Soils sampled during a biological survey of the Western Australian wheatbelt

WA Museum Records and Supplements | Updated 7 years ago

ABSTRACT – As part of a biodiversity survey, soil profiles are described and classified at 304 quadrats set in uncleared vegetation remnans throughout the Western Australian Wheatbelt. 

The Department of Agriculture, Western Australia, has developed a hierarchical soil-landscape GIS for the region. The Western Australian Soil Group layer in this classification was used to assess how well the 304 quadrats sampled the region's soils. The predominance of quadrats with sandy surface soils reflects the general nature of the region as well as the preferential clearing of its loamy and clayey soils for agriculture. 

While soils of saline drainage lines were sampled more frequently than expected, given their regional extent, it was a deliberate strategy of the survey to sample areas where biodiversity is threatened by the effects of rising saline groundwater. On the other hand, some regionally common sandy soils such as Yellow deep sand and sandy earths were under-sampled, as were the regionally less common loamy and clayey soils.

In terms of wheatbelt soil-landscapes, the Lockier and Southern Cross areas were under-sampled while peripheral areas more typical of the forest than the wheatbelt were over-sampled.

Some of this sampling bias would have been difficult to redress because the loamy and clayey soil groups and the Lockier area have been largely cleared for agriculture.