The Brazilian Cerrado is recognized as one of the most threatened biomes in the world, as the region has experienced a striking change from natural Cerrado vegetation to intense cash crop production. This paper reviews the history of land conversion in the Cerrado and the development of soil properties and water resources under past and ongoing land use. We compared soil and water quality parameters from different land uses considering 80 soil and 18 water studies conducted in different regions across the Cerrado to provide quantitative evidence of soil and water alterations from land use change. Following the conversion of native Cerrado, significant effects on soil pH, bulk density and available P and K for croplands and less-pronounced effects on pastures were evident. Soil total N did not differ between land uses because most of the sites classified as croplands were nitrogen-fixing soybeans, which are not artificially fertilized with N. In contrast, water quality studies showed nitrogen enrichment in agricultural catchments, indicating fertilizer impacts and potential susceptibility to eutrophication. Regardless of the land use, P is widely absent because of the high-fixing capacities of deeply weathered soils and the filtering capacity of riparian vegetation. Pesticides, however, were consistently detected throughout the entire aquatic system. In several case studies, extremely high-peak concentrations exceeded Brazilian and European Union (EU) water quality limits, which were potentially accompanied by serious health implications. Land use intensification is likely to continue, particularly in regions where less annual rainfall and severe droughts are projected in the northeastern and western Cerrado. Thus, the leaching risk and displacement of agrochemicals are expected to increase, particularly because the current legislation has caused a reduction in riparian vegetation. We conclude that land use intensification is likely to seriously limit the Cerrado's future regarding both agricultural productivity and ecosystem stability. Because only limited data are available, we recommend further field studies to understand the interaction between terrestrial and aquatic systems. This study may serve as a valuable database for integrated modelling to investigate the impact of land use and climate change on soil and water resources and to test and develop mitigation measures for the Cerrado.

Water research is introduced from the combined perspectives of natural and social science and cases of citizen and stakeholder coproduction of knowledge. Using the overarching notion of transdisciplinarity, we examine how interdisciplinary and participatory water research has taken place and could be developed further. It becomes apparent that water knowledge is produced widely within society, across certified disciplinary experts and noncertified expert stakeholders and citizens. However, understanding and management interventions may remain partial, or even conflicting, as much research across and between traditional disciplines has failed to integrate disciplinary paradigms due to philosophical, methodological, and communication barriers. We argue for more agonistic relationships that challenge both certified and noncertified knowledge productively. These should include examination of how water research itself embeds and is embedded in social context and performs political work. While case studies of the cultural and political economy of water knowledge exist, we need more empirical evidence on how exactly culture, politics, and economics have shaped this knowledge and how and at what junctures this could have turned out differently. We may thus channel the coproductionist critique productively to bring perspectives, alternative knowledges, and implications into water politics where they were not previously considered; in an attempt to counter potential lock‐in to particular water policies and technologies that may be inequitable, unsustainable, or unacceptable. While engaging explicitly with politics, transdisciplinary water research should remain attentive to closing down moments in the research process, such as framings, path‐dependencies, vested interests, researchers’ positionalities, power, and scale. WIREs Water 2016, 3:369–389. doi: 10.1002/wat2.1132For further resources related to this article, please visit the WIREs website.

[1] The objective of this study is the evaluation of the spatial variability and intrinsic connectivity features of model input parameters for the parameterization of process-based, spatially distributed overland flow models. Parameter scaling tools based on the statistical and geostatistical properties of an extensive field data set were developed. These allowed the reproduction of the spatial heterogeneity of model parameters associated with the soil-and vegetation-related properties of semiarid shrubland environments to a varying degree. The outcome of the study emphasizes that connectivity plays a fundamental role in the modeling of water fluxes within semiarid catchments. The larger the degree to which connected features are represented, the better the model performance. In contrast, the parameterization approaches that did not contain connected patterns of parameter values performed comparatively poorly. A spatially connected overland flow model therefore enabled the generation of realistic overland flow patterns that qualitatively resembles field surveys of overland flow generation not only at the outlet of the model domains but also within the catchments without the need of calibration.

No abstract

No abstract

No abstract

Heterogeneity of vegetation and soil properties is characteristic of semi-arid and arid environments. The potential underlying causes of the dynamics that create this spatial variability, with consequent impacts on landscape connectivity and thus ecological and ecohydrological processes, are not clearly understood. An investigation was carried out into the spatial variability of ponded infiltration rate, soil moisture, soil-aggregate stability, vegetation cover, random roughness and nutrient content in the soil (ammonium, nitrate and phosphorus) at grassland and shrubland sites for two spatial scales in the Jornada Basin, in the northern part of the Chihuahua desert. At the plant-interplant scale, statistically significant differences exist between vegetated and non-vegetated sites for soil moisture and infiltration rate within both shrublands and grasslands. The spatial distributions of all other parameters follow a more complex scheme at this scale. At the landscape scale, distinct differences exist for most parameters between the grasslands and the shrubland sites. Geostatistical analysis revealed that the autocorrelation lengths are not simply a function of average shrub sizes, but may be caused by a more complex pattern probably related to the spatial layout of rill and inter-rill areas and other localized transfers of soil resources through the redistribution of water and wind. These results demonstrate the importance of understanding spatial linkages of processes within the landscape in understanding dryland ecosystem dynamics.

Abstract. Current soil erosion and reservoir sedimentation modelling at the meso-scale is still faced with intrinsic problems with regard to open scaling questions, data demand, computational efficiency and deficient implementations of retention and re-mobilisation processes for the river and reservoir networks. To overcome some limitations of current modelling approaches, the semi-process-based, spatially semi-distributed modelling framework WASA-SED (Vers. 1) was developed for water and sediment transport in large dryland catchments. The WASA-SED model simulates the runoff and erosion processes at the hillslope scale, the transport and retention processes of suspended and bedload fluxes in the river reaches and the retention and remobilisation processes of sediments in reservoirs. The modelling tool enables the evaluation of management options both for sustainable land-use change scenarios to reduce erosion in the headwater catchments as well as adequate reservoir management options to lessen sedimentation in large reservoirs and reservoir networks. The model concept, its spatial discretisation scheme and the numerical components of the hillslope, river and reservoir processes are described and a model application for the meso-scale dryland catchment Isábena in the Spanish Pre-Pyrenees (445 km 2 ) is presented to demonstrate the capabilities, strengths and limits of the model framework. The example application showed that the model was able to reproduce runoff and sediment transport dynamics of highly erodible headwater badlands, the transient storage of sediments in the dryland river system, the bed elevation changes of the 93 hm 3 Barasona reservoir due to sedimentation as well as the life expectancy of the reservoir under different management options.