P. australis wetlands are water sources in the region,
and they are protected by the government, so the human influence
was very limited. Sampling locations were established in the
P. australis riparian wetland and at sites of intertidal mudflat culture,
vegetable, flower, fruit and rice cultivations (Fig. 1). Soil samples were
collected in March 2013. Under natural conditions (without any
human activity) all studied sites that currently have a human activity
should be a P. australis wetland such as the control.