Interactive effects of salinity and water regime on ecologically significant waterplants

Citation

Land & Water Australia. 2009. Interactive effects of salinity and water regime on ecologically significant waterplants. [Online] (Updated June 23rd, 2009)
Available at: http://lwa.gov.au/node/2964 [Accessed Tuesday 26th of April 2011 12:08:19 AM ].

Aquatic vegetation is represented by a variety of growth forms, including floating, submerged, amphibious, emergent and semi-terrestrial taxa. The persistence of these growth forms in aquatic habitats is strongly influenced by water regime; long-term flooding favours submerged species and excludes most emergent species whereas alternation in wetting and drying may allow both to persist. The artificial homogenisation of naturally fluctuating water regimes and secondary salinisation are major contributing factors to the loss of plant biodiversity in wetlands worldwide. However, the interactive effect of these processes remains poorly quantified. This project aims to predict the likely persistence of two common wetland plant species with contrasting growth forms; the emergent swamp paperbark (Melaleuca ericifolia) and the submerged aquatic eel grass (Vallisneria americana), to a number of water regime management strategies. A combination of field studies, laboratory experiments and mesocosm manipulations shall be utilised to investigate how different life stages of both species respond to salinity and water regime scenarios. Results will indicate how salinity may affect the mechanisms of species persistence during unfavourable environmental conditions, and guide managers on how to promote the persistence of species with contrasting growth forms in modified wetlands.

Project Objectives

Quantify primary and secondary (ie. interactive) impacts of rising salinity and altered water regime on different life history stages of two common native wetland plant species with contrasting growth forms; the emergent tree, Swamp paperbark (Melaleuca ericifolia) and the submerged angiosperm, Eel grass (Vallisneria americana).
To determine mechanisms of persistence for both species during unfavourable water regimes, and the limits of this tolerance.
To examine how salinity and the duration of unfavourable water regime may affect persistence.Use this information to develop a model of likely species persistence under a number of likely water regime management strategies for use in managing wetlands subject to increased salinity level.

Embed the outputs of these studies within

a rigorous and genuine adaptive management strategy, closely coordinated with relevant management agencies and linked with community and stakeholder groups and,
an extensive communication strategy associated with an existing LWA Innovations Project, ‘Innovative techiniques for managing threats to high-value aquatic systems.