Current State and Drivers of Arable Plant Diversity in Conventionally Managed Farmland in Northwest Germany

Abstract

Agricultural intensification has led to dramatic diversity losses and impoverishment of the arable vegetation in much of Europe. We analyzed the status of farmland phytodiversity and its determinants in 2016 in northwest Germany by surveying 200 conventionally managed fields cultivated with seven crops. The study was combined with an analysis of edaphic (soil yield potential), agronomic (crop cover, fertilizer and herbicide use) and landscape factors (adjacent habitats). In total, we recorded 150 non-crop plant species, many of them nitrophilous generalist species, while species of conservation value were almost completely absent. According to a post-hoc pairwise comparison of the mixed model results, the cultivation of rapeseed positively influenced non-crop plant species richness as compared to winter cereals (wheat, barley, rye and triticale; data pooled), maize or potato. The presence of grassy strips and ditch margins adjacent to fields increased plant richness at field edges presumably through spillover effects. In the field interiors, median values of non-crop plant richness and cover were only 2 species and 0.5% cover across all crops, and at the field edges 11 species and 4% cover. Agricultural intensification has wiped out non-crop plant life nearly completely from conventionally managed farmland, except for a narrow, floristically impoverished field edge strip.

Drivers of species composition in arable‐weed communities of the Austrian–Hungarian borderland region: What is the role of the country?

“…This suggests that there was an obvious difference between the weed composition of field edges and field cores. This result seems to be in line with observations previously reported from soybean and oil pumpkin fields in Hungary (Pinke et al., 2016, 2018) and other recent European studies (Wietzke et al., 2020; Yvoz et al., 2021). The influence of plot location on weed distributions can have many explanations.…”

“…A similar pattern in oilseed rape in France also was confirmed by Berquer et al (2021), who reported that weed assemblages in field cores are mainly shaped by crop height (indicating crop competition), while height has little effect in the field margins. Additionally, the effects of intensive crop management generally decrease towards the field periphery (Pinke et al, 2012;Wietzke et al, 2020;Yvoz et al, 2021), and the differences between field edge and field core can also be less marked when crop management intensity is lower (Yvoz et al, 2021).…”

Weed Composition in Hungarian Phacelia (Phacelia tanacetifolia Benth.) Seed Production: Could Tine Harrow Take over Chemical Management?

“…For example, S. annua, a retreating melliferous weed with great ecological and historical value [88], sometimes thrived in large quantities in such fields. In contrast, the spayed phacelia crops usually hosted only a few common weed species, such as the majority of conventional farmlands in Europe, where agricultural intensification absolutely impoverished the arable weed flora [89]. This highlights the importance of extensification in phacelia crops for the conservation of rare arable plants in Europe [90].…”

Short-Rotation Coppice Managed According to Ecological Guidelines—What Are the Benefits for Phytodiversity?

“…Basically, the plant communities of the surveyed SRC and all other investigated habitat types were dominated by widespread, common and non-threatened plant species. In our study region, the presence of species of conservation concern was not expected, since the establishment potential for these species is limited due to many decades of intensive agricultural use [66][67][68]. However, in many other studies on SRC in different regions of Germany and in other European countries [22][23][24][25][26]29,33,54,55,69], these woody crops did not prove to be a habitat of major importance for rare or threatened plant species.…”