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International Journal of Ecology
Volume 2012 (2012), Article ID 359892, 15 pages
http://dx.doi.org/10.1155/2012/359892
Review Article

Biodiversity of Terrestrial Ecosystems in Tropical to Temperate Australia

Department of Botany, The University of Queensland, Brisbane, QLD 4072, Australia

Received 19 September 2011; Revised 25 December 2011; Accepted 17 January 2012

Academic Editor: Panos V. Petrakis

Copyright © 2012 Raymond L. Specht. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

During the short period of annual foliage growth in evergreen plant communities, aerodynamic fluxes (frictional, thermal, evaporative) in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and leaf attributes in overstorey and understorey strata. The number of leaves produced on each vertical foliage shoot depends on available soil water and nutrients during this growth period. The area of all leaves exposed to solar radiation determines net photosynthetic fixation of the plant community throughout the year. In turn, the species richness (number of species per hectare) of both plants and resident vertebrates is determined. The species richness of unicellular algae and small multicellular isopods in permanent freshwater lagoons in Northern Australia may possibly have been increased by radiation released from nearby uranium deposits. Evolution of new angiosperms probably occurred in refugia during periods of extreme drought. When favourable climates were restored, the vegetation expanded to result in high Gamma Biodiversity (number of plant species per region) but with each major plant community having essentially the same species richness (number of plant species per hectare). The probable effects of pollution and Global Warming on biodiversity in Australian ecosystems, that experience seasonal drought, are discussed.