Monitoring diversity and tree demography in vegetation communities of the Mount Lofty - Flinders Ranges

Abstract

Surveillance monitoring of plant communities across landscape-scale climatic gradients can reveal trends in species composition and condition in the context of climate change. The TREND transect was established in 2011 across the Mount Lofty and Flinders Ranges of South Australia as a space-for-time baseline against which to monitor such changes. It was expected that re-sampling of the 150 established survey plots would reveal the presence and direction of any long-term trends at ecological community level. Here, I report progress on recent monitoring activities along TREND that were supported by the Lirabenda Endowment Fund of the Field Naturalists Society of South Australia and the Terrestrial Ecosystem Research Network. Of the original 85 species composition plots, 65 were re- sampled in 2015 or 2016. These initial re-visits reveal differences in observed diversity that are likely to relate mainly to seasonal rainfall conditions and time since fire. Specifically, drier conditions in 2015 than in 2011 coincided with slightly lower observed species richness except at seven plots that were burnt between visits, while very wet conditions in 2016 compared to 2011 coincided with higher observed species richness. Change analysis can be conducted once long-term data are available. We also conducted pilot tree demography surveys at two sites, and found that measurement of all trees within a fixed plot was better able to sample the distribution of size classes than a rapid method involving measurement of the 10 nearest trees to the plot marker which was based on the Bushland Condition Monitoring method. The future goal of TREND is to complete the first round of re- sampling of baseline plots and to instigate a rolling program of sampling for species diversity, woody species recruitment and tree demography for monitoring of composition, condition, structure and carbon.