“My number one recommendation? Consult with the local people before you do anything!” Stéphane Bovier, engineer in charge of waterways in the canton of Valais, had just given a brief explanation of the process of revitalizing and introducing flood protection measures along the Dranse river, which flows into the Rhone. Past interventions of damming and straightening the river have taken their toll on the river’s biodiversity and natural flow, with over 50% of the watershed being captured for hydroelectricity generation. Unfortunately, such interventions have rendered the Dranse more susceptible to flooding during extreme weather events – events that are becoming more frequent due to climate change.
Stéphane was speaking at a field day of the Swiss NGO Disaster Risk Reduction Platform focusing on nature-based solutions. Here we reflect on a few points of comparison between the experience in Switzerland and in North Macedonia, where Helvetas provides advisory support to the Nature Conservation Project (NCP). The importance of local consultation has been recognized and well integrated into NCP from the start – even using a professional “game” (ComMod) with stakeholders to promote collective decision-making. But comparisons between nature-based interventions in the two countries do not end there.
Promoting biodiversity within and along rivers
Revitalizing a river is a complicated matter, involving many considerations. An essential aspect is allowing the river to broaden its course and meander naturally within a wider bed – not always a popular measure with those owning rare flat agricultural land along the Dranse valley bottom. The arguments that work best are those related to reducing the risk of flooding, since these make clear financial sense; according to Stéphane, there is a ratio of roughly 1:3 in terms of every franc invested for a disaster avoided. Yet for environmental authorities and the wider scientific community, the additional opportunity to encourage recolonization by indigenous flora and fauna is an important one. Tree saplings have been planted along the riverbanks; old logs left to encourage wood-eating insects; stones piled in other places to serve as reptile residences; and ramps constructed within the riverbed to facilitate fish migration. As the river has become shallower, the water also has grown warmer, further influencing aquatic life. Overall, the river and its composition of interlinking plant, animal and insect species is gradually returning to an earlier, more complex and “nature based” state.
In North Macedonia, the NCP also works on reducing the risk of floods and promoting biodiversity within and along the Bregalnica river. Interventions focus on the replanting of riparian (riverside) forests using indigenous tree species such as white poplar (Populus alba) and white and crack willow (Salix alba and S. fragilis). Restoring such forests in places where they have been destroyed or degraded by earlier human activity represents an important step in re-establishing the whole riparian ecosystem and preventing landslides and erosion, as well as flooding. Working with the Macedonian Ecological Society, the NCP has supported a series of studies showing how the flora and fauna is responding positively to increased riparian tree cover.
Combatting invasive species
A familiar bush was flourishing close to where we stood along the Dranse: Buddleia davidii, the purple-flowering garden shrub that is now recognized as a major invasive species in much of Europe. According to Stéphane, it is now so widely spread in Valais that it is almost impossible to control. In out-competing indigenous flora and fauna and disrupting the complex web of interactions between them, invasive species are a major threat to biodiversity. Stéphane cited two plants on which eradication efforts are now focused: Giant Hogweed (Heracleum mantegazzianum) and Japanese Knotweed (Reynoutria japonica or Fallopia japonica). Both are extremely difficult to control, especially without resorting to herbicide. Nevertheless, cutting Giant Hogweed before flowering and burying it in pits is apparently quite effective, though labor-intensive.
In North Macedonia, the invasive species of greatest concern in riparian areas are the false indigo bush, Amorpha fructicosa; black locust, Robinia pseudoacacia; and Ailanthus, Ailanthus altissima. The easily dispersed seeds of the false indigo means that it readily colonizes riverbanks, forming a dense mass of vegetation. Robinia and Ailanthus are considered an environmental threat throughout much of Europe, including Switzerland where they are on the Black List of invasive species. Unfortunately, Robinia is still used in North Macedonia for the afforestation of erosive surfaces – precisely because of its rapid growth. It has now colonized many abandoned rural areas, as has Ailanthus; both represent a growing problem, but one that is currently not being controlled due to a lack of labor. They are illustrative of the dilemma of maintaining biodiverse landscapes in an area that is becoming increasingly depopulated, with people moving away to towns and other areas with better employment prospects.
Galvanizing the local population
There is perhaps one matter in which the NCP is ahead of the authorities in Valais: the use of social media (Twitter, Instagram, Facebook, and others) to inform citizens remaining in the countryside – and those who have left – about the importance of biodiversity and ecosystem health. Currently the project’s Facebook page has more than 46,000 regular followers, and public awareness surveys have shown a steady increase in public recognition of, and knowledge about, biodiversity conservation.
Co-author Svetlana Arsovska Pejovik is coordinator of NCP’s component for restoration of riparian ecosystems at the Macedonian Ecological Society.