Abstract
Background: Intensive farming affects farmland biodiversity, and some arable plants in particular. Increasing crop genetic diversity can increase crop productivity or resilience and could also benefit rare arable plants.
Aims: We examined whether barley presence, sowing density and genetic diversity impacted the rare plant Valerianella rimosa and explored possible underlying mechanisms.
Methods: In a field study near Dundee, Scotland, we sowed plots of five single barley genotypes, and all five genotypes combined, at three densities; we also had barley-free plots. Valerianella seeds were sown into half of all plots. Measured responses included early-season cover and harvest biomass of barley and common weeds, abiotic parameters (soil moisture, light) and establishment, biomass and seed production by V. rimosa.
Results: Barley presence promoted V. rimosa establishment early in the growing season, but without barley density or genetic diversity effects. By harvest, the impact of barley presence on V. rimosa abundance was lost; there were no effects on Valerianella seed production. Barley negatively impacted common weeds, but V. rimosa did not benefit from any indirect facilitation by barley, being bigger without barley.
Conclusions: Early beneficial effects of barley on V. rimosa abundance appear offset by late-season competition. However, limited impacts of barley on V. rimosa reproductive success, and negative impacts on common weeds, indicate crops might play a role in conservation management of rare arable plants by creating space in the weed community.
Acknowledgements
The authors would like to thank David C Guy, Euan Caldwell and JHI trials staff for help with the trial set-up and harvest, and Marie Gallon, Kristi Leyden and Luke Beesley for field work (monitoring and harvesting).
Disclosure statement
No potential conflict of interest was reported by the authors.
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Notes on contributors
Rob W. Brooker
Rob Brooker is a plant ecologist. His research interests include mechanisms of plant–plant interactions and their consequences for community structures and function. He has studied in particular beneficial plant-plant interactions (i.e. facilitation) in a wide range of environments around the world.
Alison J. Karley
Alison Karley is an agroecologist. She has research experience in plant production and ecology, focussing on agro-ecosystem biodiversity and pest biocontrol under reduced inputs and climate change.
Luna Morcillo
Luna Morcillo is a plant ecologist. Her research interests are focused in plant–plant and plant–soil interactions in semiarid ecosystems under limited resource availability, and their application in dryland restoration.
Adrian C. Newton
Adrian Newton is a plant pathologist. His research interests are in inter- and intra-species crop plant interactions and their consequences for disease, yield and quality. He also has interests in crop protection particularly in the context of Integrated Pest Management (IPM).
Robin J. Pakeman
Robin Pakeman is a plant ecologist. His research deals with analysing the functional links between management, vegetation and ecosystem services. He also investigates the drivers of long-term vegetation change and seed dispersal in space and time.
Christian Schöb
Christian Schöb is a plant ecologist. His research focuses on plant–plant interactions and their consequences for community assembly and biodiversity. Most of his research has been conducted in alpine or agricultural ecosystems.