Entomology Department Chair University of California, Riverside Department of Entomology, United States
Abstract: Pogonomyrmex rugosus is an important seed generalist found across the southwest United States, including among coastal sage scrub (CSS), an endangered, Mediterranean climate ecosystem found only in California. How P. rugosus interacts with and shapes the flora within CSS is potentially important for restoration efforts. Whether native fauna act as biotic filters for invasive plant species is a topic that is not often covered, with most research delving into the effects of the invasive plants on native fauna. P. rugosus nests have been found to affect the nutrients and moisture of surrounding soil. Therefore, we sought to determine P. rugous’ effect on plant species composition within CSS, and whether P. rugosus nests influence the phenology and fitness of the invasive plant species, Hirschfeldia incana. Over a period of two years, H. incana height, flowering time, seed production, and senescence was measured regularly at different distances from P. rugosus nests. Additionally, plant species composition in relation to P. rugosus nests was measured each year. During both years, H. incana abundance and growth was significantly correlated with P. rugosus nests. P. rugosus nests were also found to have a species composition distinct from non-nest areas. P. rugosus may be responsible for an overall shift in plant community dynamics, such as increases in invasive plant species populations, while simultaneously increasing biodiversity. As the number of invasive plant species increases globally, it is important to consider how granivorous and herbivorous generalists may help to either mediate or intervene biological invasions.
