A Comparative Analysis of the Ecological Niches of Erigeron canadensis L. and Erigeron annuus (L.) Pers. in Invasive Areas and Their Native Habitats

Biological invasions are a major threat to biodiversity; analyzing changes in the ecological niches of invasive species is of great significance for the prevention and control of biological invasions. Heilongjiang Province, which serves as a crucial ecological security barrier for China, has also faced invasions by invasive Asteraceae plants in recent years; however, the invasion patterns and ecological adaptation characteristics of these invasive plants remain unclear. Therefore, this study selected the representative Asteraceae species, E. canadensis and E. annuus, as the subjects of investigation. Based on data from the Heilongjiang invasive plant survey and supplementary field survey data, and in combination with distribution data from their native range in North America, the study employed methods such as ecological niche analysis and ecological niche overlap comparison and used Schoener’s D index. This study evaluates the potential suitable habitats for E. canadensis and E. annuus in Heilongjiang Province and analyzes the characteristics of niche shifts between their native and invaded habitats. The results indicate that both invasive plant species exhibit strong ecological conservatism; however, their ecological adaptation strategies in Heilongjiang Province differ, with E. annuus showing a higher degree of spread compared to E. canadensis.