AMO-Herbacées-SM3A

Assistance to the project management for the creation of seed mixes and heliophyte nurseries

Context

As part of its restoration projects, the Syndicat Mixte d'Aménagement de l'Arve et de ses Affluents (SM3A) endeavors to use plant engineering or mixed techniques, thus allowing a better integration of the works in the alluvial environment and limiting as much as possible the disturbances of the ecological functions, in particular the risks of disruption of the ecological continuity.

Plant engineering is in full expansion since GEMAPI has competently taken over the management of aquatic environments and flood prevention, as well as the regulation of dams. Indeed, the management of the numerous waterways in the Arve catchment area (1400 km) involves numerous worksites set up by the SM3A.

The present project focuses on the herbaceous plants used in the plant engineering works, i.e. the helophytes (semi-aquatic plants used at the foot of the banks) as well as the herbaceous seed mixes used on the landscaped surfaces.

The choice of plant species used in a vegetation management project has a major influence on the final result and in particular on the technical, biological and landscape performance of the project.

Objectives

For these reasons, the SM3A requires quality seed mixtures, in order to respond to the many different contexts and development objectives that a manager may face. Similarly, they need a wide choice of heliophytes to meet their current objectives. It is true that for these plants, even more so than for seeds, it is almost never possible to obtain plants of regional origin through specialized nurseries (notion of ecotype).

Once the seed mixes and the range of plants have been determined, the SM3A wishes to have sufficient autonomy so that the project managers are able to make judicious choices of plant material. This can be achieved through good guidelines and training.

The mission of the HEPIA EVA group can therefore be summarized as follows:

• to compose qualitative seed mixtures, in order to cover all the needs of the SM3A in terms of restoration;
• to elaborate a choice of heliophytic plants relevant to their projects and which will serve as a basis for the development of a nursery;
• to write a technical note justifying the options selected;
• to organize two days of training for SM3A's project managers.