Land Use Change Scenarios Research Articles

Integrating stakeholders' perspectives and spatial modelling to develop scenarios of future land use and land cover change in northern Tanzania.

Rapid rates of land use and land cover change (LULCC) in eastern Africa and limited instances of genuinely equal partnerships involving scientists, communities and decision makers challenge the development of robust pathways toward future environmental and socioeconomic sustainability. We use a participatory modelling tool, Kesho, to assess the biophysical, socioeconomic, cultural and governance factors that influenced past (1959–1999) and present (2000–2018) LULCC in northern Tanzania and to simulate four scenarios of land cover change to the year 2030. Simulations of the scenarios used spatial modelling to integrate stakeholders’ perceptions of future environmental change with social and environmental data on recent trends in LULCC. From stakeholders’ perspectives, between 1959 and 2018, LULCC was influenced by climate variability, availability of natural resources, agriculture expansion, urbanization, tourism growth and legislation governing land access and natural resource management. Among other socio-environmental-political LULCC drivers, the stakeholders envisioned that from 2018 to 2030 LULCC will largely be influenced by land health, natural and economic capital, and political will in implementing land use plans and policies. The projected scenarios suggest that by 2030 agricultural land will have expanded by 8–20% under different scenarios and herbaceous vegetation and forest land cover will be reduced by 2.5–5% and 10–19% respectively. Stakeholder discussions further identified desirable futures in 2030 as those with improved infrastructure, restored degraded landscapes, effective wildlife conservation, and better farming techniques. The undesirable futures in 2030 were those characterized by land degradation, poverty, and cultural loss. Insights from our work identify the implications of future LULCC scenarios on wildlife and cultural conservation and in meeting the Sustainable Development Goals (SDGs) and targets by 2030. The Kesho approach capitalizes on knowledge exchanges among diverse stakeholders, and in the process promotes social learning, provides a sense of ownership of outputs generated, democratizes scientific understanding, and improves the quality and relevance of the outputs.

Hydrological impacts of ethanol-driven sugarcane expansion in Brazil

Ethanol production in Brazil is projected to double between 2012 and 2030 in order to meet increased global demand, resulting in the expansion of sugarcane cultivation. Sugarcane expansion drives both direct and indirect land-use changes, and subsequent changes in hydrology may exacerbate problems of (local) water scarcity. This study assesses the impacts of projected ethanol-driven sugarcane expansion on agricultural and hydrological drought in Brazil. Drought due to sugarcane expansion is modelled using a spatial terrestrial hydrological model (PCR-GLOBWB) with spatiotemporally variable land-use change and climate change scenarios as input. We compare an ethanol scenario with increased ethanol demand to a reference situation in which ethanol demand does not increase.The results show that, on average, 29% of the Centre West Cerrado region is projected to experience agricultural drought between 2012 and 2030, and the drought deficit in this region is projected to be 7% higher in the ethanol scenario compared to the reference. The differences between the ethanol and the reference scenario are small when averaged over macro-regions, but can be considerable at a local scale. Differences in agricultural and hydrological drought between the ethanol and reference scenario are most notable in the Centre West Cerrado and Southeast regions. Locally, considerable changes may also occur in other regions, including the Northeast Coast and Northern Amazon region.Because the South East and Centre West Cerrado regions are responsible for a large proportion of agricultural production, increased agricultural drought may result in significant economic losses, while increased hydrological drought could exacerbate existing problems of water supply to large metropolitan areas in these regions. The identification of areas at risk of increased droughts can be important information for policy makers to take precautionary measures to avoid negative hydrological impacts of increased ethanol demand.

