KLIMAGRAD project takes stock

How are climate change and tourism affecting the Alpine ecosystem?

The study headed up by Technische Universität München (TUM) investigated factors like vegetation cycles and the impact of tourism, grazing and air pollutants on an Alpine ecosystem. The objective of the KLIMAGRAD project was to document the effects of these factors on the Werdenfelser Land region. In coming years, the scientists will be able to determine whether and to what extent climate change and other “man-made” influences are harming this Alpine ecosystem.

“Our study is particularly valuable as it takes it’s a holistic approach to investigating the various changes triggered by climate change and human and animal activities,” explains Prof. Annette Menzel from the Chair of Ecoclimatology at TUM, who directed the project.

Longer vegetation cycles

So how exactly is climate change impacting vegetation cycles in the Alps? A team from the Chair of Ecoclimatology at TUM decided to investigate. Geo-ecologist Christina Schuster carried out a phenological survey to record the date of emergence of flowers and leaves along with the date of leaf fall, gauging how temperature influenced the phenology in a mixed Alpine forest. She found that a one-degree rise in temperature extends the vegetation cycle by two weeks. This seasonal shift can have serious repercussions, influencing insect pollination, for example, or resulting in an increased risk of late frost.

The scientist also investigated trunk growth on birch and spruce trees. As expected, growth declined as altitude increased. In deciduous trees, longer vegetation cycles also influenced the period of trunk growth. So broad-leaf trees benefit more from rising temperatures than conifers – a potentially interesting finding for forestry managers.

Tracing air pollutants

Soil nitrogen has a particularly detrimental impact on Alpine forests. A workgroup at Helmholtz Zentrum München decided therefore to investigate nitrogen deposits in spruce forests. Their findings were alarming: As a result of harmful emissions, from traffic or agriculture for example, up to 30 kilos of nitrogen per hectare and year was recorded – a level that exceeds the critical threshold for forest damage. The repercussions can include lower species diversity and over-acidified soils.

Dr. Michael Leuchner from the TUM Chair of Ecoclimatology studied volatile organic compounds (VOC) – precursors of ground-level ozone. As an irritant gas, ozone is harmful to humans, animals and plant life. It is also a greenhouse gas. VOCs mainly result from the incomplete combustion of organic substances. The highest concentrations were measured in the valley near human settlements and roads. The levels decreased at higher altitudes, but rose again in the higher reaches of the Kreuzeck mountain where the cable car is in operation.

Impact of humans and animals on ecosystems

How do humans and animals impact vegetation in Alpine regions? Scientists from the University of Augsburg have created a detailed vegetation map of the Zugspitzplatt plateau. The effects of tourism were particularly evident around the larger mountain huts: The surrounding areas were almost completely devoid of vegetation. Along the ski slopes and hiking paths, too, plant cover was significantly diminished as a result of mechanical stress. The grazing of hundreds of sheep also left its mark on the ecosystem: The scientists discovered pastures that were stripped bare and high levels of nitrogen in the soil.  

The KLIMAGRAD project

The three-year KLIMAGRAD study was completed at the end of January 2013. The joint project involving TUM (project lead), LMU, the University of Augsburg, Helmholtz Zentrum München and Munich Botanical Gardens was financed by the Bavarian State Ministry of the Environment and Public Health. The KLIMAGRAD project relied on an extensive monitoring network set up along four altitudinal gradients in the Werdenfelser Land region, with the altitudes ranging from 700 to 1,800 meters.