LTERN Data Portal

Sampling of vegetation is stratified along the soil moisture gradient and across the range of structural variability in the vegetation. Thus three categories of soil moisture and three categories of vegetation structure (based on the height and form of shrubs) are sampled in a factorial design at 60 sites in upland swamps scattered throughout the study area (Keith and Myerscough 1993). Originally each sample site was a belt transect of 60 contiguous 0.5x0.5 m quadrats, in which presence/absence of all vascular plant taxa were recorded (based on whether they were overhanging the quadrats) and tallied to give a frequency out of 60. The sites were originally sampled in 1983, marked in the field by two wooden stakes at either end of the transect, and plotted on a 1:10 000 aerial photograph. By 2004, it was possible to relocate 54 of the 60 original transects and of these, at least one of the original markers was found for 20 transects. During the intervening years, some of the wooden markers had been consumed by fires, but based on the annotated aerial photograph, field notes and detailed recollections of the original observer (David Keith), transects were confidently reestablished within approximately 10 m of their original location. These formed the basis for establishing permanent swamp monitoring sites, which are now marked in the field at the positions of quadrats 1 and 30 with steel star pickets, extending approximately 1. 5 m above ground surface, and located on the Map Grid of Australia (Geodectic Datum of Australia) using a global positioning system. Exploration and subsampling of the 1983 data showed that the floristic relationships between the 60 sites could be adequately retrieved if species frequencies were calculated from a sample of 30 quadrats within each transect (correlation of association matrices based on 60 and 30 quadrats yielded Mantel’s R>0.95). Therefore, only the first 30 quadrats of each transect were re-sampled in 2004 (Keith et al. 2007). Vegetation sampling was repeated in 2009-2010. During 2014, soils were sampled at all 54 sites. In previous surveys, they were sampled at a random sample of 20 sites stratified by the soil moistire gradient and vegetation structure. The next census is scheduled for 2019 or within 12 months of the next bushfire, whichever occured first.