Biotic and abiotic controls of Argentine ant invasion success at local and landscape scales

*[In southern California, a factorial field experiment combining native ant removal with irrigation, revealed that Argentine ants failed to invade any dry plots, even those lacking native ants, but readily invaded all moist plots. Native ants slowed the spread of Argentine ants into irrigated plots, but did not prevent invasion. In areas without Argentine ants, native ant species showed variable responses to irrigation. At the landscape scale, Argentine ant occurrence was positively correlated with minimum winter temperature, but not precipitation. Native ant diversity increased with precipitation & was negatively correlated with minimum winter temperature. These results demonstrate that fine-scale differences in the physical environment can eclipse biotic resistance from native competitors in determining community susceptibility to invasion. Also, the results illustrate surprising complexities with respect to how the abiotic factors limiting invasion can change with spatial scale. Native & invasive species can differ in their responses to the physical environment.]