This Article was by Jill Rattray and found in the Autumn Gecko  2009 issue 39

Does ‘provenance’ matter?

Bob Makinson, conservation botanist at the Sydney Royal Botanic Gardens, delivered an excellent presentation on 2 April on reasons why the provenance, or source, of plant material is important for all of us
working towards restoring the health of the bush in the Blue Mountains.

Adding plants or seeds from another source may be necessary to help restore a local patch or species to healthy size, but there are some risks. Infra-species crossing (same species, different provenance) can cause changes in genetic diversity. This may have positive or negative effects on the offspring, including reduced seed-set or less fit progeny. Occasionally, different provenances of the same species cannot interbreed, so mixing them may even retard restoration.

Threatened species are a special case, and the consequences of a wrong decision are greater. Collection or translocation of seed or whole plants of these species should only be done with expert involvement.

For most ‘ordinary’ species, Bob pointed to recent
research results which add to the ‘Rules of Thumb’ which many of us already practice.
For the Blue Mountains, his main messages were:
Plant material ideally to be sourced from within 5km (flexible) at a similar altitude, and from similar habitat and soil-type;
Review history of source area – is it regrowth,
perhaps from a limited genetic base?
Review knowledge of the species (e.g. breeding system);
Review your goals –survivorship rate of planted material is important, but the goal is long-term viable populations, with ‘fit’ offspring, the right pollinators and dispersers, and enough genetic variability to allow future adaptation;
Source seed from populations of over 200, as smaller populations may have a narrow genetic base and produce poor seed;
If trying to establish connectivity between remnants, minimise distances to maximise gene flow.

Inter-species hybridization is more common in some genera, Eucalypts and Grevilleas being prone to it. If you have very rare species nearby, seek advice on the risk of impact on the wild plants. Gene flow from large revegetation plots of eucalypts to wild plants is increasingly common. We should keep in mind that the World Heritage status of the Blue Mountains relies largely on the abundant species of Eucalypts, and protecting their genetic integrity is important. Bob pointed to a good review paper on this issue, with pre-planting risk
assessment rules that can greatly reduce the problem.

The good news in terms of the effect of climate change on restored native bushland in the Blue Mountains was that we may be buffered to some extent – Bob
suggested that our topography will modify the mega-climate changes that are expected, and we have robust native communities and massive conserved areas. (Bushcare volunteers can take some credit for those last 2 factors). We also do not expect very large plantations of introduced Eucalypts (3 million hectares of Eucalypt plantations are planned for Australia by 2020).

Bob quoted a modified version of the doctors’ oath – “first do no (more) harm”. Nevertheless, he also stressed that we should not let fear of provenance
problems, or of climate change, paralyse our restoration efforts. In the context of the Blue Mountains, making sure we adhere to good practices with plant provenance is a way to avoid harm.

The talk led to a lively forum involving the audience of volunteers, students, nursery representatives,
professionals and concerned residents.

Several research papers relevant to the talk are
available at the Bushcare office.

Jill Rattray

This was published in the Summer Gecko 2009 for the workshop around genetic diversity and climate change.

Can planting Australian natives create problems? How can harm be done by planting a species of plant which occurs locally but has come from seed from elsewhere?

These questions are important to consider when
selecting plants for a bushcare site, or even our own
gardens in the Blue Mountains.

Bob Makinson, Coordinator for the Centre for Plant Conservation at the Royal Botanic Gardens Sydney will present the latest thinking on these issues at a forum to be held on Thursday evening 2nd April. Bob will discuss the issues of genetic integrity and climate change and how our plant selection should take these into account.

There is much confusion about the term ‘native plants’ in the broader community. Most bushcare volunteers understand the importance of planting ‘local’ native plants because we have seen ’native’ plants from other areas spread; eg Cootamundra Wattles moving into the gullies of the National Park.

Amongst bushcarers and local nurseries there is more debate about the importance of protecting ‘genetic integrity’ by planting only plants originating from the local area (of ‘local provenance’). Does Climate Change alter the practice of selecting only plants of local species from the same vegetation community, grown from seed collected from within a 5 km radius?

The forum is open to all interested bushcarers, bush regenerators, nurseries, gardeners, students, conservationists, and permaculturalists. No previous knowledge of provenance, bioregionalism or other such terms is needed – they will be explained and discussed.

This forum aims to assist us all make sense of the range of scientific evidence and opinion. It also aims to assist those in the Bushcare program work towards developing best practice guidelines for revegetation works as well as what is ‘best practice’ for adjacent Blue Mountains gardens.