The flora and vegetation of the seasonal and perennial wetlands of the southern Carnarvon Basin, Western Australia

WA Museum Records and Supplements | Updated 7 years ago

ABSTRACT – A total flora of 265 taxa was recorded from 58 wetland areas in the southern Carnarvon Basin. The flora was dominated by arid species but also included 34 temperate taxa at the northern end of their range and 18 tropical taxa at the southern end of their range. Five species (Dichopogon tyleri, Calandrinia sp. Coolcalalaya (GJK and NG 698), Myriocephalus gascoynensis ms, Lythrum sp. Towrana (RJC 2183), Psammagrostis wiseana) are endemic to the study area. The Calandrinia sp. appears not to have been collected previously. A collection of Rumex crystallinus was the first recorded in Western Australia since 1885.

Classification of the wetlands was undertaken at two different scales; at both scales heterogeneity was high. The major division in the data sets was between the saline and non-saline wetlands. Percentage of single species occurrences was high in both datasets, ranging from 46–55%; this component of the flora adds significantly to plant biodiversity but is not a predictable component of vegetation communities. In the seven-group classification no floristic groups were restricted to particular habitat types but at the finer scale sampling there is a stronger correlation between floristic community type and habitat type. At this scale the major habitat types (e.g. river pools) encompassed a range of floristic groupings. The patterns in low species richness and very patchy species distribution found in this study are similar to those reported for wetlands in the higher rainfall areas of the south west but the underlying causal factors determining these patterns remain unclear.