Local adaptation in trees

Is local best? Examining the evidence for local adaptation in trees and its scale

Lead reviewer: David Boshier, University of Oxford and Bioversity International

Collaborating institutions: Tropical Agriculture Research and Higher Education Center (CATIE), World Agroforestry Centre (ICRAF), Commonwealth Scientific and Industrial Research Organisation (CSIRO), National Institute of Agricultural Technology (INTA), Bioversity International, European Forest Genetic Resources Program (EUFORGEN), USDA-Forest Service

Systematic review protocol: Environmental Evidence 2015, 4:20

Although the importance of local provenance in sourcing planting stock for woodland production, habitat conservation and restoration remains contentious, the concept is easy to understand and the message is therefore attractive and easy to sell. With limited information about the extent and scale of adaptive variation in native trees, discussion about suitable seed sources often emphasizes ‘local’ in a very narrow sense or within political boundaries, rather than being based on sound evidence of the scale over which adaptation occurs. Provenance and progeny field trials in many parts of the world have shown that while genotype by environment interaction occurs in many tree species, this may not be expressed as a home site advantage (i.e. provenance performance is unstable across sites but not from greater fitness of local seed source).

This review will collaborate with a range of institutions to examine the evidence for local adaptation and its scale in a number of native tree species from different trial sites across the globe (tropical, Mediterranean, and temperate). These trials have been measured and, in some cases, results have been published in a range of formats. The data has, however, usually been presented to convey which provenances grow best at which sites. This project will reanalyse existing data (published and unpublished) in the context of the scale of local adaptation, and present results in two formats:

• Relating survival and/or performance (depending on what measurements exist) of provenances (classified by seed zone/provenance region of origin) to seed zone/provenance region of the planting site.
• Plotting the survival and/or performance (depending on what measurements exist) of provenances against the distance (Euclidean) between the provenance and the trial site.