Genetic Structure and Connectivity of the Red Mangrove at Different Geographic Scales through a Complex Transverse Hydrological System from Freshwater to Marine Ecosystems

Landy R Chablé Iuit,Julio Espinoza-Ávalos,Héctor A Hernández-Arana,Salima Machkour-M’Rabet,Yann Hénaut,Haydée López-Adame

doi:10.3390/d12020048

Landy R Chablé Iuit, Julio Espinoza-Ávalos + Show 4 more

Open Access

https://doi.org/10.3390/d12020048

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Journal: Diversity	Publication Date: Jan 27, 2020
Citations: 11	License type: CC BY 4.0

Affiliation: El Colegio de la Frontera Sur

Abstract

Mangrove forests are ecologically and economically valuable resources composed of trees morphologically and physiologically adapted to thrive across a range of habitats. Although, mangrove trees have high dispersion capacity, complexity of hydrological systems may lead to a fine-scale genetic structure (FSGS). The Transverse Coastal Corridor (TCC) is an interesting case of hydrological systems from fresh to marine waters where mangrove forests dominate. We evaluated genetic diversity and structure of Rhizophora mangle across a range of hydrological conditions within the TCC using inter-simple sequence repeat molecular markers. Sampling included four hydrological systems, two localities inside each system, and fringe and dwarf trees. Genetic differentiation was evaluated at local (<100 km) and fine (<10 km) scales through a set of analyses, and genetic diversity was evaluated at all scale levels and between fringe and dwarf physiognomic types. Rhizophora mangle exhibited a high genetic structure at both scales with high genetic diversity. The genetic structure observed among hydrological systems likely reflects the historical dispersion of mangroves, whereas the FSGS reflect contemporary processes such as seed dispersal restriction, habitat fragmentation, and local water flow regimes. A higher genetic diversity for dwarf than for fringe trees and differentiation between both physiognomic types at a fine-scale were observed and discussed.

Highlights

Mangrove forests are distributed worldwide in intertidal zones of tropical and subtropical regions and represent a highly productive ecosystem that contributes to functional processes such as demineralization, organic matter production, and water quality improvement
Samples of fringe and dwarf mangrove trees were pooled for the genetic structure and diversity analysis
Our results highlight a clear genetic structure for the Rhizophora mangle community across the Transverse Coastal Corridor (TCC), which shows a clear separation between Chetumal Bay

Summary

Introduction

Mangrove forests are distributed worldwide in intertidal zones of tropical and subtropical regions and represent a highly productive ecosystem that contributes to functional processes such as demineralization, organic matter production, and water quality improvement. Peninsula (YP) where the mangrove forests exhibit broad structural variations [1,5] comprising three main physiognomic types: fringe, basin, and dwarf mangroves [1]. Dwarf mangroves, which are typically less than 3 m in height [8], lack the main stem with reduced canopy size and scarce production of flowers and propagules. They are located behind fringe and basin mangroves or directly alongside of inland water bodies in environments that are characterized by a deficiency in nutrients (e.g., phosphorus) and hydrological stress [1,9]. Research associated with genetic differentiation between mangrove physiognomic types are scarce [14,15]

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