Measuring grass from space: Linda Riquelme
Channel: The Royal Society of Victoria
Date: 29/11/2022

Ongoing grazing is inhibiting regeneration in several semi‐arid woodland communities in south‐eastern Australia, including the nationally endangered Buloke Woodlands of the Riverina and Murray‐Darling Depression Bioregions. Western grey kangaroos are thought to switch from grass to lower‐quality browse, including tree seedlings, when grass biomass falls below a purported threshold.

Land managers are interested in using forage availability to inform cull targets for kangaroos, to minimise the risk that browsing poses to regeneration in these woodland communities when forage is low. They want to monitor grass biomass without the need for field data collection, which is costly and time‐consuming. Remote sensing allows for frequent observations over broad spatial scales. Linda’s work examined the ability of satellite‐derived vegetation indices (VIs) to estimate understorey biomass in semi‐arid woodlands in north‐western Victoria.

Linda found that satellite-derived VIs are promising as an easily‐available source of vegetation information; however, this study shows that VIs alone are not able to predict grass biomass to new areas. Additional landscape‐scale data (such as satellite‐derived soil moisture and tree cover) can greatly improve model performance, providing managers with a more cost‐efficient method of estimating grass biomass for herbivore management for woodland restoration in this semi‐arid landscape.

In recognition of the quality and significance of her research, Linda Riquelme is the Second Prize Winner in the Biological Sciences category for the Royal Society of Victoria's Young Scientist Research Prizes in 2022.