Hydrologic and mechanical control for an invasive wetland plant, Juncus ingens, and implications for rehabilitating and managing Murray River floodplain wetlands, Australia

• Published in: Wetlands ecology and management Vol. 18; no. 6; pp. 717 - 730
• Main Authors: Ellery Mayence, C, Marshall, David J, Godfree, Robert C
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01-12-2010; Springer Netherlands; Springer Nature B.V
• Subjects: Aquatic plants; Biomedical and Life Sciences; Clipping; Community composition; Conservation Biology/Ecology; Ecological function; Environmental Law/Policy/Ecojustice; Environmental restoration; Fatal; Field capacity; Flooding; Floodplains; Freshwater; Freshwater & Marine Ecology; Grasslands; Hydrologic regime; Hydrology; Hydrology/Water Resources; Inundation; Inundation stress; Invasive plants; Invasive species; Life Sciences; Marine & Freshwater Sciences; Mechanical control; Nonnative species; Original Paper; Plant communities; Plant community composition; Plant species; Plants (organisms); River basins; Rivers; Seedlings; Soil surfaces; Water Quality/Water Pollution; Wetland restoration; Wetlands; Australia; Wetland restoration; Flooding; Plant community composition; Inundation stress
• ISSN: 0923-4861; 1572-9834
• DOI: 10.1007/s11273-010-9191-1

Wetlands are prone to increased invasion by plant species following changes in hydrologic regime, leading to shifts in plant community composition and potentially ecosystem function and health. In this paper, the ecology and potential control of Juncus ingens, a native wetland plant in the Murray-Darling Basin of south-eastern Australia, is investigated. J. ingens has benefited from altered Murray River hydrologic conditions by expanding its range and invading seasonally-flooded grassland and riparian habitats along the Murray River. Here results of complementary glasshouse and field research of seedling and mature J. ingens growth and resilience as influenced by hydrologic regime (moist, saturated, partial inundation and when possible, complete inundation) and mechanical control (i.e., clipping) are presented. A moist hydrologic regime (soil held at field capacity) resulted in the most vigorous seedlings (13.9-73.0% more total biomass), while saturated conditions (flooding maintained level with the soil surface) resulted in the most vigorous mature J. ingens (14.1-98.4% more total biomass). Seedling mortality was greatest under complete and prolonged inundation (60% fatal with remaining 40% showing severe stress), conditions suspected to have limited prior invasion but which currently occur infrequently as a result of reduced flooding magnitude. Clipping was fatal for nearly all seedlings regardless of hydrologic regime but was only fatal for mature plants if coupled with prolonged inundation. Coupling ground-level clipping with strategic flooding may be the most effective means for controlling current populations of J. ingens and limiting further invasion, promoting re-colonisation by displaced species and rehabilitating the health of Barmah Forest and similar Murray River floodplain wetlands.