive soil erosion, ecosystem degradation, and loss of sustainable resources. An increasing rate of land use/cover changes especially in semiarid mountainous areas has resulted in important effects on physical and ecological processes, causing many regions to undergo accelerated environmental degradation in terms of soil erosion, mass movement and reservoir sedimentation. This paper, therefore, explores the impact of land use changes on land degradation in a linkage to the soil erodibility, RUSLE-K, in Cankiri–Indagi Mountain Pass, Turkey. The characterization of soil erodibility in this ecosystem is important from the standpoint of conserving fragile ecosystems and planning management practices. Five adjacent land uses (cropland, grassland, woodland, plantation, and recreational land) were selected for this research. Analysis of variance showed that soil properties and RUSLE-K statistically changed with land use changes and soils of the recreational land and cropland were more sensitive to water erosion than those of the woodland, grassland, and plantation. This was mainly due to the significant decreases in soil organic matter (SOM) and hydraulic conductivity (HC) in those lands. Additionally, soil samples randomly collected from the depths of 0–10 cm (D ₁) and 10–20 cm (D ₂) with irregular intervals in an area of 1,200 by 4,200 m sufficiently characterized not only the spatial distribution of soil organic matter (SOM), hydraulic conductivity (HC), clay (C), silt (Si), sand (S) and silt plus very fine sand (Si + VFS) but also the spatial distribution of RUSLE-K as an algebraically estimate of these parameters together with field assessment of soil structure to assess the dynamic relationships between soil properties and land use types. In this study, in order to perform the spatial analyses, the mean sampling intervals were 43, 50, 64, 78, 85 m for woodland, plantation, grassland, recreation, and cropland with the sample numbers of 56, 79, 72, 13, and 69, respectively, resulting in an average interval of 64 m for whole study area. Although nugget effect and nugget effect–sill ratio gave an idea about the sampling design adequacy, the better results are undoubtedly likely by both equi-probable spatial sampling and random sampling representative of all land uses.     

KLUM@GTAP: Introducing Biophysical Aspects of Land-Use Decisions into a Computable General Equilibrium Model a Coupling Experiment

In this paper, the global agricultural land use model Kleines Land Use Model is coupled to an extended version of the computable general equilibrium model (CGE) Global Trade Analysis Project in order to consistently assess the integrated impacts of climate change on global cropland allocation and its implication for economic development. The methodology is innovative as it introduces dynamic economic land-use decisions based also on the biophysical aspects of land into a state-of-the-art CGE; it further allows the projection of resulting changes in cropland patterns on a spatially more explicit level. A convergence test and illustrative future simulations underpin the robustness and potentials of the coupled system. Reference simulations with the uncoupled models emphasise the impact and relevance of the coupling; the results of coupled and uncoupled simulations can differ by several hundred percent.

Characterizing land-use diversity in village landscapes for sustainable mountain development: a case study from Indian Himalaya

This study aimed to analyze the ecological, socio-economic and policy implications of land-use diversity in a traditional village landscape (900–1,000 m amsl.) in the Garhwal region of Indian Himalaya. The village landscape was differentiated into three major land-use types viz., forests, settled agriculture and shifting agriculture. Settled agriculture was further differentiated into four agroecosystem types viz., homegarden system (HGS), rainfed agroforestry system (RAS), rainfed crop system (RCS) and irrigated crop system (ICS), and shifting agriculture system (SAS) was differentiated into different stages of a 4-year long cropping phase and a 7-year long fallow phase, and forests into Community Forests (CF) and Reserve Forests (RF). HGS is the most productive agroecosystem, with soil organic carbon and nutrient concentrations significantly higher than all other forest/agricultural land-uses. Farmers capitalize upon crop diversity to cope with the risks and uncertainties of a monsoon climate and spatial variability in ecological factors influencing productivity. The SAS, a land-use adopted as a means of acquiring inheritable rights over larger land holdings provided in the policies during the 1890s, is less efficient in terms of land productivity than the traditional RAS and HGS but is maintained for its high labour productivity coupled with availability of high-quality fuelwood from fallow vegetation. Dominance of fodder trees in the RAS seems to derive from policies causing shortage of fodder available from forests. Cultural norms have favoured equity by allowing hiring of labour only from within the village community and income from non-timber forest products only to the weaker section of the society. Conversion of rainfed to irrigated cropping, a change facilitated by the government, improves agricultural productivity but also increases pressure on forests due to higher rates of farmyard manure input to the irrigated crops. Existing forest management systems are not effective in maintenance of a large basal area in forests together with high levels of species richness, soil fertility and resistance to invasive alien species Lantana camara. Farmers have to spend huge amount of labour and time in producing manure, managing livestock and other subsidiary farm activities. Interlinkages among agriculture, forests and rural economy suggest a need of replacing the present policies of treating agricultural development, forest conservation and economic development as independent sectors by an integrated sustainable development policy. The policy should promote technological and institutional innovations enabling parallel improvements in agricultural productivity and functions of forest ecosystems.     

