Interspecific associations and interactions in birds: ecological and evolutionary consequences, and conservation implications

Global biodiversity is declining at an alarming rate, and this has recently been stressed in science and in the media. Current human induced changes in the environment, such as the loss of old growth forests and natural meadows, have global impact in nature. For example, the abundances of many insects have drastically declined at large areas, which in turn, has most likely partly contributed to the declines in the abundances of bird species feeding on insects. There is an urgent need for conserving nature and different measures for protecting nature are continuously planned locally, nationally and globally. Communities are complex interaction networks of multiple organisms, still current conservation plans often target single habitats or species. Due to the complexity of these interaction networks, the loss of a single species could lead to drastic and cumulative changes within the community, which we do not even understand. The effects of environmental changes in the interaction networks of animals are still poorly understood, as well as to what consequences these changes in the networks may lead to.
Traditionally, interactions between species have been examined at small geographical range, while species interactions at large geographical range and long time frames are less studied. In addition, research has traditionally focused on negative species interactions, such as competition and predation, which are suggested as the main mechanisms of interactions that shape community structure. Positive species interactions, such as information use between species, where an individual uses an individual of another species as a source of information for decision-making, are less studied and poorly understood when covering large geographical areas.
My doctoral thesis is focusing on the breeding bird communities in Finland and France, what ecological and evolutionary consequences species interactions, such as social information use, may lead to and how species interactions should be accounted for in future conservation efforts. The results suggest that positive species interactions may be more prominent in shaping community structure at large geographical areas than previously understood. The results also suggest that understanding positive species interactions could potentially help in developing novel methods for estimating bird community abundance using citizen science data. Finally, the results suggest that social information use between species may lead to ecological changes in animal communities, for example species may group or avoid each other, or evolutionary changes in animal populations, such as animal traits becoming more similar or different between species.
These results demonstrate the importance of focusing research efforts on species interactions, particularly on positive interactions, and that we need to understand the potential consequences of species interactions also within a community of multiple species and at large geographical areas. Increasing the understanding on species interactions enables us to connect interaction networks in the planning of future conservation efforts.