Abstract
Ecosystems are intimately linked with other ecosystems through exchanges of nutrients and organisms. Seas impact land systems and freshwaters their terrestrial surroundings. Streams are fueled by autumnal leaf fall and terrestrial insects provide food for fish. The reverse flow from water to land is much less understood but likely to be equally important. Masses of insects develop in freshwater but spend their adult life on land feeding, mating, dispersing or parasitising, and in so doing many might well end up in terrestrial foodwebs. In this project blackflies will be used as model organisms. They develop in running waters and adult females of 90% of the Swedish species require a blood meal to develop eggs. When rivers are regulated for hydropower blackfly breeding habitats are destroyed, This provides a unique opportunity, as a large-scale experiment, to asses the importance of mass-occurring insects by comparing processes along regulated rivers with those along free-flowing ones (controls). Different roles of blackflies in the terrestrial foodwebs will be quantified including direct effects as food for predators and indirect effects on terrestrial herbivores and their host plants. Whether blackflies contribute to pollination will also be investigated. Bilberries are important nectar producers that attract blackflies. Their pollinators, bumblebees, might be forced to visit many more flowers when the numbers of blackflies are massive and then enhance pollination.
Sweden