Long-term glacier monitoring at the LTER test sites Hintereisferner,Kesselwandferner and Jamtalferner and other glaciers in Tyrol: a source of ancillary information for biological succession studies

Background: Some 3% of the area of Tyrol is covered by glaciers. Since the end of the Little Ice Age, these glaciers have shrunk by about 50%, providing open ground for succession of biota. As the exposed bare ground becomes available for colonisation, pedogenesis, and primary succession, glaciological data provide important information for the analysis of chronosequences of biological succession.

Aims: This paper summarises long-term surveillance studies and provides information on annual glacier changes with a focus on the three Tyrolean LTER sites Hintereisferner, Kesselwandferner and Jamtalferner, together with two additional glaciers.

Methods: Annual changes in the length of 54 glaciers were recorded, with the first measurements made in 1891. In addition, the long-term mass balance data of five glaciers are presented. Two of these glaciers have been surveyed since 1953.

Results: Between 1901 and 2008, the temperature during the ablation season (May to September) increased by 1.7 °C (measured at one site in Vent). In the same period, winter (October to April) accumulation showed no significant trends. Measurements of length changes showed a general glacier retreat, with limited advances in the 1920s and 1980s. The mass balance measurements indicated mass losses since the 1980s at increasing rates, especially after 2000. The reaction of glaciers to the climate signal differed in timing and magnitude according to their topographic properties.

Conclusions: Although the Tyrolean glaciers have generally retreated since the end of the Little Ice Age, the magnitude and pace of advance or recession differs from glacier to glacier. This is important to consider in studies on succession of biological communities in glacier forelands