The role of plant provenance in restoration ecology under climate change
thesisposted on 2022-03-28, 21:09 authored by Nola Hancock
The rapidly changing climate poses a challenge for many land management and conservation activities. In particular, the need to ensure future sustainability of revegetated communities has focused attention on the critical decision as to where to source seed (and other propagules). Traditionally, industry 'best' practice has adhered to the principle of sourcing propagation material locally. This practice has been based on a perception that locally-sourced material is adapted to local conditions and will therefore confer superior plant performance. Additionally, the use of local provenance is often considered desirable as a means of 'preserving' the genetic integrity of local populations, reducing risks of outbreeding depression. In situations where source populations are small and inbred and where the environment is rapidly changing (a situation we are currently facing), this 'local is best' practice needs to be challenged. Moreover, sourcing seed from genetically-impoverished populations with little adaptive potential is increasingly being viewed as more detrimental to restoration success than potential outbreeding depression. Improved seed-sourcing guidelines, developed in the context of changing environmental conditions and based on empirical evidence, are urgently needed to support restoration projects that are sustainable in the long term. This thesis explores the 'local is best' paradigm using field and glasshouse experiments. In Chapter 2, I describe a common garden experiment comparing the establishment success of different provenances (one local vs four non-local provenances) of six widespread species (Acacia falcata, Bursaria spinosa ssp. spinosa, Eucalyptus crebra, E. tereticornis, Hardenbergia violacea and Themeda australis), all community dominants and / or widely used in restoration projects on the Cumberland Plain, western Sydney. In Chapter 3, I describe an experiment designed to test the establishment success of four provenances each of E. tereticornis and T. australis under both current and simulated future temperature conditions for 2050 in western Sydney. In Chapter 4, I describe a glasshouse experiment comparing the survival and early growth rates of three provenances each of Acacia falcata and Eucalyptus crebra under ambient and elevated CO2. In Chapter 5, I describe the results of a survey (conducted in New South Wales) investigating understanding of local provenance issues among restoration practitioners. The overall results and conclusions of the research are summarized in the final Chapter. Little evidence was found that local provenance plants had superior establishment success in the field studies. In the glasshouse experiment, intraspecific variation was found between the provenances for both species, regardless of the CO2 treatment. The results of the survey identified several inconsistencies of practice and belief within the restoration industry and that the definition of 'local provenance' is very flexible. The majority of respondents are in favour of a review of seed-sourcing policy/guidelines to allow for the inclusion of non-local provenance material. Overall, this research provides empirical support to challenge the validity of the strict adherence to the 'local is best' paradigm in general, but particularly on the Cumberland Plain, and underpins the need for improved seed sourcing guidelines.
Table of Contents1. Introduction and aims of thesis -- 2. Testing the "local provenance" paradigm: a common garden experiment in Cumberland Plain Woodland, Sydney, Australia -- Appendix -- 3. What role does 'home-site' advantage play in restoration ecology under heatwave conditions? -- Appendix -- 4. Intraspecific responsiveness to elevated CO2 of two widespread native Australian species, Acacia falcata and Eucalyptus crebra -- 5. How far is it to your local? A survey on local provenance use in New South Wales -- Appendix A -- Appendix B -- 6. Discussion and conclusion -- Appendix. Papers accepted for publication during candidature Ethics Committee Approval.
Notes"October 2012 Thesis submitted for the degree of Doctor of Philosophy" Includes bibliographical references
Awarding InstitutionMacquarie University
Degree TypeThesis PhD
DegreePhD, Macquarie University, Faculty of Science, Department of Biological Sciences
Department, Centre or SchoolDepartment of Biological Sciences
Year of Award2013
Principal SupervisorLesley Hughes
Additional Supervisor 1Michelle Leishman
RightsCopyright disclaimer: http://www.copyright.mq.edu.au Copyright Nola Hancock 2013.
Extent1 online resources (viii, 266 pages) illustrations (some coloured), maps
Former Identifiersmq:30524 http://hdl.handle.net/1959.14/285251 2134854
climate changeRevegetationNative plants for cultivationNative plants for cultivation -- Propagation -- New South Wales -- Sydneylocal adaptationEndemic plantsprovenancehome-site advantage,Endemic plants -- Propagation -- Australia -- New South Wales -- SydneyRestoration ecology -- New South Wales -- SydneyRevegetation -- New South Wales -- SydneyPlant ecology -- New South Wales -- SydneyPlant ecologyPlant introduction -- New South Wales -- SydneyRestoration ecologyNative plants for cultivation -- Seeds -- New South Wales -- Sydneyseed sourcePlant introduction