Major Land Use Changes Research Articles

Three Centuries of Global Population Growth: A Spatial Referenced Population (Density) Database for 1700–2000

The Earth’s surface has changed considerably over the past centuries. Since the start of the Industrial Revolution in the early 1700s, humans from the “Old World” started to colonize the “New World”. The colonization processes lead to major changes in global land use and land cover. Large parts of the original land cover have been altered (e.g., deforestation), leading to extra emissions of GHG’s to the atmosphere and enhancing global climate change. The spatial and temporal aspects are still not very well known. More and more global integrated environmental assessments concerning global sustainability require long time series of global change indicators, of which population is an important one. This study presents an update of the geo-referenced historical population maps for the period 1700–2000, part of the History Database of the Global Environment (HYDE), which can be used in integrated models of global change and/or global sustainability.

Assessing the effect of climate oscillations and land-use changes on streamflow in the central Spanish Pyrenees.

Plans to increase the amount of irrigated land in Mediterranean countries should consider how changes in climate and land-use affect water resources. In this study, both precipitation and temperature were used to analyze regional trends in discharge in the basins of the Central Spanish Pyrenees since the mid-20th century. Annual variations in the relationship between precipitation and discharge suggested that discharge was relatively lower in the second half of the study period, coinciding with major changes in land use. On a monthly scale, precipitation increased significantly in October, April, and July, and decreased in March, and temperature increased in January and February and decreased in April. Nevertheless, discharge has decreased significantly in most months in the past 50 years. Land-use and plant-cover changes are the only nonclimatic factor that can explain the loss of around 30% of the average annual discharge.

AN ANALYTICAL APPROACH TO ECOSYSTEM BIOGEOCHEMISTRY MODELING

Models of terrestrial ecosystem carbon and nutrient biogeochemistry commonly utilize several compartments of organic matter (OM) to simulate the storage and turnover of OM in plant–soil systems. While much work has focused on numerical simulations of ecosystems to understand responses to perturbations, relatively little work explores the analytical properties of the mathematical systems used and their implications for the understanding of terrestrial ecosystems. We explore carbon and nutrient dynamics using a 4 × 4 transfer matrix, which is similar to the mathematical core of commonly used simulation models (e.g., Century). The C and N vectors contain one pool for photosynthesizing biomass and several pools for soil detritis. The model yields steady-state solutions for the C pool size of each compartment dependent solely on the amount of the nutrient (nitrogen) stored within the compartment and the C:nutrient ratio. Furthermore, the C and nutrient storage in the model compartments depends on the inputs and losses of nutrients to and from the system as well as the coefficients for turnover from and transfer between compartments. When examining the transient behavior of the system, the eigenvalues for the system provide a useful tool for predicting and understanding the characteristic time scales with which plant–soil systems respond to perturbations. We use the model eigenvalues to examine ecosystem development from freshly exposed parent material as well as the response to a “catastrophic” disturbance event. Ultimately, the model's analytical tools can be extended to characterize soil organic matter (SOM) responses to several major land-use changes occurring in agroecosystems—including the initiation of tillage, the application of industrial fertilizers, and the introduction of reduced-tillage practices. Analysis of the eigenvalues for these cases suggests that agroecosystems tend to lose SOM more rapidly following the initiation of tillage than they can regain SOM after the initiation of conservation-tillage practices. Additionally, the amount of N export (harvesting or loss) places an important control on the storage and future productivity of agricultural systems. Overall, we suggest that the model—with straightforward and accessible steady-state solutions and eigenvalues—offers a complementary perspective to more complex numerical simulations. Corresponding Editor: D. S. Schimel

Assessing the Effect of Climate Oscillations and Land-use Changes on Streamflow in the Central Spanish Pyrenees

Plans to increase the amount of irrigated land in Mediterranean countries should consider how changes in climate and land-use affect water resources. In this study, both precipitation and temperature were used to analyze regional trends in discharge in the basins of the Central Spanish Pyrenees since the mid-20th century. Annual variations in the relationship between precipitation and discharge suggested that discharge was relatively lower in the second half of the study period, coinciding with major changes in land use. On a monthly scale, precipitation increased significantly in October, April, and July, and decreased in March, and temperature increased in January and February and decreased in April. Nevertheless, discharge has decreased significantly in most months in the past 50 years. Land-use and plant-cover changes are the only nonclimatic factor that can explain the loss of around 30% of the average annual discharge.

