Mr John Aalders1
1University Of Tasmania, Sandy Bay, Australia
Obvious edaphic factors such as salinity and moisture come to mind – but are these enough? And, should other environmental aspects, such as climate be considered?
A vegetation assessment and measurement of organic layer depth was carried out at 48 sites (238 plots) around Tasmania’s coastline including the four major offshore islands – King, Flinders, Maria and Bruny. Soil samples from each plot were assessed for moisture, bulk density, loss on ignition, pH and electrical conductivity. Additionally, climate data – mean annual rainfall, days of rain, solar exposure and four temperature variables (mean maximum, minimum, and recorded maximum and minimum) – for each site, were collected from Bureau of Meteorology weather stations.
The plant list was reduced from 44 species to 12, those that exhibited greatest presence and highest mean cover per plot, and that represented all eight saltmarsh vegetation communities recently identified round Tasmania’s coastline.
The acceptable ecological range of each of the 12 plant species was identified based on four key edaphic factors (organic layer depth, moisture, salinity and pH) and four key climate variables (mean maximum and minimum temperatures, days of rain and annual rainfall) using ANOVA, post hoc tests and (dis)similarity measures. From this, three key species were identified as pioneer plants most suitable for coastal saltmarsh restoration purposes in Tasmania.
Decision tool charts for each of the plant species were then created along with a set of instructions and examples that land managers or conservation groups can readily use.
A late starter at university, John completed a BSc with Honours in 2014. He embarked on a PhD in 2015 at the University of Tasmania with the aim of using coastal saltmarshes to test whether Tasmanian coastal IBRA bioregions are an accurate reflection of difference in coastal ecosystems.