From functional diversity to human well-being: A conceptual framework for agroecosystem sustainability

[EN] CONTEXT: Agricultural intensification contributes to global food security and well-being by supplying the food demand of a growing human population. However, ongoing land-use change and intensification seriously affect the abundance, diversity and distribution of species, besides many other impacts, thereby threatening the functioning of ecosystems worldwide. Despite the accumulating evidence that the current agricultural model is unsustainable, we are far from understanding the consequences of functional diversity loss for functioning and ecosystem service supply and the potential long-term threats to food security and human well-being. OBJECTIVE: In this review, we propose a conceptual framework to understand the relationships between functional diversity and human well-being that also considers agroecosystem health. To this end, we identify the most commonly assumed relationships linking functional diversity to regulating and provisioning agroecosystem services and their importance for human well-being, emphasising the most serious knowledge gaps in the in-dividual pathways of the conceptual framework. METHODS: A consortium formed by an international panel of experts from different disciplines including functional diversity, ecosystem services and human health compiled 275 articles. Members of the consortium proposed literature to exemplify each specific aspect of the conceptual framework in the text, in accordance with his/her field of expertise. The guideline for all experts was to focus mostly in current literature (38% of the references are from the last 5 years and 66% from the last decade), with special interest in reviews and synthesis articles (42% of the references), as well as meta-analyses and global studies (10% of the references). RESULTS AND CONCLUSIONS: The factors that influence agroecosystem health are extremely complex, involving both services and disservices related to land-use management and environmental conditions. The global human population needs sustainable and resilient agroecosystems and a concerted effort is needed to fundamentally redesign agricultural practices to feed the growing human population without further jeopardising the quality of life for future generations. We highlight the potential effects of land-use change and ecological intensification on the functional diversity of plant and animal communities, and the resulting consequences for ecosystem services and ultimately human health. SIGNIFICANCE: The resulting conceptual model is developed for researchers as well as policy makers high- lighting the need for a holistic approach to understand diversity impacts on human well-being. Finally, we document a major knowledge gap due to the lack of any studies focusing on the full pathway from diversity to human well-being.S

Agroecosystem management and biotic interactions: a review

Increasing the use of synthetic fertilisers and pesticides in agroecosystems has led to higher crop yields, accompanied by a decline in biodiversity at the levels of field, cropping system and farm. Biodiversity decline has been favoured by changes at landscape level such as regional farm specialisation, increases in field size, and the removal of hedgerows and woodlots. The loss of biodiversity in agroecosystems has increased the need for external inputs because beneficial functions are no longer provided by beneficial species as natural enemies of crop pests and ecosystem engineers. This trend has led to a strong reliance on petrochemicals in agroecosystems. However, many scientists have been arguing for more than two decades that this reliance on petrochemicals could be considerably reduced by a better use of biotic interactions. This article reviewsoptions to increase beneficial biotic interactions in agroecosystems and to improve pest management and crop nutrition whilst decreasing petrochemical use. Four agronomic options are presented. First, it has been shown that the choice of cultivar, the sowing date and nitrogen fertilisation practices can be manipulated to prevent interactions between pests and crop, in either time or space. Nevertheless, the efficacy of these manipulations may be limited by pest adaptation. Second, beneficial biotic interactions may result from appropriate changes to the habitats of natural enemies and ecosystem engineers, mediated by soil and weed management. Here, knowledge is scarce, and indirect and complex effects are poorly understood. Third, changes achieved by crop diversification and, fourth, by landscape adaptation are promising. However, these practices also present drawbacks that may not necessarily be outweighed by beneficial effects. Overall, these four management approaches provide a powerful framework to develop sustainable agronomic practices

Crop Pests and Predators Exhibit Inconsistent Responses to Surrounding Landscape Composition

