An examination of historical and future land use changes in Uganda using change detection methods and agent-based modelling

The extent of anthropogenic land use in watersheds determines the amount of pollutants discharged to streams. This indirectly and directly affects stream water quality and biological health. Most studies have therefore focused on ways to reduce non-point pollution sources to streams from the surrounding land use in watersheds. However, the mechanistic pathways between land use and the deterioration of stream water quality and biological assemblages remain unclear. This study estimated a structural equation model (SEM) representing the impact of agricultural and urban land use on water quality and the benthic macroinvertebrate index (BMI) using IBM AMOS in the Nam-Han river systems, South Korea. The estimated SEM showed that the percent of urban and agricultural land in the watersheds significantly affected both the water quality and the BMI of the streams. Specifically, a higher percent of urban land use had directly increased the biochemical oxygen demand (BOD) and total phosphorus (TP), and deteriorated the BMI of streams. Similarly, higher proportions of agricultural land use had also directly increased the BOD, total nitrogen (TN), and total phosphorus (TP) concentrations, and lowered the BMI of streams. In addition, it was observed that the percent of urban and agricultural land use had indirectly deteriorated the BMI through increased BOD. However, we were not able to observe any significant indirect effect of the percent of urban and agricultural land use through increased nutrients including TN and TP. These results indicate that increased urban and agricultural land use in the watersheds had directly and indirectly affected the physicochemical characteristics and benthic macroinvertebrate communities in streams. Our findings emphasize the need to develop more elaborate environmental management and restoration strategies to improve the water quality and biological status of streams.

Drought occurrence is influenced by a complex interplay of natural and anthropogenic factors, with human activities significantly shaping the frequency and severity of such events. Among these, land use change is a critical driver, as it alters the geographical and environmental characteristics that determine regional drought vulnerability. This study focuses on land use as a manageable and controllable factor in spatial development, with implications for minimizing the adverse impacts of human-induced environmental change. The research assesses the impact of land use transitions on drought vulnerability in the Lam Ta Kong watershed, emphasizing projected changes over the next decade. Drought vulnerability was evaluated using the Analytical Hierarchy Process, while future land use for 2032 was simulated using the Cellular Automata-Markov model, integrated with Geographic Information System tools. The projection was grounded in historical land use dynamics from 2000 to 2021, which revealed substantial shifts due to socio-economic growth. The transition was characterized by a decline in agricultural and forested land and a significant expansion of built-up areas. By 2032, urban areas are projected to expand by 33.11%, predominantly encroaching upon agricultural and forested lands. Current assessments indicate that 35.09% of the watershed is highly vulnerable to drought, with this figure anticipated to rise by 10.55% under future land use scenarios. High vulnerability zones are primarily concentrated in the midstream region of the watershed. These findings underscore the substantial influence of land use change on drought risk and highlight the urgent need to integrate land use planning into comprehensive drought mitigation strategies. Graphical Abstract This graphical abstract illustrates an assessment of the impacts of land use conversion on drought vulnerability in the Lam Ta Kong Watershed. The study employed spatial transition analysis using Geographic Information System (GIS) tools to identify historical land use change patterns. Building on this, the CA-Markov model was applied to project land use distribution for the year 2032. The projected scenario served as a basis for evaluating future drought vulnerability, integrating ten critical drought-related criteria, which are grouped into four factors, through the Analytical Hierarchy Process (AHP) within a GIS framework. This approach generated a spatially explicit drought vulnerability map, revealing that land use conversion substantially increases susceptibility to drought. The results underscore the urgent need for integrated land use planning and sustainable water resource management to mitigate escalating drought risks in the region.

From fallow ground to common ground: Perspectives on future land uses in the San Joaquin valley under sustainable groundwater management

SummaryLakes and reservoirs bury large quantities of organic carbon (C) and nutrients (nitrogen,N; phosphorus,P) in their sediments, especially when expressed relative to the small area they occupy. Global estimates ofCand nutrient burial rates in reservoirs require a quantitative understanding of the wide variation in the rates and ratios at whichC,NandPare sequestered in sediments.We examined how catchment and reservoir characteristics relate to sediment organicC,NandPconcentrations, stoichiometric burial ratios (C : P,C : N,N : P) and burial rates in 13 small reservoirs across a catchment land use gradient in theMidwesternUnitedStates.SedimentPconcentrations were positively correlated with urban catchment land use and negatively correlated with agricultural catchment land use. Stoichiometric burial ratios varied with catchment land use. BothN : PandC : Pwere positively correlated with agricultural land use, while these ratios were negatively correlated with urban land use and forested land use.In general, rates ofC,NandPburial per unit lake area were not related to land use in the catchment, but were all positively correlated with catchment area to lake area ratios. Results from our study reservoirs suggest that reservoir burial rates are more tightly coupled with morphometric catchment characteristics than with land use.Our results suggest that small reservoirs are regionally and globally significant for biogeochemical processing. However, regional variation requires that much more comprehensive sampling is needed for accurate estimates of global element burial rates.

