How does clay constrain woody biomass in drylands?

Fensham, Roderick J., Butler, Don W. and Foley, Jenny (2015) How does clay constrain woody biomass in drylands?. Global Ecology and Biogeography, 24 8: 950-958. doi:10.1111/geb.12319

Author Fensham, Roderick J.
Butler, Don W.
Foley, Jenny
Title How does clay constrain woody biomass in drylands?
Journal name Global Ecology and Biogeography   Check publisher's open access policy
ISSN 1466-8238
Publication date 2015-08
Year available 2015
Sub-type Article (original research)
DOI 10.1111/geb.12319
Open Access Status
Volume 24
Issue 8
Start page 950
End page 958
Total pages 9
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2016
Language eng
Formatted abstract
To investigate the role of clay in limiting the development of woody biomass in drylands.


Spatial data representing woody biomass, soil clay content and climate for the Australian continent were interpreted to explore the relationship between a moisture index and woody biomass on clay and non-clay substrates. Moisture and soil water potential were investigated through time for clay and sand plains. Sub-soil clay and other soil characteristics were compared between areas with and without high tree mortality after drought.

The substantially lower woody biomass on clay soils than non-clay soils in the drylands of the Australian continent verifies the inverse texture effect. A clay floodplain consistently held more water than an adjacent sandplain, but soil moisture in the clay was effectively inaccessible to plants for much longer periods because of more negative values of water potential in the clay soil. Small increases in sub-soil clay were associated with high tree mortality.

Main conclusions
Our findings suggest that the ‘inverse texture effect’, which describes the negative association of woody biomass with soil clay content in drylands, may mostly relate to the moisture-retentive properties of clay rather than being caused by reduced infiltration and enhanced evaporation from clay-rich soils. Our evidence suggests that clay soils constrain woodiness in drylands by exacerbating water stress, and confirm the fundamental role of aridity in determining woody biomass and the global distribution of grassland.
Keyword Clay
Drought-induced tree mortality
Inverse texture effect
Moisture matric potential
Soil moisture
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Biological Sciences Publications
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