Sandrine Petit

French National Institute for Agriculture, Food, and Environment (INRAE) | INRAE · Agroécologie

1. There is an urgent need to accurately model how environmental change affects the wide-scale functioning of ecosystems, but advances are hindered by a lack of knowledge of how trophic levels are linked across space. It is unclear which theoretical approach to take to improve modelling of such interactions, but evidence is gathering that linking s...

Reducing pesticide use in agriculture is necessary to preserve natural resources. However, pest control without pesticides is a challenging issue. In particular, weed infestation may cause severe losses of crop yield. Weeds have been traditionally managed solely at the field level. However, larger scales must be considered because invasive and herb...

The organisation of human-populated landscapes results from many interacting processes tied to the historical development of societies and human activities. Agriculture, in particular, has dramatically altered much of the Earth’s surface over many millennia. Landscape mosaics can be used to understand these impacts, which are increasing at an accel...

Conservation agriculture is designed to deliver more sustainable cropping systems by preserving agricultural soils with tillage abandonment. However, knowledge on the impacts of Conservation agriculture adoption on weed infestation level and potential shifts in the composition of weed communities appears low and contradictory. We used a trait-based...

Ecological intensification of agriculture (EIA) aims to assure food security by harnessing ecosystem services while minimizing external inputs and environmental harms. One manifestation of EIA proposed worldwide is agroecological farming, which will affect future landscapes, biodiversity and make assurance of crop yields more reliant on management...

The evidence that most agricultural landscapes are failing to deliver on biodiversity conservation and ecosystem services provision suggests that future landscapes will need to be more explicitly designed. Although recent research has produced a number of ecological and social principles that should form the basis of agricultural landscape design p...

Understanding the effects of the huge diversity of cropping systems on local biodiversity is challenging but necessary to implement agroecological systems. Through a functional approach, the translation of cropping systems into resource and disturbance gradients is a promising way to decipher the relationship between cropping systems and biodiversi...

Over the last 30 years, many studies have surveyed weed vegetation on arable land. The ‘Arable Weeds and Management in Europe’ (AWME) database is a collection of 36 of these surveys and the associated management data. Here, we review the challenges associated with combining disparate datasets and explore some of the opportunities for future researc...

There is a pressing need for research guiding the design and management of multifunctional landscapes that combine the delivery of production services and that of other ecosystem services. Arable weeds are an interesting model as they can impact negatively crop production but also contribute to maintain pollination and pest control services. Here,...

Reduction in herbicide use will trigger changes in weed communities. Improving our capacity to identify farming management options that will lead to weed communities offering interesting trade-offs of functions is thus timely. Functional approaches are offering a robust framework to quantify and understand the underlying mechanisms that link farmin...

Understanding effects on the huge diversity of cropping systems on local biodiversity is challenging but necessary to implement agroecological systems. Through a functional approach, the translation of cropping systems into resource and disturbance gradients is promising to decipher the relationship between cropping systems and biodiversity but has...

Cropping system (CS) diversification appears as a promising solution to increase CS sustainability. However, weed community response to different options of CS diversification remains poorly documented. Moreover, these effects are expected to be more pronounced in experimental than commercial farms because experimental farms explore more diverse co...

Carabids are important biological control agents of weeds and other pests in agricultural fields. The carabid community is built upon direct and indirect ecological effects of landscape complexity, field management intensity and biotic components that in interaction make any prediction of community size and composition challenging. We analyse a lar...

Two scientific disciplines, vegetation science and weed science, study arable weed vegetation, which has seen a strong diversity decrease in Europe over the last decades. We compared two collections of plot‐based vegetation records originating from these two disciplines. The aim was to check the suitability of the collections for joint analysis and...

There is a pressing need for indicators and methods to quantify the provision of ecosystem services as a pre-requisite to identify management options that optimize trade-offs between services. Arable weeds provide multiple services and are thus a good model to evaluate such trade–offs. This flora provides trophic resources (flowers or seeds) that s...

The widespread loss of weed diversity and associated ecosystem functions is raising important concerns. Field edges could play a major role in the maintenance of weed functional diversity in arable landscapes as these habitats still harbour high weed diversity, owing to either a reduced farming management intensity and/or to a spillover of species...

Context Agroecology combines agronomic and ecological concepts. It relies on the enhancement of biodiversity and related ecosystem services to support agricultural production. It is dependent on biological interactions for the design and management of agricultural systems in agricultural landscapes. Objectives We review the role of landscape ecolo...

Over the last decades, land management options have been investigated that aim at enhancing services to agriculture delivered by biodiversity and its associated biotic interactions. Such services can be promoted through land management strategies ranging from in-field single agricultural practices, long-term strategies compiling these agricultural...

Agriculture is under pressure to achieve sustainable development goals for biodiversity and ecosystem services. Services in agro-ecosystems are typically driven by key species, and changes in the community composition and species abundance can have multifaceted effects. Assessment of individual services overlooks co-variance between different, but...

