Spatial and temporal partitioning and tree preference in California woodland ants

Abstract

Spatial and temporal partitioning of habitat may facilitate diversity and have important impacts 10 on ant communities. To investigate niche overlap in an ant community in a northern California oak 11 woodland, we observed ant foraging on trees in 4 seasonal surveys, each lasting 2 weeks, in a 9.5-hectare 12 plot over the course of a year. Foraging activity in all 5 observed ant species differed by season, time of 13 day, and/or the genera of trees used. Of the 3 ant species most frequently observed, Camponotus 14 semitestaceus was most active during spring and summer nights, Formica moki was most active during 15 spring and summer days, and Prenolepis imparis was most active during both day and night of fall and 16 winter. All ant species preferred native trees to exotic trees and preferred evergreen trees to deciduous 17 trees. Our results suggest that native evergreen oaks such as Quercus agrifolia, currently threatened by 18 sudden oak death (Phytophthora ramorum), may be important for supporting ant biodiversity. 19 20 Acknowledgements for many hours of field work assistance. We thank Rodolfo 25 Dirzo, Daniel Friedman and Maria Wojakowski for providing advice and assistance with statistical 2 26 analysis. Leander D.L. Anderegg, Talia Borofsky, Kaleda Denton, and Tyler McFadden provided helpful 27 comments on the manuscript. The Stanford Maps and Records Office (340 Bonair Siding, Stanford, CA 28 94305) provided detailed maps of trees on the Stanford grounds that were invaluable for this project. 29 30