Influence of forest canopy closure on rates of bird predation on overwintering Monarch butterflies Danaus plexippus L.

The Monarch Butterfly Special Biosphere Reserve (MBSBR) was created in 1986 to protect the overwintering sites of the monarch butterfly Danaus plexippus. However, curl ent political and economic pressures are leading government officials to consider the authorization of logging permits in the core: areas of the reserve. In order to investigate how increased logging may impact monarch survival in the MBSBR, we studied how monarch butterfly mortality caused by bird predation is currently affected by logging extractions that occurred in the early 1980s. We monitored daily bird predation in closed and opened areas and found that monarch butterflies overwintering in areas with low tree density, low basal area, and low canopy coverage suffered higher mortality rates than monarchs in quadrats with closed for:st. Since bird predation is only one of several negative effects that logging may have on the survival of monarchs overwintering in Mexico, we recommend that logging permits should not be authorized by the government in the core areas of the MBSBR. (C) 1998 Elsevier Science Ltd. All rights reserved.