Land Use Change Impact Assessment Research Articles

Impact assessment of land-use changes on groundwater quality in Dahram watershed of Fars province

Impact assessment of land-use changes on groundwater quality in Dahram watershed of Fars province

Water balance partitioning for ecosystem service assessment. A case study in the Amazon

Rainforests ensure fundamental water-related ecosystem services that are currently threatened by land-use change, in particular deforestation. Quantitative assessments of water-related ecosystem services have traditionally focused on the benefits linked to direct water availability for humans. Under this perspective, forests have been considered as water consumers, due to high interception and transpiration rates that reduce water flows available to downstream human activities. In contrast, their role as water suppliers through transpiration from tree canopies has often been neglected. Integrating this second perspective into assessments of water-related ecosystem services from forests and other land covers is key to providing a comprehensive support to decision-making processes on land-use change. In addition, specific indicators are necessary to incorporate the contribution of the different water balance components into ecosystem service assessment.In this paper, we investigate the use of water balance partitioning for the assessment of water-related ecosystem services. We use three water balance models (two existing ones and one developed in this study) and compare, via model simulations, water balance partitioning and water-related ecosystem services of a forested and a deforested area of the Brazilian State of Rondônia. Then, we propose a set of indicators that, based on the outputs of the models, provide a multidimensional characterization of different land-use types. Regardless of the model used, the values of these indicators for the selected case study consistently point out the key role of vegetation in regulating the water cycle. Forests act as effective indirect water suppliers for human activities and are key players in moisture recycling, thanks to high evapotranspiration rates (about 68% of total precipitation). Deforested areas, instead, act as direct suppliers of water flows for human activities due to higher drainage rates (about 50% of total precipitation).The proposed methodology helps highlight the importance of comprehensive water-related ecosystem services assessments. Moreover, the indicators quantitatively support the impact assessment of land-use change on the different processes involved in the water cycle and on human activities relying, directly or indirectly, on these processes.

An integrated assessment of land-use change impact, seasonal variation of pollution indices and human health risk of selected toxic elements in sediments of River Atuwara, Nigeria

River sediments contain environmental fingerprints that provide useful ecological information. However, the geochemistry of River Atuwara sediments has received less attention over the years. One hundred and twenty-six sediments from 21 locations were collected over a two-season period from River Atuwara, and a detailed investigation of the land use and land cover (LULC) change between 1990 and 2019, analysis of selected toxic and potentially toxic metal(oid)s (TPTM) (Cu, As, Cd, Pb, Ni, Cr, Zn, Fe, Co and Al) using ICP-OES, pollution index assessment, potential source identification (using center log-transformation approach), potential ecological, and human health risk assessment were conducted. The results of the LULC change revealed that the built-up area increased by 95.58 km2, at an average rate of 3.186 km2/year over the past 30 years. The mean concentration of metal(oid)s increased in the order of Cd < As < Cr < Pb < Co < Ni < Cu < Zn < Fe < Al, and Cd < As < Cr < Co < Pb < Ni < Cu < Zn < Fe < Al during the dry and wet seasons, respectively. Meanwhile, the statistical analysis of the data spectrum inferred possible contamination from lithological and anthropogenic sources. According to the pollution load index, 90.48% of the sediment samples are polluted by the metal(oid)s. Potential ecological risk assessment identified Ni, As, and Cd as problematic to the ecological community of River Atuwara. Regarding the metal-specific hazard quotient via ingestion route, the risks are in order of Co ≫ As ≫ Pb > Cr > Cd > Al > Ni > Cu > Zn > Fe for both seasons and the carcinogenic risk for children via ingestion route presented a value higher than the safe limits for As, Cd, Cr, and Ni during both seasons. This outcome highlights the need for prompt action towards the restoration of environmental quality for communities surrounding River Atuwara.

Assessment of landuse change impact on runoff and sediment yield of Patiala-Ki-Rao watershed in Shivalik foot-hills of northwest India.

