Sprinkler systems as a cause of intensification grassland use in the Swiss Engadin
2014
Graf, R. | Korner, P. | Birrer, S., Schweizerische Vogelwarte, Sempach (Switzerland)
During a long-term monitoring from 1987 to 2010, changes in vegetation and land-use intensity at irrigated versus non-irrigated study sites were investigated in the Swiss Engadin. Specifically, vegetation surveys were compared between the years 1987/88 and 2009/10 to identify whether and how proportions of extensively used (no-input) hay meadows to low-intensity meadows changed (including a range of meadows used at intermediate intensity). We discovered that not only older but also the latest sprinkler systems were set up in areas covering a high proportion of extensively used meadows of conservation concern. Before the survey, 40 % of the vegetation around sprinklers installed in the 1980s was extensively or less intensively used. The same was true for 56 % of the vegetation around sprinklers installed by 2009/10. The proportion of low-intensity meadows under irrigation systems from the 1980s decreased drastically to 13.5 %. For newer sprinkler systems, such an effect was not observed. Study areas holding irrigation systems experienced general land-use intensification, also outside the irrigated area. Conversely, the proportion of extensively and less intensively used meadows has increased in all study areas without irrigation systems. Managers involved in irrigation projects have repeatedly affirmed that additional irrigation systems were installed solely to achieve stable yields in dry years, and that these additions would not lead to further land-use intensification. This assertion, however, does not apply to the study sites presented here.
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