Dr Diane Allen¹, Dr Matthew Pringle¹, Professor Ram Dalal^1,2, Dr Don Butler¹, Dr Tom Orton^1,2,3, Associate Professor Tom Bishop³, Dr Beverley Henry⁴

¹Queensland Government Department Of Environment And Science, Dutton Park, Australia, ²University of Queensland, St Lucia, Australia, ³University of Sydney, Sydney, Australia, ⁴Queensland University of Technology, Brisbane, Australia

In this poster presentation, we provide a case study examining Soil and land management within the Brigalow Belt bioregion of Queensland, Australia.  Occupying less than 10% of its former approximately 7.5 million hectare distribution, recovery of this ecological community is a focus for biodiversity planning assessments (State of Queensland, 2018), although the interactions between soil and variation in land management across the large area are complex.

With an SOM cycling focus, we present a ‘snapshot’ of measured data from 45 sites representing remnant uncleared native brigalow forest, native brigalow forest cleared then maintained as pasture for >10 years, and regrowing native brigalow forest ranging from 10 to 58 years. We consider SOM properties including C and N dynamics (stocks, fractions and natural abundance signatures) and associated soil physical, biological and chemical properties.  We illustrate two common approaches to statistical modelling – regression trees and linear mixed models – to SOM data, including explanatory variables relating to climate, soil and past land management, the interactions between them. We visualise the data in the form of regression trees linked to linear mixed models, explicitly accounting for spatial autocorrelation and enabling the presentation of realistic uncertainties alongside the models’ predictions.

Finally, we explore ‘where next’ for SOM understanding in this ecological community, in the context of emerging policy areas of land restoration and environmental accounts.

Biography:

Dr Diane Allen is a principal scientist within Queensland Government Department of Environment and Science, Science Delivery, Landscape Sciences Unit.  Part of a Soil Processes team, she has a background in examining soil processes in relation to land use and land use change in sub-tropical and tropical ecosystems, including sugarcane, wetlands, rangelands, afforestation and regrowth. An active member of Soil Science Australia and an adjunct at University of Queensland School of Agriculture and Food Sciences, Di enjoys supporting early career students and the intersection of science and policy areas.