Thematic groups

The three thematic groups are representative of the research strengths involved in the ZAL that have particularly contributed to the development of knowledge on the territory.

These thematic groups form the basis of scientific discussions within the ZAL network and are intended to structure the research conducted on the sites and other fields and at the scale of the reference territory, namely the Loire catchment areaIndeed, spatial and temporal dynamics are constrained by global changes such as climatic forcings, the restructuring of human activities, or biological invasions, which translate at the local or regional scale into key variables for the functioning of riverine systems. Understanding the influence of these global changes will require estimating and quantifying the contribution of different major variables (abiotic, biotic, and anthropogenic) to the dynamics of biodiversity, the balances of matter, energy, and associated compounds (in particular, water, sediments, carbon, and contaminants) on the functioning of different riverine socio-ecosystems (minor/major beds, catchment heads, urbanised areas) according to fluvial and anthropogenic gradients. During the 2020-2024 project, the Zonal Action Areas objectiveswill develop reflections and work on the interactions that exist between these thematic groups in order to obtain multi-thematic and multi-site resultsThe focus will not be on concentrating or reinforcing research efforts within each of these three groups, but rather on developing research work at their interfaces.

Global transfers and changes

How do global forcings translate to local and regional scales in key variables for understanding the functioning of Loire socio-ecosystems?

This overarching theme focuses on areas of study such as soils, sediments, water bodies, and Loire ecosystems, all of which are represented at least at one site within the ZAL platforms, and their spatial and temporal dynamics are constrained by global changes. It highlights how climatic pressures, the reshaping of human activities, and biological invasions translate, at a local or regional scale, into key variables for the functioning of these Loire systems.

To determine and understand sediment, nutrient, and contaminant transfers at different spatial and temporal scales. What are the links between these transfers and the functioning of the hydrosystem?

This will involve quantifying the material, energy and associated compound (in particular, carbon and contaminants) balances in different depositional environments (peat bogs, riverbed, agricultural plot, urban area, but also at the soil-plant scale) according to fluvial and anthropic gradients. To achieve this, the work will build on the "Large Rivers" and "Headwaters" platforms in order to model the phenomena involved (e.g. soil erosion, hydrosedimentary dynamics, archiving methods, etc.) in these transfers and their responses to global changes (climate change, land use and pollution).

The long-term effects of climate change can result in modifications to the carbon, water, and more generally the energy balance of ecosystems of interest, such as wetlands. For instance, initial results from the instrumented research site at La Guette peatland (integrated into the SNO Tourbières) have fostered knowledge about the processes at play, as well as ecological engineering for the integrated restoration of peatlands (hydrology, biodiversity, carbon storage), while enabling knowledge transfer to managers. The establishment of the Platform on the major rivers of the Loire basin will allow for an understanding of the effects of climatic forcings at different scales on the dynamics of the Loire. For example, more or less moderate low-water periods could subject plant or animal species, such as the black poplar, gomphid dragonflies, or certain fish species, to varying degrees of drought intensity and duration, and could therefore alter the population dynamics of these species. The aim will be to better understand the effect of these changes in dynamics on communities and potentially to develop conservation strategies with managers. Other ongoing and future work concerns the transfer of contaminants and matter along fluvial and anthropogenic gradients. For example, work on soil erosion dynamics and matter transfer in headwater catchments towards the hydrosystem in an intensive agricultural context, carried out at the instrumented site of Le Louroux, helps to better understand sediment transfer from an intensive agricultural zone and to estimate the infilling processes of a body of water. In timeThis involves quantifying the evolution of sediment flows through high-frequency monitoring and modelling of agricultural drain output into the hydrosystem. This allows for the determination of management strategies to limit these transfers. A second instrumented site is studying transfer processes along an urbanisation gradient on the headwater stream of the Égoutier (Orléans Metropolitan Area) through a coupling between a diachronic approach based on sedimentology and (organic and mineral) geochemistry, and a synchronic approach based on instrumentation and measurement. in situgeochemical fluxes and signatures. This work is articulated with research conducted on a larger scale on the temporal dynamics of the quality of surface sediments and those stored in the minor riverbed (metal and organic contaminants) across the entire Loire basin.

