ORIGINAL PAPER Hybridization rate and climate change: are endangered species at risk? R. A. Sa ´nchez-Guille ´n • J. Mun ˜oz • J. Hafernik • M. Tierney • G. Rodriguez-Tapia • A. Co ´rdoba-Aguilar Received: 5 December 2013 / Accepted: 5 June 2014 Ó Springer International Publishing Switzerland 2014 Abstract Many species are altering their geographic range due to climate change creating new sympatric pop- ulations of otherwise allopatric populations. We investi- gated 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 endan- gered 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 9 I. demorsa individuals: F 1 (first generation) hybrids are produced but do not reach sexual maturation. However, RI in I. denticollis 9 I. gemina hybrids is high but incomplete and unidirectional: only I. gemina females produced F 1 hybrids which mate with males and females of I. denticollis and between them producing BC 1 (back- crosses) and F 2 (second generation) viable hybrids. Maxi- mum 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. denti- collis. However, the current pattern of extinction may not continue due to the contraction in ranges of the four species. Keywords Climate change  Range shifts  Sympatric distributions  MAXENT  Hybridization and introgression  Displacement and extinction Introduction Currently, there is an increasing body of evidence of altered range distributions in response to rising global Electronic supplementary material The online version of this article (doi:10.1007/s10841-014-9637-5) contains supplementary material, which is available to authorized users. R. A. Sa ´nchez-Guille ´n (&)  A. Co ´rdoba-Aguilar (&) Departamento de Ecologı ´a Evolutiva, Instituto de Ecologı ´a, Universidad Nacional Auto ´noma de Me ´xico, Apdo. Postal 70-275, Ciudad Universitaria, 04510 Mexico, DF, Mexico e-mail: rguillen@uvigo.es A. Co ´rdoba-Aguilar e-mail: acordoba@ecologia.unam.mx J. Mun ˜oz Real Jardı ´n Bota ´nico (RJB-CSIC), Plaza de Murillo 2, 28014 Madrid, Spain J. Mun ˜oz Centro de Biodiversidad y Cambio Clima ´tico, Universidad Tecnolo ´gica Indoame ´rica, Machala y Sabanilla, Quito, Ecuador J. Hafernik Department of Biology, San Francisco State University, San Francisco, CA 94132, USA M. Tierney USDA Forest Service, Tahoe National Forest, 15924 Hwy 49, Camptonville, CA 95922, USA G. Rodriguez-Tapia Unidad de Geoma ´tica, Instituto de Ecologı ´a, Universidad Nacional Auto ´noma de Me ´xico, Mexico, DF, Mexico 123 J Insect Conserv DOI 10.1007/s10841-014-9637-5