Experimental rewilding may restore abandoned wood-pastures if policy allows

Pablo Garrido,Grzegorz Mikusiński,Lars Edenius,Anna Jansson,Carl-Gustaf Thulin,Anna Skarin

doi:10.1007/s13280-020-01320-0

Pablo Garrido, Grzegorz Mikusiński + Show 4 more

Open Access

https://doi.org/10.1007/s13280-020-01320-0

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Abstract

Large herbivores play key roles in terrestrial ecosystems. Continuous defaunation processes have produced cascade effects on plant community composition, vegetation structure, and even climate. Wood-pastures were created by traditional management practices that have maintained open structures and biodiversity for millennia. In Europe, despite the broad recognition of their biological importance, such landscapes are declining due to land-use changes. This calls for finding urgent solutions for wood-pasture conservation. To test whether introducing an ecological replacement of an extinct wild horse could have positive effects on wood-pasture restoration, we designed a 3-year rewilding experiment. Horses created a more open wood-pasture structure by browsing on seedlings and saplings, affected tree composition via selective browsing and controlled the colonization of woody vegetation in grassland-dominated areas. Thus, rewilding could be a potential avenue for wood-pasture restoration and biodiversity conservation. However, such benefits may not materialize without a necessary paradigm and political shift.

Highlights

Large herbivores play a key role in the functioning of many terrestrial ecosystems (Doughty 2017)
Since the offset of the global human expansion, prehistoric megaherbivore faunas have been largely depleted (Sandom et al 2014), which led to the progressive simplification of megafaunas on ecosystems, with cascade effects on plant community composition, vegetation structure, and fire regimes (Gill 2014)
To enrich a browserdominated herbivore community by introducing an ecologically functional substitute of an extinct large herbivore grazer, may mitigate current biodiversity declines and restore abandoned wood-pastures. This may occur by the above-mentioned replacement of former human management practices by analogue large herbivore functions (Pedersen et al 2019)

Summary

INTRODUCTION

Large herbivores play a key role in the functioning of many terrestrial ecosystems (Doughty 2017). In Sweden as in the rest of Europe, the abandonment of these traditional management practices clearly threatens the conservation value of wood-pastures and associated biodiversity (Bergmeier and Roellig 2014; Plieninger et al 2015; Garrido et al 2017) This calls for finding plausible alternatives for restoring these declining ecosystems (Wright et al 2012). To enrich a browserdominated herbivore community by introducing an ecologically functional substitute of an extinct large herbivore grazer, may mitigate current biodiversity declines and restore abandoned wood-pastures This may occur by the above-mentioned replacement of former human management practices by analogue large herbivore functions (Pedersen et al 2019). We investigated the cumulative effect of horse browsing on the vegetation structure and composition, and quantified (1) browsing pressure, (2) tree consumption, and (3) tree selectivity estimates for eight common tree species This novel knowledge is crucial for implementing future rewilding experiments, biodiversity conservation, and wood-pasture restoration programs. This may not materialize without a necessary paradigm and political shift to promote rewilding interventions

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RESULTS

DISCUSSION