Field margins are important habitats for various plant species in agro-ecosystems but they can also be
exposed to agrochemicals. In this experimental field study, effects of herbicide, insecticide, and fertilizer
misplacements in field margins on the plant frequency and reproductive capacity of four wild plant
species (Ranunculus acris, Lathyrus pratensis, Vicia sepium, Rumex acetosa) were investigated from 2010 to
2012. Individual and combined effects of the agrochemicals were studied in a randomized block design
and plant community assessments were performed every year. Additionally, seeds of the four species
were harvested in 2012 to detect effects on plant reproduction. Plant frequencies of the four species
were significantly reduced in all herbicide and fertilizer treatments in the third year. The plant frequency
of R. acris and L. pratensis was more affected in the fertilizer treatments than in the herbicide treatments,
whereas the plant frequency of V. sepium and R. acetosa was similarly affected by fertilizer and herbicide
treatments. However, the treatment combinations of fertilizer and herbicide resulted in additive effects
on the plant frequency of V. sepium and R. acetosa. Furthermore, herbicide treatments suppressed the
formation of flowers and, hence, led to a significantly reduced seed production of R. acris, L. pratensis,
and V. sepium. Because field margins are exposed to repeated agrochemical applications over several
years, the observed effects will possibly lead to shifts in plant community compositions and cause the
disappearance of the affected plants in the long run. In the current risk assessment of herbicides for
nontarget plants no reproduction effects are considered, and therefore, it seems that herbicide effects on
wild plants species are potentially underestimated.
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