Urbanization and Invasion of Mangroves Swamps
Nadir Mumtaz (Maritime Analyst)
The rapid increase in population and corresponding urbanization in coastal megacities has been accompanied by frenzied land reclamation driven mostly by anthropogenic factors .
Mangroves are prevalent all over except Antarctica. Seaward land reclamation entails the formation of artificial land facade structures extending over the sea employing innovative engineering designing.
Coastal megacities have flourished rapidly over the last four decades leading to massive and uneducated land reclamation.
To placate conservations the trend is planting of fresh mangroves instead of incentivizing conservation of existing mangrove forests.
National economic priorities spur infrastructure development, coastal economic development zones and enlargement of port facilities.
Mangroves Global Spread
Asia has the biggest tract area of mangrove coverage comprising almost 42% of the world’s mangroves and predominantly swamps are found in Indonesia and Malaysia .
The State of Florida in the US encompasses almost 190,000 ha and its prominent species include wading birds, pelicans as well as the endangered crocodile.
Mangroves Benefits
For those not exposed to marine conservation suffice to say that mangrove swamps are coastal wetlands typically prominent in tropical and subtropical regions exemplified by halophytic trees and shrubs having the unique ability to thrive in brackish to saline tidal waters.
Mangrove swamps flourish as estuaries at the juncture of fresh and salt water resplendent with an amazing and impenetrable maze of woody habitat.
From a marine conservationist perspective mangrove forests enable ecosystems to sustain endangered species as nurseries for fish and marine species including shellfish, worms, protozoa, barnacles ,oysters , juvenile fish , shrimps and other invertebrates.
From mangrove refuges marine species enter reefs critically replenishing the ocean’s fish stock a vital source of livelihood for many developing maritime countries. Some megacities have untreated sewage and effluence entering rivers from industrial complexes and emptying into the sea.
Diverse geospatial consequences of complex coastal geomorphology combined with natural and anthropogenic elements emphasize the susceptibility of coastlines to external sea surges .Swamps shelter harbors and coastlines from siltation , erosion ,sea swells and damages of storm surges
.The UN Environment Programme is about mangrove forests sequestering carbon within their roots, trunks and in the soil estimated at 22 million tons of carbon annually.
Salt marshes or coastal vegetated ecosystems enable marine species survival , stabilize shorelines and prevents erosion which naturally protects critical port infrastructure and manages carbon sequestration.
Costal Reclamation Megaprojects
The glittering spectacle of the Palm Resorts of Dubai , construction of the new Hong Kong airport, artificial islands in the South China Sea , development of “Baia de Luanda” in Angola and the construction of a contiguous Mumbai from islands are manifestations of marine reclamation.
In contrast to the edifice of the Palm Resorts of Dubai the Flevoland province in Netherlands was artificially made through draining lakes making it the youngest province as it came into being in the year 1986 .
The uniqueness of its design is that it is the largest man made island in Netherlands and is protected by embankments or dykes .
Despite being below sea level the Flevoland province is reflective of flood risk management engineering designing against storm surges from the North Sea which had wrecked havoc in the past.
Flevoland also serves as a fresh water logistic and touristic hub replete with the world famed tulips . Megacities are conspicuously coastal and the extent of coastal land expansion and potential environmental impact can be deduced from coastal megacities developed from the years 1985 to 2019 .
The Global Diversity report 5 has identified coastal degradation , untreated sewage and pollution from plastic waste as severely impacting marine ecosystems such as coral reefs .
International Rationale for Mangroves Conservation
The South Carolina (S.C.) State Ports Authority created 22 ares of salt marshlands on Dawn Islands as a precursor to making it the greenest port in the Southeast.
The S.C State Ports Authority abandoned plans for a new cruise ship terminal the permitting of which had attracted the ire and legal challenge from environmental and historic preservation groups.
The marshy swamps creation was required by federal permit for the Leatherman terminal the construction of which had caused the destruction of wetlands .
The project cost around $4 million involving the conversion of a dormant dredge disposal site , an aquatic habitat to invasive species , into a wetland with more than 100,000 native marsh plants.
The project is hailed as a contemporary green flagship success story .The restored salt marsh in Charleston Harbor is said to have improved water quality establishing an aquatic habitat for juvenile shrimp , fish and invertebrates of the creek and un interrupted tidal flow from the harbor .Sporadic marine conservation efforts are underway in Kenya’s Gasi Bay through planting of seedlings .
Nigeria has the largest reserve of water friendly trees in Africa but the country’s mangroves are ranked amongst the worst degraded compelling the country to launch a mangrove sustainability initiative to increase mangrove cover.
Carbon Sequestration Potential of Mangroves
Maximum canopy height is an indicator of light interception that reflects the carbon storage potential or carbon sequestration naturally capable of reducing atmospheric concentration of carbon dioxide.
Additionally if marine species diversity influences carbon storage the complementarity hypothesis is substantiated as being a mechanism for the storage of blue carbon.
Mangroves contribution towards protecting juvenile marine species, its role in tidal flow and preventing siltation in harbors, protecting port infrastructure against ocean swells , carbon sequestration and preserving estuaries is in contemporary times being gradually recognized as invaluable.
References :
https://doi.org/10.1016/j.apgeog.2017.12.015
https://doi.org/10.17528/cifor/008099
https://www.oneearth.org/six-projects-restoring-vital-mangrove-forests-around-the-world/
https://doi.org/10.1038/s41467-021-24207-4
https://doi.org/10.1016/j.ocecoaman.2018.01.009
https://www.conservation.org/priorities/mangroves
https://www.epa.gov/wetlands/mangrove-swamps
https://www.iucn.org/news/forests/201708/mangroves-nurseries-world’s-seafood-supply
https://factsanddetails.com/world/cat53/sub335/item2182.html
https://www.cbd.int/gbo/gbo5/publication/gbo-5-en.pdf
https://news.mongabay.com/2022/12/global-study-reveals-widespread-salt-marsh-decline/