Fallen logs: creating patchiness in chenopod scrublands
of South Australia
Alexandra Bowman and José Facelli
University of Adelaide
Summary. Resource heterogeneity is a prominent feature of arid ecosystems, yet little is known about the dynamics of patch formation or their dissipation. We aimed to assess patch formation and dissipation associated with introducing and removing fallen logs.
We introduced logs and artificial logs to open spaces and assessed changes to soil nutrient contents and annual plant communities after three years. Pairs of fallen logs were also selected and one of each pair was removed. We deployed soil temperature and moisture probes and collected soil samples to determine dissipation of soil nutrient contents and soil seed bank over one year.
Three years was not long enough to change soil nutrient contents or annual plant communities when introducing logs, but unplanned destocking had strong effects on soil nutrient contents. The removal of logs produced immediate changes to the soil microclimate, but accumulated nutrients and seeds in the soil remained after one year. Patch formation next to logs occurs between 3 and 12 years in situ. Additionally, the removal of logs creates patches that are unique to any others, but the role of this new patch type in the system is unknown, as is the length of its persistence.