A study carried out by scientists from Eawag and WSL reveals that the biodiversity of insects and spiders is crucial to maintain the abundance of essential nutrients, in particular omega-3 and omega-6 fatty acids, in terrestrial and aquatic ecosystems. These nutrients, which are essential for birds, reptiles, amphibians and small mammals, depend on the diversity and biomass of the species they consume.
Importance of aquatic insects: Insects such as dragonflies, which are rich in omega-3 thanks to aquatic algae, provide more nutrients than their terrestrial counterparts.
Decline linked to loss of biodiversity: A decline in species reduces both biomass and fatty acids content in food webs.
Differences between environments: Urban terrestrial ecosystems have a lower fatty acid content due to reduced biomass and the absence of predators such as spiders. In contrast, aquatic environments remain stable sources of nutrients, even in urban environments.
Protecting biodiversity, particularly in agricultural and urban areas, is essential to preserve food webs and ensure access to these key nutrients. At the same time, it is imperative to improve water quality to maximise the benefits of aquatic ecosystems.