2015 Conference

Poster Presentation

Native ants are displaced by invasive species and habitat destruction, and can lower ant species richness.  We examined factors that correlate with species richness and abundance of ants in urban gardens.  We placed pitfall traps at 19 urban garden sites in Central California between May-September 2013 to collect ants.  We measured 60 habitat factors at local (e.g. vegetation, ground cover) and landscape (surrounding land cover) scales.  The results were that we collected 7 ant species and 2,969 individuals.  The most abundant species were: Linepithema humile (80.3% of individuals), Tetramorium caespitum (7.4%), and Hypoponera opacior (6.4%).  Of these, only Hypoponera opacior is native to Northern California.  Ant richness was highest in sites with low weed cover, with low leaf litter cover, and with more open space and development within 5 km.  Ant abundance was higher in sites with low mulch cover, high rock and grass cover, and high tree canopy cover.

In sum, most ant species and individuals collected in urban areas were invasive ants, and they thrive in developed habitats with bare ground (no mulch or leaf litter), and with open space and grass.  More research is needed to understand the factors that drive loss of native species in favor of invasive ants in urban habitats.