How to quantify and model water and sediment flows in large rivers (like the Loire and its tributaries) to assess their impact on socio-ecosystems over time?

Quantifying the dynamics of bedload and morpho-sedimentary and hydraulic processes over the current and recent periods (<200 years) to disentangle the influence of the main control factors (floodplain management, hydrology, biogeomorphology, etc.) and assess their effects on socio-ecosystems. Several studies on the analysis of past and recent morpho-sedimentary dynamics are being conducted on the Loire and two of its tributaries (the Cher and the Allier). These include studying and modelling the interactions between the different control factors (management, sediment transport, bedload storage and de-storage, and lateral dynamics, sediment archiving methods, etc.) at different time and space scales. Understanding these processes makes it possible to assess their effects on the dynamics of animal and plant communities and on management and uses. Furthermore, more specific research work aims to better understand the impacts of river system restoration work initiated within the framework of the implementation of the Water Framework Directive (e.g. the R-Temus project on the Armorican Loire).

 

Trajectory of the Loire territories

Place recent dynamics within the longer-term relationship between the environment and societies in the Loire region.

The objective of this structuring theme is to provide knowledge about the relationships that societies have with the Loire, as well as their spatial manifestations. It therefore involves understanding the economic and social structures that shape the Loire landscapes and contribute to maintaining and modifying them, from fishing to major developments (dams, embankments, etc.), from agriculture to urban planning, from individual actions to collective approaches.

This theme is structured around several timescales: long-term (Upper Pleistocene, Holocene, recent centuries) to forward-looking (societal adaptation to predicted changes), highlighting the construction of landscapes and territories through the lens of sustainable development. These timescales allow us to examine heritage, from the natural to the cultural. A multi-scalar approach will be developed, from the watershed to the intra-plot scale, including river valley sections.

Several questions are at the forefront of this theme:

What are the recent socio-economic and natural dynamics (over the last century) and how do they affect Loire socio-eco(hydro)systems? How do these trajectories determine the functioning of Loire territories and their inter-relations with the world?

What are the main long-term changes that have affected societies and landscapes in the basin? How are socio-economic dynamics coupled with natural dynamics? What are the characteristics of long-term socio-environmental co-evolution? Are societies resilient to risks, particularly riverine risks? What are the main developments made to the Loire riverbed and its tributaries?

Regarding the recent approach, the work focuses on different issues that span Loire Valley societies. Loire landscapes, natural and cultural heritage, flood risk, and the restoration of aquatic environments are all subjects studied through the prism of Loire Valley dynamics and trajectories.

Regarding the long-term approach, the Zone Atelier Loire has benefited from numerous studies since its creation and has remained very active in structuring geo-historical data (maps, Lidar data, etc.). This next contract will be an opportunity to integrate data from archaeology, particularly from preventive and underwater archaeology, by selecting sedimentological and archaeobotanical data, archaeozoological data, and all channel structures (bridges, dykes, groynes, mills, etc.) and Platforms.

The methodologies developed will be those of archaeology and environmental history, environmental sciences, spatial planning, sociology, political sciences, and geography.

Biodiversity and Functions of Loire Socio-Ecological Systems

The Loire is a heavily human-altered river, although its structure and functions remain well preserved compared to other rivers in Central Europe. Whilst globally, populations of vertebrate fauna dependent on rivers have declined by 17% compared to 1970, different patterns are observed in the Loire. Indeed, the populations of certain heritage species (beaver, otter) have increased, whilst some populations of migratory fish have stabilised (salmon, shad) or continue to decline (eel). A similar observation can be made regarding terrestrial ecosystems for plant and animal species. The Loire still flows in a semi-natural manner within its embanked channel, which allows for a certain degree of resistance and resilience of native biodiversity to global changes. Human-river interactions are the cause of major impacts (channel incision, loss of water flow rhythm and morphogenic floods, vegetation growth on sandbanks, extreme low water levels, various forms of pollution, etc.) but also offer hope for a societal commitment to conserving biological and cultural diversity as well as the functionality of this socio-ecosystem. This overarching theme proposes to focus on the interactions between society and the Loire ecosystem in order to best predict its future development by addressing the following questions:

Under what terms do diversities (landscape, ecosystemic, taxonomic, functional, phylogenetic) modulate the functioning of socio-ecosystems and, in return, how does the functioning of these systems direct the dynamics of these biodiversities?