Exploring an integrated spatially model for land-use scenarios simulation in a metropolitan region

Spatial simulation of land-use change scenarios in metropolitan areas is essential for analyzing both the causes and consequences of various future scenarios and is also valuable for land-use planning and management. However, current simulation models primarily focus on spatial and rarely on quantitative driving factors. This article aims to simulate future scenarios of land-use changes in the Tehran metropolitan region (TMR) by combining different models to fill this gap. Thus, in the first step, land-use changes were analyzed in the period 1985, 2000, and 2015. Then, by identifying the impact of driving factors and land-use transition potentials with Logistic regression (LR), land-use changes were allocated using the Cellular Automata (CA) method. Finally, with the validation of the model, four scenarios of the current trend(CT), socioeconomic growth(SEG), ecological-oriented(EO), and integrated development(ID) were suggested with the combination of the System Dynamic (SD) model. The results show that the trend of land-use changes in TMR has led to the destruction of grassland, agricultural, and uncultivated lands and the continuation of this trend will increase the damage of built-up areas on valuable natural and ecological resources. In this way, proximity to roads, distance from built-up areas, and natural factors had the greatest impact on changes. Based on future scenarios in 2030, the change in the SEG-scenario shows a rapid increase in built-up areas (2858km2) and encroachment on agricultural lands (2171km2). In the EO-scenario, destruction of grassland and agricultural lands and the growth of built-up areas will be limited, while CT-scenario leads to the high growth of built-up areas along with destructive impacts on natural and open spaces. In the ID-scenario, the built-up areas and grasslands will increase to 2808km2 and 7438km2, respectively. Accordingly, policy-makers can use simulation of different scenarios to mitigate probable consequences of land-use changes in the metropolitan regions.

Assessing hydrologic and water quality effects of land use conversion to Brassica carinata as a winter biofuel crop in the southeastern coastal plain of Georgia, USA using the SWAT model

AbstractCarinata (Brassica carinata) is an industrial oilseed feedstock for renewable fuels grown as a winter crop in the southeast US, which may provide a new rotation alternative and benefits for water quality. However, the effects of carinata on water quantity and quality at the watershed and local scales are unknown. In this study, we use the Soil and Water Assessment Tool (SWAT) to assess the potential influence of carinata on water balance components, nutrients and sediment loads under plausible future scenarios of land use change in the upper Suwannee River Basin in the Atlantic Coastal Plain Physiographic Region near Tifton in South‐Central Georgia. Three future scenarios are considered, including planting stand‐alone carinata in winter fallow land every third year, planting stand‐alone winter wheat in winter fallow land every third year, and carinata and winter wheat in rotation, one year of winter carinata followed by two years of winter wheat during simulation periods. The results show that under all three future scenarios, surface runoff, sediment, phosphorus, and nitrogen loadings decrease at both watershed and local scales, with higher average monthly reductions in the stand‐alone carinata scenario versus the stand‐alone winter wheat scenario. When carinata and winter wheat were planted over 36% of the total watershed area, reduction in total sediment, mineral phosphorus, and nitrate loads was ranging from 11.5% to 50.0%. However, when only 12% of the total watershed area was converted to carinata, the simulated reductions ranged from 3.8% to 14.0%. This suggests that the extent of carinata planting is crucial in assessing its hydrologic and water quality benefits. Overall, these results indicate that planting the biofuel carinata as a winter crop can reduce sediment and nutrient loading and provide water quality benefits to downstream waterbodies.

Simulated Atmospheric Response to Four Projected Land-Use Land-Cover Change Scenarios for 2050 in the North-Central United States

AbstractLand-use land-cover change (LULCC) has become an important topic of research for the central United States because of the extensive conversion of the natural prairie into agricultural land, especially in the northern Great Plains. As a result, shifts in the natural climate (minimum/maximum temperature, precipitation, etc.) across the north-central United States have been observed, as noted within the Fourth National Climate Assessment (NCA4) report. Thus, it is necessary to understand how further LULCC will affect the near-surface atmosphere, the lower troposphere, and the planetary boundary layer (PBL) atmosphere over this region. The goal of this work was to investigate the utility of a new future land-use land-cover (LULC) dataset within the Weather Research and Forecasting (WRF) modeling system. The present study utilizes a modeled future land-use dataset developed by the Forecasting Scenarios of Land-Use Change (FORE-SCE) model to investigate the influence of future (2050) land use on a simulated PBL development within the WRF Model. Three primary areas of LULCC were identified within the FORE-SCE future LULC dataset across Nebraska and South Dakota. Variations in LULC between the 2005 LULC control simulation and four FORE-SCE simulations affected near-surface temperature (0.5°–1°C) and specific humidity (0.3–0.5 g kg−1). The differences noted in the temperature and moisture fields affected the development of the simulated PBL, leading to variations in PBL height and convective available potential energy. Overall, utilizing the FORE-SCE dataset within WRF produced notable differences relative to the control simulation over areas of LULCC represented in the FORE-SCE dataset.

