Seed longevity and germination of the emerging invasive species wavyleaf basketgrass (Oplismenus undulatifolius) under varied light regimes

Abstract

Invasive non-indigenous species pose a serious threat to native biodiversity and ecosystem functioning. Understanding how species performance varies under conditions in the current and invaded range can help to predict dynamics of the invading species in its new environment. Plants with the ability to alter growth in response to variation in light conditions may be favored in landscapes that experience frequent disturbance, as these species may be able to exploit a wide range of niches. Seed bank persistence may also play a critical role in successful plant invasion, as extended seed viability may increase the chance of outlasting unfavorable conditions, maintain population genetic diversity, and allow re-invasions. This study investigated seed longevity and the effect of light intensity on germination of wavyleaf basketgrass [Oplismenus undulatifolius (Ard.) P. Beauv], a newly established invasive species in US mid-Atlantic forest understories. Oplismenus undulatifolius seeds were collected across five years from the original site of introduction in Maryland USA and stored in standard lab conditions, then subjected to germination trials under four light conditions in a controlled growth chamber. Seeds remained viable for at least nine years, and light intensity did not significantly impact seed germination. Our study demonstrates the importance of evaluating environmental and temporal effects on germination traits, since the scope of surveillance in the field may need to be expanded based on new information about environmental tolerance. Long-term monitoring may also be necessary to effectively control invasive plant populations capable of forming a persistent seed bank.