Re-establishment of native macrophytes in lake parkinson following weed control by grass carp

Abstract

The rnacrophyte communities present in Lake Parkinson (37°19′S 174°41′E), a 1.9 ha eutrophic sand‐dune lake, are described 5 years after removal of grass carp (Ctenopharyngodon idella Val; 218 kg ha−1). Eradication of the adventive submerged species Egeria densa Planchon (dependenton vegetative reproduction from stem fragments) as a result of grass carp stocking led to the re‐establishment of a predominantly native macrophyte association from seeds, spores, and buried rhizomes after grass carp removal. Emergent Eleocharis sphacelata R. Br. re-established around the lake margins and throughout the lake’s shallow southwestern arm, whereas submerged communities domin ated by Potamogeton ochreatus Raoul and Nitella hookeri A. Br. grew to a maximum depth of 5 m. © Crown copyright 1990.