Biodiversity of Overstorey Trees in Relation to Canopy Productivity and Stand Density in the Climatic Gradient from Warm Temperate to Tropical Australia

• Published in: Biodiversity letters 1994-03, Vol.2 (2), p.39-45
• Main Authors: Specht, Alison, Specht, Raymond L.
• Format: Article
• Language: English
• Subjects: Annuals; Biodiversity Research; Forest canopy; Leaves; Overstory; Plant biodiversity; Plant communities; Plants; Species; Tropical rain forests; Vegetation
• ISSN: 0967-9952
• DOI: 10.2307/2999667

The structure (Foliage Projective Cover, Leaf Area Index and stocking density of trees and tall shrubs) of mature evergreen plant communities and the annual growth of the foliage canopy are predictable from the arid to the perhumid climatic zones, from the warm temperate to the tropical climatic regions of Australia. Biodiversity (mean number of species of trees and tall shrubs per hectare) of the overstorey is related to the annual growth (tonnes dry weight per hectare per year) of the foliage canopy The mean number of stems of each species in a hectare of overstorey doubles from thirty to almost sixty in the 10⚬C temperature gradient from southern to northern Australia The interception of solar radiation by the overstorey canopy reduces the foliage cover of the understorey, the net photosynthesis of this stratum, and hence the species richness of the understorey. In any ecosystem, the biodiversity of most vertebrate classes parallels that of vascular plants, which appears to be related to annual growth of the foliage shoots in the overstorey canopy The processes which determine the species richness of plants and animals within an ecosystem need urgent identification so that maintenance of biodiversity can be based on scientific principles