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Managing agricultural landscapes to support biodiversity conservation requires profound structural changes worldwide. Often, discussions are centered on management at the field level. However, a wide and growing body of evidence calls for zooming out and targeting agricultural policies, research, and interventions at the landscape level to halt and reverse the decline in biodiversity, increase biodiversity-mediated ecosystem services in agricultural landscapes, and improve the resilience and adaptability of these ecosystems. We conducted the most comprehensive assessment to date on landscape complexity effects on nondomesticated terrestrial biodiversity through a meta-analysis of 1,134 effect sizes from 157 peer-reviewed articles. Increasing landscape complexity through changes in composition, configuration, or heterogeneity significatively and positively affects biodiversity. More complex landscapes host more biodiversity (richness, abundance, and evenness) with potential benefits to sustainable agricultural production and conservation, and effects are likely underestimated. The few articles that assessed the combined contribution of linear (e.g., hedgerows) and areal (e.g., woodlots) elements resulted in a near-doubling of the effect sizes (i.e., biodiversity level) compared to the dominant number of studies measuring these elements separately. Similarly, positive effects on biodiversity are stronger in articles monitoring biodiversity for at least 2 y compared to the dominant 1-y monitoring efforts. Besides, positive and stronger effects exist when monitoring occurs in nonoverlapping landscapes, highlighting the need for long-term and robustly designed monitoring efforts. Living in harmony with nature will require shifting paradigms toward valuing and promoting multifunctional agriculture at the farm and landscape levels with a research agenda that untangles complex agricultural landscapes' contributions to people and nature under current and future conditions.

With the Convention on Biological Diversity conference (COP15), United Nations Climate Change Conference (COP26), and United Nations Food Systems Summit, 2021 is a pivotal year for transitioning towards sustainable food systems. Diversified farming systems are key to more sustainable food production. Here we present a global dataset documenting outcomes of diversified farming practices for biodiversity and yields compiled following best standards for systematic review of primary studies and specifically designed for use in meta-analysis. The dataset includes 4076 comparisons of biodiversity outcomes and 1214 of yield in diversified farming systems compared to one of two reference systems. It contains evidence from 48 countries of effects on species from 33 taxonomic orders (spanning insects, plants, birds, mammals, eukaryotes, annelids, fungi, and bacteria) of diversified farming systems producing annual or perennial crops across 12 commodity groups. The dataset presented provides a resource for researchers and practitioners to easily access information on where diversified farming systems effectively contribute to biodiversity and food production outcomes., (© 2021. The Author(s).)

• Sustainable agricultural systems need to provide more than just food. • We analyse the effect of farming system diversification on biodiversity and yield. • Biodiversity and/or yield benefit in 78% of 764 cases; win-win outcomes in only 23%. • Probability of a synergy or trade-off is influenced by crop choices and bioclimate. • More field studies collecting data on multiple outcomes are critically needed. To leverage agriculture's potential to better benefit both people and nature, policymakers need clear messages about which farming practices positively impact biodiversity and yields, and when trade-offs arise. Existing reviews analyse effects of different agricultural practices on either biodiversity or yield, without considering interactions. Here, we applied multinomial and quantile regression models to synthesize global evidence of synergies and trade-offs between biodiversity and yield, using 764 paired observations (from 43 studies across 18 countries) comparing diversified and simplified farming systems. Results show that farmland diversification led to win-win outcomes for biodiversity and yield in 23% of cases, while a win for biodiversity coupled with a loss in yield was the most likely outcome (28% of cases). Yield and biodiversity responses were negatively correlated, meaning that diversifying farming systems solely in pursuit of production goals is unlikely to lead to markedly better outcomes for biodiversity, or vice-versa. Yet certain situations made win-win significantly more likely, including when crop and animal production, or multiple diversification practices (e.g., intercropping and cover crops), were combined, when no agrochemicals were applied, when diversification occurred in temperate climates, and when diversification enhanced below-ground taxa. Win-win was also more likely than lose-lose when biodiversity was measured as richness or richness-evenness, but not abundance, suggesting that in certain contexts diversified farming can effectively enhance species diversity while increasing agricultural yields. Overall, crop commodity group and bioclimatic location were amongst the most important contextual factors influencing the likelihood of a synergy or trade-off between biodiversity and yield, and diversification that accounts for these is less likely to lead to unexpected outcomes. Our novel method and up-to-date review show that farmland diversification frequently leads to better outcomes for biodiversity and/or agricultural production when compared to monocultures and farmland stripped of natural vegetation, opening a pathway to more sustainable agricultural production. [ABSTRACT FROM AUTHOR]

Homogenisation and intensification of agricultural ecosystems are among the most important threats to biodiversity, linked to declines in pollinators, soil biota and ecosystem functioning. Diversification has been proposed as a way to restore ecosystem functioning in agricultural landscapes. To manage agricultural land for multiple ecosystem functions, evidence is needed of the effect of diversification on functionally distinct taxa. We contribute to closing this knowledge gap through a global meta-analysis of 161 peer-reviewed articles addressing the abundance and richness of six distinct functional groups: autotrophs, decomposers, natural enemies, pests, pollinators, and other. We found diversified farming systems increased overall species richness by 26% on average, relative to simplified farming systems. However, the effect of diversified farming on the overall mean abundance was weak. Our study shows diversified farming systems enhanced the abundance and richness of beneficial species while reducing the abundance of pests (e.g., weeds, herbivores), thus providing benefits for both agricultural production and biodiversity. The positive effect of diversified farming systems on the overall mean species richness was stronger in farms in more simplified landscapes, i.e., those that are further from natural and semi-natural habitats or have a lower proportion of seminatural vegetation in a 1 km radius. Pollinator's abundance and richness were highest in diversified farming plots located far away from natural and semi-natural habitats. In contrast, proximity to these natural and semi-natural habitats (<250 m) increased the positive effect of diversified farming systems on natural enemies' abundance, while reducing the number of pests. Our results add to the body of evidence calling for the repurposing of policies, regulations, and international agendas to promote, support and incentivize the adoption of diversified farming practices for supporting biodiversity. Spatial planning of diversification schemes should consider the landscape context of farms to ensure the greatest benefit of intervention. • Largest global meta-analysis to date of diversified farming effects on non-domesticated biodiversity. • Diversified farming systems have 26% higher species richness than simplified systems. • There is a higher abundance and richness of beneficial species, and fewer pests' abundance, in diversified farming systems. • Diversifying farms in simplified landscapes has highest potential to benefit the overall mean richness of biodiversity. • Effects of diversified and simplified farming systems are highly variable across functional groups and landscape complexity. [ABSTRACT FROM AUTHOR]