Spatial and temporal partitioning and tree preference in California woodland ants

Spatial and temporal partitioning of habitat may facilitate diversity and have important impacts on ant communities. To investigate niche overlap in an ant community in a northern California oak woodland, we observed ant foraging on trees in 4 seasonal surveys, each lasting 2 weeks, in a 9.5-hectare plot over the course of a year. Foraging activity in all 5 observed ant species differed by season, time of day, and/or the genera of trees used. Of the 3 ant species most frequently observed, Camponotus semitestaceus was most active during spring and summer nights, Formica moki was most active during spring and summer days, and Prenolepis imparis was most active during both day and night of fall and winter. All ant species preferred native trees to exotic trees and preferred evergreen trees to deciduous trees. Our results suggest that native evergreen oaks such as Quercus agrifolia, currently threatened by sudden oak death (Phytophthora ramorum), may be important for supporting ant biodiversity.