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Dylan Bristol

Candidature

PhD Candidate

Thesis Title

Ecosystem functioning of threatened ecological communities of the Cumberland Plains

Research Project

Dylan BristolEucalypt Woodlands such as the Cumberland Plain Woodlands were once dominant throughout the Sydney bioregion providing many ecosystem services such as nutrient, carbon and water cycling, pollution regulation, and providing suitable habitats for native Flora and Fauna. Much of the Cumberland Plain Woodland has been severely degraded from nutrient and heavy metal pollution following rapid urbanization since European colonization resulting in substantial loss of habitat and diversity for native plants and animals. Degradation of the soils from urbanization combined with projected climate extremes creates ideal conditions for the growth of invasive species which can outcompete native species impacting biodiversity and belowground processes.

My key objectives of my PhD is to assess the current state of the Cumberland Plain Woodlands to better understand what structures their biodiversity and functioning, with a particular focus on soil biota and processes, and create a benchmark of the current state of health of the Woodlands for future monitoring. The germination, growth and establishment of native grasses will be monitoring throughout a gradient of degraded soils using vegetation as a degradation metric and verified by analysis of the soils. I will then identify how degradation through nutrient and heavy metal pollution affects plant growth and soil biodiversity, and associated impacts on soil processes, and climate change resistance and resilience. Lastly, I will assess whether manipulating plant and soil biodiversity can help remediate the impacts of degradation and climate change resistance and resilience.

The findings of my study will help understand the links between vegetation integrity, soil biodiversity, soil functions, and how these and changed by degradation. This project will also identify whether the risks associated with projected increases in climate extremes will impact the health of above and belowground diversity and functions in addition to threats experienced from degradation. My findings will also help inform restoration and conservation efforts by providing insight into methods of ameliorating degraded soils under climate extremes by potentially changing soil microbiomes and attempting to alter soil biota through soil inoculation.

Publications

Nielsen UN, Bristol D, Blyton M, Delroy B, Powell JR, (2024) 'Elevated CO2 enhances decomposition and modifies litter-associated fungal assemblages in a natural Eucalyptus woodland', Functional Ecology, vol.38, no.8, pp 1751-1764

Jerzy Szejgis; Yolima Carrillo; Thomas C. Jeffries; Feike A. Dijkstra; Jeff Chieppa; Sebastian Horn; Dylan Bristol; Premchand Maisnam; David Eldridge; Uffe N. Nielsen (2024) ‘Altered rainfall greatly affects enzyme activity but has limited effect on microbial biomass in Australian dryland soils’, Soil Biology and Biochemistry, vol. 189. Doi: 10.1016/j.soilbio.2023.109277.

Dylan Bristol; Kamrul Hassan; Joseph C. Blankinship; Uffe N. Nielsen (2023) ‘Responses of nematode abundances to increased and reduced rainfall under field conditions: A meta‐analysis’, Ecosphere, vol 14 (1). doi: https://doi.org/10.1002/ecs2.4364.

Premchand Maisnam; Thomas C. Jeffries; Jerzy Szejgis; Dylan Bristol; Brajesh K. Singh; David J. Eldridge; Sebastian Horn; Jeff Chieppa; Uffe N. Nielsen (2023) ‘Severe Prolonged Drought Favours Stress-Tolerant Microbes in Australian Drylands’, Microbial Ecology, vol. 86, pp. 3097-3110. doi: 10.1007/s00248-023-02303-w.

Supervisors

A/Professor Uffe Nielsen, Professor Jeff Powell, Dr Yolima Carrillo