When local isn't best

Abstract

This paper attempts to explain circumstances under which local may be or may not be best. Natural selection may lead to local adaptation (LA), or it may be constrained by gene flow, founder effects, small population size, genetic drift, and archetype. ‘Specialist’ species display greater LA than ‘generalist’ species. Local genotypes are to a certain extent transient, being a consequence of past historical genetic patterns. Two recent meta-analyses found that while local performance exceeded the performance of a randomly chosen nonlocal population in 71% of comparisons, general adaptation across environments was as frequent as LA. Genotypes for restoration are most likely to be effective if they are adapted to current site conditions. As environmental change accelerates, both globally and locally, exceptions to ‘local is best’ may increase. For these reasons, ‘local is best’ may be better thought of as a testable hypothesis rather than as a general assumption. While either local or nonlocal plant material may be most effective for restoration practice depending on individual circumstances, local material will continue to be the first choice for restoration practitioners whenever this option is feasible and effective.

Does origin always matter? Evaluating the influence of nonlocal seed provenances for ecological restoration purposes in a widespread and outcrossing plant species

“…2014). However, introgression and hybridization between nonlocal and indigenous provenances can alter population genetic compositions as nonlocal genotypes might function as effective drivers for invasions below the species level (Jones 2013). This can lead to the homogenization, coexistence, or extinction of the regional and/or nonlocal gene pools with effects on the genotypic or allelic richness (Hughes et al.…”

Genetic structure of the American ginseng (Panax quinquefoliusL.) in Eastern Canada using reduced-representation high-throughput sequencing

“…The idea behind this is to minimize the impact on local genotypes given the small population sizes, maximise local adaptation and minimize outbreeding depression (Broadhurst et al 2008). Whether this strategy is the best one, however, is debatable (Jones 2013) and should be investigated further for the American ginseng. Indeed, a large proportion of the markers supporting this structure might be neutral and thus may not indicate locally adapted genotypes.…”

The potential of novel native plant materials for the restoration of novel ecosystems

“…However, due to the advent of novel ecosystems and altered ecosystem states, there is only limited reason to believe that local genotypes that are presumably products of natural selection are particularly well adapted to the new conditions. Thus, the ecological grounds for the exclusive use of local plant materials in restoration are weak ( Jones, 2013b). The principal genetic objection to novel/non-local plant materials involves the claim that such plant materials may introduce unadapted genes that may display undesirable genetic interactions upon hybridization with remnant local plant material on the restoration site.…”

“…However, this model may not be optimal for the many degraded rangeland systems in need of restoration ( Jones, 2013a) because they have often become modified to the point of becoming "novel ecosystems" (Hobbs et al 2013). In such situations, "local is best" may be better viewed as a testable hypothesis than as dogma ( Jones, 2013b). If and when local isn't best ( Jones, 2013b), adjusting the restoration approach to reflect biological reality may be both justified and desirable.…”

“…In such situations, "local is best" may be better viewed as a testable hypothesis than as dogma ( Jones, 2013b). If and when local isn't best ( Jones, 2013b), adjusting the restoration approach to reflect biological reality may be both justified and desirable.…”