In the UN Decade on Ecosystem Restoration, large knowledge gaps persist on how to increase biodiversity and ecosystem functioning in cash crop-dominated tropical landscapes. This study presents findings from a large-scale, 5-year ecosystem restoration experiment in an oil palm landscape enriched with 52 tree islands, assessing ten biodiversity indicators and 19 ecosystem functioning indicators. Results show higher biodiversity and ecosystem functioning in tree islands compared to conventionally managed oil palm, with larger islands leading to larger gains in multidiversity. Tree enrichment did not decrease oil palm yield. The study concludes that enriching oil palm landscapes with tree islands is a promising restoration strategy, but shouldn't replace forest protection.

Delphine Clara Zemp, Nathaly Guerrero-Ramirez, Fabian Brambach, Kevin Darras, Ingo Grass, Anton Potapov, Alexander Röll, Isabelle Arimond, Johannes Ballauff, Hermann Behling, Dirk Berkelmann, Siria Biagioni, Damayanti Buchori, Dylan Cravens, Rolf Daniel, Oliver Gailing, Florian Ellsäßer, Riko Fardiansah, Nina Hennings, Bambang Irawan, Watit Khokthong, Valentyna Krashevska, Alena Krause, Johanna Kückes, Kevin Li, Hendrik Lorenz, Mark Maraun, Miryam Sarah Merk, Carina C. M. Moura, Yeni A. Mulyani, Gustavo B. Paterno, Herni Dwinta Pebrianti, Andrea Polle, Di Ajeng Prameswari, Lena Sachsenmaier, Stefan Scheu, Dominik Schneider, Fitta Setiajiati, Christina Ani Setyaningsih, Leti Sundawati, Teja Tscharntke, Meike Wollni, Dirk Hölscher, Holger Kreft