Some like it hot: Maternal-switching with climate change modifies formation of invasive Spartina hybrids

Authors: GALLEGO-TEVAR, BLANCA - University Of Sevilla; INFANTE-IZQUIERDO, MARIA - Universidad De Huelva; FIGUEROA, ENRIQUE - Odiel Marshes Natural Wetland Reserve Park Andalucia; MUNOZ-RODRIQUEZ, ADOLFO - Universidad De Huelva; Grewell, Brenda; CASTILLO, JESUS - University Of Sevilla

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2019
Publication Date: 4/15/2019
Citation: Gallego-Tevar, B., Infante-Izquierdo, M.D., Figueroa, E., Munoz-Rodriquez, A.F., Grewell, B.J., Castillo, J.M. 2019. Some like it hot: Maternal-switching with climate change modifies formation of invasive Spartina hybrids. Frontiers in Plant Science. 10:484. https://doi.org/10.3389/fpls.2019.00484.
DOI: https://doi.org/10.3389/fpls.2019.00484

Interpretive Summary: Climate change can induce temporary, spatial or behavioral changes in species, so that only some species can adapt to new climatic conditions. Invasive species are predicted to be promoted under the context of global change, given their high tolerance to environmental factors and phenotypic plasticity. Once in the invaded range, these species can hybridize with native species thus introducing their genotype into the native biota. However, the effects that climate change will have on this process of invasion by hybridization remains unclear. We evaluated the historical establishment of the reciprocal hybrids between the native Spartina maritma and the invasive S. densiflora in the Gulf of Cadiz (SW Iberian Peninsula) relative to climatic changes during the period 1955-2017. Based on age of clones determined from their lateral expansion rates, our results show the establishment of S. maritima x densiflora and S. densiflora x maritima in the Gulf of Cadiz has occurred in the last two centuries and has been related to changes in air temperature and rainfall during the flowering periods of their parental species, with antagonist impacts on both hybrids. Thus, the hybrid S. densiflora x maritima has established in years with mild temperatures in late spring and early summer coincident with a lengthened flowering phase and increased pollen production of S. maritima, and the early flowering period of S. densiflora. Moreover, the establishment of this hybrid occurred in years with above average spring/summer rainfalls, probably due to the reduction in salinity in middle marshes. However, the hybrid S. maritima x densiflora, was established mainly with increased air temperatures in spring/summer when the proportion of pollen:ovule of S. maritima was reduced favoring its pollination by S. densiflora. Consequently, the native and endangered species S. maritima is threatened due to the increased establishment of S. maritima x densiflora with climate warming, as both taxa share the same habitat and the hybrid shows a remarkably higher competitive potential. As climate warming accelerates, our results support the need for accelerated management as a biological conservation priority to curtail the spread of hybridization-prone alien cordgrasses and their invasive offspring to support coexistence of rare native plant species and salt marsh plant communities.

Technical Abstract: Climate change can induce temporary, spatial or behavioral changes in species, so that only some species can adapt to new climatic conditions. Invasive species are predicted to be promoted under the context of global change, given their high tolerance to environmental factors and phenotypic plasticity. Once in the invaded range, these species can hybridize with native species thus introducing their genotype into the native biota. However, the effects that climate change will have on this process of invasion by hybridization remains unclear. We evaluated the historical establishment of the reciprocal hybrids between the native Spartina maritma and the invasive S. densiflora in the Gulf of Cadiz (SW Iberian Peninsula) relative to climatic changes during the period 1955-2017. Based on age of clones determined from their lateral expansion rates, our results show the establishment of S. maritima x densiflora and S. densiflora x maritima in the Gulf of Cadiz has occurred in the last two centuries and has been related to changes in air temperature and rainfall during the flowering periods of their parental species, with antagonist impacts on both hybrids. Thus, the hybrid S. densiflora x maritima has established in years with mild temperatures in late spring and early summer coincident with a lengthened flowering phase and increased pollen production of S. maritima, and the early flowering period of S. densiflora. Moreover, the establishment of this hybrid occurred in years with above average spring/summer rainfalls, probably due to the reduction in salinity in middle marshes. However, the hybrid S. maritima x densiflora, was established mainly with increased air temperatures in spring/summer when the proportion of pollen:ovule of S. maritima was reduced favoring its pollination by S. densiflora. Consequently, the native and endangered species S. maritima is threatened due to the increased establishment of S. maritima x densiflora with climate warming, as both taxa share the same habitat and the hybrid shows a remarkably higher competitive potential. As climate warming accelerates, our results support the need for accelerated management as a biological conservation priority to curtail the spread of hybridization-prone alien cordgrasses and their invasive offspring to support coexistence of rare native plant species and salt marsh plant communities.