Provenancing Strategies

In addition to matching the provenance to the focal site, many other provenancing strategies have been suggested as response to predicted climate change. Breed et al. (2012) developed a decision tree for selection of a provenancing strategy (local, predictive, composite, and admixture) based on confidence surrounding climate change distribution modeling and data on population genetic and/or environmental differences between populations. No single strategy is likely to work universally, so selection of provenancing strategy should consider species genetic variation and local adaptation combined with climate projections for focal site.

Table 7. The synopsis on provenancing strategies (Ivetić and Devetaković 2016).

Strategy	Short description	Advantages	Disadvantages	Best to use	Source
Local provenancing	Collection of seeds very close to the focal site. Risk level depends on original population size.	No risk of maladaptation and outbreeding depression. Low failure rates.	Risk of genetic drift. Low production of new genotypes. Conditions driving local adaptation can change.	Where only local populations remain and no large change of distribution is predicted.	Broadhurst et al. 2008; Breed et al. 2012; Sgró et al. 2011
Predictive provenancing	Use of genotypes that are determined to be adapted to projected conditions. Requires data on local adaptation of many populations. Requires climate projections for the target species and planting site.	Low risk of maladaptation, inbreeding depression and outbreeding depression. Low risk of failure if seed source is matched well with predicted environments.	High risk of failure if seed source is poorly matched with predicted environments. Lack of data on local adaptation for most species. Uncertainty of climate change predictions.	For species expressing local adaptation to environmental variables.	Sgró et al. 2011; Breed et al. 2012
Composite provenancing	Mimic natural gene flow patterns by use of seed mixture from populations at various distances to the focal site.	Encourages production of new genotypes, potentially facilitating rapid adaptation to novel conditions.	Using seed from distant source may result in maladaptation to local conditions. Outbreeding depression risk.	Where no significant range shifts is predicted and only small local populations remain.	Broadhurst et al. 2008; Breed et al. 2012
Admixture provenancing	Collection of seeds from wide array of provenances, capturing a wide selection of genotypes from various environments with no spatial bias towards the focal site.	Build evolutionary resilience, by introduction of more additive genetic variation.	Risk of introducing invasive genotypes. High risks of introducing maladapted seed. High risk of outbreeding depression.	Where drastic changes are confidently predicted, but growth data is lacking.	Breed et al. 2012
Climate-adjusted provenancing	Combine genetic diversity and adaptability, targeting projected climate change directions. Collection of seeds biased toward the direction of predicted climatic change, but not exclusive to it.	Enhance climate-resilience of planting material by mixing genotypes from a climatic gradient, including local genotypes as well.	Risk of outbreeding depression. Risk of disruption of local adaptation to non-climatic factors.	Where data on inter-population genetic variation are available.	Prober et al. 2015