Why are mangrove forests so important?

Mangrove forests play a crucial role in benefiting both the environment and society by providing essential ecosystem services

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By Alex

Mangrove forests

Mangrove forests play a vital role as one of Earth’s most important ecosystems. In addition to being biodiversity havens, these plants hold immense significance for humanity, contributing significantly to the global economy. Despite their fundamental importance, the unfortunate reality is that mangrove forests are slowly disappearing, requiring urgent protection, as no other ecosystem on the planet compares to them.

What kind of plant is a Mangrove?

The term “mangrove” encompasses various plant species from families such as Acanthaceae, Lythraceae, Combretaceae, Arecaceae, and Rhizophoraceae. These are predominantly woody plants that thrive along the low coasts of tropical marine environments, especially in areas periodically submerged by tides. Their notable characteristic lies in their ability to colonize highly saline soils, a challenge typically intolerable for other plant species.

Characteristics of Mangroves

The most prevalent mangrove species can attain heights of 10-11 meters, featuring sturdy, thick leaves measuring 5 to 15 cm in length. Light yellow flowers and aerial roots characterize these plants. The intricate and visually striking roots emerge from the water, forming a dense network that supports both the soil and the plant. The fruit, while still attached to the tree, develops a downward-growing root, eventually giving rise to a new plant upon reaching the ground.

Mangroves exhibit resilience in challenging habitats, thriving in direct contact with seawater amid tides and floods. They can endure oxygen deficiencies and nutrient-poor soils. Aerial roots not only provide structural support but also absorb oxygen from the air in high-water conditions.

Moreover, as sea salt poses a threat to mangroves, some species filter water, expelling salt through their leaves. Alternatively, in certain cases, salt accumulates in older leaves and bark, returning to the sea when they fall.

Geographic Distribution of Mangroves

Mangrove forests are prevalent in tropical and subtropical latitudes surrounding the equator, thriving in dense woodlands along tidal estuaries, salt marshes, and muddy coasts. They represent a rare group of terrestrial plants capable of withstanding contact with saltwater. The largest existing mangrove forests are situated in Thailand, Mexico, and Indonesia.

However, these ecosystems are entirely absent in cold regions due to their inability to endure low temperatures.

What ecosystems Hos Brackish Areas and Mangrove Forests

Mangrove forests, or mangroves, predominantly exist in tropical and subtropical marine regions across both hemispheres. The Indian and Pacific oceans boast the most biodiverse mangrove forests globally.

Globally, approximately 137,000 square km of mangrove forests span 118 countries, underscoring their widespread presence and ecological significance.

mangrove forests

The Ecological Role of Mangroves Forests

Mangroves fulfill multiple beneficial roles. Firstly, they play a crucial role in combating climate change by absorbing significant amounts of CO2. Additionally, they serve as natural infrastructure, safeguarding coasts from the impacts of flooding.

Simultaneously, mangroves act as a source of sustenance and refuge for fish and other animals. Despite these remarkable attributes, mangroves face the threat of extinction due to the combined effects of climate change and rising sea levels.

Let’s delve into a more detailed examination of the resources provided by mangroves.

Mangroves and CO2

Mangroves absorb carbon dioxide from the atmosphere, storing it in the waterlogged soil for centuries. They can conserve up to 10 times more carbon dioxide per hectare compared to typical terrestrial forests, making them a significant asset for the overall health of the planet.

A Fuel Source

Mangrove twigs, with their high calorific value, are utilized for charcoal and firewood production. Notably, one ton of mangrove firewood equates to five tons of Indian coal, burning efficiently without generating smoke.

Construction Material

The hard nature of mangrove wood makes it suitable for construction timber. Leaves, especially those from the Nypa genus, are employed in thatching roofs, crafting mats, and weaving baskets.

Nutritional Source

Mangroves offer affordable and nutritious feed for buffalo, sheep, goats, and camels, which are authorized to graze in mangrove areas. This practice is widespread in countries like India, Pakistan, and Indonesia.

mangrove forests
Mangrove forests play a crucial role in supporting biodiversity and providing various ecological services

Honey Production

Mangroves attract honey bees, supporting beekeeping activities. The Sundarbans, the world’s largest mangrove forests, enable around 2,000 people to extract approximately 111 tonnes of honey annually, constituting 90% of India’s mangrove honey production.

