Saltmarshes in SE England are eroding rapidly and one potential impact is the loss of habitat for fishes. Saltmarshes have been created by setting back the existing line of flood defence through managed realignment. The use by fishes of natural and managed realignment habitats at Tollesbury, Abbotts Hall and Orplands was examined (2005-07). Three seasonal groups were apparent in the fish assemblages of the managed realignment sites: February-April (Pomatoschistus microps and Sprattus sprattus), May-September (Dicentrarchus labrax and Atherina presbyter) and October-January (Liza aurata and Liza ramada). The sites were used mainly by 0- and 1-group fishes and adult P. microps. The mean abundance (July - August 2007) was 558 0.1 ha' (range 76 - 2699 0.1 ha'). In summer, small (< 30 mm) zooplanktivorous D. labrax fed successfully at all sites. Larger (30-59 mm) D. labrax consumed more macroinvertebrates in the Tollesbury managed realignment and two established marshes than at Abbotts Hall and Orplands. By autumn there were no site-specific differences in gut fullness of D. labrax. Stable isotope ratio analysis and gut contents analysis revealed that small (< 50 mm) D. labrax, S. sprattus and A. presbyter assimilated zooplankton which eat detritus, resuspended microphytobenthos and some phytoplankton. L. aurata assimilated zooplankton and microphytobenthos. P. microps (20-50 mm) and A. presbyter (80-99 mm) assimilated benthic meiofauna. Larger (50-230 mm) D. labrax assimilated macroinvertebrates which eat microphytobenthos, Ulva spp., C3 plants and detritus. Some recommendations for saltmarsh restoration are provided with an estimate of the economic value of bass in saltmarshes,to highlight further areas of research.

This thesis focuses on exploring the concept of managed realignment as a potential climate change adaptation strategy in Sweden. The empirics is based on the qualitative case study research within three Swedish municipalities of Trelleborg, Halmstad and Karlstad. The concept of territorial governance was used as the analysis framework for the empirical data. The aim of this thesis is to contribute to further research on managed realignment in Sweden, point out on current constraints and potentials of managed realignment within Swedish context and the current needs for making it a potential climate adaptation strategy in Sweden.

Conservation of intertidal habitats in the UK is vital in order to continue to support nationally and internationally important populations of non-breeding waterbirds. Historic reclamation for agriculture and industry has resulted in the loss and degradation of large areas of these intertidal habitats in estuaries and they continue to be threatened by sea-level rise. Managed realignment is one method which is increasingly being used to restore intertidal habitats. As managed realignment is a relatively new restoration technique, the extent to which knowledge of the biology of estuaries is applicable to managed realignment sites is unclear. Habitat restoration is often unsuccessful or incomplete, so a detailed knowledge of both the natural system and the characteristics of restored systems will usually be necessary to recreate fully-functional estuarine habitats. This thesis focuses on Nigg Bay Managed Realignment Site (Nigg Bay MRS), the first managed realignment site in Scotland, and follows the first four years of ecological development to gain an understanding of how breached realignment can be used to restore intertidal habitats to support non-breeding waterbirds. This thesis has six major aims: (i) to describe the development of saltmarsh, (ii) to describe the development of intertidal flat, (iii) to describe the colonisation by non-breeding waterbirds (iv) to determine how tidal cycle and weather affect patterns of waterbird use, (v) to determine which factors affect the spatial distribution of waders and finally (vi) to determine the patterns of use by individual birds. Four summers after the re-establishment of tidal conditions, almost all of the saltmarsh species recorded on the nearby saltmarsh had colonised Nigg Bay MRS, although recognisable communities had yet to establish. Three winters after the re- establishment of tidal conditions in Nigg Bay MRS, the sediments had a significantly smaller particle size and higher organic matter content compared to the fine sands of the adjacent intertidal flats. The intertidal invertebrate community also differed from the adjacent intertidal flats. Nigg Bay MRS attracted large numbers of non-breeding waterbirds and supported each of the most common wader and wildfowl species present in the wider estuary. Nigg Bay MRS performs a number of important functions for non-breeding waterbirds by: (i) providing a foraging and resting habitat when the tide is absent and intertidal sediments in Nigg Bay are exposed; (ii) providing a foraging resource as the tide passes over the intertidal sediments within the site once the intertidal flats in Nigg Bay are inundated; and (iii) providing a high tide roosting site. On days with low temperatures and high wind speeds, more waterbirds use Nigg Bay MRS, suggesting that it is likely to be providing sheltering benefits. Nigg Bay MRS also provides top-up feeding habitat. The factors that often influence the spatial distributions of waders in estuaries appear to be operating within Nigg Bay MRS. Wader densities are greater on the intertidal flats when they are accessible than on the saltmarsh. Wader densities are also greatest close to creeks and drainage channels, possibly due to higher invertebrate densities, more accessible prey or sheltering benefits. Colour-ringing and radio-tracking of Common Redshank established that Nigg Bay MRS has a subset of regular users, including both adults and juveniles, and the wader assemblage at night may differ from the assemblage during the day. These findings are discussed in terms of the implications for locating, designing and managing future managed realignment projects.

