Dr Adam Canning1
1James Cook University, Townsville, Australia
Biography:
Dr Adam Canning is an ecologist, employed as a Senior Research Officer at TropWATER, James Cook University, and is interested in how agroecological practices and nature-based solutions can be used to better support the provision of productive agriculture within ecologically healthy catchments that support high water security.
Abstract:
Payment for ecosystem service (PES) schemes incentivize ecosystem restoration or improved land management practices that provide benefits such as water quality improvements, carbon sequestration, flood regulation, and habitat enhancement. Demonstrating these benefits is crucial for the integrity of PES schemes, but high assessment costs often make small-scale projects unviable, particularly when relying on expensive lab analysis. While vegetative restoration projects increasingly receive payments for carbon sequestration, the water quality benefits of floodplain reforestation are often overlooked. Reforested floodplains can remove nitrogen from floodwaters through vegetation sequestration and denitrification. If these nitrogen removal benefits could be demonstrated using a simple, cost-effective method, PES schemes could reward landholders for restoring floodplain vegetation. This is particularly relevant in Australia’s Great Barrier Reef catchment, where significant nutrient load reductions are needed. This study, conducted at a flood-prone sugarcane farm in north Queensland, experimentally tested nitrate leaching rates under different nitrate application levels between sugarcane and restored Melaleuca, simulating floodwater deposition. The restored Melaleuca site exhibited significantly lower nitrate leaching compared to the sugarcane site, despite similar nitrate deposition rates. Additionally, soil microbial assemblages, assessed via environmental DNA metabarcoding, reflected nitrate deposition and removal, with a positive correlation between nitrate-reducing bacteria diversity and deposition rates, independent of vegetation type. This suggests that metabarcoding soil microbial assemblages could be a promising, cost-effective method for indicating nitrate removal, meriting further investigation across diverse locations.