Potential penetration of exotic aquatic plants into natural environment through ornamental plant industry in Sri Lanka

Aquatic plant industry has shown a rapid growth during past few decades in its export capacity and thus there are number of registered exporting companies directly involved in this business. This study was conducted to evaluate the invasion risk of exotic aquatic plant species to the natural environment through ornamental aquatic plant industry. Information of major aquatic plant nurseries in Sri Lanka were obtained from the National Plant Quarantine Service of Sri Lanka (NPQS). A field survey was performed in aquatic and semi-aquatic habitats within 1 km radius from four major nurseries selected in order to understand whether any species has escaped from the nurseries. photographs and the GPS data of the escaped species were taken. Echinodorus argentinensis, Mayaca sellowiana, Ceratophyllum demersum, Hydrilla verticillata, Hydrocotyle verticillata, Micranthemum umbrosum, Echinodorus grandiflorus, Echinodorus decumbens and Alternanthera sessilis were detected in natural habitats around some nurseries giving evidence for invasion risk from the nurseries. This finding indicates the necessity of implementing policy decisions and amending regulation on importation and cultivation of aquatic plant species in Sri Lanka.