Representation Of Land Use Research Articles

Research priorities in land use and land‐cover change for the Earth system and integrated assessment modelling

AbstractThis special issue has highlighted recent and innovative methods and results that integrate observations and modelling analyses of regional to global aspect of biophysical and biogeochemical interactions of land‐cover change with the climate system. Both the Earth System and the Integrated Assessment modeling communities recognize the importance of an accurate representation of land use and land‐cover change to understand and quantify the interactions and feedbacks with the climate and socio‐economic systems, respectively. To date, cooperation between these communities has been limited. Based on common interests, this work discusses research priorities in representing land use and land‐cover change for improved collaboration across modelling, observing and measurement communities. Major research topics in land use and land‐cover change are those that help us better understand (1) the interaction of land use and land cover with the climate system (e.g. carbon cycle feedbacks), (2) the provision of goods and ecosystem services by terrestrial (natural and anthropogenic) land‐cover types (e.g. food production), (3) land use and management decisions and (4) opportunities and limitations for managing climate change (for both mitigation and adaptation strategies). Copyright © 2010 Royal Meteorological Society and Crown Copyright.

Differentiation in the fertility of Inceptisols as related to land use in the upper Solimões river region, western Amazon

The Upper Solimões river region, western Amazon, is the homeland of indigenous populations and contains small-scale agricultural systems that are important for biodiversity conservation. Although traditional slash-and-burn agriculture is being practiced over many years, deforestation there is relatively small compared to other Amazon regions. Pastures are restricted to the vicinity of cities and do not spread to the small communities along the river. Inceptisols are the main soil order (>90%) in the area and have unique attributes including high Al content and high cation exchange capacity (CEC) due to the enrichment of the clay fraction with 2:1 secondary aluminosilicates. Despite its importance, few studies have focussed on this soil order when considering land use effects on the fertility of Amazon soils. Thus, the objective of this study was to evaluate changes in soil fertility of representative land use systems (LUSs) in the Upper Solimões region, namely: primary rainforest, old secondary forest, young secondary forest, agroforestry, pasture and agriculture. LUSs were significantly differentiated by the chemical attributes of their topsoil (0–20 cm). Secondary forests presented soil chemical attributes more similar to primary rainforest areas, while pastures exhibited the highest dissimilarity from all the other LUSs. As a whole, soil chemical changes among Inceptisols dominated LUSs showed patterns that were distinct from those reported from other Amazon soils like Oxisols and Ultisols. This is probably related to the presence of high-activity clays enriched in exchangeable aluminum that heavily influenced the soil chemical reactions over the expected importance of organic matter found in most studies conducted over Oxisol and Ultisol.

Seasonal variations in nitrogen mineralization under three land use types in a grassland landscape

Soil nitrogen (N) mineralization is an important component of the N cycling process in ecosystems. In this study, we assessed the seasonal patterns of net soil N mineralization and nitrification using an intact soil core incubation method in the upper 0–10 cm soil layer in three representative land use types. These included a fenced steppe, an abandoned field and a crop field in a grassland landscape of Inner Mongolia, China. The study was conducted from September 2004 to August 2005. Our results demonstrate marked seasonal variations in inorganic N pools, net nitrogen mineralization and net nitrification. Net N mineralization was higher in the crop field than in the fenced steppe and the abandoned field. Daily rates of N mineralization and nitrification during the growing season were approximately twice their corresponding mean annual rates. Accumulative mineralization and nitrification of N during the growing season accounted for about 90 and 85% of that measured for the entire year. Rates of mineralization and nitrification were positively correlated with soil bulk density, but negatively correlated with soil pH. Net N mineralization and nitrification were strongly regulated by land use, precipitation, soil water and temperature.

Numerical modeling of algae in the patuxent estuary

The Patuxent Estuary, a tributary of the Chesapeake Bay, has suffered excessive algal productivity over the last several decades. Although the phosphorus and nitrogen loads from point sources have been dramatically reduced since the 1980s and 1990s with costly management practices, the algal bloom problem has not been improved significantly. A physical‐biological model using the CE‐QUAL‐W2 framework was developed to address the eutrophication processes in the Patuxent Estuary and serve as a linkage between watershed model and aquatic ecosystem and fishery model. The model was calibrated with 1997–1998 data and verified with 1998–1999 data. The impact of land use change in the Patuxent Watershed on algal productivity was examined by running scenarios representing land use changes and subsequent load reduction or load increase. Model results revealed that there is no simple positive or negative correlation between watershed nutrient loads and algae productivity. Under low freshwater inflow conditions, nutrients are the limiting factors, while physical transport plays a more important role than nutrients under high flow conditions. In addition to watershed nutrient loads, internal nutrient release from sediment may become important under low dissolved oxygen conditions.