As one of the last agricultural frontiers of the humid tropics, Amazonia is the largest area of the world currently undergoing frontier settlement. Although the earliest intrusions of foreign populations into Amazonia date from pre-Hispanic times, the large-scale entrance of peasant colonists into the vast region is a recent phenomenon. Much of this movement represents the spontaneous migration of peoples, but governments in the region have also become increasingly interested in opening up and integrating Amazonia to national and international economies. These actions are frequently seen as potential solutions to a number of national problems, including the need to increase agricultural production, correct spatial imbalances in the distribution of population, exploit frontier lands for reasons of national security, and defuse potentially serious political problems resulting from the existing agrarian structure, landlessness, and unemployment. The upper basin of the Amazon in Ecuador, bordering on the eastern slopes of the Andes, is one such area of frontier settlement. Recent decades have witnessed the rapid conversion of these Amazonian forests to agricultural uses through a series of schemes bearing such labels as land development and colonization. Most forest intervention in the region has come at the hands of colonist farmers attempting to establish land claims along transport routes originally constructed to aid in petroleum exploration and exploitation. These are farmers who formerly have made a living in long-established farmlands and who, for various reasons (population pressures, pervasive poverty, maldistribution of farmland, lack of inputs for intensive cultivation, lack of nonagrarian livelihood opportunities, and generally inadequate rural development) have been increasingly squeezed out of their homelands. A marginal person by virtue of his low socioeconomic and political status, the farmer often perceives

The domination of forestland and forest policies by agriculture is a major problem in the U.S. Historically, forestland presented a formidable obstacle that had to be overcome if farming was to take place. Thus, forestland was converted to agricultural land. Forestland was cleared and put into production of agricultural commodities. Therefore, it can be shown that there is a relationship between agricultural land use and forestland use. This relationship has shown forest use to be a weak competitor for agricultural land. This study traces out the historical interactions between agricultural and forestry policies. Trends in agricultural and forestry land use are identified and related to specific policies and/or institutional connections.

Agricultural influence on landscape sensitivity in the Upper Mississippi River Valley

We explored land use, fish assemblage structure, and stream habitat associations in 20 catchments in Opequon Creek watershed, West Virginia. The purpose was to determine the relative importance of urban and agriculture land use on stream biotic integrity, and to evaluate the spatial scale (i.e., whole-catchment vs riparian buffer) at which land use effects were most pronounced. We found that index of biological integrity (IBI) scores were strongly associated with extent of urban land use in individual catchments. Sites that received ratings of poor or very poor based on IBI scores had > 7% of urban land use in their respective catchments. Habitat correlations suggested that urban land use disrupted flow regime, reduced water quality, and altered stream channels. In contrast, we found no meaningful relationship between agricultural land use and IBI at either whole-catchment or riparian scales despite strong correlations between percent agriculture and several important stream habitat measures, including nitrate concentrations, proportion of fine sediments in riffles, and the abundance of fish cover. We also found that variation in gradient (channel slope) influenced responses of fish assemblages to land use. Urban land use was more disruptive to biological integrity in catchments with steeper channel slopes. Based on comparisons of our results in the topographically diverse Opequon Creek watershed with results from watersheds in flatter terrains, we hypothesize that the potential for riparian forests to mitigate effects of deleterious land uses in upland portions of the watershed is inversely related to gradient.

Land use and land cover changes (LULCC) as a part of ecosystems has a significant impact on carbon budget. According to IPCC, approximately 23% of carbon was emitted from the human activities in agriculture, forestry and other land use (AFOLU) from 2007 to 2016. However, land cover includes crucial sector for carbon stock, as well. The land cover consists of five categories which are used area, agricultural land, forest, grass, wet land, and barren. Among these categories, forest counts because of its capacity of carbon sequestration. It is essential to manage the land use and land cover changes effectively since it has lots of influences on carbon cycles. Also, the sustainable management of land use and land cover changes could contribute to reducing the carbon emissions such as preventing deforestation and revegetation. Therefore, this study aims at analyzing the frequent land use change region using hot spot analysis in South Korea and North Korea and estimating the carbon emission and removals from land cover changes. First of all, we tracked the land cover changes at 10 years interval from 1980s to 2010s and identified the general trends. The changed area and ratio of each land cover were varied in both countries, but they had similar characteristics which is land cover changes from forest to cropland and from cropland to forest. It occurred for last four decades. To define the which region has been changed, the hot spot analysis was utilized. The change from forest to cropland appeared in southwest region of North Korea, major agriculture land. On the other hand, the transition from agriculture land to forest seemed to be minor, but the distinguished figure was created during the 2000s to 2010s change. The carbon emission was estimated at the hot spot area and these repeated changes led to additional carbon emission. This study would contribute to preventing the land cover changes frequent by defining the region to be managed.

