Vanishing glaciers threaten alpine biodiversity

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With glaciers melting at unprecedented rates due to climate change, invertebrates that live in the cold meltwater rivers of the European Alps will face widespread habitat loss, warn researchers.

Many of the species are likely to become restricted to cold habitats that will only persist higher in the mountains, and these areas are also likely to see pressures from the skiing and tourism industries or from the development of hydroelectric plants.

The research study — led jointly by the University of Leeds and University of Essex — calls on conservationists to consider new measures to protect aquatic biodiversity.

Invertebrates — key role in ecosystems

The invertebrates, which include stoneflies, midges and flatworms, play a key role in nutrient cycling and organic matter transfer to fish, amphibians, birds and mammals in the wider Alpine ecosystem.

Using glacier, landscape and biodiversity mapping data collected across the Alps, scientists from across Europe simulated how key invertebrate populations across the mountain range are likely to change between now and 2100 because of climate change.

As the climate warms, the modelling predicted the invertebrate species would seek out colder conditions in the highest parts of the mountain range. In the future, these colder areas are also likely to be prioritised for skiing or tourism or the development of hydropower plants.

Lee Brown, Professor of Aquatic Science at the University of Leeds who co-led the research, said: “Conservationists need to be thinking about how protected area designations must evolve to take into account the effects of climate change.

“It may be that some species will have to be moved to refuge areas if we want to safeguard their survival as many of them are not strong fliers so they cannot disperse easily through the mountains.”

Alpine climate is changing rapidly

The research, involving a collaboration between nine European research institutions, brought together data on invertebrate species distribution in the Alps, an area that covers more than 34,000 square kilometres, and mapped it alongside expected changes to glaciers and river flows.

There was sufficient data to model what was likely to happen to 19 invertebrate species, mainly aquatic insects, that live in the cold-water regions of the Alps.

Dr Jonathan Carrivick, from the School of Geography at Leeds who co-led the research, said: “We have quantified that as glaciers melt and retreat, the rivers running through the Alps will experience major changes in their water source contributions.

“In the short term, some will carry more water and some new tributary rivers will form, but over several decades from now — most rivers will become drier, flow slower and become more stable, and there could even have periods in a year when there is no water flow. Additionally, most water in Alpine rivers will also be warmer in the future.”

Losers and winners

By the turn of the century, the modelling predicts that most of the species would have experienced “consistent losses” of habitat.

Those hardest hit are expected to be the non-biting midges, Diamesa latitarsis grp., D. steinboecki, and D. bertrami; the stonefly, Rhabdiopteryx alpina; and mayfly, Rhithrogena nivata.

However, several species are expected to benefit from the habitat changes, including the flatworm, Crenobia alpina and the flat headed may fly, Rhithrogena loyolaea.

Other species would find refuge in new locations. The scientists predict the stonefly Dictyogenus alpinus and the caddisfly Drusus discolor will be able to survive in the Rhone valley in southeast France while other species will be lost from the rivers that flow into the Danube basin.

Conservation

Writing in the paper, the researchers describe the “substantial work” that is necessary to protect the biodiversity in rivers that are being fed by retreating glaciers. The locations where glaciers still exist late in the 21st century are likely to be prioritised for hydropower dam construction and ski resort development.

Dr Martin Wilkes, from the University of Essex and who co-led the research, said: “The losses we predict for Alpine biodiversity by the end of this century relate to just one of several possible climate change scenarios.

“Decisive action by world leaders to reduce greenhouse gas emissions could limit the losses. On the other hand, inaction could mean that the losses happen sooner than we predict.”

Understanding how invertebrate populations respond to climate changes is key to understanding how biodiversity in high mountainous areas can be affected, and the techniques developed in the study could be applied to other mountain environments.

The UK’s Natural Environment Research Council contributed to the funding of the study.



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