Landuse change significantly alters the hydrologic characteristics of the land surface within a watershed. In the present study, the impact of landuse change (2006-2016) on runoff and sediment yield has been assessed in Patiala-Ki-Rao watershed (5140 ha) located in Shivalik foot-hills, using remote sensing, geographical information system (GIS), and Water Erosion Prediction Project (WEPP) watershed model. The watershed has seven major landuse classes, namely agriculture, built-up, fallow land, forest, grass land, streams, and water bodies. The landuse change analysis indicated that the area under all the landuses decreased except built-up that increased by 372.27 ha (112.04%). Forest is the most affected landuse among all watershed landuses that shrinked by 194.90 ha followed by agriculture (64.57 ha), grass land (50.81 ha), streams (30.42 ha), fallow land (21.86 ha), and water bodies (9.72 ha). Runoff and sediment yield for the landuse of the years 2006 and 2016 were simulated by the WEPP model using two climate scenarios (2006 and 2016). The simulated runoff, sediment yield, and sediment delivery ratio increased by 18.62%, 48.04%, and 32.23% under Climate-2006 and 26.78%, 30.23%, and 16.09% under Climate-2016 due to change in landuse during a period of 10 years. This clearly indicates that landuse change in 10 years has greatly influenced the hydrology of the watershed and requires urgent land allocation policy in place for sustainable development in the area.

Impact of forest cover and conservation agriculture on sediment export: A case study in a montane reserve, south-western China

Reforestation and agricultural conservation have long been recognized as important in reducing on-site soil loss and off-site sediment export. Quantitative assessment of their effectiveness is critical, and assists cost-benefit analysis and decision-making in land management and landscape planning. We applied a paired watershed approach to monitor 1-year sediment export in two watersheds with forest-dominated (reference) and mosaic (target) land use in the Naban River Watershed National Natural Reserve (NRWNNR) in Xishuangbanna, south-western China. Analysis of land-use change in the target watersheds showed decreasing total forest cover (FC) (from 57% to 47%), but increasing FC in steep areas (from 54% to 59%) from 2007 to 2012. A distributed hydrological model (Land-Use Change Impact Assessment, LUCIA) was well calibrated and validated through field data from the two watersheds. Scenarios were created representing different FCs (from 31% to 83%) and agricultural management (as-usual and conservation). Simulation results quantified the relation between FC and sediment export as a logarithmic or logit model, indicating at least one turning point of FC, beyond which further forest reduction should significantly increase sediment export. This point was identified in the range between 57% and 61% of the target watershed under as-usual management; it was shifted to 47%–53% by conservation agriculture. Compared with the reference (with 83% FC), conservation agriculture was able to almost fully compensate for increased sediment export by forest reduction to 57% in 2007. However, when forest was reduced further to 47% in 2012, sediment export increased significantly. We concluded that total FC was as important as FC in montane watershed management in steep areas; and crop type conversion, such as rubber to maize in this study, and on-site agriculture management affect more to sediment export than agricultural expansion. We recommend conservation agriculture as an efficient tool for reducing sediment export on a watershed scale.

Uncertainty in simulation of land-use change impacts on catchment runoff with multi-timescales based on the comparison of the HSPF and SWAT models