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies

A whole earth approach to nature-positive food: biodiversity and agriculture

Agriculture is the largest single source of environmental degradation, responsible for over 30% of global greenhouse gas (GHG) emissions, 70% of freshwater use and 80% of land conversion: it is the single largest driver of biodiversity loss (Foley JA, Science 309:570–574, 2005, Nature 478:337–342, 2011; IPBES. Global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. IPBES Secretariat, Bonn, 2019; Willett W et al. The Lancet 393:447–492, 2019). Agriculture also underpins poor human health, contributing to 11 million premature deaths annually. While too many still struggle from acute hunger, a growing number of individuals, including in low to middle-income countries (LMICs), struggle to access healthy foods. Greater consideration for, and integration of, biodiversity in agriculture is a key solution space for improving health, eliminating hunger and achieving nature-positive development objectives. This rapid evidence review documents the best available evidence of agriculture’s relationships with biodiversity, drawing on the contributions of leading biodiversity experts, and recommends actions that can be taken to move towards more biodiversity/nature-positive production through the delivery of integrated agricultural solutions for climate, biodiversity, nutrition and livelihoods. The analysis, which takes a whole-of-food-system approach, brings together a large body of evidence. It accounts for aspects not typically captured in a stand-alone primary piece of research and indicates where there are critical gaps.Fil: Declerck, Fabrice A.J.. The Alliance of Bioversity International and the International Center for Tropical Agriculture ; FranciaFil: Koziell, Izabella T.. The International Centre for Integrated Mountain Development; NepalFil: Benton, Tim. Chatham House; Reino UnidoFil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Norte. Instituto de Investigaciones En Recursos Naturales, Agroecologia y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones En Recursos Naturales, Agroecologia y Desarrollo Rural.; ArgentinaFil: Kremen, Claire. University of British Columbia; CanadáFil: Maron, Martine. University of Queensland; AustraliaFil: Rumbaitis Del Rio, Cristina. World Resources Institute; Estados UnidosFil: Sidhu, Aman. The Alliance of Bioversity International and the International Center for Tropical Agricultura; FranciaFil: Wirths, Jonathan. The Consortium of International Agricultural Research Centers ; Sri LankaFil: Clark, Michael. University of Oxford; Reino UnidoFil: Dickens, Chris. International Water Management Institute; Sri LankaFil: Estrada Carmona, Natalia. The Alliance of Bioversity International and the International Center for Tropical Agriculture ; FranciaFil: Fremier, Alexander K.. Washington State University; Estados UnidosFil: Jones, Sarah K.. The Alliance of Bioversity International and the International Center for Tropical Agriculture ; FranciaFil: Khoury, Colin K.. The Alliance of Bioversity International and the International Center for Tropical Agriculture ; FranciaFil: Lal, Rattan. Ohio State University; Estados UnidosFil: Obersteiner, Michael. University of Oxford; Reino UnidoFil: Remans, Roseline. The Alliance of Bioversity International and the International Center for Tropical Agriculture ; FranciaFil: Rusch, Adrien. Institut National de la Recherche Agronomique; FranciaFil: Schulte, Lisa A.. Natural Resource Ecology and Management; Estados UnidosFil: Simmonds, Jeremy. University of Queensland; AustraliaFil: Stringer, Lindsay C.. University of York; Reino UnidoFil: Weber, Christopher. World Wide Fund For Nature; Estados UnidosFil: Winowiecki, Leigh. World Agroforestry Center; Keni

The interplay of landscape composition and configuration: new pathways to manage functional biodiversity and agroecosystem services across Europe

Managing agricultural landscapes to support biodiversity and ecosystem services is a key aim of a sustainable agriculture. However, how the spatial arrangement of crop fields and other habitats in landscapes impacts arthropods and their functions is poorly known. Synthesising data from 49 studies (1515 landscapes) across Europe, we examined effects of landscape composition (% habitats) and configuration (edge density) on arthropods in fields and their margins, pest control, pollination and yields. Configuration effects interacted with the proportions of crop and non‐crop habitats, and species’ dietary, dispersal and overwintering traits led to contrasting responses to landscape variables. Overall, however, in landscapes with high edge density, 70% of pollinator and 44% of natural enemy species reached highest abundances and pollination and pest control improved 1.7‐ and 1.4‐fold respectively. Arable‐dominated landscapes with high edge densities achieved high yields. This suggests that enhancing edge density in European agroecosystems can promote functional biodiversity and yield‐enhancing ecosystem services

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies

Analyse des déterminants des attaques de Meligethes aeneus (Coleoptera, Nitidulidae) et de sa régulation biologique à l'échelle d'un paysage agricole: contribution à l'amélioration de la protection intégrée du colza.