Establishing an air pollution monitoring network for intra-urban population exposure assessment: A location-allocation approach

Abstract This study addresses two objectives: (1) to develop a formal method of optimally locating a dense network of air pollution monitoring stations; and (2) to derive an exposure assessment model based on these monitoring data and related land use, population, and biophysical information. Previous studies have located monitors in an ad hoc fashion, favouring the placement of monitors in traffic “hot spots” or in areas deemed subjectively to be of interest. We apply our methodology in locating 100 nitrogen dioxide monitors in Toronto, Canada. Locations identified by the method represent land use, transportation infrastructure and the distribution of at-risk populations. Our exposure assessments derived from the monitoring program produce reasonable estimates at the intra-urban scale. The method for optimally locating monitors may have widespread applicability for the design of pollution monitoring networks, particularly for measuring traffic pollutants with fine-scale spatial variability.

Modelling the spatial distribution of agricultural land use at the regional scale

Agriculture is the most important land use in Europe in geographic terms and because of this it plays a central role in the quality of the wider environment. Whilst the spatial patterns of agricultural land use have changed considerably in recent times, further changes are likely as a result of the influences of policy reform, socio-economics and climate change. Understanding, therefore, how agricultural land use might respond to global environmental change drivers is a research question of considerable importance. The first step, however, in projecting potential future changes in agricultural land use is to be able to understand and represent in models both the socio-economic and physical processes that control current land use distributions. Thus, this paper presents an approach to modelling the spatial distribution of agricultural land use at the regional scale. The approach is based on the simulation of farm-scale decision making processes (based on optimisation) and the response of crops to their physical environment. Regional scale applications of the model are undertaken through the use of spatially-variable, geographic data sets (soils, climate and topography) combined with economic data. Examples of the application of the model are given for two regions of England: the north-west and east Anglia. These regions were selected to give examples of contrasting land use systems within the context of northern European agriculture. The model results are compared statistically with observed distributions of agricultural land use for the same regions in a quasi-validation exercise. The comparison suggests that the model is very good at representing land use that is aggregated at the regional level, and at representing general spatial trends in land use patterns. Some differences were observed, however, in land use densities between the modelled and observed data. The results suggest that the basic hypothesis of the model: that farmers are risk averse, profit maximisers, is a reasonable assumption for the regions studied. However, further study of decision making processes would be likely to improve our ability to model agricultural land use distributions. This includes, for example, the role of farmer attitudes to risk, differing views on future prices and profitability, and the effect of time lags in the decision process.

An integrated urban development and ecological simulation model

This paper develops an integrated strategy to model the urban development and ecological dynamics in the Central Puget Sound Region. This effort is part of the Puget Sound Regional Integrated Synthesis model (PRISM) – an interdisciplinary initiative at the University of Washington aiming to develop a dynamic and integrated understanding of the environmental and human systems in the Puget Sound. We describe a model that predicts the environmental stresses associated with urban development and related changes in land use and human activities under alternative demographic, economic, environmental, and policy scenarios. We build on UrbanSim, an existing urban simulation model developed by Waddell [42]. The principal urban actors, represented in the model as objects corresponding to businesses, households, developers, and governments, make choices about location of activities and land development. We extend the object properties and methods now implemented in the UrbanSim model to predict three types of human-induced environmental stressors: land conversion, resource use, and emissions. The core location model in UrbanSim will be revised from its current aggregate structure to one based on microsimulation, and from a zone description of space to one based on a high-resolution grid structure. We will use a spatially explicit process-based landscape modeling approach to replicate ecosystem processes and represent land use–cover interactions at the regional scale. The output of the urban ecological model will serve as the input to several biophysical models for hydrology, hillslope stability, water quality, atmosphere, and ecosystems. Ecological changes will feed back on the choices of both households and business locations, and availability of land and resources.

