Decrease of weed species diversity in Baden-Wuerttembergia – a comparison of vegetation surveys in 1948/49, 1975–1978 and 2011 in the area of Mehrstetten – recommendations for agriculture and nature conservation | Rückgang von Ackerunkräutern in Baden-Württemberg – ein Vergleich von vegetationskundlichen Erhebungen in den Jahren 1948/49, 1975–1978 und 2011 im Raum Mehrstetten – Empfehlungen für Landwirtschaft und Naturschutz
2013
Gerhards, R. | Dieterich, M. | Schumacher, M.
In the period from the beginning of grain cultivation in Central Europe until the middle of the last century, the number of arable weed species has steadily increased due to diverse and extensive cropping systems. Since 1950, crop production systems have been intensified, arable land has been used for development (construction), chemical and mechanical weed control has improved and many crops have disappeared. These factors all have contributed to a strong decrease of weed species diversity. Based on detailed vegetation assessments this pattern was confirmed in the Mehrstetten area (Reutlingen County). Sampling data from 2011 were compared to data available for the same sites from 1948/1949 and 1975–1978. In the period covered, weed diversity decreased from by 64 % (97 species). Abundance of weed species was significantly higher in the field margins as compared to the center of the fields. Vegetation data obtained in 2011 no longer allowed for the identification of plant species communities since no species distinctly characterizing certain communities were recorded. There was no shift in the Ellenberg, Zeigerwerte von Pflanzen in Mitteleuropa, 1991, indicator values. None of the 23 endangered species still present in 1948/49 was recorded in 2011. Based on survey results, we assume that decrease in weed species diversity was caused by intensive cropping practices associated with the use of mineral fertilizer and herbicides as well as other effective methods of weed control.
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