How do direct and indirect biotic interactions, within or between trophic level(s), condition the structure and functioning of communities?

What are the relationships between community structure and/or population dynamics and environmental variations at different timescales (seasonal/interannual)?

The aim will be to assess the contribution of various key variables (abiotic, biotic and anthropogenic) to biodiversity dynamics and the functioning of different socio-ecosystems (floodplains, agricultural plots, urban areas). Research will be carried out primarily on the Platforms to monitor populations (animal/plant), model gains or losses in the diversity of various taxa based on the future evolution of these parameters, and understand the impact of past and current management practices on the functioning of these ecosystems. For example, the process of urbanisation is causing profound changes to landscapes, with a reduction in agricultural and forest areas in favour of built-up areas. This phenomenon is leading to significant changes in biodiversity and associated ecological functions, and it is becoming urgent to reconcile ecological and societal challenges within urban ecosystems. It is in this context that the sites of the Urban Environment Platform will enable us to understand the influence of environmental conditions, planning practices and management on ecological processes in urban landscapes. This will involve, for example, understanding the response of plant communities and pollinators to the artificialisation of land, or identifying individual and collective human values and behaviours towards the various elements of biodiversity in urban areas. In the channel of major rivers, it is necessary to identify and understand the environmental conditions and factors determining the level of diversity (genetic, species and functional) and to assess their consequences in terms of the functioning of the river system and the services provided to the socio-ecosystems of the Loire region. The sites of the ‘Major Watercourses’ platform will enable testing along a river gradient to determine whether the level of stressors (stress and disturbance) and their temporal and spatial variability have a major impact (relative to biotic filters) on the structure of specific, functional or phylogenetic biodiversity. The aim will also be to determine whether the anthropogenic context (development works, riverbank management, agricultural activities) alters the physical disturbances (substrate erosion, sediment deposition, etc.) that cause the stresses described above. All this work on the Platforms will be coordinated with the biodiversity observatory to establish protocols and cross-cutting actions across the Platforms, with a view to identifying organisms’ adaptation strategies to environmental variations at different timescales (seasonal/interannual), and determining the thresholds of adaptability to these changes. These Platforms will also help to identify the levers that can be mobilised to encourage the adoption of management practices more favourable to biodiversity, improve knowledge and perception of biodiversity within the Loire socio-ecosystems, but above all to propose decision-support tools enabling the reconciliation of ecological, social and economic values and in fineto preserve and/or promote the different levels of diversity.

In addition to the OBLA, certain research questions will be cross-cutting to the three structuring themes that will be developed in the ZAL during the next project. One of them concerns invasive species This has already been the subject of work during the previous project (2015-2020). In fact, Loire ecosystems are under pressure from numerous invasive alien species (IAS), some of which can impact biodiversity, the functioning of socio-ecosystems and the services they provide. The three platforms "Urban Environments", "Catchment Heads" and "Large Rivers" are perfectly suited to understanding the impacts of these IAS due to the significant disturbances these environments undergo and the corridors they represent for the dispersal of these species. It will be necessary, in particular, to understand how IAS impact socio-ecosystems, how they are managed (or can be managed) by local stakeholders, and what impacts these management methods have on the functioning of SES. For example, it will be necessary to develop methods (geomatics, use of socio-economic and historical data) to better characterise the urban matrix and to evaluate how its spatio-temporal heterogeneity influences the spatial distribution of these IAS. These platforms will provide knowledge on the dispersal of IAS, the resistance and resilience of ecosystems to these biological invasions, and will be able to provide answers allowing for the management of Loire ecosystems that will limit the spread and development of these species, while also better understanding citizen perception of these species.

