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Given the potential for climate change to increase soil erosion and its associated adverse impacts, modelling future rates of erosion is a crucial step in its assessment as a potential future environmental problem, and as a basis to help advise future soil conservation strategies. Despite the wide range of previous modelling studies, iri the majority of cases limitations are apparent with respect to their treatment of the direct impacts (climate change), and their failure to factor in the indirect impacts (changing land use and management). In this study, these limitations are addressed in association with the modelling of future soil erosion rates for six hillslopes in Northern Ireland using the Water Erosion Prediction Project (WEPP) model. The direct impacts are handled using statistical downscaling methods, enabling the generation of site- specific, daily resolution future climate change scenarios, and a simple sensitivity analysis approach is employed to investigate the previously unstudied impacts of sub-daily rainfall intensity changes. Finally, the frequently neglected indirect impacts of changing land use and management are examined using a scenarios-based approach. Results indicate a mix of soil erosion increases and decreases, depending on which scenarios are considered. Downscaled climate change projections in isolation generally result in erosion decreases, whereas large increases are projected when land use is changed to a row crop which requires annual tillage, and / or where large changes in sub-daily rainfall intensity are applied. The off-site impacts of erosion are likely to become a more considerable environmental issue with respect to water quality and 'muddy flooding' under a wide range of future scenarios. The overall findings illustrate the potential for increased soil erosion under future climate change, and illuminate the need to address key limitations in previous studies with respect to the treatment of both the direct and indirect impacts of climate change.

The soil biota are a vital component of belowground systems, driving many key processes such as nutrient cycling, underwriting soil structural integrity and providing crucial ecosystem services to the wider environment. In agricultural systems, tillage practices are known to impact upon both the soil biota and surface erosion processes, but little is understood about the relationships between these three factors. This work addresses this issue within the framework of an EU Life/ Syngenta project “Soil and water protection for northern and central Europe” (SOWAP). Within this component of the SOWAP programme, the influence of different soil management practices on the size and overall composition of the soil microbial community was determined and related to the propensity for erosion, at a variety of spatial scales. Microbial biomass and phenotypic structure, measured using phospholipid fatty acid (PLFA) analysis, were used to determine the effect tillage had on microbial communities at sites in Belgium, Hungary and the UK. The field sites were split into differing tillage practices on the same slope. Samples were taken prior to, and three years after, the adoption of inversion (conventional) and non-inversion tillage techniques. In addition, samples were taken periodically from two sites in the UK (Loddington, Leicestershire and Tivington, Somerset) to assess the temporal changes in microbial community size and structure under the tillage practices. Other soil, agronomic and ecological properties were measured at the field scale by SOWAP project partners. These field trials were supported by small plot rainfall simulations at the Loddington field site and by laboratory-based microcosm-scale studies using manipulated microbial communities and controlled rainfall, to further characterise microbial effects on soil erodibility. The results showed that across the European sites microbial community size was reduced in conventionally tilled soils. However there was no effect of tillage type on microbial biomass at the Tivington site after three years. Microbial community structure showed significant seasonal changes greater than those relatable to tillage type. It was notable that the fungal biomarker PLFA 18:2ω6 decreased in conventionally tilled soils. The small-scale experimentation using rainfall simulators and manipulated microbial communities was designed to specifically observe relationships between soil microbial communities, water movement and erodibility. These experiments showed that the presence of microbes in soils impacted upon both erosion processes and hydrological properties. There was a trend showing a decreased sediment concentration in runoff from soils containing a living microbial community. Propensity to runoff and infiltration was altered differentially as a result of microbial inocula derived from soils under different tillage practices. There was evidence that there was a specific and characteristic fraction of the microbial community susceptible to mobilisation by runoff and infiltrate waters, and hence potentially prone to relocation within the ecosystem. Linking the laboratory experiments to field rainfall simulations demonstrated the difficulty of controlling environmental variables, particularly at larger scales. Nevertheless, the same basic trends were observed at both laboratory and small plot scales.

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Die Begrünung von erosionsgefährdeten Abflussbahnen ist eine wichtige Maßnahme des Boden- und Gewässerschutzes, die kombiniert werden kann mit Maßnahmen des Naturschutzes. Die Broschüre gibt Auskunft über die Lage und Verbreitung der erosionsgefährdeten Abflussbahnen. Zur Größe und Pflege der Begrünungsfläche werden ebenso Hinweise gegeben wie zu erosionsmindernden Maßnahmen auf den angrenzenden Ackerflächen.

