ANBG Friends Plant Science Group - Technical Talk

Transition zones between Australian plant provinces (phytogeographic regions): from plants and myxomycetes

Dr Peter Wellman, Research Associate at ANBG. Peter retired from a career in geology (from palaeontology to geophysics), and is at present a research associate at the ANBG mainly working on the distribution of Australian slime moulds (myxomycetes).

Monday 3rd April 2017 at 10.30 am in the ANBG Theatrette

This talk looks at the nature of the boundaries between the six main plant geographic regions of Gonzalez-Orozco et al. (2014). The boundaries of the regions are found to be generally consistent, within experimental error, with both vascular-plant distribution boundaries (from the best known tree distributions), and myxomycete information. However, the plant information shows that the region boundaries have much smoother curves than the phytogeographic region model, and in many areas a mean annual rainfall contour is the best estimate of the region boundary. The transition zones at the region boundaries are similar in width for the plants and myxomycetes. They are generally 200-300 km wide, but can be as narrow as 140 km and as wide as 440 km. The transition zones cover about 40% of the area of Australia. For vascular plants some plants cross the region boundary, for others their distribution terminates within the transition zone, while a few are restricted in distribution to a band along the transition zone, and can extend for up to 1000 km along it. This pattern of change for vascular plants differs from that found in the only two myxomycete traverses observed across transition zones. On the myxomycete traverses, only a small proportion of the species cross from one region to the other. Most species of a region cross the adjacent transition zone and their distribution ends near the far edge of the transition zone.