From stream to land: Ecosystem services provided by stream insects to agriculture

摘要

The connection between aquatic and terrestrial habitats has increased scientific interest in ecological subsidies, focusing on how the transfer of matter and energy between adjacent ecosystems can modify the ecosystems functioning. Much attention has focused on subsidies associated with winged aquatic insects in pristine areas, but their existence and implications in agricultural landscapes are rarely considered. We reviewed current knowledge on the dominant types of winged stream insects involved in terrestrial ecosystem subsidizing and how agricultural practices can affect their communities. We compiled published data that illustrate the contribution of winged stream insects to ecological services in agroecosystems. Agricultural intensification has resulted in profound environmental modifications of streams and a decrease in large-bodied and sensitive taxa of Ephemera, Plecoptera and, to a lesser degree, Trichoptera orders, whereas more tolerant and small-bodied taxa of the Diptera order may increase. In return, these changes in stream invertebrate communities can modify the transfer of aquatic subsidies to agroecosystems. Winged stream insects can disperse up to 150?m from the stream bank, depending on species. They pollinate both wild and cultivated plants, fertilize the soil (depositing up to 12?mg?N/m2per day) during emergence outbreaks and feed natural enemies of crop pests during crucial periods of the year. Promising evidence suggests that they can support the related ecosystem services (pollination, soil fertilization and crop pest control), indicating the need for further research. Another area of focus can include the influence of agricultural practices on the amount and type of emerging aquatic insects. Future research on aquatic subsidies in agricultural landscapes may provide new insights into the management and provision of ecosystem services to agriculture, while simultaneously ensuring the conservation of rich freshwater biodiversity for optimal ecosystem functioning.