The Assessment of Climate Change and Land-Use Influences on the Runoff of a Typical Coastal Basin in Northern China

Land use and climate change are the two major driving factors of watershed runoff change, and it is of great significance to study the influence of watershed hydrological processes on water resource planning and management. This study takes the Changyang River basin as the study area, builds a SWAT model and explores the applicability of the SWAT model in the basin. Moreover, we combine data on land use and climate change in different periods to construct a variety of scenario models to quantitatively analyze the impacts of different scenarios on runoff. The results show that the R2 and Ensof the model are 0.71 and 0.68 in the calibration period, respectively, and those in the verification period are 0.68 and 0.65, respectively, indicating that the SWAT model has good applicability in simulating the runoff of the Changyang River basin. Under the comprehensive scenario of land use and climate change on runoff, we found that land use and climate change have a certain contribution to the change in runoff. Therefore, the runoff of the basin increased by 0.22 m3/s, in which land-use change caused the runoff in the basin to increase by 0.07 m3/s attributed to the decreased area of arable land and the increased area of urban land in the basin. Moreover, climate change has caused the runoff in the basin to increase by 0.13 m3/s, mainly influenced by the increased precipitation. The results show that climate change has a more significant effect on runoff in the basin.

Assessing the effects of agricultural intensification on natural habitats and biodiversity in Southern Amazonia.

The ongoing trend toward agricultural intensification in Southern Amazonia makes it essential to explore the future impacts of this development on the extent of natural habitats and biodiversity. This type of analysis requires information on future pathways of land-use and land-cover change (LULCC) under different socio-economic conditions and policy settings. For this purpose, the spatially explicit land-use change model LandSHIFT was applied to calculate a set of high-resolution land-use change scenarios for the Brazilian states Para and Mato Grosso. The period of the analysis were the years 2010-2030. The resulting land-use maps were combined with maps depicting vertebrate species diversity in order to examine the impact of natural habitat loss on species ranges as well as the overall LULCC-induced effect on vertebrate diversity as expressed by the Biodiversity Intactness Index (BII). The results of this study indicate a general decrease in biodiversity intactness in all investigated scenarios. However, agricultural intensification combined with diversified environmental protection policies show least impact of LULCC on vertebrate species richness and conservation of natural habitats compared to scenarios with low agricultural intensification or scenarios with less effective conservation policies.

Analyzing Land-Use Change Scenarios for Ecosystem Services and their Trade-Offs in the Ecological Conservation Area in Beijing, China.

It is generally believed that land-use changes can affect a variety of ecosystem services (ES), but the relationships involved remain unclear due to a lack of systematic knowledge and gaps in data. In order to make rational decisions for land-use planning that is grounded in a systematic understanding of trade-offs between different land-use strategies, it is very important to understand the response mechanisms of various ecosystem services to changes in land-use. Therefore, the objective of our study is to assess the effects of land-use change on six ecosystem services and their trade-offs among the ecosystem services in the ecological conservation area (ECA) in Beijing, China. To do this, we projected future land-use in 2030 under three different scenarios: Business as Usual (BAU), Ecological Protection (ELP), and Rapid Urban Development (RUD), using GeoSOS-FLUS model. Then, we quantified six ecosystem services (carbon storage, soil conservation, water purification, habitat quality, flood regulation, and food production) in response to land-use changes from 2015 to 2030, using a spatially explicit InVEST model. Finally, we illustrated the trade-offs and/or synergistic relationships between each ecosystem service quantified under each of the different scenarios in 2030. Results showed that built-up land is projected to increase by 281.18 km2 at the cost of water bodies and cultivated land from 2015 to 2030 under the RUD scenario, while forest land is projected to increase by 152.38 km2 under the ELP scenario. The carbon storage, soil conservation, habitat quality, and the sum of ecosystem services (SES) would enrich the highest level under the ELP scenario. Land-use strategies that follow the ELP scenario can better maintain the ecosystem services and sustainable development of natural and social economic systems.

