Raw data from the manuscript “Beyond species averages: intraspecific trait variation reveals how Solenopsis invicta functionally rewrites community assembly rules”

Biological invasions are recognized for their capacity to alter species composition and restructure local ecological communities. A central question in ecology, however, revolves around the mechanisms driving these transformations: do dominant invaders induce functional homogenization, or do they trigger more intricate reorganizations? To address this, an individual approach that accounts for intraspecific trait variation (ITV) is essential, yet its role under intense invasion pressure remains inadequately explored. An investigation was conducted along an invasion gradient in Kunming, China, to elucidate the effects of the invasive ant Solenopsis invicta on the structure of native ant communities. A multifaceted analytical approach was employed, combining community composition data, trait distribution analyses, and hierarchical assembly models to examine functional characteristics at the individual forager level. A primary outcome of this analysis was the establishment of a strong inverse relationship between S. invicta population density and native species richness. Contrary to the hypothesis of functional homogenization, the invasion appeared to induce a sophisticated re-sorting of functional traits. The competitive pressure exerted by S. invicta selectively displaced native ants possessing similar functional traits, which consequently promoted an increase in niche segregation among the remaining native species. A notable directional selection towards diminutive body size was observed in surviving native populations, providing clear evidence for functional trait displacement. The results underscore the pivotal role of intraspecific trait variation as a mechanism that facilitates species coexistence in environments characterized by high competitive intensity. This study substantiates the concept that dominant invasive species can serve as powerful competitive filters, driving niche differentiation rather than convergence, thereby offering a mechanistic framework for predicting community restructuring following biological invasions.