The Environmental agency in the Franche Comté region discusses here the method tested during early programmes for ecological continuity.
Some French departments and regions started work on ecological networks and ecological continuity before the Grenelle agreements decided to create the French National ecological network. For some of them, the preparation of their Service plans for rural and natural areas (SSCENR)  led them to launch a mapping phase for ecological networks as early as 1999.
Following an initial SSCENR map drafted in 1999, the Franche-Comté region continued in 2002 with discussions on the notions of green infrastructure (DIREN et al., 2002), ecological continuity (Vedovati et Vanpeene, 2005), fragmentation (Lethuillier, 2007), mapping of a regional ecological network ( Ponchon, 2006; Coulette, 2007; Frochot, 2009) and good practices to maintain ecological continuities  (Strub, 2008). This document sums up those discussions which highlighted the methods that must be set up jointly with the local stakeholders to encourage widespread adoption of ecological networks. The goal of the joint discussions is to produce actual efforts in the field to restore and maintain ecological networks. This proposal to define methods and terminology in view of analysing ecological continuities was put forward by the regional environmental agency (DREAL) and validated by the regional scientific council for natural heritage (CSRPN) of the Franche Comté region in January 2008 (Collectif, 2008).
The DREAL approach comprises the following steps:
- mobilise organisations and stakeholders;
- set up a shared framework for discussions;
- run a diagnosis with a report on the current status;
- set priorities and prepare concrete projects for implementation.
This approach includes a proposal for a method designed for use on all scales of work and precision. The idea is to analyse terrestrial ecological continuities via a single set of questions (systematically raised) whatever the project conditions. In responding to each of the questions, the lead times, available means, existing knowledge, desired precision, size of the studied territory, type and progression of the project for which the study is carried out, etc. are all factors taken into account in selecting the best suited tools and sources (bibliographic analysis, spatial analysis, travel-cost modelling, expert advice, analysis of environmental fragmentation, field inventories, etc.). No particular techniques are recommended, all potential approaches and sources of information must be brought into play. Only one thing is considered certain, that is that the real knowledge is in the field and all hypotheses and assumptions must be confronted as early as possible with a trip to the field and/or expert advice.
The issues of aquatic biological continuities (aquatic travel, continuities along and across rivers) are not analysed here.
Five major principles guided the discussions in view of proposing this framework for an effective and operational method.
Vary the scales used for analysis and diagnostics
Even in a local project, it is necessary to widen the scope to determine the importance (local, regional, national) of the detected continuities. Conversely, vast projects require very local checks in important sectors (major constraints or the habitat of high-value species) on the functioning of an ecological continuity.
Reason in terms of (eco)-landscape units rather than administrative borders
Each landscape (and landscape unit) functions in its own way and provides precious clues to where continuities are located (tree lines, valley bottoms, etc.).
Start by mapping environments, then address the needs of flag species
In that selection of target species is always difficult, this method proposes systematically addressing the continua, then filling out the diagnostics with information on the needs of flag species if any exist in the studied territory.
Assign ecological continuities to three levels
These continuity levels depend on the available knowledge or the targeted degree of detail. The levels are 1) important sectors (there is a particular issue for ecological continuity), 2) travel routes (it is possible using arrows to indicate where continuity occurs) and 3) corridors (ecological continuity is clearly identified and can be precisely mapped).
Produce topical maps and launch the participative process using the maps
Maps of the inventory and protection perimeters, continua, territorial fragmentation, etc. are all information sources that should be used to better understand how ecological networks function in a given territory. It is on the basis of these maps and the participative process allowing the territorial stakeholders to pull the information together that an overall summary map can be drawn up presenting their shared commitments and projects.
It was possible to devise a four-step process based on the stated principles and the discussions held (table 1). Prior to the recommendations made for the National ecological network, this process made it possible to develop acceptance of the conservation issues in ecological networks and to propose projects through a participatory approach.
The two examples below illustrate how the method could be applied to two projects, one large in scale and the other more local. These examples are purely informative in nature and are not intended as detailed solutions to be applied directly (in particular, use is not made of all the potential bibliographical and cartographic data).
Example 1. Large-scale (regional) linear-infrastructure (rail) project
In this case, the project would take place over a significant period of time and have a major impact on ecological continuities. It would thus be possible to adapt the various study steps to the different project phases (table 2).
Example 2. Small town, near a major centre, planning (PLU, local urbanisation plan) to extend a residential subdivision and set up a special development zone
The project has the potential to significantly impact ecological continuities (urbanisation). But the diagnostics must be carried out over a short time span and with limited means (table 3). The town was recently the site of a development project (the design studies are available). Studies for the ecological network were carried out in the framework of the SCOT (local development plan) currently being set up.
In 2008, DREAL launched a work group to set up efforts to solve conflicts concerning infrastructure and fauna. The proposed method was used in part in setting up this work group and a certain number of practical lessons were drawn from the analysis of how the "National ecological network infrastructure" group functioned.
The topic (How to deal with a disagreement?) is more motivating for stakeholders than the theory of ecological networks. The system of workshops with technical assistants to work on a precise agenda was very effective. The best study scale was that of a project combining the local level, strong involvement by all stakeholders and solid knowledge on the functioning of the environment.
The experience gained showed that there is no point in setting up a very large, comprehensive group, it is better to start with a core group of motivated people that will grow on its own as the meetings go by. In the end, the group comprised 26 organisations including some that DREAL was not in the habit of meeting, e.g. infrastructure managers (highways, rail, electricity), State services (environment, agriculture, industry), local governments (region, department), environmental-protection associations, hunting associations, etc.
The diversity of the groups brought together, even though it can result in opening up old wounds, is a key factor for project success and to achieve effective implementation of the decided work programme. It makes it possible to discuss internal data from each organisation and to draw attention to their work, as well as to establish dialogue between groups. However, this project made clear the difficulty of readily sharing unprocessed data and finally opted to share experiences as a more pragmatic means to advance.
The diversity of stakeholders also made it possible to discuss the mixing of biodiversity-preservation issues with many other territorial-development policies and the many threats weighing on biodiversity and ecological continuity (infrastructure, urbanisation, etc.), but also the many possible synergies (landscapes, amenities, flood risks, public safety, etc.).
The establishment of a common language, with the necessary terminology, was a step that took a great deal of time, but was indispensable in creating a project shared by all.
When a scientist acts as mediator, he or she ensures the mixing of cultures and rigor during discussions, and encourages greater confidence between stakeholders.
The regional level (in the regional ecological-continuity plans) in the National ecological network and its local application in development projects (infrastructure, urbanisation, PLUs and development projects) could make good use of this very pragmatic approach in that it has shown its effectiveness in the Franche Comté region.
 Article 23 of law 99-533 voted 25 June 1999 on territorial planning and sustainable development, modifying law 95-115 voted 4 February 1995 on territorial planning and development.
 The meaning here is that of a link, in a very general sense, between two environmentally similar environments. The term comprises both corridors and travel routes.
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Référence électronique :
PIEL, Arnaud ; VANPEENE, Syvie, A practical analysis of ecological continuity on diverse territorial scales - Example of a method employed prior to the French ecological-network project, Revue Science Eaux & Territoires, Public policy and biodiversity, numéro 03bis, 2011, p. 116-121, 15/03/2011. Disponible en ligne sur <URL : http://www.set-revue.fr/practical-analysis-ecological-continuity-diverse-territorial-scales-example-method-employed-prior> (consulté le 24/10/2021), DOI : 10.14758/SET-REVUE.2011.3BIS.22.