Are Iron-Rich Calcareous Mine Sites Easily Invaded by Invasive Plant Species?

Abstract

Plant diversity in relatively harsh environments, such as metal-polluted areas tends to be relatively low. Invasive plants may invade harsh environments more easily than native plants. However, studies often find fewer invasive species in stressful edaphic habitats (such as serpentine soils). Those examples may represent relatively extreme conditions. Moderately stressful habitats may be more invaded given the advantages of invasive plants. We surveyed the plant diversity in four site pairs across three seasons. Sites consist of abandoned mines and reference sites. The mine sites have calcareous soils with relatively high iron, basic pH, and lower nutrients than reference sites. Results: There were 153 plant species among the four site pairs. Around 80 and 66% of species in calcareous and reference sites were introduced species respectively. Diversity varied across seasons but tended to be lower in the mine sites. One of the mines was significantly more invaded. Across sites, the number of invasive species and their abundances was not different from that of native species. Invasive plants are as capable of invading moderately stressful calcareous sites as native species, with some sites tending to be even more invaded.