Ecological biogeography of mangroves in Sri Lanka

M D Amarasinghe,K A R S Perera

doi:10.4038/cjs.v46i5.7459

M D Amarasinghe, K A R S Perera

Open Access

https://doi.org/10.4038/cjs.v46i5.7459

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Abstract

The relatively low extent of mangroves in Sri Lanka supports 23 true mangrove plant species. In the last few decades, more plant species that naturally occur in terrestrial and freshwater habitats are observed in mangrove areas in Sri Lanka. Increasing freshwater input to estuaries and lagoons through upstream irrigation works and altered rainfall regimes appear to have changed their species composition and distribution. This will alter the vegetation structure, processes and functions of mangrove ecosystems in Sri Lanka. The geographical distribution of mangrove plant taxa in the micro-tidal coastal areas of Sri Lanka is investigated to have an insight into the climatic and anthropogenic factors that can potentially influence the ecological biogeography of mangroves and sustainability of these mangrove ecosystems.

Highlights

Interactions between organisms and their environment, both abiotic and biotic, are crucial in determining their current spatial distribution on the planet
The objective of this study was to have an insight into the potential factors, both natural and anthropogenic that determine biogeography of mangrove plant species in Sri Lanka
Exclusivity of true mangrove species to inter-tidal zone provides a surrogate to study change in the mangrove environment, as exclusivity represents the extent to which these species are adapted to the inter-tidal environment and their ability to perform ecological functions in this harsh environment

Summary

Introduction

Interactions between organisms and their environment, both abiotic and biotic, are crucial in determining their current spatial distribution on the planet. The objective of this study was to have an insight into the potential factors, both natural and anthropogenic that determine biogeography of mangrove plant species in Sri Lanka. In this respect, exclusivity of true mangrove species to inter-tidal zone provides a surrogate to study change in the mangrove environment, as exclusivity represents the extent to which these species are adapted to the inter-tidal environment and their ability to perform ecological functions in this harsh environment. Presence of non-exclusive species (mangrove associates) in the typical mangrove habitats indicates change, especially of salinity and inundation regimes This emphasizes the importance of identification of plants as true and associate species. An attempt to reduce subjectivity in this respect is presented in the paper on “Historical biogeography of mangroves in Sri Lanka” in this volume

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