Which Traits Make Weeds More Successful in Maize Crops? Insights from a Three-Decade Monitoring in France

Abstract

A major aim in invasion biology is identifying traits distinguishing alien invasive and alien non-invasive plants. Surprisingly, this approach has been, so far, poorly used to understand why some arable weeds are abundant and widespread while others are rare and narrowly distributed. In the present study, we focused on the characteristics of successful weeds occurring in maize fields, one of the most important crops worldwide. Two national weed surveys conducted in France were used to identify increasing and decreasing species based on 175 and 484 surveyed fields in the 1970s and the 2000s, respectively. Weed trait values related to regional frequency, local abundance, and specialization to maize were identified with phylogenetic generalized least-squares (PGLS). We found a positive relationship between regional frequency and local abundance, i.e., the most widespread weeds were also locally more abundant. We highlighted that weeds with the C4 photosynthetic pathway and summer emergence were more abundant, more frequent, and more specialized to maize crops. More generally, we highlighted two successful strategies: On the one hand, traits related to a general weediness syndrome with rapid resource acquisition (high SLA and Ellenberg-N) and high colonization capacity (seed longevity, fecundity, and wind dispersal); on the other hand, traits related to specific adaptation to spring cultivation (thermophilous species with summer emergence, late flowering, and C4 photosynthetic pathway). Deviations from the abundancy–frequency relationships also indicated that species of the Panicoideae sub-family, species with Triazine-resistant populations, and neophyte species were more abundant than expected by their regional frequency. To some extent, it is therefore possible to predict which species can be troublesome in maize crops and use this information in weed risk assessment tools to prevent new introductions or favor early detection and eradication. This study showed how tools developed in functional and macro-ecology can be used to improve our understanding of weed ecology and to develop more preventive management strategies.

Ecological Specialization and Rarity of Arable Weeds: Insights from a Comprehensive Survey in France

“…To better integrate the ecological diversity of weeds in studies of weed population and community dynamics, we proposed an index of habitat specialization that can serve as a flexible measure of weediness in place of a too sharp binary categorization of weeds. A weediness index can also integrate species characteristics such as functional traits, allowing greater weed frequency and performance in agricultural fields [ 1 , 60 ].…”

Identifying high-impact invasive plants likely to shift into northern New England with climate change

“…Invasive species can vary in their magnitude of ecological and socioeconomic impacts (Blackburn et al 2014), but are known to alter native communities and ecological processes (Pyšek et al 2012) and reduce ecosystem services (Milanović et al 2020). Invasive plants can also cause harm through loss of crop and forest productivity (Fried et al 2019;Nikolić, 2018), economic costs of management and control (Pimentel et al 2005), and hazards to human health (Potgieter et al 2017;Pyšek and Richardson 2010). Consequently, range-shifting invasive plants with the potential to cause substantial harm to ecosystems and/or socioeconomic systems are a top management concern.…”

Long-Term Soil Nutrient Management Affects Taxonomic and Functional Weed Community Composition and Structure

“…However, our results did not show that treatments with high fertility homogenized the weed community by reducing the ecological niche. Thus, (i) continuous corn production before the start of the corn-alfalfa rotation experiment in 2001 favored species adapted to high fertility levels, as demonstrated by previous research (Fried et al, 2020); and (ii) since the start of the experiment, high weed diversity did not emerge in the low fertility treatment (InorgN0) as previous studies would suggest (Storkey et al, 2010). An alternative explanation is that herbicide weed management during the experiment might have kept new species from establishing or present species from dominating the community (Adeux et al, 2019a;Cordeau et al, 2020).…”