A project undertaken at the School of Biological, Earth and Environmental Sciences, University of New South Wales, and supervised by Miriam Munoz-Rojas.
Extensive dryland areas in Australia have been heavily degraded resulting in biodiversity loss and reduced ecosystem productivity and functionality. These degraded conditions position the country as one of the climate change vulnerable “hot-spots” globally. Despite the widely accepted importance of these water-limited landscapes and the large amounts of money invested in ecosystem restoration, success rates are generally low due to the extensively altered or degraded soil conditions. This project has explored and developed new technologies to increase plant recruitment and soil function through effective targeted delivery of native soil microorganisms in degraded arid soils.
An important outcome of this project is that we found that cyanobacteria can be successfully incorporated into extruded soil pellets and redistributed via watering to modify properties of degraded soil substrates (Roman et al., 2020). This technology has been also tested in field trials, opening a wide range of opportunities for application in large scale soil restoration programs (Dadzie et al.,2022). With this project, we found that native soil microorganism such as soil bacteria and cyanobacteria from biocrust, have the ability of promoting seed germination and emergence of key native plants used in dryland restoration in areas like the Pilbara region, e.g. Acacia spp. and Triodia spp. (Chua et al., 2020; Dadzie et al., 2022). Our results also showed that introduced cyanobacteria do not impact nativeresident bacterial communities under controlled conditions. The preservation of these indigenous soil bacteria indicates that, in the short term, cyanobacterial inoculants can colonize soils without affecting significantly the natural community (Jimenez-Gonzalez et al., 2022). In our trials, inoculated cyanobacteria also promoted the development of an artificial biocrust on the topsoil and sequestered gypsum (CaSO4⋅2H2O) on the soil surface, which could be a mechanism to decrease desiccation and salt stress and improve habitability.
The outcomes of this project are expected to provide cost-effective, environmentally-based techniques for land managers, conservation agencies and government departments to help those overcome critical barriers to plant recruitment, and enhance restoration outcomes.
Chua, M., Erickson, T., Merritt, D., Chilton, A., Ooi, M.K.J. and Muñoz-Rojas, M. (2020) Bio-priming seeds with cyanobacteria: effects on native plant growth and soil properties. Restoration Ecology 28, S168-S176. doi: 10.1111/rec.13040
Dadzie, F. A., Moles, A. T., Erickson, T. E., Slavich, E., & Muñoz‐Rojas, M. (2022) Native bacteria and cyanobacteria can influence seedling emergence and growth of native plants used in dryland restoration. Journal of Applied Ecology.doi:10.1111/1365-2664.14293
Jiménez-González, M. A., de Lima, N. M., Chilton, A. M., Almendros, G., & Muñoz-Rojas, M. (2022) Biocrust cyanobacteria inoculants biomineralize gypsum and preserve indigenous bacterial communities in dryland topsoil. Geoderma, 406,115527. doi:10.1016/j.geoderma.2021.115527
Roman, J.R., Chilton, A.M., Canton, Y., Muñoz-Rojas, M. (2020) Assessing the viability of cyanobacteria pellets for application in arid land restoration. Journal of Environmental
Management 270, 110795. doi:10.1016/j.jenvman.2020.110795