Les territoires et les paysages littoraux sont soumis à des risques naturels de mieux en mieux identifiés et croissants (tempêtes, submersions…), notamment sous les effets du changement climatique, dont les manifestations, pas seulement eustatiques, auront d’autres conséquences sur les paysages. Comment, dans une logique proactive, tirer parti des modifications de paysages tout en limitant, contrôlant, voire corrigeant les dérives induites par la hausse du niveau marin sur les littoraux ? L’objectif est de montrer qu’il est possible de s’ajuster à ces risques par la prise en compte des paysages et par la pratique d’une gestion plus douce et raisonnée des aménagements côtiers. Après avoir établi un bilan argumenté sur la prise en compte du paysage dans les stratégies aujourd’hui mises en œuvre pour réduire les risques d’inondation et de submersion, la thèse évalue comment le projet de paysage, processus holistique de conception et de partage de visions à long terme, peut-il être un outil de réduction de la vulnérabilité du territoire et de sa société. Puis, la thèse se focalise sur la Camargue, territoire deltaïque emblématique dont les processus naturels et sociaux ont permis d’inventer une société et des paysages créateurs de richesses dans un équilibre dynamique face aux risques permanents d’inondation et de submersion. Cependant, avec, entre autres causes, celle du changement climatique, cet équilibre stratégique est remis en question et nécessite d’élaborer les hypothèses d’une autre Camargue. Ainsi, dans une dimension exploratoire, la thèse propose une illustration argumentée de nouveaux modèles de développement et d’ajustement du système camarguais. La double prise en compte du paysage et du changement climatique et les premiers résultats de l’étude de dépoldérisation des Bas-Champs Picards, nous amènent à revendiquer la mise en œuvre d’une politique de renouvellement littoral en tant que réponse aux problèmes des territoires côtiers d’aujourd’hui et plus encore de demain. / Coastal territories and landscapes are submitted to increasing yet better identified natural risks (storms, flooding, etc.), especially under the effects of climate change. Its reflections, the eustatic ones among others, have various consequences on the landscape. How is it possible, in a proactive reasoning, to take advantage of the lanscape alterations at the same time as limitating, controling and why not correcting the excesses due to the sea level rise on the coasts ? The aim is to show that it is possible to adjust to these risks upon taking landscapes into account and managing the coastal structures a lighter and better thought-out way.An argued assessment on the way the landscape is taken into account in current strategies used to reduce the flooding risks, is followed with an evaluation of the way the landscape project, a holistic process of designing and sharing long term visions, can be used as a tool to reduce the vulnerability of both the territory and its society. Then, the thesis focuses on the emblematic Camargue delta, a territory which natural and social processes allowed to develop a society together with lanscapes creators of wealth in a dynamic balance considering the permanent flooding risks. However, keeping in mind, among other causes, that of climate change, this strategic balance is being questioned and needs the elaboration of hypotheses for another form of Camargue. Thus, in an exploratory dimension, the thesis suggests an argued illustration of new models of development and adjustment for the system of Camargue. Taking into account both the landscape and climate change, the first results of a study on managed realignment in Bas-Champs, Picardie, lead us to a demand for the implementation of a coastal regeneration policy as the answer to the issues of coastal terriories for today, and even more for tomorrow.