Profiling native and introduced perennial garden plants in Puerto Rican urban residential yards

Worldwide the number of non-native species escaping from cultivation into native habitats is steadily increasing with no signs of saturation. Species that eventually become invasive may generate unwanted social and ecological conditions especially in areas of conservation concern. This study built upon prior biodiversity work from 432 residential yards in the San Juan Metropolitan Area of Puerto Rico to evaluate the natural history and functional traits of native and non-native plant species in these green spaces. We reviewed the literature for a total of 361 plant species to extract information on their taxonomy, native distribution range, invasive status (casual, naturalized or invasive), life-form and ecological and biological species attributes. We then evaluated the relationship between their attributes and their probability of escaping cultivation and become invasive. Our results show that non-native species growing in yards are more likely to succeed in becoming invasive if they have vegetative growth, a mixed breeding system, and an unspecialized dispersal mode. We also found that native and non-native species occurring in residential yards share similar adaptive strategy scores. Most plant species that have already become invasive originated from Asia and America a fact that is likely tied to the US nursery trade. We used the combined results of this and prior studies to understand the factors facilitating plant invasion and to generate recommendations for the development of management strategies that may limit the spread of non-native ornamentals with the potential to escape cultivation and become invasive on this island.