Assessment of urban sprawl using landscape metrics and Shannon’s entropy model approach in town level of Barrackpore sub-divisional region, India

A city has expanded from the core to peripheral areas through the growth of urbanization process and based on criteria, such as economic development, social, political forces as well as morphological characteristics. Due to increases in the population and anthropogenic activities in a city, the spatial boundary has also extended to provide accommodation along with the fringe areas that lead to fragmentation of urban morphology and influence the local ecology. From the historical past to present conditions and future predictions of urban growth would be able to visualize by space-borne remote sensing techniques to plan the appropriate infrastructure of the city. The present study analyzed the spatio-temporal land-use patterns in the town level in the Barrackpore sub-division area of West Bengal, which has become very compact urban areas in the eastern zone of the country. The spatial assessment of the urban growth pattern of 16 municipalities has been analyzed using remotely sensed data for the year of 1972, 2001 and 2016 with the spatial landscape metrics approach and Shannon’s entropy model. The overall scenario of land use changes reveals that the non-urban areas (vegetation, agriculture, wetland and water bodies) have been decreasing, on the other hand, built-up areas are increasing during the decades. Spatial landscape metrics indicate the nature of the fragmentation of the urban landscape, compactness of the towns and provided the intensity about the sprawl characteristics. The results show that the whole urban landscapes of every town are aggregating into a large patch in the recent years (2016) as compared to the past years. The fragmentation of landscape into small patches happened from 1972 to 2001 on a large scale that indicates sprawl; the conversion of small patches to large single urban patches can be seen from 2001 to 2016 pointed out the maximally aggregation of town which would affect the ecological environment. Shannon’s entropy model was applied to understand the level of urban growth at every corner of municipalities by the zoning of each town. The value of Shannon’s model confirms the dispersed random urbanization in the outskirt of the towns. The spatio-temporal urban sprawl monitoring through these two methods would help the towns’ administration, planners to manage and take better planning to build sustainability for livelihood.

Does Urban planning affect urban growth pattern? A case study of Shenzhen, China

It is essential to understand how urban plans affect urban growth patterns in order to improve current urban planning and management systems. Few studies have been conducted to analyse urban growth patterns of Shenzhen, an international megacity located in southern China, but none of them revealed the relationships between urban planning and urban growth patterns. This study explores the effects of urban master plans on urban growth patterns in different plan periods in Shenzhen. We first quantified the urban growth patterns comparing pixel- and patch-based methods. Three methods resulted in different quantities and spatial characteristics of urban growth. We then explored the relationships between urban growth patterns and urban planning in Shenzhen through multinomial logistic regression models. Across two planning periods, the master plans together with other socio-economic, physical, proximity, accessibility and neighbourhood factors shaped the urban growth patterns of Shenzhen. Out of the master plan elements, planned main roads in the Master Plan of Shenzhen 1996–2010 and the planned built-up zone in the Master Plan of Shenzhen 2010–2020 ha d stronger effects on urban growth patterns but contributed less than most other factors, e.g. distance to ocean. The importance of the other influence factors also varied over time. This changing effect suggests that we need to consider carefully whether driving factors might change in their importance over time when investigating future scenarios of urban land use change. Overall, this approach could also be applied to monitor progress in the paradigm shift towards an integrated urban-rural development in China.

