Hybridization as a facilitator of species range expansion

Abstract

Explaining the evolution of species geographical ranges is fundamental to understanding how biodiversity is distributed and maintained. The solution to this classic problem in ecology and evolution remains elusive: we still do not fully know how species geographical ranges evolve and what factors fuel range expansions. Resolving this problem is now more crucial than ever with increasing biodiversity loss, global change and movement of species by humans. Here, we describe and evaluate the hypothesis that hybridization between species can contribute to species range expansion. We discuss how such a process can occur and the empirical data that are needed to test this hypothesis. We also examine how species can expand into new environments via hybridization with a resident species, and yet remain distinct species. Generally, hybridization may play an underappreciated role in influencing the evolution of species ranges. Whether-and to what extent-hybridization has such an effect requires further study across more diverse taxa.

Demographic, Taxonomic, and Genetic Characterization of the Snook Species Complex (Centropomus spp.) along the Leading Edge of Its Range in the Northwestern Gulf of Mexico

“…Pfennig et al. () demonstrated that hybridization could play a key role in the persistence of some populations at the edge of their range. Although hybridization among species of snook has not been observed in the wild (Tringali et al.…”

Sleeping with the enemy: introgressive hybridization in two invasive centrarchids

“…genetic rescue) or for new mutations to arise (Pfennig et al ., ). Such scenarios support the idea that IH may be correlated with the successful establishment and spread of alien invasive species (Lowe et al ., ; Pfennig et al ., ).…”

“…Freshwater fishes in particular have received considerable attention, as closely related species often display similar behavioural, biological and ecological characteristics, in addition to exhibiting external fertilization and high genomic compatibility (Hubbs, ; Kovach et al ., ; Mallet, ; Smith, ), thereby potentially increasing the likelihood of IH in these taxa. Such interspecific admixture may provide sufficient genetic variation, either through increased genetic diversity or via the transfer of adaptive alleles, to facilitate the establishment and spread of novel populations (Wilson & Bernatchez, ), while counteracting extinction by maintaining and increasing the size of hybrid populations (Drake, ), ultimately permitting population persistence (Pfenning et al ., ). This is of particular concern in an invasion context, as hybrids between native and invasive species may outcompete and displace native taxa (Mallet, ).…”

Interspecies gene flow is a key evolutionary process for the adaptation of long-lived species to new environmental conditions

“…It is generally accepted that species' survival depends directly on their ability for adaptive evolution that is also a key component of range expansion (Pfennig et al, 2016). In each species, populations survive environmental change due to the production of alleles and epialleles for traits that are adaptive to the new environment.…”

“…Conversely, local adaptation is theoretically expected and has indeed been found to result mostly from admixture, more particularly from the hybridization of congeneric species (Abbott et al, 2013;Stelkens et al, 2014). In recent years, interspecific admixture involving repeated introgression in contact areas has been shown to be a facilitator of species range expansion by creating genetic variation that allows populations to adapt to selective pressures, either through the transfer of specific adaptive alleles, the selection of novel gene-combinations facilitating evolutionary innovation, or through the local increase of genetic and epigenetic diversity that allows the persistence of threatened populations (or species) and/or the creation of the conditions for further adaptation ( Bräutigam et al, 2013;Pfennig et al, 2016).…”