Hydrological modeling has provided key insights into the mechanisms of land-use change impacts on runoff. However, the uncertainty of this impact is poorly understood. This paper examines the uncertainty originated from hydrological models' parameters and structure in simulating hydrological responses to land use change on daily, monthly and annual time scales. Two hydrological models, SWAT and HSPF, were applied to simulate the runoff response in the Xitiaoxi basin of eastern China. The effects of three land use scenarios (in 1985, 2002 and 2014) were analyzed with respect to the expansion of urban areas and reduction of cropland and forests. The changes in streamflow with multi-timescales between two models were compared at the whole basin and the sub-basin scales. The parameter uncertainty was estimated based on a sequential uncertainty analysis method (SUFI-2). The results indicate that the two models (SWAT and HSPF) could reproduce the observed daily and seasonal flows well, but they cannot accurately reconstruct the extreme flows (such as annual 7-day minimum discharge, R_7dMIN). The effect of parameter uncertainty on streamflow varies over time scales. The simulated annual and monthly runoff change values show large discrepancies but with same trends. The simulated changes for annual maximum discharge (R_1dMAX) and R_7dMIN often show different signs. The average width of the predictive interval in the relative change of different flow characteristics exceeded 100% of the average relative changes for both models. HSPF tends to present larger relative changes for the annual and monthly runoffs compared to SWAT. Moreover, the model choice could affect the direction change in R_1dMAX and R_7dMIN. However, when land use change was significant to a certain degree, both models simulated increased R_1dMAX and decreased R_7dMIN, but with different significance levels. The study suggests that the model structure represents an additional uncertainty, which should be accounted for in the land-use change impact assessment.

Modelling weed management strategies to control erosion in rubber plantations

The role of weeds in soil conservation in agroforestry systems has been largely ignored. We used the Land Use Change Impact Assessment (LUCIA) model to simulate the effects of weed management on erosion in rubber plantations (Hevea brasiliensis Muell. Arg). In order to quantify the impact of a dynamic, spatially explicit multi-layer plantation structure on erosion processes in agroforestry systems, we updated LUCIA's erosion module. Its new version simulates soil detachment due to rainfall and runoff, considering the separate effects of the tree canopy and surface cover on soil erosion. The updated LUCIA model was calibrated and validated based on an established rubber plantation experiment in Xishuangbanna, Southwest China, to evaluate the impact of different weeding strategies on soil loss. The model successfully represented the impact of the dynamic multi-layer structure on erosion and was able to predict well the effects of weed management on soil loss and runoff at the test site over 1 year, with a modelling efficiency (EF) of 0.5–0.96 and R2 of 0.64–0.92. Subsequently, we validated the ability of the model to simulate surface cover changes under rubber plantations of different age (up to 40 years). Simulation outputs for 4-, 12- and 18-year-old rubber plantations revealed satisfying to good results. However, the predicted change in surface cover for old rubber plantations (25- and 36-year) failed to meet the field trends. The model predicted the greatest erosion in the year when the rubber canopy started to close. During this period, weed growth was limited by light, while litter input from rubber was insufficient to provide good soil cover. Four weeding strategies (“clean-weeding”, “twice-weeding”, “once-weeding” and “no-weeding”) were designed for scenario simulations. Based on the results of 20-year runs, we concluded that “once-weeding” and “no-weeding” both efficiently minimized soil loss during one rotation length. A high degree of surface and weed cover (over 95% and 60%) under “no-weeding” makes this management strategy with dense undergrowth hardly acceptable by local farmers due to reduced tree accessibility for tapping and increased potential danger through poisonous caterpillars. “Once-weeding”, on the other hand, controlled overgrowth of understory vegetation by keeping weed cover below 50%. We therefore suggest “once-weeding” as an improved herbicide management strategy in rubber plantations, to meet ecological system service maintenance and to facilitate adoption in practice.

A dynamic artificial neural network for assessment of land-use change impact on warning lead-time of flood

Floods always require innovative models for flood forecasting. This paper proposes a dynamic artificial neural network (DANN) model for evaluating land-use change impact (LUCI) scenarios on weighted average of warning lead-time of flood (WAWLTF) in an urbanised watershed. The simulated floods of a calibrated HEC-HMS hydrological model were used for training and testing of DANN model. The features of proposed DANN's structure were determined by minimisation of a new flood forecasting error (FFE) index. Results showed that the proposed procedure was able to optimise features of DANN structure by minimising FFE and produced an appropriate DANN model for assessment of LUCI on WAWLTF. The results also denoted that practicing suitable watershed management in future may improve WAWLTF encouragingly but never compensates negative impact of urbanisation completely. In conclusion, the model can be used as an efficient tool in similar urbanised watershed for assessment of LUCI on WAWLTF.

