Synthesis on the effectiveness of soil translocation for plant community restoration

Abstract

Many degraded ecosystems need active restoration to conserve biodiversity and re‐establish ecosystem function, both highlighted targets of the UN Decade on Ecosystem Restoration and the proposed EU Nature restoration law. Soil translocation, where both plant propagules and their associated soil biota are co‐introduced, has increasingly been proposed as a powerful restoration technique for terrestrial ecosystems. However, a synthesis of the effectiveness of this method across ecosystems is lacking. To address how soil translocation affects restoration success, we performed a meta‐analysis synthesizing data from 46 field experiments and their respective reference ecosystems in 17 countries across four continents. In each experiment, vegetation composition was recorded in response to soil translocation treatments and the resultant vegetational changes (diversity and composition) were quantified. We found that soil translocation leads to plant community development further away from the control and more towards the reference plant communities compared with treatments where only plant propagules were introduced. However, the variability of effect sizes among experiments was large, suggesting strong dependence of restoration success on restoration context. We found that restoration success was more likely on loamy soils and when translocation treatments were implemented over larger spatial areas (>180 m2). Furthermore, we found that restoration success either consistently increased or decreased over time depending on the experiment. Not only is this congruent with positive feedbacks between plant and soil communities driving plant community development, but it also suggests that the composition of the translocated plant and soil communities, and initial starting conditions, are critical for long‐term restoration success. Synthesis and applications. Our analysis highlights soil translocation can be a successful restoration method across a broad range of ecosystems. However, its implementation needs to depend on a thorough evaluation of local conditions and the potential added value. Further refinement of soil translocation techniques is needed to increase success rates.

Ten principles for restoring campo rupestre, a threatened tropical, megadiverse, nutrient‐impoverished montane grassland

“…However, in topsoil translocation experiments without fertilization, fast‐growing herbs dominated in the initial years, but were replaced over the following years by woody, slow‐growing species (Onésimo et al 2021). These results, coupled with recent synthesis showing that soil translocation can be an effective technique for restoring plant community diversity and composition (Gerrits et al 2023), indicate promising results for seed‐based restoration. We propose seed‐based restoration to be implemented after resilience to fire has been achieved by restoring species with USOs.…”

“…Seed‐based strategies are widely used as a relatively low‐cost, large‐scale grassland restoration (D'Agui et al 2022; Gerrits et al 2023) and post‐mining sites (Dalziell et al 2022). However, seed‐based strategies often show low success for campo rupestre (Le Stradic et al 2014; Figueiredo et al 2021), as indicated by low seedling emergence, and the prevalence of invasive species in the initial years of restoration.…”

Soil seed bank development of smoke‐responsive plant species in a 23‐year restoration chronosequence and implications for resilience to fire

“…SSBs provide a crucial source of seeds for restoration (Gerrits et al, 2023;Waryszak et al, 2020) and can indicate the availability of seeds for post-fire recruitment (Smith et al, 2001). Understanding SSB development over time can assist in predicting likely responses to disturbances.…”

“…Fire is a common disturbance globally (Bowman et al, 2009), and many plant species have evolved adaptations promoting regeneration following fire including smoke‐responsive, persistent soil seed banks (SSB; Pausas & Keeley, 2014). SSBs provide a crucial source of seeds for restoration (Gerrits et al, 2023; Waryszak et al, 2020) and can indicate the availability of seeds for post‐fire recruitment (Smith et al, 2001). Understanding SSB development over time can assist in predicting likely responses to disturbances.…”

Rewiring critical plant–soil microbial interactions to assist ecological restoration

“…It has therefore been suggested that restoring and maintaining healthy soil microbial communities would benefit ecological restoration (here referring to the re‐establishment of native plant communities; Coban et al, 2022). However, a recent global meta‐analysis has clearly shown that manipulations of soil microbial communities during ecological restoration have had varied success (Gerrits et al, 2023), suggesting that the wholesale manipulation of soil microbial communities is difficult, if not impossible, partly due to the altered abiotic soil properties of degraded lands.…”