The role of exotic and native hybrids during ecological succession in salt marshes

Authors: GALLEGO-TEVAR, BLANCA - University Of Seville; Grewell, Brenda; FIGUEROA, ENRIQUE - University Of Seville; CASTILLO, JESUS - University Of Seville

Submitted to: Journal of Experimental Marine Biology and Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/17/2019
Publication Date: 11/24/2019
Publication URL: https://handle.nal.usda.gov/10113/6765589
Citation: Gallego-Tevar, B., Grewell, B.J., Figueroa, E., Castillo, J.M. 2019. The role of exotic and native hybrids during ecological succession in salt marshes. Journal of Experimental Marine Biology and Ecology. 523:151282. https://doi.org/10.1016/j.jembe.2019.151282.
DOI: https://doi.org/10.1016/j.jembe.2019.151282

Interpretive Summary: Ecological succession in the classic sense, the study of progressive changes in species abundance and community composition over time, has long been a focus in ecology. Through long-term study of community dynamics has improved, understanding of succession continues to be relevant and offers insights that can be key for successful conservation and restoration of ecosystems, particularly in the context of rapid global environmental change. Invasive plant species are a recognized global change factor, and hybridization between native and invasive alien plant species has the potential to change the trajectory of plant community development in response to disturbance. Knowledge of factors that influence species colonization and abundance during the process of ecological succession is key for conservation and restoration efforts. The tolerance of species to environmental stresses and interspecific interactions among colonizing species influence progressive stages of ecological succession, so their integrated analysis over time becomes fundamental. In this sense, species with high expected tolerance to stress or high competitive ability, such as invasive species or transgressive hybrids, may acquire a relevant role in the ecological succession, inhibiting its development. We studied the role of native Sarcocornia and exotic Spartina hybrids on the development of primary vegetation succession in Southwest Iberian Peninsula. A particular focus was on hybrids from Spartina densiflora, originating in South America, that are impacting estuarine marshes in Spain and the Pacific Coast of the United States. Main sedimentary characteristics and halophyte community structure were recorded in successional and non-successional coastal salt marshes during ca. 12 years. Native Sarcocornia hybrids increased their abundance in successional and non-successional marshes over time without inhibiting the development of succession, since they occurred and persisted concurrent with colonization by other native halophytes. Furthermore, the spread of native Sarcocornia hybrids coincided with the decrease in the cover of invasive Spartina densiflora. On the contrary, exotic Spartina hybrids inhibited the development of succession by outcompeting other halophytes in the non-successional marsh. However, these sterile hybrids were not yet present in the successional marsh where the parental species S. densiflora had just started to invade. This study reveals different roles of invasive and native hybrid halophytes in the development of ecological succession, providing new valuable knowledge for the management and conservation of salt marshes.

Technical Abstract: Knowledge of factors that influence species colonization and abundance during the process of ecological succession is key for conservation and restoration efforts. The tolerance of species to environmental stresses and interspecific interactions among colonizing species influence progressive stages of ecological succession, so their integrated analysis over time becomes fundamental. In this sense, species with high expected tolerance to stress or high competitive ability, such as invasive species or transgressive hybrids, may acquire a relevant role in the ecological succession, inhibiting its development. We studied the role of native Sarcocornia and exotic Spartina hybrids on the development of primary vegetation succession in Southwest Iberian Peninsula. Main sedimentary characteristics and halophyte community structure were recorded in successional and non-successional coastal salt marshes during ca. 12 years. Native Sarcocornia hybrids increased their abundance in successional and non-successional marshes over time without inhibiting the development of succession, since they occurred and persisted concurrent with colonization by other native halophytes. Furthermore, the spread of native Sarcocornia hybrids coincided with the decrease in the cover of invasive Spartina densiflora. On the contrary, exotic Spartina hybrids inhibited the development of succession by outcompeting other halophytes in the non-successional marsh. However, these sterile hybrids were not yet present in the successional marsh where the parental species S. densiflora had just started to invade. This study reveals different roles of invasive and native hybrid halophytes in the development of ecological succession, providing new valuable knowledge for the management and conservation of salt marshes.