Volume 182, February 2015, Pages 134–142
Rewilding with large herbivores: The importance of grazing refuges for sapling establishment and wood-pasture formation
Highlights
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- Rewilding aims to restore ecological processes with minimum human intervention.
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- It can be applied on abandoned agricultural lands to restore wood pasture landscapes.
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- We studied effects on sapling establishment in Europe’s oldest rewilding area.
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- We found that grazing refuges are essential for sapling establishment.
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- Rewilding projects should warrant grazing refuges for wood pasture restoration.
Abstract
Rewilding
is a novel nature management type that aims at restoring natural
processes with minimal human intervention. It is increasingly employed
on abandoned agricultural lands in Europe, but empirical studies are
scarce. Rewilding may lead to formation of wood-pastures, arguably the
primeval landscape in parts of Europe before Neolithic times. We
investigated sapling establishment, a key process for wood-pasture
formation, in the Oostvaardersplassen: Europe’s oldest large-scale
rewilding area, with high densities of free-roaming large herbivores. We
transplanted saplings of pioneers, spiny shrubs, and hardwood species
and studied how herbivore accessibility (grazed control, partial and
full exclosure), vegetation type (tall roughs; short lawns) and
soil-tillage (mimicking wild boar rooting) affected sapling survival for
four years. No single sapling survived in grazed controls, while
survival in exclosures was 25%. Differences in survival between partial
and full exclosures were minor, indicating that reduced herbivore access
is sufficient for sapling survival. Survival was higher in lawn than in
rough in both exclosure types and for all species, indicating positive
effects of preceding grazing. Soil tillage initially benefitted all
species, but effects lasted for pioneers only, suggesting that – once
introduced – wild boar rooting may affect woody species composition. We
conclude that rewilding with herbivores can successfully form
wood-pasture landscapes on abandoned agricultural land as long as
grazing refuges are present that allow for sapling establishment. As
grazing refuges are generally lacking on abandoned agricultural lands,
where most rewilding is foreseen, we recommend that future projects
consider the presence – or creation – of grazing refuges.
Graphical abstract
Keywords
- Sapling browsing;
- Tree recruitment;
- Large herbivores;
- Pasture woodland;
- Shifting mosaics;
- Associational resistance
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