Saturday, 12 April 2014

Could more aquatic wildlife mean more food for us?

I make the case in a conference paper published this week* that aquatic invertebrates can be used to guide land management to improve crop yields. Driven by the demands of the Water Framework Directive for cleaner water in our streams and rivers, it is very much the vogue to use aquatic invertebrate communities as indicators of the negative effects of food production on freshwater as many species are affected by the loss of soil and nutrients from farmland to water.  But the loss of soil and nutrients from farmland to water does little for food production either!  Aquatic invertebrate communities can be considered as indicators of how well agricultural soils are being managed.
Aquatic invertebrates in a mixed arable/grass and an all-grass catchment
In our largely arable School Farm demo catchment, mayflies were present in just a third of the numbers present in a nearby low input pasture catchment stream, while caddis fly numbers were only 18% of those present in the comparison catchment. Stone flies were totally absent from the School Farm stream, whereas they exceeded caddis fly numbers in the pasture stream. It is probably unrealistic to expect invertebrate communities associated with arable land to be as rich as those associated with stable soils under low input pasture.  However, we expect our current improvements in soil management within the School Farm catchment to improve soil function, and that means benefits both to food production and to aquatic wildlife.

*Stoate, C. 2014. Delivering integrated farm management in practice: understanding ecosystem services. Delivering multiple benefits from our land: sustainable development in practice. SRUC/SEPA Biennial Conference, Edinburgh, 15-16 April 2014.

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