Im Freistaat Sachsen tritt jährlich mehr oder weniger ausgeprägt nach lokalen Starkregenereignissen Bodenerosion auf. In der Öffentlichkeit werden die Erosionsschäden meist erst beachtet, wenn über den Ackerboden hinaus Siedlungs- und Verkehrsbereiche betroffen sind. Bodenerosion kann eine schädliche Bodenveränderung begründen, die nach § 4 Bundesbodenschutzgesetz abzuwehren oder zu sanieren ist. Für die Frage, ob eine schädliche Bodenveränderung vorliegt, enthält die Arbeitshilfe Hinweise.

Im Freistaat Sachsen tritt jährlich mehr oder weniger ausgeprägt nach lokalen Starkregenereignissen Bodenerosion auf. In der Öffentlichkeit werden die Erosionsschäden meist erst beachtet, wenn über den Ackerboden hinaus Siedlungs- und Verkehrsbereiche betroffen sind. Bodenerosion kann eine schädliche Bodenveränderung begründen, die nach § 4 Bundesbodenschutzgesetz abzuwehren oder zu sanieren ist. Für die Frage, ob eine schädliche Bodenveränderung vorliegt, enthält die Arbeitshilfe Hinweise.

Die Begrünung von erosionsgefährdeten Abflussbahnen ist eine wichtige Maßnahme des Boden- und Gewässerschutzes, die kombiniert werden kann mit Maßnahmen des Naturschutzes. Die Broschüre gibt Auskunft über die Lage und Verbreitung der erosionsgefährdeten Abflussbahnen. Zur Größe und Pflege der Begrünungsfläche werden ebenso Hinweise gegeben wie zu erosionsmindernden Maßnahmen auf den angrenzenden Ackerflächen.

Cette thèse traite du comportement géomorphologique des littoraux situés entre la pointe du Grouin et Cap Fréhel. Ce littoral est composé de quatre systèmes côtiers : des côtes basses (système vaseux et système plage dune), et des côtes rocheuses (système falaise dure et système falaise meuble). La dynamique de ces systèmes est régie par des transferts depuis des sites sources vers des sites puits. La variation de ces transferts, dans le temps et l’espace conditionne le rythme d’évolution du littoral. Les systèmes plages –dunes et falaises meubles (qui sont souvent associés au sein d’une seule cellule sédimentaire en tant que puit et source) sont particulièrement sensibles à ces variations et aux processus d’érosion. De plus, l’augmentation des pressions anthropiques depuis les années 60 a mené à une artificialisation de zones côtières et à une modification profonde des flux sédimentaires. Dans ce contexte, nous retraçons la mobilité récente du trait de côte et nous tentons de reconnaître les principaux types de fonctionnements morphodynamiques à long et à moyen terme. Nous essayons aussi de déterminer le rôle respectif des forçages naturels et anthropiques. L’analyse est fondée sur le traitement numérique de photographies aériennes pour retracer la cinématique du trait de côte et pour quantifier les tendances et les rythmes d’évolution. L’analyse met en relation les variations du trait de côte avec une base de données SIG décrivant les facteurs contrôlant l’évolution. La combinaison des résultats obtenus a permis de noter que le recul du trait de côte est contrôlé par des processus d’érosion accélérée lors d’événements intenses (tempêtes) et par des processus d’érosion anthropique. Le déficit sédimentaire de certaines plages est peut être aussi lié à une pénurie des apports livrés par les falaises meubles. Les rôles respectifs de ces deux forçages (tempêtes et anthropisation) sont hautement variables suivant les sites et aucune règle générale ne peut être établie sur la région. IL n’y a que des cas particuliers. / This PhD deals with the geomorphologic behavior of the Northern coast of Brittany between the Pointe du Grouin and Cap Frehel. The coastline is comprised of four coastal systems: low coasts (marsh system, and dune system) and rocky coasts (hard rock cliffs, soft rocks cliffs). The dynamics of these systems is controlled by transfers of energy and sediment (from source sites to sink sites). The variation of these transfers in time and space modifies the sedimentary stock and therefore the rate of morphological evolution of the coastline. The dunes / soft cliffs association puit sites and source sites) are especially sensitive to these variations and show many erosion processes and features. Moreover the increase in anthropogenic pressures since the 60s has led to increasing artificial coastal areas. In this context, we trace the recent mobility of the coastline and we try to identify the main types of morphodynamics behavior in the evolution of coastal forms. The analysis is based on the digital processing aerial photography in order to quantify the trends of the evolution. The analysis links the changes with a GIS database describing the factors controlling the evolution of the coastline. Results show that retreat is controlled by accelerated erosion process during storms and by anthropogenic processes. The sediment deficit of some beaches may be related to a shortage of inputs from the soft cliffs. The respective roles of storms and anthropic forcing are highly variable from one site to another and no general rule may be constructed for the entire region