The utility of the “Arable Weeds and Management in Europe” database: Challenges and opportunities of combining weed survey data at a European scale

Over the last 30 years many studies have surveyed weed vegetation on arable land. The “Arable Weeds and Management in Europe” (AWME) database is a collection of 36 of these surveys and the associated management data. Here we review the challenges associated with combining disparate datasets and explore some of the opportunities for future research that present themselves thanks to the advent of the AWME database. We present three case studies repeating previously published national scale analyses with data from a larger spatial extent. We demonstrate that i) the standardisation of abundance data to a common measure, prior to the analysis of the combined dataset, has little impact on the outcome of the analyses, ii) the increased length of environmental or management gradients allows for greater confidence in conclusions, iii) the main conclusions of analyses done at different spatial extents remain consistent. These case studies demonstrate the utility of a Europe-wide weed survey database, for clarifying or extending results obtained from studies at smaller scales. This Europe-wide data collection offers many more opportunities for analysis that could not be addressed in smaller datasets; including questions about the effects of climate change, macro-ecological and biogeographical issues related to weed diversity as well as the dominance or rarity of specific weeds in Europe

Arable Weeds and Management in Europe

“Arable Weeds and Management in Europe” is a collection of weed vegetation records from arable fields in Europe, initiated within the Working Group Weeds and Biodiversity of the European Weed Research Society (EWRS). Vegetation-plot data from this scientific community was not previously contributed to databases. We aim to prove the usefulness of collection for large scale studies through some first analyses. We hope to assure other weed scientists who have signalled willingness to share data, and plan to construct a full data base, making the data available for easy sharing. Presently, the collection has over 60,000 records, taken between 1996 and 2015. Many more studies for potential inclusion exist. Data originate mostly from studies exploring the effect of agricultural management on weed vegetation. The database is accompanied with extensive meta-data on crop and weed management on the surveyed fields. The criteria for inclusion were a minimum amount of information on the cultivated crop, and a georeference. Most fields were surveyed repeatedly, i.e. transects, multiple random plots, or repeated visits. All surveys aimed to record the complete vegetation on the plots. Sometimes, taxa were identified only to genus level, due to survey dates very early in the vegetation period. Plant taxonomy is standardized to the Euro+Med PlantBase