From mapping to action: bringing data down to earth, to restore natural environments

At almost 2900 metres above sea level, the Grand Bénare mountains are home to habitats and species with high heritage value. However, those environments are under many types of pressure, notably from invasive exotic species, fires, erosion or overtourism. The issue is no longer just knowing where habitats to be preserved and degraded zones are: it is now important to decide where to intervene, in which ways and in what order.

A map with a new function

The diagnosis of the mountain range was based on extensive fieldwork: 1050 hectares were covered, taking 88 man-days, supplemented by remote sensing data. That combination served to characterise the degree of invasion and to distinguish between intact, less invaded, moderately invaded and highly invaded sectors. However, the novelty lay mainly in how the data were used: the map is not the end result, but a decision support tool.

This rationale fits neatly into ReMiNat, a research and innovation project aimed at federating players in Réunion around a spatialised, operational strategy to restore natural environments. In Grand Bénare, it has now truly taken shape: a ten-year programme to steer human and financial resources towards the sectors where they will be of most use. Managers are now implementing part of the programme: the Réunion National Park and the French Forestry Board (ONF) are working on an area of around 1000 ha. Three brigades are crisscrossing the mountains regularly to set up these actions.

From pixel to operation: each situation calls for an action

The programme translates mapping into grassroots decisions. In as-yet intact or scarcely invaded zones, the priorities are surveillance and prevention. Isolated foci may be surveyed and targeted. In less or moderately invaded zones, there are plans for restoration operations. Lastly, on invasion frontlines, the aim is to stop the spread. In other words, the idea is not to take the same action everywhere, but to adapt efforts to the state of the environment, the dynamics of the invasion, and the feasibility of interventions.

ReMINaT's approach has one central principle: constant dialogue between scientific data, expertise and grassroots realities. Réunion National Park management stresses that "including the different partners in this co-constructed approach serves to build a coherent management strategy on the scale of the mountain range".

A collective strategy to allow scaling up

This roadmap is being built with the Réunion National Park, ONF, the Mascarin national botanical conservatory, the State, the Regional Council and the Departmental Council, along with CIRAD, the University of Réunion and the other players involved in conserving natural environments. Each partner is contributing its data, expertise, field experience and intervention capacity.

The result is a programme designed to be put into practice: over ten years, with prioritised interventions and a funding requirement currently  estimated at between 7 and 12.5 million euros. The plan is also to monitor and assess interventions, continue the diagnosis in zones that have not yet been inventoried, and test new restoration techniques.

This is where the approach comes into its own: data do not stay on a map. They become decisions, and then operations. In Grand Bénare, mapping has now provided a shared roadmap to protect those sectors that are still intact, intervene where invasion is progressing, and restore the most degraded environments. This is a very concrete way to apply research: in the choices made by managers, in resource planning, and, in future, in restoration operations.

Grand Bénare in figures:

• 4500 ha - area of the mountain range
• 1050 ha - area covered for diagnosis
• 10 years of programming
• € 7 to 12.5M - estimated funding required for implementation