Effect of landscape structure on anopheline mosquito density and diversity in northern Thailand: Implications for malaria transmission and control

The influence of landscape structure on anopheline mosquito density and diversity was studied in a comparison of agricultural and forested landscapes in northern Thailand. Agriculture locations had significantly higher landscape diversity, more patches, smaller mean patch sizes, and more complex patch shapes than forest locations. Mosquito collections were undertaken during both dry and wet seasons from October 1997 to December 1999. The density of two forest-associated species, Anopheles maculatus s.s. and Anopheles minimus s.l., both primary malaria vectors in Thailand, was significantly higher in forest locations in at least one season. The density of two paddy field-associated species, Anopheles aconitus and Anopheles hyrcanus group did not differ between locations. Anopheles aconitus is a secondary malaria vector and An. hyrcanus group is not considered as a vector in Thailand. The density of An. minimus s.l. was positively related to forest mean patch size, various water and paddy field landscape metrics and negatively related to landscape diversity. Anopheles hyrcanus group was also positively related to water metrics. Anopheline species diversity was negatively related to landscape diversity. Forest fragmentation resulting from human economic activities often increases landscape heterogeneity, which may result in a reduction in anopheline species diversity, as was the case in this study. There are indications that the effect of fruit orchards on anopheline diversity might be different in the dry season compared to the wet season. Fruit orchard landscape metrics affected species diversity negatively in the dry season and positively in the wet season. One reason for this could be that pesticides are typically applied in fruit orchards during the dry season. The conversion of forests to fruit orchards is a major land-use change in northern Thailand. These results show the complexity of vector status in northern Thailand and that vector and agriculture pest control are intricately interrelated. It is therefore important to include both the public health and agricultural sectors in controlling malaria vectors in the country. Our results also indicate that if landscape management should be used for malaria control in northern Thailand large-scale reduction and fragmentation of forest cover would be needed. Such drastic actions do not agree well with current global objectives concerning forest and biodiversity conservation

CO2 and land-use effects on Australian vegetation over the last two centuries

Coincident with major changes in land use and management in Australia over the past 200 years, there has been a 20% increase in the concentration of carbon dioxide ([CO2]) in the atmosphere. We investigate the way in which these two factors have modified the natural vegetation at the continental scale. We describe landscapes in terms of the abundance of three leaf functional types, 'turgor' (T), 'mesic' (M) and 'sclerophyll' (S). We have previously shown that continental-scale estimates of the TMS composition can be made from climatic and satellite data. In this study, we extend those results by estimating the TMS composition for the 'natural' vegetation (i.e. the present vegetation if there had been no change in land use and management). By comparing those estimates with the existing vegetation, we show that changes in land use have resulted in a large increase in the abundance of T leaves (seasonally green leaves of annual and ephemeral herbaceous plants) and there is a corresponding decline in plants with M and S leaves (evergreen trees, shrubs and perennial grasses). We then use a water use efficiency model to estimate the natural vegetation cover 200 years ago when the [CO2] was about 280 μmol mol–1. According to the model, 200 years ago the seasonally green (T) vegetation cover was similar to that at the present (excluding cultural vegetation cover), but there was lower evergreen cover. The increase in evergreen cover with increasing [CO2] could have been expressed as an increase in trees, shrubs or grasses having M and S leaf forms, depending on soil moisture and nutrient availability. According to our model, while 'woody vegetation thickening' may have been exacerbated by the increase in [CO2], other changes associated with European settlement are also important.