Climate change and land use change are the two main factors affecting the regional water cycle and water resources management. However, runoff studies in the karst basin based on future scenario projections are still lacking. To fill this gap, this study proposes a framework consisting of a future land use simulation model (FLUS), an automated statistical downscaling model (ASD), a soil and water assessment tool (SWAT) and a multi-point calibration strategy. This frameword was used to investigate runoff changes under future climate and land use changes in karst watersheds. The Chengbi River basin, a typical karst region in southwest China, was selected as the study area. The ASD method was developed for climate change projections based on the CanESM5 climate model. Future land use scenarios were projected using the FLUS model and historical land use data. Finally, the SWAT model was calibrated using a multi-site calibration strategy and was used to predict future runoff from 2025–2100. The results show that: (1) the developed SWAT model obtained a Nash efficiency coefficient of 0.83, which can adequately capture the spatial heterogeneity characteristics of karst hydro-climate; (2) land use changes significantly in all three future scenarios, with the main phenomena being the interconversion of farmland and grassland in SSPs1-2.6, the interconversion of grassland, farmland and artificial surfaces in SSPs2-4.5 and the interconversion of woodland, grassland and artificial surfaces in SSPs5-8.5; (3) the average annual temperature will show an upward trend in the future, and the average annual precipitation will increase by 11.53–14.43% and (4) the future annual runoff will show a significant upward trend, with monthly runoff mainly concentrated in July–September. The variability and uncertainty of future runoff during the main-flood period may increase compared to the historical situation. The findings will benefit future water resources management and water security in the karst basin.

The main objective of this research was to evaluate land use and land cover (LULC) change in Battambang province of Cambodia over the last two decades. The LULC maps for 1998, 2003, 2008, 2013 and 2018 were produced from Landsat satellite imagery using the supervised classification technique with the maximum likelihood algorithm. Each map consisted of seven LULC classes: built-up area, water feature, grassland, shrubland, agricultural land, barren land and forest cover. The overall accuracies of the LULC maps were 93%, 82%, 94%, 93% and 83% for 1998, 2003, 2008, 2013 and 2018, respectively. The LULC change results showed a significant increase in agricultural land, and a large decrease in forest cover. Most of the changes in both LULC types occurred during 2003–2008. Overall, agricultural land, shrubland, water features, built-up areas and barren land increased by 287,600 hectares, 58,600 hectares, 8300 hectares, 4600 hectares and 1300 hectares, respectively, while forest cover and grassland decreased by 284,500 hectares and 76,000 hectares respectively. The rate of LULC changes in the upland areas were higher than those in the lowland areas of the province. The main drivers of LULC change identified over the period of study were policy, legal framework and projects to improve economy, population growth, infrastructure development, economic growth, rising land prices, and climate and environmental change. Landmine clearance projects and land concessions resulted in a transition from forest cover and shrubland to agricultural land. Population and economic growth not only resulted in an increase of built-up area, but also led to increasing demand for agricultural land and rising land prices, which triggered the changes of other LULC types. This research provides a long-term and detailed analysis of LULC change together with its drivers, which is useful for decision-makers to make and implement better policies for sustainable land management.

