My PhD research at the University of Melbourne is focused on the analysis of vegetation monitoring data from multiple sources. Comparing monitoring data between two time periods to assess vegetation change is a common process in environmental management and ecology. This process can be relatively straight forward if the data are equivalent, i.e., have been collected in the same way. If the data have been collected using different survey methods then comparisons become much less simple. This situation can arise when monitoring methods are updated or data are sourced from different studies.
I am investigating this issue through an example comparing subjective categorical surveys done in 1994/95 by Doug Robinson and Sally Mann, with a fully quantitative survey I did in 2009/10. The study location is along the Broken, Boosey and Nine Mile Creeks that run north-west from near Benalla to the Murray River in Barmah Forest. This is a beautiful area of remnant native open riparian woodland vegetation in variable condition. The tree canopy is dominated by the iconic River Red Gums (Eucalyptus camaldulensis) as well as Grey Box (Eucalyptus microcarpa) and Yellow Box (Eucalyptus meliodora). The creek frontages are mostly crown land (some private) and since 2002 many areas were included in what is now the Broken Boosey State Park. This native vegetation is a small remnant surrounded by a vastly modified agricultural landscape and much of it has been (and continues to be) licenced for grazing by cattle or sheep. Parks Victoria, DSE and the Goulburn-Broken CMA are responsible for managing these frontages and it is extrememly important that they are protected.
My study aims to identify the changes in these frontages over time in response to changes in managment and land uses while addressing the issues of type of surveys used.