Hybridization rate and climate change: are endangered species at risk?
Many species are altering their geographic range due to climate change creating new sympatric populations of otherwise allopatric populations. We investigated whether climate change will affect the distribution and thus the pattern of hybridization between two pairs of closely related damselfly species [Ischnura damula and I. demorsa, and I. denticollis and I. gemina (this, an endangered species)]. Thus, we estimated the strength of pre and postmating reproductive barriers between both pairs of species, and we predicted future potential distribution under four different Global Circulation Models and a realistic emissions scenario of climate change by using maximum entropy modelling technique. Our results showed that reproductive isolation (RI) is complete in I. damula × I. demorsa individuals: F1 (first generation) hybrids are produced but do not reach sexual maturation. However, RI in I. denticollis × I. gemina hybrids is high but incomplete and unidirectional: only I. gemina females produced F1 hybrids which mate with males and females of I. denticollis and between them producing BC1 (backcrosses) and F2 (second generation) viable hybrids. Maximum entropy models revealed a northern and westward shift and a general reduction of the potential geographic ranges. Based on the pattern of hybridization, for I. damula and I. demorsa there is a current threat as well as a rapid displacement and/or extinction of I. gemina by I. denticollis. However, the current pattern of extinction may not continue due to the contraction in ranges of the four species.
KeywordsClimate change Range shifts Sympatric distributions MAXENT Hybridization and introgression Displacement and extinction
To two anonymous reviewers for their valuable comments and the following colleagues for clarifying and/or providing information about distribution ranges: Rich Bailowitz, Rob Cannings, Doug Danforth, Erland Nielsen, Tim Manolis, Mike May, Dennis Paulson, Leah Ramsay and Tom Schultz. Tania Pollak provided information from her recent survey of Ischnura gemina populations. Raúl Iván Martínez Becerril provided help looking for the literature, and Jesús Ramsés Chavez Ríos for comments on the first draft of this manuscript. This research was funded by two PAPIIT grants (IN 204610 and IN 222312). RSG was supported by a postdoctoral grant (DGAPA-UNAM) from Universidad Nacional Autónoma de México. J.M. is currently supported by grant CGL2012-38624-C02-02 of the Ministry of Economy and Competitiveness of Spain.
Conflict of interest
We confirm that we have no conflict of interests.
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