Changes in weed vegetation across transects in maize fields

Weed vegetation in Central Europe has strongly changed during the last decades in response to changing agricultural practices. In addition, the cultivation of certain crops such as maize has expanded strongly. Fields are characterized by gradients from the edge to the interior, which may have ramifications on the weed vegetation. Here, we analyzed the composition of weed vegetation in maize fields from the edge to the interior documented by 101 transects consisting of three plots (10 m²) from Central Europe. In total, 203 species were recorded, including 107 (52 %) natives, 48 (24 %) archaeophytes, and 48 (24 %) neophytes. While the edge plots had a median species richness of nine species, the central plots (10 m from the field edge) and the interior plots (50 m from the field edge) both had a median of four species. Weed species cover declined more drastically from a median of 28.9 % total cover to 6.2 % to 5.0 %. Community indices (based on Ellenberg Indicator Values) changed along transects. Mean community index for light decreased towards the center, while the community index for moisture increased. The community index for nutrients increased from the edge to the central plot, but not to the interior plot. Species turnover was significant between the edge, central and interior plots. Species richness of the transects was influenced by landscape context and climate. Mean annual temperature, the amount of surrounding forests and maize fields were significant negative predictors of species richness, whereas surrounding water bodies, ruderal vegetation and built-up areas were significant positive predictors. Given that maize cultivation has rapidly expanded during the last decades, making it one of the most important crops in Central Europe, our study provides important insights into the composition of weed vegetation of a major, yet understudied component of modern agricultural landscapes.