The growing recognition of the environmental and health issues associated to pesticide use requires to investigate how to manage weeds with less or no herbicides in arable farming while maintaining crop productivity. The questions of weed harmfulness, herbicide efficacy, the effects of herbicide use on crop yields, and the effect of reducing herbic...

“Arable Weeds and Management in Europe” is a collection of weed vegetation records from arable fields in Europe, initiated within the Working Group Weeds and Biodiversity of the European Weed Research Society (EWRS). Vegetation-plot data from this scientific community was not previously contributed to databases. We aim to prove the usefulness of co...

Résumé : Pour comprendre comment gérer les adventices avec peu ou pas d'herbicides en grandes cultures, étudier la nuisibilité des adventices, l'efficacité et les effets des herbicides et de leur réduction sur le rendement est nécessaire. Cette question a été étudiée depuis des années mais les résultats apparaissent souvent contradictoires. Notre a...

Carabids are generalist predators that contribute to the agricultural ecosystem service of seedbank regulation via weed seed predation. To facilitate adoption of this ecosystem services by farmers, knowledge of weed seed predation and the resilience of seedbank regulation with co-varying availability of alternative prey is crucial. Using assessment...

In arable farming, weeds provide important floral and seed resources that have the potential to support the provision of ecosystem services such as pollination or pest control. Estimating the production of these weed resources in the landscape is however not trivial as large-scale surveys of weed communities are usually conducted once in the season...

The interest in the knowledge of weed communities of arable land is growing worldwide. Italy is one of the most biodiverse, geographically and environmentally heterogeneous, and rich in arable weed species countries in Europe. Thus, in this study, the geo-environmental factors influencing the floristic composition, the species richness, and the Sha...

Arable field margins are valuable habitats providing a wide range of ecosystem services in rural landscapes. Agricultural intensification in recent decades has been a major cause of decline in plant diversity in these habitats. However, the concomitant effects on plant functional diversity are less documented, particularly in Mediterranean areas. I...

L’agroécologie a été choisie par l’Inra comme l’un des chantiers de prospective interdisciplinaire destiné à identifier les fronts de recherche en réponse à de grands défis sociétaux. Quatre-vingt chercheurs ont dressé un bilan, et proposé des pistes de recherche pour l’agroécologie, et cet ouvrage en synthétise les principales conclusions. L’agroé...

Les agriculteurs présents dans une même situation de production peuvent différer dans leurs objectifs et donc leurs pratiques. Afin de tester l'effet d'une pratique particulière (ex. désherbage chimique) sur la communauté adventice, il est donc nécessaire de tenir compte de l'ensemble des autres pratiques, formant une stratégie agricole. Nous avons...

Understanding the contribution of naturally occurring assemblages of carabids to weed seed predation is necessary for the implementation of conservation biological control. Identifying key species, and their combinations, that drive high seed mortality is important to promote natural biocontrol of weeds and appropriate field management for conservi...

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For future arable agriculture, there is a need for more sustainable methods to manage weeds that are less reliant on herbicides and maintain food production. Control of weeds by natural enemies is an agro-ecological alternative to reduce the use of herbicides. While strong evidence points to carabid beetles exerting a regulatory effect on certain w...

Carabid beetles may play a role in the regulation of arable weeds, when seed predation is directly density‐dependent and consumption increases more than proportionally with seed density. We quantified the effect of seed and carabid density on consumption by two carabid species (Poecilus cupreus and Harpalus affinis) of the weed species Taraxacum of...

Complex landscapes including semi-natural habitats are expected to favour natural enemies thereby enhancing natural pest biocontrol in crops. However, when considering a large number of situations, the response of natural biocontrol to landscape properties is globally inconsistent, a possible explanation being that local agricultural practices coun...

Arable agriculture is still highly reliant on herbicides to manage weeds. As part of the necessary shift towards a reduction in pesticide use, the regulatory effect of seed-eating carabid beetles on weeds has received increasing attention in agroecological research. While strong evidence points to carabids exerting a regulatory effect on certain we...

The prediction of pest regulation by multi-predator communities often remains challenging because of variable and opposite effects of niche complementarity and predator interference. Carabid communities are regulating weeds in arable fields and include a mix of species ranging from granivores to predators that are obligate omnivores. It is not clea...

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In the context of a shift towards pesticide reduction in arable farming, weed management remains a challenging issue. Integrated Weed Management currently recommends agronomic practices for weed control, but it does not integrate the use of biodiversity-based options, enhancing the biological regulation of weeds. Here, wereview existing knowledge r...

Significance Decades of research have fostered the now-prevalent assumption that noncrop habitat facilitates better pest suppression by providing shelter and food resources to the predators and parasitoids of crop pests. Based on our analysis of the largest pest-control database of its kind, noncrop habitat surrounding farm fields does affect multi...

