|Whitford, Walt -|
|Barness, G. -|
|Steinberger, Yosef -|
Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 23, 2007
Publication Date: April 15, 2008
Citation: Whitford, W.G., Barness, G., Steinberger, Y. 2008. Effects of three species of Chihuahuan Desert ants on annual plants and soil properties. Journal of Arid Environments. 72:392-400. Interpretive Summary: There area about 750 different species of ants in the United States. About one-tenth of these difference species occur in the hot deserts of the southwestern United States. These species are important components of the biodiversity of these environments and may be useful indicators of changing climate patterns or impacts of changing land uses. This study, partly funded by the National Science Foundation, examined effects & species of ants common in the Chihuahuan Desert on soil nutrients and plant productivity. These ant colonies build long-lived nests that can have important effects on soil and vegetation. Average colonies life spans are 5-8 years for some species, with some colonies persisting for up to 35 years. The study concluded that the length of time a colony persists in a location is more important factor affecting soil nutrition and plant productivity than other studied factors. These ants are important to the nutrient cycling and productivity of these desert environments.
Technical Abstract: We tested the hypothesis that ant species, which occupy the same nest for a decade or longer, would modify nest soils by increasing soil nutrients and microorganisms resulting in increased biomass, density, cover and species richness of annual plants. We measured soil properties and annual plants on nest soils of three species of Chihuahuan Desert ants (Pogonomyrmex rugosus—seed harvester, Aphaenogaster cockerelli—generalist forager, and Myrmecocystus depilis—liquid collector-insect scavenger) in comparison to paired reference soils at several locations. There were no differences in nest and reference total soil nitrogen of M. depilis and of P. rugosus on three catena soils. Total soil nitrogen of nest-modified soils was higher than of reference soils of A. cockerelli and P. rugosus in a desert grassland site. Soil microbial biomass and respiration were not significantly different among ant species at most locations with the exception of P. rugosus at the base of the catena. Annual plant biomass was higher on M. depilis and A. cockerelli nest soils than on the reference soils. Annual plant biomass was higher on P. rugosus nest soils than on reference soils at the base of the catena and in the grassland but not at the mid-slope and top of the catena. The effects of long-lived ant colony nests on soil properties and vegetation vary in time and space but are independent of the feeding behavior of the ant species.