Natural hybridization reduces vulnerability to climate change

Abstract

Under climate change, species unable to track their niche via range shifts are largely reliant on genetic variation to adapt and persist. Genomic vulnerability predictions are used to identify populations that lack the necessary variation, particularly at climate-relevant genes. However, hybridization as a source of novel adaptive variation is typically ignored in genomic vulnerability studies. We estimated environmental niche models and genomic vulnerability for closely related species of rainbowfish (Melanotaenia spp.) across an elevational gradient in the Australian Wet Tropics. Hybrid populations between a widespread generalist and several narrow range endemic species exhibited reduced vulnerability to projected climates compared to pure narrow endemics. Overlaps between introgressed and adaptive genomic regions were consistent with a signal of adaptive introgression. Our findings highlight the often-underappreciated conservation value of hybrid populations and indicate that adaptive introgression may contribute to evolutionary rescue of species with narrow environmental ranges.

A community genomics approach to natural hybridization

“…Yet we recognize that hybridization is not necessarily negative. For example, adaptive introgression between generalist and specialist rainbow fishes has seemingly diminished climate change vulnerability in admixed individuals compared to pure populations [10]. It is thus viewed as a valuable component of “evolutionary rescue” and an underappreciated conservation tool [10].…”

“…Moreover, hybridization is predicted to increase in frequency with global environmental change [11,12], a recognition consistent with our finding of hybrid occurrence in lockstep with climate-related variables. Therefore, baseline estimates are required to gauge the increase in hybridization, predict which ecosystems will be so impacted (and how severely), and promote a more robust conservation/management strategy that allows those impacts to be understood and adjudicated (if so needed) [10]. Future studies like ours will be performed at the whole-genome level, with a resolution more robust for detecting and untangling hybridization and its genomic consequences [24].…”

“…Moreover, hybridization is expected to increase in lockstep with global environmental change [11,12]. Therefore, baseline estimates are needed to precisely gauge increases in hybridization and detect where it impacts ecosystems [10,13]. Attempts to understand the geographic patterns and processes of hybridization have not often considered an array of taxa.…”

A community genomics approach to natural hybridization

“…Hybridization and introgression are often considered maladaptive threats to biodiversity [6,9]. However, it is becoming more appreciated that the genetic novelty injected into a lineage through introgressive hybridization can be adaptive [8] and even provide evolutionary rescue [10]. Moreover, hybridization is expected to increase in lockstep with global environmental change [11,12].…”

“…Moreover, hybridization is expected to increase in lockstep with global environmental change [11,12]. Therefore, baseline estimates are needed to precisely gauge increases in hybridization and detect where it impacts ecosystems [10,13]. Attempts to understand the geographical patterns and processes of hybridization have not often considered an array of taxa.…”