The three thematic groups are representative of the research strengths involved in the ZAL that have particularly contributed to the development of knowledge on the territory.

These thematic groups form the basis of scientific discussions within the ZAL network and are intended to structure the research conducted on the sites and other fields and at the scale of the reference territory, namely the Loire catchment areaIndeed, spatial and temporal dynamics are constrained by global changes such as climatic forcings, the restructuring of human activities, or biological invasions, which translate at the local or regional scale into key variables for the functioning of riverine systems. Understanding the influence of these global changes will require estimating and quantifying the contribution of different major variables (abiotic, biotic, and anthropogenic) to the dynamics of biodiversity, the balances of matter, energy, and associated compounds (in particular, water, sediments, carbon, and contaminants) on the functioning of different riverine socio-ecosystems (minor/major beds, catchment heads, urbanised areas) according to fluvial and anthropogenic gradients. During the 2020-2024 project, the Zonal Action Areas objectiveswill develop reflections and work on the interactions that exist between these thematic groups in order to obtain multi-thematic and multi-site resultsThe focus will not be on concentrating or reinforcing research efforts within each of these three groups, but rather on developing research work at their interfaces.

Global transfers and changes

How do global forcings translate to local and regional scales in key variables for understanding the functioning of Loire socio-ecosystems?

This overarching theme focuses on areas of study such as soils, sediments, water bodies, and Loire ecosystems, all of which are represented at least at one site within the ZAL platforms, and their spatial and temporal dynamics are constrained by global changes. It highlights how climatic pressures, the reshaping of human activities, and biological invasions translate, at a local or regional scale, into key variables for the functioning of these Loire systems.

To determine and understand sediment, nutrient, and contaminant transfers at different spatial and temporal scales. What are the links between these transfers and the functioning of the hydrosystem?

This will involve quantifying the material, energy and associated compound (in particular, carbon and contaminants) balances in different depositional environments (peat bogs, riverbed, agricultural plot, urban area, but also at the soil-plant scale) according to fluvial and anthropic gradients. To achieve this, the work will build on the "Large Rivers" and "Headwaters" platforms in order to model the phenomena involved (e.g. soil erosion, hydrosedimentary dynamics, archiving methods, etc.) in these transfers and their responses to global changes (climate change, land use and pollution).

The long-term effects of climate change can result in modifications to the carbon, water, and more generally the energy balance of ecosystems of interest, such as wetlands. For instance, initial results from the instrumented research site at La Guette peatland (integrated into the SNO Tourbières) have fostered knowledge about the processes at play, as well as ecological engineering for the integrated restoration of peatlands (hydrology, biodiversity, carbon storage), while enabling knowledge transfer to managers. The establishment of the Platform on the major rivers of the Loire basin will allow for an understanding of the effects of climatic forcings at different scales on the dynamics of the Loire. For example, more or less moderate low-water periods could subject plant or animal species, such as the black poplar, gomphid dragonflies, or certain fish species, to varying degrees of drought intensity and duration, and could therefore alter the population dynamics of these species. The aim will be to better understand the effect of these changes in dynamics on communities and potentially to develop conservation strategies with managers. Other ongoing and future work concerns the transfer of contaminants and matter along fluvial and anthropogenic gradients. For example, work on soil erosion dynamics and matter transfer in headwater catchments towards the hydrosystem in an intensive agricultural context, carried out at the instrumented site of Le Louroux, helps to better understand sediment transfer from an intensive agricultural zone and to estimate the infilling processes of a body of water. In timeThis involves quantifying the evolution of sediment flows through high-frequency monitoring and modelling of agricultural drain output into the hydrosystem. This allows for the determination of management strategies to limit these transfers. A second instrumented site is studying transfer processes along an urbanisation gradient on the headwater stream of the Égoutier (Orléans Metropolitan Area) through a coupling between a diachronic approach based on sedimentology and (organic and mineral) geochemistry, and a synchronic approach based on instrumentation and measurement. in situgeochemical fluxes and signatures. This work is articulated with research conducted on a larger scale on the temporal dynamics of the quality of surface sediments and those stored in the minor riverbed (metal and organic contaminants) across the entire Loire basin.

