Best practice restoration: building the evidence-base for restoring eucalypt woodlands of Southern Australia
Date
2017
Authors
Gellie, Nicholas James Court
Editors
Advisors
Lowe, Andrew
Journal Title
Journal ISSN
Volume Title
Type:
Thesis
Citation
Statement of Responsibility
Conference Name
Abstract
Approximately a third of the Earth’s surface is degraded. The enormous scale of degradation has stimulated multilateral agreements with ambitious restoration targets (e.g. The Bonn Challenge aspires to restore 350 million ha by 2030). Humankind has greater awareness than ever before of the factors contributing to landscape degradation, and has developed sophisticated practices to assist in its repair. The principal management intervention used to combat the biodiversity declines associated with land degradation is restoration. However, unprecedented environmental challenges from climate change, rapid biodiversity loss, and human population pressures add to the complexity of achieving sustainable restoration outcomes. There are valid concerns that sub-optimal restoration interventions are jeopardizing outcomes, which brings into question our capacity to reach global targets. To establish a strategic approach for improving restoration practice and to promote resilient outcomes, I reviewed current restoration practices and found that the management of plant genetic resources and inconsistent monitoring of projects are key impediments to optimal restoration outcomes. I found a suitable mechanism for investigating these knowledge gaps, through embedded experiments, and subsequently established them in restoration projects. I addressed the plant genetic resource knowledge gaps by testing in situ the relationship between plant fitness and seed origin for six Myrtaceae species. I investigated plant fitness in three empirical studies that included five common garden experiments, from provenances spanning 2.5 degrees of latitude (ca. 460 km) in southern Australian eucalypt woodlands, and found sub-optimal plant performance was common. Furthermore, signals of maladaptation occurred in two of my three empirical studies. I determined that the Myrtaceae species I studied persisted in a range of climatic conditions by combining specific adaptations to aridity and acclimating to new environmental conditions via phenotypic plasticity. I confirmed that this response was strongly directional (e.g. arid to mesic), and the genetic diversity harboured in non-local provenances could be harnessed to counteract plant fitness concerns (e.g. adaptation lags due to climate or lack of connectivity due habitat fragmentation), and ultimately help to achieve more sustainable outcomes. I then explored the utility of high throughput 16S amplicon sequencing (e.g. metabarcoding soil eDNA) as an assessment tool to assist in monitoring restoration performance. I used metabarcoding of soil eDNA to assess a chronosequence of restoration and found that the process of restoration (i.e. revegetation of the native plant community) strongly impacted soil bacteria, an important functional component of the ecosystem. I observed dramatic changes of the bacterial community after eight years of revegetation, where the bacterial communities in younger sites were more similar to cleared degraded land and older restoration sites were more similar to remnant native stands. This work has identified evidence of community flux and functional recovery following restoration that would remain unrecognised through orthodox monitoring. The synthesis of this work supports the use of evidence-based approaches to iteratively improve restoration practices. Science-practice synergies will come from harvesting the knowledge of these approaches and networking the results more broadly is the most efficient mechanism to achieve best-practice restoration and resilient project outcomes.
School/Discipline
School of Biological Sciences
Dissertation Note
Thesis (Ph.D.) -- University of Adelaide, School of Biololgical Sciences, 2018
Provenance
This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals