Changes in Nothofagus pumilio forest biodiversity during the forest management cycle. 2. Birds

Human activities, such as logging, modify the forest structure and the micr oenvironments of the original Nothofagus forests. The aims of this work wer e to evaluate changes in the diversity and relative abundance of birds and to analyze their trophic relationships with insect and plant communities al ong the Nothofagus pumilio forest management cycle. Data was collected usin g a point sampling method along transects located in different forest struc tures during the summer season, by direct (sight) and indirect (hearing) re cognition following sunrise. Bird diversity and abundance significantly var ied along the forest management cycle. Seven new species appeared after har vest, but the total number did not vary by the end of the forest management cycle, and there was no significant loss of species. Bird abundance was di rectly related to the insect abundance and plant biomass. Relationship betw een groups (lower plants, monocotyledons and dicotyledonous) is also discus sed. Major studies in bird ecology are necessary to develop new silvicultur al alternatives based on the more sensitive species to harvest. Forest mana gement strategies and mitigation alternatives must be incorporated into for est planning in order to maintain the original structure of bird communitie s and the equilibrium with other forest species.