How to quantify and model water and sediment flows in large rivers (like the Loire and its tributaries) to assess their impact on socio-ecosystems over time?

Quantifying the dynamics of bedload and morpho-sedimentary and hydraulic processes over the current and recent periods (<200 years) to disentangle the influence of the main control factors (floodplain management, hydrology, biogeomorphology, etc.) and assess their effects on socio-ecosystems. Several studies on the analysis of past and recent morpho-sedimentary dynamics are being conducted on the Loire and two of its tributaries (the Cher and the Allier). These include studying and modelling the interactions between the different control factors (management, sediment transport, bedload storage and de-storage, and lateral dynamics, sediment archiving methods, etc.) at different time and space scales. Understanding these processes makes it possible to assess their effects on the dynamics of animal and plant communities and on management and uses. Furthermore, more specific research work aims to better understand the impacts of river system restoration work initiated within the framework of the implementation of the Water Framework Directive (e.g. the R-Temus project on the Armorican Loire).

 

Trajectory of the Loire territories

Place recent dynamics within the longer-term relationship between the environment and societies in the Loire region.

The objective of this structuring theme is to provide knowledge about the relationships that societies have with the Loire, as well as their spatial manifestations. It therefore involves understanding the economic and social structures that shape the Loire landscapes and contribute to maintaining and modifying them, from fishing to major developments (dams, embankments, etc.), from agriculture to urban planning, from individual actions to collective approaches.

This theme is structured around several timescales: long-term (Upper Pleistocene, Holocene, recent centuries) to forward-looking (societal adaptation to predicted changes), highlighting the construction of landscapes and territories through the lens of sustainable development. These timescales allow us to examine heritage, from the natural to the cultural. A multi-scalar approach will be developed, from the watershed to the intra-plot scale, including river valley sections.

Several questions are at the forefront of this theme:

What are the recent socio-economic and natural dynamics (over the last century) and how do they affect Loire socio-eco(hydro)systems? How do these trajectories determine the functioning of Loire territories and their inter-relations with the world?

What are the main long-term changes that have affected societies and landscapes in the basin? How are socio-economic dynamics coupled with natural dynamics? What are the characteristics of long-term socio-environmental co-evolution? Are societies resilient to risks, particularly riverine risks? What are the main developments made to the Loire riverbed and its tributaries?

Regarding the recent approach, the work focuses on different issues that span Loire Valley societies. Loire landscapes, natural and cultural heritage, flood risk, and the restoration of aquatic environments are all subjects studied through the prism of Loire Valley dynamics and trajectories.

Regarding the long-term approach, the Zone Atelier Loire has benefited from numerous studies since its creation and has remained very active in structuring geo-historical data (maps, Lidar data, etc.). This next contract will be an opportunity to integrate data from archaeology, particularly from preventive and underwater archaeology, by selecting sedimentological and archaeobotanical data, archaeozoological data, and all channel structures (bridges, dykes, groynes, mills, etc.) and Platforms.

The methodologies developed will be those of archaeology and environmental history, environmental sciences, spatial planning, sociology, political sciences, and geography.

Biodiversity and Functions of Loire Socio-Ecological Systems

The Loire is a heavily human-altered river, although its structure and functions remain well preserved compared to other rivers in Central Europe. Whilst globally, populations of vertebrate fauna dependent on rivers have declined by 17% compared to 1970, different patterns are observed in the Loire. Indeed, the populations of certain heritage species (beaver, otter) have increased, whilst some populations of migratory fish have stabilised (salmon, shad) or continue to decline (eel). A similar observation can be made regarding terrestrial ecosystems for plant and animal species. The Loire still flows in a semi-natural manner within its embanked channel, which allows for a certain degree of resistance and resilience of native biodiversity to global changes. Human-river interactions are the cause of major impacts (channel incision, loss of water flow rhythm and morphogenic floods, vegetation growth on sandbanks, extreme low water levels, various forms of pollution, etc.) but also offer hope for a societal commitment to conserving biological and cultural diversity as well as the functionality of this socio-ecosystem. This overarching theme proposes to focus on the interactions between society and the Loire ecosystem in order to best predict its future development by addressing the following questions:

Under what terms do diversities (landscape, ecosystemic, taxonomic, functional, phylogenetic) modulate the functioning of socio-ecosystems and, in return, how does the functioning of these systems direct the dynamics of these biodiversities?

