Background
In the UN Decade for Ecological Restoration revegetation is key, but it often fails due to environmental stress factors.
Seeding vs. planting dilemma
The choice of revegetation method ―direct seeding in the field or planting nursery-grown seedlings― can influence the response of plants to stress factors such as drought. The balance between both methods may depend on how the species and functional traits, such as seed size and root depth, interact with environmental conditions.
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While planting has the advantage of greater seedling emergence, it is also more expensive and suffers from machinery impacts.
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Alternatively, seeding is cheaper and more flexible but has the problem of seed predation.
The potential of Oaks in ecological restoration
Seeded vs. planted Holm oaks. Credit: Laura Levy
Oaks (genus Quercus) are widely distributed across the Northern Hemisphere and confer resilience of forest ecosystems to disturbances due to the ability to resprout.
Objectives & Methods
With this research we seek:
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To estimate the effect of seeding vs. planting of Oaks on plant performance at a European scale.
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To estimate the influence of environmental conditions (e.g. aridity gradient), functional traits, and phylogenetic relationship between species in this effect.
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To do so, we are conducting a field experiment replicated by an European network of participants following a standardised open access protocol for seed collection, direct seeding, nursery cultivation, outplanting, herbivory protection, maintenance, and seedling measurement.
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Research will last four years, split into six phases:
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1) Establishment of experimental sites.
2) Selection of local oak species.
3) Seeding and planting.
4) Measurement of seedling performance.
5) Measurement of co-variates (soil characteristics, seed mass, seed germination).
6) Data analysis and collaborative publishing.
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In order to evaluate the seeding vs. planting balance over the years we have established two cohorts. A first one from 2021 to 2024 and a second one from 2022 to 2025.
Seeding and planting at the IFAPA experimental site, Spain. Credit: Lot Amorós
The seed shelter
In this research, we are using seed shelters for the acorns seeded in the field. This device was developed by Alexandro Leverkus and Jorge Castro (University of Granada, Spain) and it is designed to protect acorns from small predators.
Acorn collection and seeding with seed shelters. Credit: Maria Sameiro Patricio
Seed shelter. Credit: Alex Leverkus
Local Oaks
In this project participants work with native, locally growing oak species:
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Quercus cerris
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Quercus coccifera
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Quercus faginea
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Quercus frainetto
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Quercus ilex
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Quercus petraea
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Quercus pubescens
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Quercus pyrenaica
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Quercus robur
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Quercus rubra
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Quercus suber
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Quercus trojana
Quercus Trojana. Credit: Paola Mairota