Burning season and vegetation coverage influenced the community-level physiological profile of Mediterranean mixed-mesogean pine forest soils

Knowledge of forest soil ecology is necessary to assess vulnerability to disturbances, such as wildfires, and improve its microbial diversity and functional value. Soil microbiota play an important role in forest soil processes and are a key driver of postfire recovery, but they are very vulnerable to heat. According to future scenarios for climate and land-use change, fire regimes will undergo transformations in semiarid terrestrial ecosystems, mainly in the Mediterranean Basin. To develop tools for forest management in fire-prone areas, i.e., fire prevention, we assessed the impact of prescribed burnings on soil microorganisms in Mediterranean mixed pine forests. We hypothesised that low severity fire burns would not influence the functional diversity of soil microorganisms, although the burning season could influence that response due to seasonal variations in its vulnerability. We used the Biolog EcoPlate System to record soil biological indicators and assess the effect of the prescribed burning season (early or late season) on bacterial communities, including the soil–plant interphase. The soil microbiome response differed significantly according to vegetation coverage but prescribed burning season was not directly related. Burning increased the proportions of soil organic matter and soil organic carbon, and also promoted cation-exchange capacity and total phosphorus, which were higher following spring burns. Microbial richness and the Shannon–Weaver diversity index both showed a positive correlation with vegetation cover. However, microbial richness was triggered after burning uncovered patches of vegetation. We also noted differences in the usage pattern for the six substrate groups defined in our study: the use of carboxylic acids, amino acids and carbohydrates was higher in unburned plots and those subject to late burns, whereas amino acids did not predominate in early burn plots.

Soil conservation efficiency assessment based on land use scenarios in the Nile River Basin

Soil conservation is one of the most important ecosystem services, as it has a positive impact on soil fertility and land productivity. Although soil conservation includes multiple facets, existing research on soil conservation has rarely considered the combination of soil erosion and sediment within its analysis. In this context, this paper uses the Revised Universal Soil Loss Equation (RUSLE) and the Sediment Delivery Ratio (SDR) module of Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) to develop a Soil Conservation Efficiency Index that accounts for both soil erosion conservation efficiency and river sediment transport conservation efficiency. A natural growth and reforestation scenario of land use change was applied and modelled with the Nile River Basin from 2010 to 2100. Three main results were obtained: (1) From 2000 to 2010, grassland increased by 4.34%, and the forest decreased by 4.91%. (2) From 2000 to 2100, soil conservation presents a declining tendency in the two scenarios, and the soil conservation amounts based on soil erosion and sediment were 1550.48 ± 177.12 and 100.93 ± 6.24 (t ha−1 y−1) in a natural growth scenario, respectively, and 1576.78 ± 63.21 and 104.41 ± 0.30 (t ha−1 y−1) in a reforestation scenario, respectively. (3) It was found that the reforestation scenario was the most effective. With soil erosion conservation efficiency being most effective in the first fifty years, and the river sediment transport conservation efficiency being more effective from 2010 to 2100. Overall, when reducing the conversion rate of forest land by 0.5 times and increasing the rate of conversion to forest by 0.5 times, the effect of land use changes to river sediment transport conservation efficiency has a longer-term effect than changes to soil erosion conservation efficiency.

Spatial impact of cropland supplement policy on regional ecosystem services under urban expansion circumstance: a case study of Hubei Province, China

ABSTRACT The Cropland Supplement Policy (CSP) helps maintain the total area of cropland in China as urban areas expand, but can result in environmental degradation as areas of more natural habitat are turned into cropland. Current and future impacts of the CSP are explored under different land-use change scenarios by comparing the differences in ecosystem services value (ESV) at province level. Scenario-based simulation results suggest that in Hubei province, the CSP cost 19.53 billion CNY in the period 2000 to 2015 and would cost an additional 12.54 billion CNY in the period 2015 to 2030 in terms of ESV loss. A policy analysis framework for land-use planning is proposed which enables ecological impacts of the CSP to be considered.

