Lianas shape the ecology of tropical canopy ants

Lianas (woody vines) create an extensive network of connections between tree crowns that
is used by arboreal ants to access distant patchy resources. Consequently, the distribution
of lianas is likely to influence canopy ant ecology. To test this hypothesis, my students and
I are surveying the resident ant fauna of a large-scale liana removal project in Panama.
Liana removals were combined with experimental additions of connectivity, nest sites, and
food resources in a replicated design. One year after lianas were cut, average ant species
richness in liana removal plots declined by 22% relative to controls. The addition of artificial
connectivity increased ant species richness by ca. 25% from June 2011 to June 2012,
while trees in liana removal plots without added ropes lost ca. 30% of their ant species
over the same time interval. These trends suggest that the presence of connectivity is an
important determinant of local ant species richness in the tropical forest canopy. Increasing
liana abundance is likely to be a key driver of changes in tropical forest structure over the
next century; clarifying the ecological associations between lianas and ants is essential to
understanding and predicting the consequences of such changes.