Land-use changes and their social driving forces in Czechia in the 19th and 20th centuries

This paper is an overview of the major land-use changes in Czechia over the past 150 years, with a focus on the social forces driving these changes. Sources of land-use data are also discussed. Though economic development is seen as the key impact on land use before 1945, under communism (1948–89), the importance of political decisions was crucial. The post-war period is analysed in greater detail as this was the era of the most significant landscape changes. The most recent period encompassed a return to market conditions, resulting in environmentally favourable land-use changes.

Predictions in catchment hydrology: an Australian perspective

Throughout Australia, there are strong regional differences in hydrological response to landscape and climate; however, in general terms, in Australian catchments the flows are typically peakier, base flows are of lower proportion, runoff coefficients are smaller, and dry periods are longer and more variable, than in European and North American catchments. In this context, this paper assesses the model types available to improve understanding and prediction of catchment flows and transport. Included in this is the concept of information and its influence on appropriate model complexity, as well as a characterization of the principal factors inhibiting model performance. The ability to predict the effects on flows and water quality of anything but major changes in climate and land use is limited. Improvement of understanding and prediction relies on the following: more rigorous testing of models to assess their ability to separate climate and land use effects on hydrological response; the use and improved interpretation of spatial data; more and better monitoring of hydrological response at a range of scales; complementary use of conceptual and distributed models; and integration of modelling with other information such as that from geochemical studies including tracer analysis.

Global biodiversity scenarios for the year 2100.

Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.

Principal land use changes anticipated in Europe

Major changes in land use may be anticipated in Europe in the decades to come as a result of technological, socio-economic and political developments as well as global environmental change. The type and effects of these changes will strongly depend on policy decisions which are governed, amongst others, by: (i) an increasing agricultural productivity; (ii) an increasing realization of the need to conserve bio-diversity and environmental quality for current and future generations; (iii) pressure from an increasingly urban population to emphasize non-agricultural forms of land use in terms of nature and landscape conservation; (iv) increasing market-driven demand for high quality produce made with environmentally friendly forms of management; and (v) increasing food demand on the world market as the world population doubles and purchasing powers increases, particularly in Asia. These developments occur now both in Eastern and Western Europe, even though historical developments during the last 50 years have been strikingly different in these two regions. Collectivization in Eastern Europe after World War II was associated with higher yields but also with unfavourable changes in land use and cropping patterns causing acidification, soil erosion, salinization and chemical pollution. The change to democracy in the late 1980s implied a change from an essentially quantity- to a more quality-oriented type of agriculture, like in Western Europe where an industrialized agriculture had also caused environmental problems. Emphasis is now being placed on rational land use, which includes optimization of farm size and the development and implementation of economically viable crop production techniques which result in high quality produce as well as limited adverse environmental side effects. However, these ideals are far from being realized. According to some studies, the technical possibilities of modern agriculture can theoretically in future provide an adequate volume of produce from only 30 to 50% of the current agricultural area in western Europe. This implies potential for other forms of land use in the remaining land area. However, other studies emphasizing low external input agriculture or extrapolation of historical trends, indicate that the current land area may be needed to produce adequate food, certainly when considering the future world market demand. This conclusion is also supported by the fact that theoretical production levels are often much higher than real levels, because of various agronomic and socio-economic factors. A major challenge for the decades ahead is to avoid uncontrolled developments of land use with possibly adverse socio-economic and environmental effects; the latter include the time-delayed release of harmful chemicals, currently held in some soils, into the environment and the enhanced emission of radiatively active trace gases from soils to atmosphere. Controlled developments yielding sustainable forms of agricultural land use in some areas and nature development in others, is to be preferred and should ideally be based on eco-regional approaches. The authors advocate initiation of comprehensive, exploratory studies for Europe in which sustainable production of major land units is defined as a function of different types of land management and in which Europe is seen as part of the world economy. Six exploratory studies are reviewed in this paper; however, none of these scenario studies has the necessary comprehensive character and none is based on adequate land data.