Simulated deforestation versus satellite data in Roraima, Northern Amazonia, Brazil

Cenários de mudança de uso e cobertura da terra na Amazônia são necessários para subsidiar decisões que podem evitar a emissão de milhões de toneladas de CO2 para a atmosfera. Portanto, é importante avaliar modelos que visam a geração de cenários futuros. O atual estudo avaliou cenários gerados para o período 2011-2017 em Roraima, norte da Amazônia. Comparou-se o desmatamento simulado com os dados de satélite do PRODES. O mapeamento compreendeu (i) uma Área de Uso Silvo-pastoril – AUS (excluindo terras indígenas, unidades de conservação e não-floresta) intersectada com (ii) uma grade de nove (9) células de 10.000 km2 (100 × 100 km) para avaliações. O cenário de 2013 apresentou a maior similaridade (55,2%) com o mapa correspondente do PRODES. Apesar das divergências entre o desmatamento simulado nos cenários e o desmatamento oficial, no geral, as avaliações demonstraram a validade do modelo e a sua habilidade para gerar cenários que representam, de forma realística, o desmatamento ocorrido em Roraima no período analisado.

Water balance components estimation under scenarios of land cover change in the Vea catchment, West Africa

ABSTRACT The need for a detailed investigation of the Vea catchment water balance components cannot be overemphasized due to its accelerated land-cover dynamics and the associated impacts on the hydrological processes. This study assessed the possible consequences of land-use change scenarios (i.e. business as usual, BAU, and afforestation for the year 2025) compared to the 2016 baseline on the Vea catchment’s water balance components using the Soil and Water Assessment Tool (SWAT) model. The data used include daily climate and discharge, soil and land use/land cover maps. The results indicate that the mean annual water yield may increase by 9.1% under the BAU scenario but decrease by 2.7% under the afforestation scenario; actual evapotranspiration would decrease under BAU but increase under afforestation; and groundwater recharge may increase under both scenarios but would be more pronounced under the afforestation scenario. These outcomes highlight the significance of land-cover dynamics in water resource management and planning at the catchment.

Nitrogen sources, processes, and associated impacts of climate and land-use changes in a coastal China watershed: Insights from the INCA-N model

The Integrated Nitrogen CAtchments (INCA-N) model was applied to identify the sources and processes controlling riverine nitrogen (N) export in the Jiulong River watershed, coastal China. Future riverine N exports were simulated under various scenarios of climate and land-use changes. The modeling results showed good agreement between the observed and simulated values of streamflow, N concentrations, and loads. It was revealed that fertilizer application, atmospheric N deposition, and sewage discharges were the main N sources, while the primary N cycling processes included soil nitrification, soil denitrification, and N leaching. Nitrate-N exports were predominantly impacted by climate change, whereas ammonium-N exports were more affected by land-use change. The coupled effects of climate and land-use changes were projected to amplify nitrogen export by 30%, 36%, and 36% for nitrate-N and 32%, 48%, and 71% for ammonium-N during the years for 2030s, 2050s, and 2080s, respectively.

Identification of Marginal Landscapes as Support for Sustainable Development: GIS-Based Analysis and Landscape Metrics Assessment in Southern Italy Areas

Landscape is increasingly characterized by a multifaced nature. In scientific literature and landscape governance, new landscape definitions are often coined to explain new meanings and to define specific intervention strategies and tools. The present study purposes a framework for the identification of hybrid landscapes as support for land-use planners, which aim to guarantee development opportunities as well as natural heritage preservation and valorization. “Marginal lands” were identified starting from EU Directives and scientific approaches, by means of multicriteria analysis. Different scenarios were built: (1) no-change; (2) energy crops; (3) green infrastructures. An ecosystem services approach, via landscape metrics analysis, was used to compare the possible effects of scenarios. About 20% of the study area, an internal area of the southern Apennines, was identified as suitable for land-use change in a medium-short time, and scenarios of land-use changes show a better condition, in terms of fragmentation, than as a current asset. Results showed the strategic role and potentialities of marginal lands, as a trade-off between nature conservation and development issues, suggesting new opportunities for green infrastructures and a renewable energies chain. The study allowed for deepening the close connection among landscape planning approaches, land use change scenarios building and environmental assessment, focused on the ex-ante evaluation stage.