How do direct and indirect biotic interactions, within or between trophic level(s), condition the structure and functioning of communities?

What are the relationships between community structure and/or population dynamics and environmental variations at different timescales (seasonal/interannual)?

The aim will be to assess the contribution of various key variables (abiotic, biotic and anthropogenic) to biodiversity dynamics and the functioning of different socio-ecosystems (floodplains, agricultural plots, urban areas). Research will be carried out primarily on the Platforms to monitor populations (animal/plant), model gains or losses in the diversity of various taxa based on the future evolution of these parameters, and understand the impact of past and current management practices on the functioning of these ecosystems. For example, the process of urbanisation is causing profound changes to landscapes, with a reduction in agricultural and forest areas in favour of built-up areas. This phenomenon is leading to significant changes in biodiversity and associated ecological functions, and it is becoming urgent to reconcile ecological and societal challenges within urban ecosystems. It is in this context that the sites of the Urban Environment Platform will enable us to understand the influence of environmental conditions, planning practices and management on ecological processes in urban landscapes. This will involve, for example, understanding the response of plant communities and pollinators to the artificialisation of land, or identifying individual and collective human values and behaviours towards the various elements of biodiversity in urban areas. In the channel of major rivers, it is necessary to identify and understand the environmental conditions and factors determining the level of diversity (genetic, species and functional) and to assess their consequences in terms of the functioning of the river system and the services provided to the socio-ecosystems of the Loire region. The sites of the ‘Major Watercourses’ platform will enable testing along a river gradient to determine whether the level of stressors (stress and disturbance) and their temporal and spatial variability have a major impact (relative to biotic filters) on the structure of specific, functional or phylogenetic biodiversity. The aim will also be to determine whether the anthropogenic context (development works, riverbank management, agricultural activities) alters the physical disturbances (substrate erosion, sediment deposition, etc.) that cause the stresses described above. All this work on the Platforms will be coordinated with the biodiversity observatory to establish protocols and cross-cutting actions across the Platforms, with a view to identifying organisms’ adaptation strategies to environmental variations at different timescales (seasonal/interannual), and determining the thresholds of adaptability to these changes. These Platforms will also help to identify the levers that can be mobilised to encourage the adoption of management practices more favourable to biodiversity, improve knowledge and perception of biodiversity within the Loire socio-ecosystems, but above all to propose decision-support tools enabling the reconciliation of ecological, social and economic values and in fineto preserve and/or promote the different levels of diversity.

In addition to the OBLA, certain research questions will be cross-cutting to the three structuring themes that will be developed in the ZAL during the next project. One of them concerns invasive species This has already been the subject of work during the previous project (2015-2020). In fact, Loire ecosystems are under pressure from numerous invasive alien species (IAS), some of which can impact biodiversity, the functioning of socio-ecosystems and the services they provide. The three platforms "Urban Environments", "Catchment Heads" and "Large Rivers" are perfectly suited to understanding the impacts of these IAS due to the significant disturbances these environments undergo and the corridors they represent for the dispersal of these species. It will be necessary, in particular, to understand how IAS impact socio-ecosystems, how they are managed (or can be managed) by local stakeholders, and what impacts these management methods have on the functioning of SES. For example, it will be necessary to develop methods (geomatics, use of socio-economic and historical data) to better characterise the urban matrix and to evaluate how its spatio-temporal heterogeneity influences the spatial distribution of these IAS. These platforms will provide knowledge on the dispersal of IAS, the resistance and resilience of ecosystems to these biological invasions, and will be able to provide answers allowing for the management of Loire ecosystems that will limit the spread and development of these species, while also better understanding citizen perception of these species.

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