An alpine river, the Tagliamento, may reveal ways to prevent biodiversity loss.

Biodiversity loss is exacerbated by global warming, increased pollution and habitat loss. Human enterprise is much to blame for the alteration of river ecosystems: management (channeling), land use (agriculture and development), introduction of new species and acid rain. At the same time, freshwater aquatic systems account for less than 2 percent of the available water supply – a fact that makes freshwater Alpine rivers highly valuable. Conservation efforts are key to management of rivers and restoration of these fragile resources.

Alpine rivers are important to biodiversity, but the majority of them have been diked or canalized. The alteration of flows have changed, if not severed, the natural dispersal of water, nutrients and species over the Alpine floodplain. The exception is the Tagliamento River that flows from the Italian Alps to the Adriatic Sea. It is the only large structurally intact Alpine river in Europe and provides a glimpse of Alpine rivers in the pristine state, according to James Layzer, editor of A Reference River System for the Alps: the ‘Fiume Tagliamento.’

The Tagliamento has features that promote biodiversity, such a braided system, floodplain and riparian zone. A braided river, which consist of small channels separated by small bars, helps regulate current. It also increases biodiversity by providing a habitat for invertebrates, fish and hydrophytic plants. Because the Tagliamento River follows an original course, it supports nutrient recharge and discharge from the terrestrial landscape. The floodplain enable proper exchange and is home to flood tolerant plant species that can repopulate Alpine areas. The all important riparian zone, or transitional space between the terrestrial and aquatic systems, has specialized plants that support wildlife. It also functions as a buffer that transforms nutrients, sediment and toxins and eases erosion.

If Alpine biodiversity is adversely affected by habitat loss, fragmentation, and disruption from major climatic events, such as flooding, then proper management of fragile river systems is crucial to prevent the loss of biota. River management concepts that focus on conservation, restoration, and prevention of biodiversity loss should include Alpine river studies.

That’s exactly what researchers did at the ESF workshop. Ecologists looked at Alpine Rivers, specifically, the role riparian plants play in providing habitats for other species to colonize, flow regulation and nutrient cycling. The goal is ecosystem establishment with links to floodplains where space is available in hopes of developing sustainable Alpine river management policy that will prevent further biodiversity loss.