Soil organisms have an important role in aboveground community dynamics and ecosystem functioning in terrestrial ecosystems. However, most studies have considered soil biota as a black box or focussed on specific groups, whereas little is known about entire soil networks. Here we show that during the course of nature restoration on abandoned arable land a compositional shift in soil biota, preceded by tightening of the belowground networks, corresponds with enhanced efficiency of carbon uptake. In mid- and long-term abandoned field soil, carbon uptake by fungi increases without an increase in fungal biomass or shift in bacterial-to-fungal ratio. The implication of our findings is that during nature restoration the efficiency of nutrient cycling and carbon uptake can increase by a shift in fungal composition and/or fungal activity. Therefore, we propose that relationships between soil food web structure and carbon cycling in soils need to be reconsidered.

Luján Soto, R., M. Cuéllar Padilla, M. Rivera Méndez, T. Pinto-Correia, C. Boix-Fayos, and J. De Vente. 2021. Participatory monitoring and evaluation to enable social learning, adoption, and out-scaling of regenerative agriculture. Ecology and Society 26(4):29. https://doi.org/10.5751/ES-12796-260429

Floods and droughts are becoming increasingly frequent and intense in the Mediterranean region. Nature‐based solutions (NBS) are being put forward as cost‐effective solutions for climate change adaptation to reduce the impacts of floods and droughts and provide multiple other benefits and ecosystem services. This fundamental change in adaptation to extreme climate events is supported by scarce empirical evidence and fragmented knowledge on NBS effectiveness and feasibility to mitigate increasingly prolonged and extreme droughts and floods, leading to limited uptake. Expert‐based approaches can help assemble the fragmented empirical evidence and identify implementation barriers and opportunities to inform policy and decision‐makers at an early stage in the selection of NBS. In this study, we conducted expert consultation to gather experts' perceptions on the most effective and feasible NBS to mitigate the adverse effects of floods and droughts in the large Mediterranean Segura River basin in southeast Spain. Our results show that, according to experts, reforestation of headwaters and NBS affecting river and floodplain morphology should be prioritized over solutions in agricultural land and urban areas. Conversely, NBS affecting river and floodplain morphology were perceived as least feasible to implement due to required land expropriations resulting in high economic costs, social rejection and low political support. Experts considered NBS as promising solutions to mitigate floods and droughts and complementary to grey infrastructures; however, they were more convinced about the effectiveness for mitigation of floods than for droughts. To overcome barriers and support NBS implementation, responsible governance of the territory, provision of training to policy makers and economic investment stood out as priority actions. Read the free Plain Language Summary for this article on the Journal blog.

The objective of this work is to evaluate the impact of regenerative agriculture alternatives in rainfed almond crops on a range of ecosystems services. A Multi-Criteria Analysis (MCA) was conducted to evaluate the different land management alternatives integrating different quantitative and qualitative indicators based on long-term field research. Three land management alternatives were analyzed: (i) conventional management, (ii) native cover crops, and (iii) seeded cover crops. MCA was able to evaluate the performance of the three alternatives considering different priorities of two groups of farmers (conventional and regenerative) and score the different scenarios. The alternative of natural cover crops had the best score in almost all the groups of ecosystem services and economic indicators. The sustainability, acceptance, and stability of the scenarios were achieved and provided an integrated view of impacts that can help decision making.

Regenerative agriculture (RA) is gaining increasing recognition as a plausible solution to restore degraded agroecosystems. In Mediterranean drylands, RA has been limitedly adopted by farmers due to its initial state of development and lack of empirical evidence on its impacts. To support its large-scale adoption, we carried out a participatory monitoring and evaluation project in the high steppe plateau of Southeast Spain, involving local farmers applying RA in their almond farms. To assess the effect of RA, we studied 9 farms and selected in each farm one field with regenerative management and one nearby field with conventional management based on frequent tillage (CT). We clustered fields under regenerative management based on the different RA practices being applied and distinguished 4 types of RA treatments: 1) reduced tillage with green manure (GM), 2) reduced tillage with organic amendments (OA), 3) reduced tillage with green manure and organic amendments (GM&OA), and 4) no tillage with permanent natural covers and organic amendments (NT&OA). We used physical (bulk density and aggregate stability), chemical (pH, salinity, total N, P, K, available P, and exchangeable cations) and biological (SOC, POC, PON, microbial activity)  soil propertoes and the nutritional status of almond trees (leaf N, P and K) to evaluate the impacts of RA compared to CT. We found that GM treatment improved physical soil properties, presenting regenerative fields higher soil aggregate stability. Our results showed that OA improved most soil chemical and biological soil properties, however physical properties remained similar. RA treatments combining ground covers and organic amendments (GM&OA and NT&OA) exhibited greater overall soil quality restoration than individual practices, improving physical, chemical and biological soil properties. NT&OA stood out for presenting the highest soil quality improvements. All RA treatments maintained similar crop nutritional status compared to CT. We conclude that RA has strong potential to restore the physical, chemical and biological quality of soils of woody agroecosystems in Mediterranean drylands without compromising their nutritional status, thereby enhancing their resilience to climate change and long term sustainability.