Land-Use Planning in the Chaco Plain (Burruyacú, Argentina). Part 1: Evaluating Land-Use Options to Support Crop Diversification in an Agricultural Frontier Area Using Physical Land Evaluation

The Burruyacú district (Tucumán province, Argentina) is a farming frontier in the western Chaco plain, at the foothills of the sub-Andean mountain ranges, where agricultural land-uses are in conflict with the conservation and management of the Chaco forest. Over the last decades, large-scale farming rapidly expanded due to population pressure, attractive market prices, easy accessibility, favourable annual rainfall, fertile soils, and flexible land tenure. Cropland extension, mainly for heavily mechanized soybean production, has resulted in important reduction of the Chaco forest and also caused physical soil degradation, especially soil compaction, and soil erosion. Land suitability was assessed using the Food and Agriculture Organization (FAO) framework for a set of crops ecologically adapted to the area, including soybean, maize, wheat, sugarcane, citrus, and safflower. Only 16% of the study area has high suitability for most of the selected crops. Major limitations for cropping are low annual rainfall and flooding in the east of the study area, and topography (slope) and flooding in the west. As climate varies over relatively short periods of time, with recurrent cycles of dry and rainy years, land suitability for the selected crops was also assessed under extreme but realistic climatic conditions. Under rainy-year conditions, almost all the study area is unsuitable or marginally suitable for most of the crops. Under dry-year conditions, the study area is unsuitable for all crops, except safflower, which is more drought-resistant. This article proposes alternatives to the mono-cropping of soybean with the aim to help farmers make adequate decisions on land-use and management under deteriorating environmental conditions and for addressing the issue of competitive land uses in the context of land-use planning.     

Modelling the response of surface water quality to the urbanization in Xi'an, China

The study investigated the response of surface water quality to urbanization in Xi'an, China. We qualitatively described the change in urban land use from 1996 to 2003, analyzed the status of the surface water environment, and constructed a model of urban expansion to simulate the water environment's response to urbanization. Our results revealed that patterns of land use changed dramatically, the rate of economic growth exceeded that of urbanization during the study period, and increasing urban land use was correlated with fluctuations in water quality. The simulated results suggested that urbanization had reached the environmental carrying capacity based on the average land utility and the marginal costs of pollution.     

Successful de-fragmentation of woodland by planting in an agricultural landscape? An assessment based on landscape indicators

Habitat fragmentation is the focus of much conservation concern and associated research. In some countries, such as Britain, the main phase of fragmentation occurred centuries ago and the focus of conservation management is now on restoration and recovery. Scenario studies have suggested that spatial targeting is preferable if landscape scale restoration is to be achieved, and that this should bring greater benefits than site-focussed activities but this has rarely been tested in practice. In Britain, woodland expansion has been encouraged through a number of financial incentives, which have evolved from instruments that encouraged almost any addition to the potential woodland resource, to grant schemes that have set out to restore connectivity to remnant ancient woodland. This study assessed the degree of de-fragmentation achieved by woodland expansion on the Isle of Wight and in particular the success of spatial targeting of new woodland planting implemented through grant aid in the JIGSAW (Joining and Increasing Grant Scheme for Ancient Woodland) scheme. Five steps in the re-development of broad-leaved woodland were tested using eight indicators - six commonly used landscape metrics, and two ecologically scaled indicators derived from application of least-cost network evaluation. Only half of the measures indicated de-fragmentation over the whole sequence of five steps. However, the spatial targeting did appear successful, when compared to equivalent untargeted grant-aided woodland expansion, and resulted in positive change to six of the eight indicators. We discuss the utility of the indicators and ways in which future targeting could be supported by their application.