Attenuation of nitrate in aquitard sediments of southern Ontario

To examine nitrate persistence, detailed geochemical profiling, using core-squeezed water and piezometer samples, was carried out at five sites in southern Ontario where groundwater is moving downward in silt-rich aquitard sediments at rates of 16 to more than 20 cm year −1. Elevated levels of NO 3 −-N (5–50 mg 1 −1) that occur in the shallow groundwater as a result of agricultural activity, were found to be consistently attenuated, generally to very low levels (< 0.05 mg 1 −1-N), at the ‘redoxcline’, the horizon marking the boundary between the surficial weathered (brown) sediments and the underlying unweathered (grey) sediments. Tritium dating suggests that groundwater at the redoxcline depths (3–5 m) was recharged between 1970 and 1980, thus the N03 depletion appears to result from biodegradation reactions since no major landuse changes have occurred during this period. The close association of the nitrate depletion zones with the redoxcline, where, in particular, sediment sulphur contents increase abruptly, and where also porewater SO 4 2− levels increase, suggests that the dominant attenuation reaction is autotrophic denitrification using reduced sulphur compounds present in the unweathered sediment as the electron donor. Mass balance calculations suggest that the increase in the downward rate of migration of the redoxcline, owing to added sulphur consumption from NO 3 − contamination, is only about 1 mm year −1 at these sites. Review of the literature indicates that most silt- and clay-rich sediments have S contents in the same range, or higher, than those investigated here, thus, in most cases where aquifers are overlain by several metres or more of unweathered confining sediments, it is likely that a high degree of protection is afforded from surficial NO 3 − contamination.

Prediction of river discharge and surface water quality using an integrated geographical information system approach

Abstract A methodology is developed for the prediction of river discharge and surface water quality (indexed by nitrogen loading) of a predominantly rural catchment using simple models in an integrated Geographical Information System (GIS). River discharge is predicted using the Soil Conservation Service (SCS) runoff Curve Number model, and surface water quality by the export coefficient model. Main input variable to these models is information on land-use along with ancillary information such as soils. Land-use is an important parameter that affects both discharge and water quality, and it can be derived from classification of remotely sensed images. Unlike conventional models, the models employed here do not require large amounts of data on several hydro-meteorological variables. The models are applied to a rural catchment in eastern England where major land-use changes have occurred in the recent past. Historical land-use data are derived from a variety of sources including maps, aerial photographs and remotely sensed satellite images for various dates ranging from 1931 to 1989. A GIS is a valuable means to enable large amounts of spatial data to be integrated, and to facilitate data manipulation for the specific application of the models. Results are validated using observed runoff and water quality records, and it is shown that the model predictions are of acceptable accuracy. This study demonstrated an application of a GIS to employ simple models to predict river discharge and water quality.

Recovery from acidification in Lake �rvattnet, Sweden

Lake Orvattnet has been monitored extensively for both chemical and biological variables since 1967. The lake acidified during the 1960's and pH was mostly below 5 throughout the 1970's. Due to the acidification, peat moss (Sphagnum spp.) expanded over the lake bottom and the only surviving fish species was perch (Perca fluviatilis), but it experienced reproduction problems. In the mid 1980's, the Sphagnum cover collapsed, and by 1989 it had almost disappeared. There has been a clear recovery of the perch population. Recovery of the lake is also recorded by diatom assemblages in the lake sediment. Diatom-inferred pH increased from 4.7 to 4.9. The development of measured lake-water pH is unclear, but acid episodes in spring have become less severe. By 1993, atmospheric sulphate deposition had decreased by 30–40% in this area of Sweden compared to the late 1960's. Lake-water sulphate concentrations have decreased by ∼30% since the 1960's. Nitrogen deposition has increased over the last decades, but is not yet contributing to lake acidification. No major land-use changes have occurred and changes in hydrology cannot explain the observed changes in chemistry and biology. We ascribe the recent recovery in the lake to reduced deposition of sulphate. In conclusion, Lake Orvattnet has begun to recover from acidification.