Studying the effects of crop management and landscape context on pest populations and natural pest control at multiple spatial scales is a pre-requisite for developing innovative crop protection strategies and increasing the sustainability of agroecosystems. The aim of this study was to explore the relative importance of oilseed rape crop management and landscape context on pollen beetle (Meligethes aeneus Fabr.) density, damage and parasitism rates by its main parasitoids Tersilochus heterocerus, Phradis morionellus and P. interstitialis. In our multi-scale analysis we found that pest abundance and crop damage were mainly determined by and positively correlated with landscape complexity at scales ranging from 1500 m to 2000 m. The positive effect of landscape complexity on pollen beetle density and crop damage in our study region was due to the role of seminatural habitats for overwintering. Pollen beetle damage was also affected by local management as it was negatively correlated with the nitrogen nutrition status of the plants. We found that various variables at different spatial scales influenced parasitism rates. Parasitism rates were positively influenced by landscape complexity, proximity to previous year oilseed rape fields and the proportion of these latter with reduced tillage. By comparing the nutritional state of parasitoids at the time of emergence and foraging in the field, we found that parasitoids emerge with relatively small amounts of sugars and that the total amount of sugars at the end of flowering was always significantly higher than the total amount of sugars at the beginning of flowering. Finally, by studying the accuracy of simple landscape indicators to predict pollen beetle infestations and successful biological control, we found that some indicators were informative and had good discriminatory ability. Using indicators values, optimal thresholds and posterior probabilities, we were able to compute maps of areas at risk for pest infestation and/or allowing successful biological control of pollen beetle. Our study demonstrated the importance of taking into account both farming practices and semi-natural habitats scattered in the landscape to understand population dynamics and biological control in agroecosystems. Our findings open new perspectives in terms of integrated pest management strategies maximizing biological control at the landscape scale.L'étude de l'influence des pratiques agricoles et du contexte paysager sur les populations de bioagresseurs et de leurs ennemis naturels est une étape essentielle à la conception de systèmes de culture minimisant l'usage des produits phytosanitaires et optimisant les régulations biologiques. L'objectif principal de ce travail était d'analyser et de comprendre l'influence des pratiques agricoles et des habitats semi-naturels sur les attaques de méligèthes (Meligethes aeneus Fabr.), l'un des principaux insectes ravageurs du colza en Europe, et sa régulation naturelle via ses parasitoïdes univoltins Tersilochus heterocerus, Phradis morionellus et P. interstitialis. Dans notre approche exploratoire multi-échelle nous avons d'abord mis en évidence que la densité et les dégâts de méligèthes étaient positivement corrélés à la complexité du paysage, calculée dans un rayon allant de 1500 m à 2000 m autour de la parcelle. Nous avons également mis en évidence l'importance de l'état de nutrition azotée de la culture sur les dégâts de méligèthes à travers les capacités de compensation de la plante. L'effet positif important de la complexité du paysage observé sur notre site d'étude provient du rôle majeur joué par les habitats semi-naturels, et particulièrement des forêts, sur l'hivernation des méligèthes. A différentes échelles spatiales, la complexité du paysage, la proximité aux colzas de l'année précédente et la proportion de colza de l'année précédente avec un travail du sol simplifié ont influencé positivement le taux de parasitisme des larves de méligèthes. Ensuite, en comparant les teneurs en sucres des parasitoïdes à l'émergence et au champ, nous avons pu montrer que les parasitoïdes adultes émergeaient avec des teneurs en sucres relativement faibles et que ces dernières augmentaient avec le temps passé au champ depuis le début de la floraison du colza. Enfin, nous avons montré que certains indicateurs paysagers comme la proportion de forêt ou la proportion d'habitats semi-naturels permettaient d'identifier des situations paysagères à risque de fortes infestations ou favorables à une régulation biologique efficace. Notre étude met en évidence l'importance de considérer conjointement les pratiques agricoles et la structure du paysage pour comprendre les dynamiques de populations et les interactions trophiques dans les agroécosystèmes. L'ensemble des résultats et des connaissances produites dans ce travail permet de formuler de nouvelles pistes de gestion des populations de méligèthes utilisant la régulation naturelle

Data pest and biological control

Data pest and biological contro