Marais d'Episy: maintaining open environments of very high heritage value
The "Marais d'Episy" sensitive natural area is a peat marsh, a rare environment in the Île-de-France region. The Seine-et-Marne department manages and promotes this site as part of its ENS policy.The area is protected by an Arrêté Préfectoral de Protection de Biotope and is included in the Natura 2000 site "basse vallée du Loing".The exemplary nature of its management has been recognized by the inclusion of the Episy marsh on the "Green List" of protected areas.
A new management plan for the marsh will be implemented in 2023, in line with the new reference system drawn up by the French Office for Biodiversity, which anticipates threats and proposes solutions to remedy them. Influencing factors are identified (natural dynamics, hydraulic functioning, climate change). They are associated with pressures to be managed (closure of environments by woody colonization, etc.) and a specific action strategy.
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Context
Challenges addressed
Among the main challenges identified is the fight against the closure of the environment and the potential impact of grazing on part of the site. An assessment of the impact of grazing was carried out in 2023, showing that grazing pressure is generally adapted (extensive grazing) to the site and its issues, with certain limitations (selective grazing, for example, which does not prevent occasional woody colonization).
The challenge put forward (and needing to be better assessed) will therefore be that of combating the closure of meadow and peatland environments, by clearing woody vegetation or mowing herbaceous vegetation, so as to maintain the most emblematic environments of the marsh in an optimal state of conservation.
Location
Process
Summary of the process
The elements of the site diagnosis, the management assessment and the creation of a dedicated scientific committee have laid the foundations for the deployment of a new action plan from 2023. This plan is intended to be shared and concerted, notably within the site's Scientific Committee. Management measures, in particular those aimed at maintaining open environments, are accompanied by means and results indicators. Progressive, they will be evaluated each year with the support of the aforementioned tools, and will guarantee optimal conversation on the site for years to come.
Building Blocks
landscape diagnosis and perception
Current management principles (such as late mowing for export) are considered favourable and should be maintained. In order to preserve the mosaic of habitats and landscapes of the low-alkaline peat bog (northern sector), management actions should be considered to contain the cladia that is advancing on typical low-alkaline mire habitats. Localized sprigging could limit the expansion of the Marisque. In addition, management practices need to be correlated and refined with the ecology and location of the heritage species present.
Enabling factors
In order to provide a regular diagnosis of the state of health of the site's environments and landscapes, a number of measures are implemented:
- regular inventories of vegetation and flora by the Department's service providers to assess the effectiveness of management measures implemented
- implementation of a new management plan as of 2023, based on an adapted reference framework, to target the best management measures
- creation of a scientific council in 2023, which will meet regularly to discuss the site's evolution
Lesson learned
Ecological studies carried out on the site in 2022 and 2023 determined that the ratio of mowing to grazing areas (considering the northern and southern parts of the site) was balanced and conducive to habitat conservation and the maintenance of vegetation diversity. In view of this favorable result, the current split between mowing and grazing is maintained.
With regard to the grazed southern sector, and considering that the overall grazing pressure reflects a punctual trend towards progressive closure (grazing refusals, woody rejections), it was deemed worthwhile to undertake the following actions in the short term:
- selective clearing of undergrowth and crushing of overgrown areas, with export of cuttings;
- introduce rotational grazing and consider enclosing certain areas.
Lastly, we need to monitor the evolution of the woody cover to justify whether or not it is appropriate to carry out one-off interventions, which can be costly and time-consuming.
concerted management
As part of the implementation of the new management plan, a scientific committee will meet regularly to discuss the development of the site and the state of conservation of the natural environment. The effectiveness of concerted, shared governance and management has been demonstrated on the site.
Enabling factors
The Scientific Committee brings together experts who have worked on the site, as well as the relevant government and local authorities. It is thus representative of local, institutional and scientific players (also in the context of the site's classification as an APPB (Arrêté Préfectoral de Protection de Biotope).
Lesson learned
The effectiveness of concerted, shared governance and management has been demonstrated. As a result, the site is currently involved in :
- work carried out by the Conseil départemental's own management team of 7 agents specialized in work on natural areas;
- work carried out by companies specializing in the management of natural environments, within the framework of public contracts with technical specifications adapted to work in sensitive natural areas (mowing equipment adapted to fragile soils in particular);
- monitoring of the work carried out and its effectiveness, through regular studies carried out by specialized firms, as well as sharing of information at meetings of the Natura 2000 "Basse Vallée du Loing" steering committee and the scientific committee for the Episy marsh.
step-by-step implementation
the new site management approach will be implemented progressively, in stages. The corresponding deliverables will be proposed and discussed by the site's Scientific Committee and the Natura 2000 site's COPIL.
Enabling factors
In order to gradually adapt an exemplary conservation management approach to combat habitat closure, specific studies have been carried out to assess the effectiveness of mowing and grazing, based on changes in vegetation and flora taxa since at least 2010. These studies were based directly on multi-taxon inventories carried out at regular intervals on the marsh. These elements are taken into account in the site's 2023 action plan.
Lesson learned
Consequently, short- and medium-term management actions have been identified. In the short term, it is planned to carry out selective clearing and crushing of the overgrown areas (grazed area), with export of the cuttings. Similarly, it is proposed to maintain mowing techniques in the northern zone.
In the medium term, it is recommended to continue ecological monitoring of the conservation status of open environments (every 5 years), as well as monitoring of heritage flora and entomofauna.
Impacts
Beneficiaries
- the quality of the site's remarkable environments and vegetation (maintenance of good ecological status)
- services rendered:
In the context described, hay production associated with mowing is sold to local farmers, although no target is set each year. The marsh is not currently used for meat production, but this situation could change over the next few years as a result of possible new partnerships with livestock farmers.
More specifically, in 2022, the entire northern zone (5.5 ha) was mowed, resulting in the production of around 160 bales of hay, which were then recycled by an organic market gardener in the commune of Dormelles for use as mulch and compost.
Beneficiaries
In 2022, the entire northern zone (5.5 ha) was mowed, resulting in the production of around 160 bales of hay, which were recycled by an organic market gardener in the commune of Dormelles for use as mulch and compost.