Climate Change and Soil Erosion in Britain

The recent increase in soil erosion in Britain is the result of continued intensification of farming and a major land-use change from spring-planted to autumn-planted cereals. Field studies of erosion and computer models are the basis of this attempt to predict changes of rates under future climate conditions. Increases in winter rainfall, summer storm frequency, the area of irrigated land, and the introduction of new erosion-susceptible crops such as maize, will increase erosion rates. Off-farm impacts of flooding and pollution will continue to pose a greater threat, at least in the short term, than soil loss or yield reduction as a result of soil thinning. We require more detailed information on future climate, land-use change and economic conditions to make prediction of erosion rates less speculative.

Importance of Wild Animals and Their Parts in the Culture, Religious Festivals, and Traditional Medicine, of Nigeria

Utilization of animal wildlife and their by-products by farmers in Nigeria, as confirmed by this survey, is for cultural and religious ceremonies and traditional medicine. The pattern of consumption of wild animals depends on what species are available in different ecological zones. In traditional medicine, some wildlife by-products are acceptable nation-wide, while in religion, farmers are very selective — especially the Muslims. Culturally, utilization is largely by tribal and ethnic background. In the installation of traditional rulers and in performing traditional rites, some specific wild animals and their byproducts must be sacrificed.Wild animals are so vital to the rural people that adequate consideration must be given to maintaining wildlife habitats when rural development projects are planned. This is especially important when these projects involve major land-use changes or modification of traditional agricultural practices. Much of the small mammal, bird, and reptile, habitat is comprised of small wild patches, marshes, or narrow riparian strips, which can easily be destroyed by short-sighted activities. This wildlife is a valuable renewable resource which can continue to produce benefits only if adequate habitats and protection are available.

Estimating the effects of land-use change on global atmospheric CO2 concentrations

Determining how land-use change effects atmospheric CO2 concentrations requires new approaches to research because of the large area and the long period of time involved. This special issue of the CanadianJournalofForestResearch presents a series of papers that demonstrate one approach to the problem. Estimates of the flux of carbon to the atmosphere are based on site-specific information concerning the effects of land-use change on the carbon content of terrestrial vegetation. This spatially explicit approach combines historical and current information on land-use change for a specific area. South and southeast Asia was chosen for the study because the region is undergoing major land-use changes and makes a significant contribution to atmospheric CO2. The results of the study have assisted in reducing the uncertainty about the magnitude of carbon release while providing new constraints to the analysis.

Land-use and Threats to Parks in the Neotropics

The ecological consequences of contemporary land-use in the neotropics have important influences on national park management in the region. Historical patterns suggest that major land-use changes have occurred regularly, and that these patterns have recently intensified. Is there a relationship between specific land-uses and specific threats to protected areas? Can this relationship be detected in a population of parks?In a survey of managers of 183 national parks, 122 returned questionnaires from 19 countries in the neotropics. We found that a range of land-uses, from livestock grazing to quarrying, are occurring in and around the parks. The results of our statistical analysis indicate that many of these activities are associated with specific threats to park resources: for example, poaching for subsistence was statistically associated with each of the ten most-reported threats.We offer two suggestions for improving our understanding of environmental degradation within parks. First, that research and park management be expanded to acquire a regional focus, namely that the land-transforming activities which threaten park resources can best be understood by incorporating the regional-social and political-economic contexts in the analysis. Second, that the influences of the global economic system be increasingly considered in conceptual frameworks of conservation biology.

Evaluation of Hydrologic Models Used to Quantify Major Land‐Use Change Effects

An evaluation was made of the capabilities of watershed models when applied in the absence of site calibration data and limited validation data to predict the effects of major landuse changes upon ...

Discussion of paper by A.R. Croft, ‘Some sedimentation phenomena along the Wasatch Mountain Front’

A major change in land use for a specific area is generally expected to result in a major change in sediment production. But major changes in sediment production have been noted without seemingly major changes in land use. This is the case discussed by Mr. Croft in his paper dealing with the three stages of sedimentation on the lake terraces between the Wasatch Mountains and the Great Salt Lake.