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What drives plant biodiversity in the clay floodplain grasslands of NSW?

Lewis, T. and Clarke, P.J. and Whalley, R.D.B. and Reid, N. (2009) What drives plant biodiversity in the clay floodplain grasslands of NSW? Rangeland Journal, 31 (3). pp. 329-351.

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Article Link(s): http://dx.doi.org/10.1071/RJ08056

Publisher URL: http://www.publish.csiro.au/home.htm

Abstract

An assessment of the relative influences of management and environment on the composition of floodplain grasslands of north-western New South Wales was made using a regional vegetation survey sampling a range of land tenures (e. g. private property, travelling stock routes and nature reserves). A total of 364 taxa belonging to 55 different plant families was recorded. Partitioning of variance with redundancy analysis determined that environmental variables accounted for a greater proportion (61.3%) of the explained variance in species composition than disturbance-related variables (37.6%). Soil type (and fertility), sampling time and rainfall had a strong influence on species composition and there were also east-west variations in composition across the region. Of the disturbance-related variables, cultivation, stocking rate and flooding frequency were all influential. Total, native, forb, shrub and subshrub richness were positively correlated with increasing time since cultivation. Flood frequency was positively correlated with graminoid species richness and was negatively correlated with total and forb species richness. Site species richness was also influenced by environmental variables (e. g. soil type and rainfall). Despite the resilience of these grasslands, some forms of severe disturbance (e. g. several years of cultivation) can result in removal of some dominant perennial grasses (e. g. Astrebla spp.) and an increase in disturbance specialists. A simple heuristic transitional model is proposed that has conceptual thresholds for plant biodiversity status. This knowledge representation may be used to assist in the management of these grasslands by defining four broad levels of community richness and the drivers that change this status.

Item Type:Article
Corporate Creators:QPIF
Additional Information:© Australian Rangeland Society. © CSIRO
Keywords:Biodiversity; cultivation; flooding; floodplains; grassland management; soil fertility; soil types; species diversity; stocking rate; tenure systems. flooding; Mitchell grasslands, grazing Astrebla grassland; calcareous grasslands; seasonal rainfall; tallgrass prairie.
Subjects:Science > Statistics
Science > Botany > Plant ecology
Deposited On:30 Nov 2009 04:47
Last Modified:07 Jun 2015 15:09

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