Introduction
Fish ponds represent the interweaving of an ecosystem and a socio-economic system, which is managed by humans to support nature's contributions to people (NCPs). These agroecosystems are mainly a heritage of the past, in which land unsuitable for cultivation was transformed into fish-production sites, which can also serve as reservoirs for watering livestock or irrigating crops (Rougier de la Bergerie, 1819). Thus, from the beginning, ponds were created to provide goods and services.
Today, a wide variety of social groups have a range of expectations about and uses for ponds, which serve three categories of purposes (Díaz et al., 2018): non-material or cultural NCPs (e.g., learning and inspiration), regulating NCPs (e.g., regulation of water quantity, regulation of the climate) and material NCPs (e.g., provision of food and feed). It has been shown that not all NCPs are compatible with one another. For instance, food provision conflicts the most with the other NCPs, such as creation of habitat for biodiversity and regulation of water quality and quantity (Bartrons et al., 2024). As ponds help address societal challenges such as meeting demand for fish, one potential approach is to promote nature-based solutions (NbS) (IUCN, 2020). Based on agroecological principles and considering biodiversity as both a driver and a goal, NbS provide an inclusive governance framework built on a culture of compromise. With this in mind, field experiments were performed in 10 fish ponds in France (FEAMP SEPURE project, 2020–2023).
Materials and methods
Researchers and pond fish farmers developed new pond-management strategies together that were designed to make the ponds more economically and environmentally efficient. Management scenarios were based mainly on selecting fish species (planned biodiversity) of economic interest, as a function of their compatibility and complementarity in exploiting resources (Lecocq et al., 2024). Ten scenarios were selected and applied over two consecutive annual production cycles to 10 ponds in three major fish-production regions in France (i.e., Dombes, Brenne and Lorraine).
Biophysical, productivity and environmental analyses were then performed that considered nine NCPs divided into the three NCP categories: Fish production, Fertiliser sources (material NCPs), Climate regulation, Water-quantity regulation, Nutrient retention (regulating NCPs), Creation of habitat for biodiversity, Primary production and Abundance of macroinvertebrates and macrophytes (non-material NCPs).
Results and discussion
The diversity of NCPs identified demonstrated the multifunctionality of ponds. Across all scenarios, most NCPs were regulating NCPs. The functioning of ponds is closely related to their overall biodiversity (both planned and associated). Pond productivity increases when planned biodiversity (fish species assemblages) contains more species and age cohorts. High associated biodiversity supports a high-quality environment and biological productivity. Furthermore, the field experiments in the SEPURE project showed that attention to pond management when stocking fish (i.e., the species, age cohorts, and proportions of each species selected) is essential to ensuring that biodiversity and production do not conflict.
Acknowledgments
This work, part of the ValoSEPURE project, was funded by FEAMPA (Fonds Européen pour les Affaires Maritimes, la Pêche et l'Aquaculture) and FranceAgriMer.
References
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