Weed seed predation by carabid beetles (Coleoptera, Carabidae) may contribute to weed control in crop fields but to date, evidence of weed regulation by carabids is scarce. Predation rates are driven by several factors (crop management techniques, habitat quality, pedoclimate, carabids’ abundance and activity and their weed seed preferences). Model...

The French National Institute for Agricultural Research (INRA) has established an ambitious, multi-scale, agricultural experimental infrastructure (the CA-SYS platform). CA-SYS covers an area of 120 ha and will be initiated in autumn 2018. The aims of CA-SYS are to: i) design and evaluate new agroecological systems; ii) study the transition from cu...

Weed seed predation by carabid beetles (Coleoptera, Carabidae) may contribute to weed control in crop fields but to date, evidence of weed regulation by carabids is scarce. Predation rates are driven by several factors (crop management techniques, habitat quality, pedoclimate, carabids’ abundance and activity and their weed seed preferences). Model...

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Seed predation by insects is a potentially promising approach to the regulation of weeds that could offset herbicide use as part of integrated weed management. Using the example of carabid beetles, as the most intensively studied grouping of insect weed seed predators, this chapter describes the current state of knowledge in this subject area and h...

Animals foraging in the wild have to balance speed of decision making and accuracy of assessment of a food item’s quality. If resource quality is important for maximizing fitness, then the duration of decision making may be in conflict with other crucial and time consuming tasks, such as anti-predator behaviours or competition monitoring. Individua...

Supporting dataset. All data needed to evaluate the conclusions in the paper are present in the paper and in the supplementary materials. (ZIP)

Mean number (bootstrapped +/- 95%CI) of seeds eaten per individuals after one hour of test in each treatment separated by sex. Different letters correspond to statistically significant difference between treatments (post-hoc pairwise comparison with Tukey adjustment for multiple comparisons). The sample sizes are shown above the x-axis. (PDF)

Kaplan-Meier plot for the latency to first movement as a function of the treatments. Each curve represents, for a given treatment group, the proportion of individuals with no movement as a function of the time since the start of the experiment: control (continuous line, n = 70), intraspecific competition (grey line, n = 71), interspecific competiti...

Mean duration (bootstrapped +/- 95%CI) of handling time in each treatment. Different letters correspond to statistically significant difference between treatments (post-hoc pairwise comparison with Tukey adjustment for multiple comparisons). The sample sizes are shown above the x-axis. (PDF)

Promoting the weed seed predation service by carabids requires an understanding of the spatio-temporal distribution of carabid species during the cropping season. In the present study, we analyzed the spatio-temporal dynamics of three abundant seed-eating carabid species in oilseed rape (OSR) and its adjacent habitat (cereal crop or grassy field ma...

Weed management is a critical issue as it is faced with a daunting set of challenges linked to crop productivity and farmland biodiversity. Developing new strategies for weed management requires a clear understanding of the relative role of local management and landscape heterogeneity on weeds. Yet few studies have investigated the combined effect...

Weeds must be considered in any conceptual framework that seeks to explain, explore and analyse biodiversity if the focus is on human activities and utilisation of natural systems. This chapter concentrates on weeds in annual and perennial crops associated with terrestrial systems used for agricultural purposes: weeds of non-terrestrial or nonagric...

L'objectif du projet CASIMIR est de proposer des protocoles de caractérisation de l'évolution des bioagresseurs, de leurs dégâts et de l'intensité de la régulation biologique dans les parcelles agricoles afin d'évaluer l'effet des systèmes de culture. En collaboration avec le réseau DEPHY, le projet CASIMIR propose des protocoles simplifiés de suiv...

Recent concern over possible ways to sustain ecosystem services has triggered important research worldwide on ecosystem processes at the landscape scale. Understanding this complexity of landscape functioning calls for coupled and spatially-explicit modelling approaches. However, disciplinary boundaries have limited the number of multi-process stud...

The ecosystem services (EcoS) concept is being used increasingly to attach values to natural systems and the multiple benefits they provide to human societies. Ecosystem processes or functions only become EcoS if they are shown to have social and/or economic value. This should assure an explicit connection between the natural and social sciences, b...

Recent studies suggest that weed seed predation by carabid beetles may partly substitute for chemical weed control in agriculture. Promoting this weed regulation service would require enhancement of the in-field abundance of seed-eating carabids, yet, the diversity of the habitat, trophic requirements and spatial scales of response of different spe...

In agriculture, landscape management research has proven extremely valuable for explaining species amount, such as how species capture and utilize changed landscape resources to maintain population size and community diversity. What is surprising is the apparent lack of comparable studies on the effects of landscape properties and management on spe...

Amongst the biodiversity components of agriculture, weeds are an interesting model for exploring management options relying on the principle of ecological intensification in arable farming. Weeds can cause severe crop yield losses, contribute to farmland functional biodiversity and are strongly associated with the generic issue of pesticide use. In...