Monarch (Danaus plexippus L. Nymphalidae) migration, nectar resources and fire regimes in the Ouachita Mountains of Arkansas
Monarchs (Danaus plexippus) pass through the Ouachita Mountains in large numbers in September and October on their annual migration to overwintering sites in the Transvolcanic Belt of central Mexico. Monarchs are dependent on nectar resources to fuel their migratory movements. In the Ouachita Mountains of west-central Arkansas migrating monarchs obtain nectar from a variety of plant species, especially Bidens aristosa and other composites. Fire suppression has greatly altered the structure of forest communities, with major implications for ecological relations. Sites that are undergoing restoration to a shortleaf pine-bluestem grass community following thinning and frequent prescribed fire, and thought closely resemble pre-European conditions, support increased abundances of nectar resources and migrating monarchs compared to untreated controls. These results suggests that widespread fire-suppression since the early 1900s has substantially reduced nectar production for migrating monarchs in the Ouachita Mountains Physiographic Region.