Change of land use land cover (LULC) has been known globally as an essential driver of environmental change. Assessment of LULC change is the most precise method to comprehend the past land use, types of changes to be estimated, the forces and developments behind the changes. The aim of the study was to assess the temporal and spatial LULC dynamics of the past and to predict the future using Landsat images and LCM (Land Change Modeler) by considering the drivers of LULC dynamics. The research was conducted in Nashe watershed (Ethiopia) which is the main tributary of the Upper Blue Nile basin. The total watershed area is 94,578 ha. The Landsat imagery from 2019, 2005, and 1990 was used for evaluating and predicting the spatiotemporal distributions of LULC changes. The future LULC image prediction has been generated depending on the historical trends of LULC changes for the years 2035 and 2050. LCM integrated in TerrSet Geospatial Monitoring and Modeling System assimilated with MLP and CA-Markov chain have been used for monitoring, assessment of change, and future projections. Markov chain was used to generate transition probability matrices between LULC classes and cellular automata were used to predict the LULC map. Validation of the predicted LULC map of 2019 was conducted successfully with the actual LULC map. The validation accuracy was determined using the Kappa statistics and agreement/disagreement marks. The results of the historical LULC depicted that forest land, grass land, and range land are the most affected types of land use. The agricultural land in 1990 was 41,587.21 ha which increased to 57,868.95 ha in 2019 with an average growth rate of 39.15%. The forest land, range land, and grass land declined annually with rates of 48.38%, 19.58%, and 26.23%, respectively. The predicted LULC map shows that the forest cover will further degrade from 16.94% in 2019 to 8.07% in 2050, while agricultural land would be expanded to 69,021.20 ha and 69,264.44 ha in 2035 and 2050 from 57,868.95 ha in 2019. The findings of this investigation indicate an expected rapid change in LULC for the coming years. Converting the forest area, range land, and grass land into other land uses, especially to agricultural land, is the main LULC change in the future. Measures should be implemented to achieve rational use of agricultural land and the forest conversion needs to be well managed.

This study examines relationships between anthropogenic influence and mercury concentrations in biota along an elevational river gradient with intensifying agricultural and urban land use in the Oldman River basin, Alberta, Canada. We use nitrogen stable isotope signatures (δ15N) indicative of anthropogenic sources of N to indicate the extent of land use influence on the river ecosystem. δ15N values in biota increased by 4.2‰ along the river gradient, consistent with increasing nitrogen sources from sewage and manure. Mercury concentrations in longnose dace ( Rhinichthys cataractae ), suckers ( Catostomus catostomus , Catostomus commersonii ), and net-spinning caddisfly larvae, the most abundant macroinvertebrates, all increased downstream; dace ranged from 0.023 ppm total mercury below the Oldman reservoir to 0.10 ppm total mercury downstream of Lethbridge. Dace consumed mostly insect larvae, and no increase in trophic position (as estimated by δ15N) was observed along the gradient. Fish directly exposed to agricultural and urban effluents had significantly lower mercury levels, or showed no difference, relative to reference sites, which suggests that these effluents play no significant role in elevating mercury levels in river food webs.

This chapter examines the influence of agricultural land uses on the occurrence of landslides in the humid tropical environments of Kigezi highlands in South Western Uganda. Analysis of the agricultural land use practices is a prerequisite to understanding landscape fragility and community resilience to landslide hazards. An analysis of agricultural land use patterns was undertaken through interpretation of Sentinel 2A images for 2016. The imagery data was acquired from the European Space Agency (ESA) Sentinels Scientific Data Hub. Field surveys and investigations were also carried out to establish and map the spatial distribution of landslide hazards. Six agricultural land use categories were identified, namely, annuals, perennials, grazing, fallow, wood lots and agroforestry. Considering the agricultural land use patterns, annual crops are the dominant agricultural land use type spanning 69% of the total area followed; by perennials (13%). Grazing land and fallows covered 11% and 5%, respectively. The study revealed that annual crop land is the most affected agricultural land use category. Out of the 65 landslide scars mapped, 31% occurred on annual crop areas. Wood lot areas experienced the least landslide occurrence (4%). A close spatial distribution of agricultural land use practices and landslide occurrence is discernible. It is recommended that a comprehensive tree planting campaign be carried out in areas prone to landslides since it was inferred that wood lots suffered least from landslides. It is also recommended that farmers be encouraged to restore and manage terrace bunds which could help to check on water velocity and consequently increase on slope stability.

Agricultural land use is essential for prosperity and sustainability of a city. However, the performance of detecting agricultural land use based on vegetation parameters will be substantially reduced when the vegetation changed in type, quantity and condition. This study believed that soil moisture, a fundamental soil parameter, is able to detect agricultural land use. A method was proposed to evaluate city-scale agricultural land use detection capability based on three temporal statistics of soil moisture in both local and global perspectives. Using GF-1 images as a data source, an experiment in Wuhan city was performed to discuss the city-scale agricultural land use detection capability based on soil moisture. Soil moisture were inverted by the modified perpendicular drought index derived from GF-1 images. Under the visual and quantitative comparisons, it was found that the temporal mean of soil moisture performed much better than the temporal standard deviation of soil moisture and the temporal coefficient of variance of soil moisture. The overall accuracy and Kappa coefficient of the temporal mean of soil moisture reach 91.7% and 0.81, respectively, demonstrating its great capability of detecting city-scale agricultural land use. A global analysis is implemented by regression analyses with true zonal agricultural statistics, showing a high global accuracy in agricultural land use detection.