Weed vegetation of arable land in Central Europe: Gradients of diversity and species composition

Abstract

Question: What are the main broad‐scale spatial and temporal gradients in species composition of arable weed communities and what are their underlying environmental variables? Location: Czech Republic and Slovakia. Methods: A selection of 2653 geographically stratified relevés sampled between 1954–2003 was analysed with direct and indirect ordination, regression analysis and analysis of beta diversity. Results: Major changes in weed species composition were associated with a complex gradient of increasing altitude and precipitation and decreasing temperature and base status of the soils. The proportion of hemicryptophytes increased, therophytes and alien species decreased, species richness increased and beta diversity decreased with increasing altitude. The second most important gradient of weed species composition was associated with seasonal changes, resulting in striking differences between weed communities developed in spring and summer. In summer, weed communities tended to have more neophytes, higher species richness and higher beta diversity. The third gradient reflected long‐term changes in weed vegetation over past decades. The proportion of hemicryptophytes and neophytes increased, while therophytes and archaeophytes decreased, as did species richness over time. The fourth gradient was due to crop plants. Cultures whose management involves less disturbances, such as cereals, harboured less geophytes and neophytes, and had higher species richness but lower beta diversity than frequently disturbed cultures, such as root crops. Conclusions: Species composition of Central European weed vegetation is mainly influenced by broad‐scale climatic and edaphic factors, but its variations due to seasonal dynamics and long‐term changes in agricultural management are also striking. Crop plants and crop‐specific management affect it to a lesser, but still significant extent.

Diversity of current weed vegetation on arable land in selected areas of the Czech Republic

“…Contrastingly, we found a higher species richness in the less productive areas where the intensification factors were not as highly employed. Our results confirm the findings of Lososová et al (2004) and Fried et al (2008), who also recorded higher species richness in agrophytocoenoses at higher altitudes.…”

“…The results of this study endorse the findings of Fried et al (2008), who also indicated a reduction in β-diversity at higher altitudes (> 300 m) and with extreme soil pH (acidic or alkaline) or on sandy soils. Lososová et al (2004) also reported a clear decrease in β-diversity with increasing altitude. As for individual crops under conventional and organic farming, greater β-diversity was recorded for the root crops and winter cereals, respectively (Figure 3).…”

“…The β-diversity assessment (i.e., the mean difference in weed species composition among the relevés) was performed according to Lososová et al (2004) in Juice 6.5 software (Tichý 2002). We partitioned the dataset along the different identified gradients (i.e.…”

“…soil, climate) influence the occurrence of weed species in agrophytocoenoses. One of the priority factors considered in this regard is the effect of altitude, which is associated with many other ecological habitat parameters and the types of farming used in certain regions (Lososová et al 2004). However, Cimalová and Lososová (2009) show that on regional scale, the relative importance of different crop types and their associated management on changes in arable weed species composition is higher than the relative importance of climatic variables.…”

Experience with using Ellenberg’s R indicator values in Slovakia: Oligotrophic and mesotrophic submontane broad-leaved forests

“…As an alternative, a national system of plant indicators was developed by Jurko (1990). Nevertheless, EIVs have been widely used by many authors in Slovakia, and in numerous fields of environmental and ecological science (e.g., Lososová et al 2004;Uherčíková & Némethová 2006;Janišová et al 2010;Chovancová & Križová 2010). The two main aspects of the criticism are addressed in this study: (i) Ellenberg's R indicator values should be validated for a particular region, and (ii) calibration to physical pH measurements can significantly increase performance of plant indicator systems (e.g., Lawesson et al 2003;Wamelink et al 2005).…”