The role of oceanic currents in the dispersal and connectivity of the mangrove Rhizophora mangle on the Southwest Atlantic region

Author(s)

Madeira, Andre Guilherme ; Tsuda, Yoshiaki ; Nagano, Yukio ; Iwasaki, Takaya ; Zucchi, Maria Imaculada ; Kajita, Tadashi ; Mori, Gustavo Maruyama

• Document type: Journal article
• Source: MOLECULAR ECOLOGY RESOURCES; v. N/A, p. 16-pg., 2023-05-12.

Abstract

Dispersal is a crucial mechanism to living beings, allowing them to reach new resources such that populations and species can occupy new environments. However, directly observing the dispersal mechanisms of widespread species can be costly or even impractical, which is the case for mangrove trees. The influence of ocean currents on mangrove dispersal is increasingly evident; however, few studies mechanistically relate the patterns of population distribution with the dispersal by oceanic currents under an integrated framework. Here, we evaluate the role of oceanic currents on connectivity of Rhizophora mangle along the Southwest Atlantic. We inferred population genetic structure and migration rates, simulated the displacement of propagules and tested our hypotheses with Mantel tests and redundancy analysis. We observed populations structured in two major groups, north and south, which is corroborated by other studies with Rhizophora and other coastal plants. Inferred recent migration rates do not indicate ongoing gene flow between sites. Conversely, long-term migration rates were low across groups and contrasting dispersal patterns within each one, which is consistent with long-distance dispersal events. Our hypothesis tests suggest that both isolation by distance and isolation by oceanography (derived from the oceanic currents) can explain the neutral genetic variation of R. mangle in the region. Our findings expand current knowledge of mangrove connectivity and highlight how the association of molecular methods with oceanographic simulations improve the interpretation of the dispersal process. This integrative approach is a cost- and time-efficient strategy to include dispersal and connectivity data into marine protected areas planning and management. (AU)

• FAPESP's process: 14/22821-9 - Population and functional genomics on the evolutionary study of neotropical Rhizophora species in face of historical and current climate changes
• Grantee: Gustavo Maruyama Mori
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 18/02655-8 - Unveiling the genetic diversity of Rhizophora species from the western world and South Pacific using RAD-seq
• Grantee: Andre Guilherme Madeira
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• FAPESP's process: 20/07967-8 - Integration of population genomics and biophysical modeling of dispersion by ocean currents for the inference of the connectivity of mangrove trees on the Brazilian coast
• Grantee: Andre Guilherme Madeira
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 13/08086-1 - Population and functional genomics and an ecophysiological approach on the evolutionary study of neotropical mangrove species in face of historical and current climate changes
• Grantee: Gustavo Maruyama Mori
• Support Opportunities: Scholarships in Brazil - Post-Doctoral