The impact of global trends on bioenergy production, food supply and global warming potential – an impact assessment of land-use changes in four regions in Germany using linear programming

Agricultural land use faces global trends such as increasing energy costs, rising agricultural commodity prices and augmenting demand for bioenergy. Our aim is to assess the impact of these trends on the use of arable land for bioenergy and food production, as well as on greenhouse gas emissions and energy requirements from crop production, using linear programming farm type models for scenario simulations in four case study areas in Germany. The results suggest that the analysed global trends are critical for the allocation of land for food or energy crop production. The impacts of agricultural production on farm incomes and services, such as the provision of food and bioenergy, vary notably between the case study areas and the analysed trends. Different agricultural production systems will respond differently to changing boundary conditions in terms of bioenergy production and food supply. Assessing the impact on bioenergy and food production requires taking into account the particular setting in which production is carried out, as well as the local-specific interdependencies of land use and the provision of ecosystem services.

Crop production versus surface-water regulation: assessing tradeoffs for land-use scenarios in the Tat Hamlet Watershed, Vietnam

Local land uses play a critically important role in regulating hydrological services like surface-water runoff. This runoff influences the supply of water to streams and lowland agriculture. Land-use management decisions, in turn, are influenced by economic return. This article examines the tradeoffs between surface-water runoff regulation and income from crop production by using the land-use change impact assessment model and an economic analysis for a case study in Tat Hamlet Watershed, north Vietnam. The traditional composite swidden agriculture was used as baseline scenario, since it has been practised by farmers in the study area for decades. Two alternative scenarios were tested and compared with the composite swidden agriculture: expansion of maize monoculture and introduction of rubber plantations in the uplands. Among the land-use scenarios tested, rubber plantations appear to be better alternatives than maize monocropping in terms of surface-water regulation and improving economic return. However, implementation should consider the interests of local stakeholders as well as an analysis of possible risks and uncertainties involved.

GIS-based impact assessment of land-use changes on groundwater quality: study from a rapidly urbanizing region of South India

This study attempts to assess the influence of changing land-use patterns on the groundwater quality of the hard rock aquifer system in the Maheshwaram watershed, near Hyderabad, India. The study area is a rapidly urbanizing region with land development progressing at a fast pace. To study the impact of this rapid urbanization and overall land-use transition, a groundwater quality index (GQI) was prepared within a geographical information system (GIS). The GQI integrates the different water quality parameters to give a final index value that can be used for spatio-temporal comparisons. The land-use transitions were closely monitored from 2003 to 2008 using multispectral satellite images. The land-use pattern has changed drastically with an increase in the built-up area at the expense of other land uses. The analysis reveals a rapid deterioration of groundwater quality related mainly to the increase in built-up land with unsewered sanitation and poultry farms. Seasonal variability of the groundwater quality was also assessed. Mean GQI decreased from 84.16 to 83.26 over a period of 5 years from 2003 to 2008, while seasonal variability of water quality increased. GQI and Seasonal Variability of water quality were integrated in GIS to yield a groundwater sustainability map, in terms of water quality. Zones of sustainable and unsustainable groundwater use were demarcated for better decision making related to municipal land allotment in this rapidly urbanizing region.

Landscape assessment for sustainable planning

Abstract The 1st International Conference on Impact Assessment of Land Use Changes (IALUC) was held from the 6th to 9th of April 2008 at Humboldt University in Berlin, Germany. At the meeting, 160 oral presentations (including five plenary speeches) and 69 posters by representatives from 39 countries were presented. Papers and posters in four general sessions (Tools and Models, Policies and Scenarios, Scale and Indicators, and Participation and Socio-Economy) considered various aspects of the impact assessment of land use and landscape changes. This special section of the journal Ecological Indicators consists of nine selected presentations from different sub-sessions of the IALUC conference considering the use of indicators in landscape assessment.