Spatial Simulation of Codesigned Land Cover Change Scenarios in New England: Alternative Futures and Their Consequences for Conservation Priorities

AbstractScientists are increasingly engaging with stakeholders to codesign scenarios of land use change necessitating methods to translate the resulting qualitative scenarios into quantitative simulations. We demonstrate a transparent method for translating participatory scenarios to simulations of land use and land cover (LULC) change using the New England Landscape Futures (NELF) project as a case study. The NELF project codesigned four divergent narrative scenarios that contrast with a Recent Trends scenario projecting a continuation of observed changes New England over the past 20 years. Here, we (1) describe the process and utility of translating qualitative scenarios into spatial simulations using a dynamic cellular land change model, (2) evaluate scenario LULC configuration relative to the Recent Trends scenario and to each other, (3) compare the fate of forests within stakeholder‐defined areas of concern, and (4) describe how a user‐inspired outreach tool was developed to make the simulations and analyses accessible to a diverse user group. The associated simulations are strongly divergent in terms of the amount of LULC change and the spatial pattern of change. Among the scenarios, there is a fivefold difference in the amount of high‐density development and a twofold difference in the amount of protected land. Features of the simulations can clearly be linked back to the original storylines. Overall, the rate of LULC change has a greater influence on stakeholder areas of concern than the spatial configuration. The simulated scenarios have been integrated into an online mapping tool via a user‐engagement process meeting the needs of a variety of stakeholders.

What do models tell us about water and sediment connectivity?

Connectivity has been embraced by the geosciences community as a useful concept to understand and describe hydrological functioning and sediment movement through catchments. Mathematical modelling has been used for decades to quantify and predict erosion and transport of sediments, e.g. in scenarios of land use change or conservation measures. Being intrigued by both models and the connectivity concept, as a group of modellers we aimed at investigating what different models could tell us about connectivity. Therefore, we evaluated the response of contrasted spatially-distributed models to landscape connectivity features and explained the differences based on different model structures. A total of 53 scenarios were built with varying field sizes and orientations, as well as the implementation of soil conservation measures. These scenarios were simulated, for two rainfall intensities, with five event- and process-based water and soil erosion models – EROSION3D, FullSWOF_2D, LandSoil, OpenLISEM and Watersed. Results showed that rainfall amount plays the most important role in determining relative export and connected area of runoff and sediment in all models, indicating that functional aspects of connectivity were more important than structural connectivity. As for the role of structural landscape elements, there was no overall agreement between models regarding the effects of field sizes, crop allocation pattern, and conservation practices; agreement was also low on the spatial patterns of connectivity. This overall disagreement between models was unexpected. The results of this exercise suggest that the correct parameterization of runoff and sediment production and of routing patterns may be an important issue. Thus, incorporating connectivity functions based on routing would help modelling forward. Our results also suggest that structural connectivity indices may not suffice to represent connectivity in this type of catchment (relatively simple and monotonous land cover), and functional connectivity indices should be applied.

Nutrient mitigation under the impact of climate and land-use changes: A hydro-economic approach to participatory catchment management

Excessive nutrient loadings into rivers are a well-known ecological problem. Implemented mitigation measures should ideally be cost-effective, but perfectly ranking alternative nutrient mitigation measures according to cost-effectiveness is a difficult methodological challenge. Furthermore, a particularly practical challenge is that cost-effective measures are not necessarily favoured by local stakeholders, and this may impede their successful implementation in practice. The objective of this study was to evaluate the cost-effectiveness of mitigation measures using a methodology that includes a participatory process and social learning to ensure their successful implementation. By combining cost data, hydrological modelling and a bottom-up approach for three different European catchment areas (the Latvian Berze, the Swedish Helge and the German Selke rivers), the cost-effectiveness of 16 nutrient mitigation measures were analysed under current conditions as well as under selected scenarios for future climate and land-use changes. Fertiliser reduction, wetlands, contour ploughing and municipal wastewater treatment plants are the measures that remove nutrients with the highest cost-effectiveness in the respective case study context. However, the results suggest that the cost-effectiveness of measures not only depends on their design, specific location and the conditions of the surrounding area, but is also affected by the future changes the area may be exposed to. Climate and land-use changes do not only affect the cost-effectiveness of measures, but also shape the overall nutrient loads and potential target levels in a catchment.