Monitoring rewilding from space: The Knepp estate as a case study.

Rewilding is increasingly considered as an option for environmental regeneration, with potential for enhancing both biodiversity and ecosystem services. So far, however, there is little practical information on how to gauge the benefits and limitations of rewilding schemes on ecosystem composition, structure and functioning. To address this knowledge gap, we explored how satellite remote sensing can contribute to informing the monitoring and evaluation of rewilding projects, using the Knepp estate as a case study. To our knowledge, this study is the first to assess the impacts of rewilding as an ecological regeneration strategy on landscape structure and functioning over several decades. Results show significant changes in land cover distribution over the past 20 years inside rewilded areas in the Knepp estate, with a 41.4% decrease in areas with brown agriculture and grass, a roughly sixfold increase in areas covered with shrubs, and a 40.9% increase in areas with trees; vegetation in the rewilded areas also showed a widespread increase in annual primary productivity. Changes in land cover and primary productivity are particularly pronounced in the part of the estate that began its rewilding journey with a period of large herbivore absence. Altogether, our approach clearly demonstrates how freely available satellite data can (1) provide vital insights about long-term changes in ecosystem composition, structure and functioning, even for small, heterogeneous and relatively intensively used landscapes; and (2) help deepen our understanding of the impacts of rewilding on vegetation distribution and dynamics, in ways that complement existing ground-based studies on the impacts of this approach on ecological communities.