UV Protection

Equipped with special mechanisms to cope with intense sunlight and solar UV-B radiation, mangroves create an environment free from harmful UV-B effects. Certain species, such as Avicennia, adapt seamlessly to arid areas with strong sunlight, while Rhizophoraceae species exhibit greater UV-B tolerance.

Greenhouse Effect Reduction

Mangroves, among the carbon-rich forests in the tropics, mitigate the effects of greenhouse gases through chlorophyll photosynthesis. They surpass phytoplankton in tropical oceans in CO2 absorption, displaying increased biomass accumulation with rising CO2 levels.

Protection from Extreme Events

Mangrove forests shield coastlines from storms and cyclones, as exemplified by the resilience observed during the super-cyclone in India in 1999. Areas lacking mangroves experienced severe consequences, while regions with dense forests remained largely unaffected.

Furthermore, mangroves offer protection from tsunamis, acting as a buffer against wave attacks and tow flow. Their effectiveness in reducing tsunami damage surpasses that of structures like concrete dams. For instance, 30 trees covering 10 square meters each, in a 100-meter-wide band, can significantly decrease the maximum pressure.

mangrove forests
Mangroves also protect coastlines from tsunamis and floods.

Sediment Absorption

Mangrove forests effectively capture suspended sediments, acting as sediment sinks by trapping particles from seawater through their aerial roots. During low tide, these particles settle within the forests, retaining essential nutrients, and contributing to the recycling of carbon, sulfur, and nitrogen.

Mangroves exhibit resilience to human-generated organic waste due to three factors: the habitat’s flow disperses waste widely, vegetation filters nutrients from the water, and mangrove sediments, algae, and microbes absorb pollutants. Notably, sediments possess a significant capacity to absorb and retain heavy metals, preventing their dissemination to neighboring coastal areas, although plants themselves do not accumulate heavy metals due to specific physiological adaptations.

Support for Fauna and More

Mangrove forests play a pivotal role in fish production, acting as a crucial “nursery” for numerous fish species. Approximately 80% of fishing relies, directly or indirectly, on mangroves and other coastal ecosystems. Beyond fish, mangroves support diverse wildlife, including deer, crocodiles, sea turtles, monkeys, snakes, pigs, wild cats, Bengal tigers, insects, and various bird species.

Detached parts of mangrove plants, such as leaves, stems, flowers, and fruits, enrich surrounding waters as they decompose, releasing nutrients. This decomposed organic matter, along with microbial biomass, becomes a protein-rich resource vital for a wide variety of organisms.

Biomass Production

The layer composed of mangrove debris, including leaves, seeds, and branches, is termed “litter.” Litter serves as a crucial carbon source, contributing significantly to the global carbon cycle, with mangrove biomass reaching up to 700 t/ha. Habitat variations, such as poor soils or aridity, can influence litter production. Decomposition of litter further contributes to dissolved organic matter production, potentially supporting coastal waters and fisheries.

Interactions with Other Ecosystems

Mangroves contribute to intricate food webs, with living vegetation serving as a valuable food resource for insects, crustaceans, and some vertebrates. Primary production is transferred to various trophic levels through the decomposition of plant remains. Organic carbon produced by mangrove forests can accumulate in sediments or be transported offshore to support marine communities and coral reefs. Nutrients released into the sea stimulate the multiplication of primary producers like plankton, fostering a thriving ecosystem.

Blue Carbon Ecosystems

Mangrove forests are recognized as Blue Carbon ecosystems, absorbing carbon dioxide from the air and storing it in their soils. Blue carbon refers to the carbon dioxide removed from the atmosphere by ocean and coastal ecosystems through the continuous growth of marine plants and the accumulation and burial of organic matter in the soil.

Why are Mangrove Forests at Risk?

Despite their critical importance, mangroves are rapidly disappearing. Between 2001 and 2012, the world lost between 35 and 97 square miles of mangrove forests annually.

Causes of this destruction include deforestation for wood and shrimp aquaculture, the extraction of resources for medicines, cosmetics, and insecticides, the impact of global temperature increases, rising sea levels leading to destructive floods, intensified precipitation, and tourism.

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