Plant introductions to invasion: History, public awareness, and the case of Ardisia crenata

Ardisia crenata Sims (Myrsinacea), an understory shrub native to northeastern Asia, invades mesic hardwood forests in the Gulf Coastal Plain and north central Florida. The potential for A. crenata to invade pine flatwoods systems was examined by introducing seeds and seedlings into hardwood and flatwoods sites in north central Florida, and by testing its response to light, pH, and flooding in the greenhouse. Ardisia crenata successfully established, survived and grew in flatwoods, systems though it showed less growth and survival in pine forests. Growth was enhanced mostly by phosphorous. Greenhouse studies revealed that A. crenata was inhibited by high light and long-term, complete flooding, although it had successful survival strategies when partially flooded. On suitable sites A. crenata demonstrated tolerance of a fairly wide variety of site conditions, suggesting other forests are at risk of invasion. Current distribution may be limited by seed dispersal and by the cumulative effects of better growth and survival in hardwood forests.; Although invasive ornamental species like A. crenata threaten the integrity of natural systems, gardeners demand access to thousands of exotic species, unaware of the potential detrimental effects on natural systems. A brief history of ornamental gardening illustrates how modern gardeners have come to expect a wide variety of ornamental species in the landscape. Over the last 500 years extensive plant exploration and introductions have been carried out, aided by technological advances and prosperity found in nursery trade. Horticultural writers and others popularized ornamental gardening, leading to modern landscaping practices dominated by the use of non-native species.; A survey of 237 retail nursery customers, in Florida, Louisiana, and Texas examined customer non-native plant environmentalism. Respondents typically demonstrated moderate levels of awareness of the problem of plant invasions, and high levels of concern. However, customer knowledge of plant materials and purchasing practices indicated they generally do not engage in environmentally sound gardening practices: customers bought few native species, they were unfamiliar with the native range of plants, and they reported no preference for native plants. Nurseries sold mostly non-native species and personnel were largely unfamiliar with plant native range.