Sub-regional linear programming models in land use analysis: a case study of the Neguev settlement, Costa Rica

The paper deals with linear programming as a tool for land use analysis at the sub-regional level. A linear programming model of a case study area, the Neguev settlement in the Atlantic zone of Costa Rica, is presented. The matrix of the model includes five submatrices each encompassing a different farm type. The farm types are distinguished on the basis of land-labour ratios, considering farm size and three different soil types, and assuming a fixed availability of household labour. Land use activities are defined as a combination of a land unit (three soil types, with or without forest cover) and land type (cassava, logged forest, maize, palm heart, pasture with cattle, pineapple, plantain and tree plantain). These represent land use systems with fixed input-output coefficients. Two indicators for sustainability are taken into account: soil nutrient depletion and biocide use. These are built into the model via constraints, marking upper limits to the use of renewable resources and to the waste flow into the environment. The linear programming model forms part of the USTED (Uso Sostenible de Tierras En el Desarrollo) methodology for the analysis and planning of sustainable land use. Several land use scenarios are analysed to assess whether the income of all farms in the Neguev can increase through an improved, and sustainable, land use. First, a base scenario is calculated to serve as a reference for assessing the impact of policy measures. A striking feature of the base scenario is the large area with palm heart in comparison to the actual area. Sustainability-related policy measures studied are increasing biocide prices, and quantitative restrictions on biocide use and soil nutrient losses. Doubling the biocide price hardly affects its use, while a quantitative restriction on the use of biocides per ha of 50% in comparison to the base scenario use, reduces average incomes by less than 1%. A similar conclusion applies to soil nutrient depletion. Restricted to 'critical nutrient losses' per year over a ten year period, specified per land unit per farm type, average incomes are reduced by less than 3%. Other scenarios concern the impact of decreasing palm heart prices, as a consequence of increased supply, the influence of increasing wages and the role of the discount rate.

TYPES OF AGRICULTURAL LAND USE IN MOSCOW OBLAST

A study of basic types of agricultural land use in Moscow Oblast regionalizes oblast agriculture according to a series of indices representing land use intensity and productivity: level of capital investment, intensity of fertilizer application, crop rotation schemes, mean farm size, percent of arable land, and number of farm workers. The categories identified ranged from a zone of intensive commercial livestock-feeding and hothouse operations, for the most part lying within or inside the greenbelt of the city, to space-extensive livestock breeding operations along the western and southwestern edges of the oblast having a very small proportion of marketable output (translated by Andrew R. Bond).

An evaluation of the structure and function of tropical homegardens

Homegardens represent land use systems involving deliberate management of multipurpose trees and shrubs in intimate association with annual and perennial agricultural crops and, invariably, livestock, within the compounds of individual houses, the whole crop-tree-animal unit being intensively managed by family labour. Known by different names in various places, these agroforestry systems are common in all ecological regions of the tropics and subtropics, especially in humid lowlands with high population density. An analysis of the structural and functional aspects of ten selected homegarden systems from different ecological and geographical regions shows that the average size of the homegarden units is less than 0·5 ha; yet they are composed of a large number of woody and herbaceous species, carefully structured to form 3–5 vertical canopy strata, with each component having a specific place, as well as function. Food production is the primary function of most homegardens, the vast majority of them being subsistence production systems. While there is a remarkable similarity among the different homegardens with respect to the type and nature of the herbaceous crops, the nature of woody perennials varies, depending on environmental and ecological factors. In general, most woody components produce fruits or other types of food in addition to other outputs such as fuelwood, timber, etc. These various food products provide a substantial proportion of nutritive and energy requirements of the local diet. Moreover, the species diversity and varying production cycles of the different components ensure continuous production throughout the year from the homegarden unit. Little or no research has been done to improve homegarden systems. Structural complexity, species diversity, multiple output nature, tremendous variability from farm to farm, etc., are some of the main characteristics that make the homegardens extremely difficult models to work with according to the currently available research procedures.

Effectiveness of a computer land use planning system for corridor selection

Spatial computer models were applied to a route location problem in eastern Wisconsin. Data included soil associations, land cover, slope, and land use stored by 1/9 km cells. Models were constructed to represent land use ideas supported by various sectors of society. Routes automatically selected by each model were plotted on a medium intensity soil map to test their effectiveness in avoiding prime agricultural land. In an area that was mainly classified in US Department of Agriculture capability classes I and II (82 per cent), routes selected by the various models included from 46 per cent to 86 per cent classes I and II land. Other tests indicated improvements in model performance with increasing length. Subtle differences in models provided significantly different route locations within 17 km. Major differences in models showed significantly different locations within 6 km.(a) (TRRL)