Speaker
Description
Introduction
Given the major impacts of chemical-based agriculture and landscape simplification on biodiversity, alongside climate change and human health, it is urgent to produce food in more sustainable ways (1). Crop fields and agricultural landscapes must promote biodiversity conservation and associated functions, including ecological regulation (e.g., predation, pollination), carbon sequestration, maintenance of water quality, and soil health protection (2). However, quantitative assessment of agroecosystem multifunctionality remains scarce (3), and few studies have simultaneously addressed belowground and aboveground organisms and functions (4). A better understanding of trade-offs and synergies between this wide range of taxa and functions would greatly inform the transition towards multifunctional agriculture.
Interactions between field- and landscape-scale factors are likely major drivers of multifunctionality in crop fields, but remain overlooked. For example, the effectiveness of local agri-environment schemes such as organic farming in promoting biodiversity and associated functions may depend on landscape context (5). In addition, landscape-scale studies are generally restricted to a context of chemical-based agriculture. Frequent agrochemical disturbances might undermine the beneficial effects of increased landscape heterogeneity (antagonistic effect) by preventing or limiting the spillover and population growth of beneficial organisms into conventional fields (6,7).
In this work, we investigated the effects of organic farming at field scale, total length of hedgerow networks in the landscape, and their interaction on the multifunctionality of winter cereal fields. We hypothesized that hedgerow landscapes promote the multifunctionality of crop fields, but also that their beneficial effects are stronger in organic systems, which are more prone to ecological intensification.
Methods
We conducted the study in the southern part of the Zone Atelier Armorique, a Long-Term Socio-Ecological Research site in Brittany, France. We selected 40 winter cereal fields under conventional vs organic farming, located along a gradient of total hedgerow length in the landscape. In 2019, we collected 21 indicators through sampling of crop fields and interviews with farmers. These indicators were used to estimate five agroecosystem goods: biodiversity conservation, nutrient cycling and soil structure, pest and disease regulation, food production, and socio-economic performance.
Results and discussion
Organic farming had higher level of functionality than conventional farming for many indicators, especially those related to biodiversity conservation and pest and disease regulation, despite a trade-off with food production. Total hedgerow length had much lower influence than organic farming on indicators, although we observed some positive interactions. Granivorous carabid abundance and semi-net margin were maximal in organic fields located in denser hedgerow landscapes. We conclude that reducing agrochemical input in crop fields is necessary to promote agroecosystem multifunctionality, whereas preservation of seminatural habitats alone is likely insufficient. Our study shows that organic farming and preservation of hedgerows are compatible or even preferable. More broadly, our results call for more ambitious research into the myriad possible combinations of farming practices and agri-environmental measures at both field and landscape scales, going beyond the context of chemical-based agriculture.
References
1. Altieri, M. A. & Nicholls, C. I. Agroecology and the emergence of a post COVID-19 agriculture. Agric Hum Values 37, 525–526; 10.1007/s10460-020-10043-7 (2020).
2. Kremen, C. & Merenlender, A. M. Landscapes that work for biodiversity and people. Science 362; 10.1126/science.aau6020 (2018).
3. Hölting, L., Beckmann, M., Volk, M. & Cord, A. F. Multifunctionality assessments – More than assessing multiple ecosystem functions and services? A quantitative literature review. Ecol Indic 103, 226–235; 10.1016/j.ecolind.2019.04.009 (2019).
4. Bardgett, R. D. & van der Putten, W. H. Belowground biodiversity and ecosystem functioning. Nature 515, 505–511; 10.1038/nature13855 (2014).
5. Concepción, E. D., Díaz, M. & Baquero, R. A. Effects of landscape complexity on the ecological effectiveness of agri-environment schemes. Landscape Ecol 23, 135–148; 10.1007/s10980-007-9150-2 (2008).
6. Stein-Bachinger, K., Preißel, S., Kühne, S. & Reckling, M. More diverse but less intensive farming enhances biodiversity. Trends Ecol Evol 37, 395–396; 10.1016/j.tree.2022.01.008 (2022).
7. Madin, M. B. & Nelson, K. S. Effects of landscape simplicity on crop yield: A reanalysis of a global database. PloS One 18, e0289799; 10.1371/journal.pone.0289799 (2023).
| Keywords | aboveground-belowground functioning; agroecology; biodiversity conservation; ecological intensification, ecosystem service |
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