Identity and Diversity of Invasive Plant Affecting the Growth of Native Lactuca indica

Despite the significant number of studies that have recently focused on plant invasion and invasive plants' success, many uncertainties still exist on the effects of invasive plant identity and diversity on the native plant response under different levels of diversity. A mixed planting experiment was conducted using the native Lactuca indica (L. indica) and four invasive plants. The treatments consisted of 1, 2, 3, and 4 levels of invasive plants richness in different combinations in competition with the native L. indica. Here, the results showed that native plant response depends on the invasive plant identity and invasive plant diversity, which increases the native plant total biomass under 2-3 levels of invasive plant richness and decreases under high invasive plant density. This plant diversity effect was more significant in the native plant relative interaction index, which shows negative values except under a single invasion with Solidago canadensis and Pilosa bidens. The native plant leaf nitrogen level increased under four levels of invasive plant richness, which means more affected by invasive plant identity than invasive plant diversity. Finally, this study demonstrated that native plant response under invasion depends on the identity and diversity of invasive plants.