Scientists theorize that the earliest mangrove species originated in the Indo-Malayan region, where there are far more mangrove species than anywhere else in the world.
Because of their unique floating propagules and seeds, certain of these early mangrove species spread westward, borne by ocean currents, to India and East Africa, and eastward to the Americas, arriving in Central and South America between 66 million years ago (upper Cretaceous period) and 23 million years ago (lower Miocene epoch).
During that time, mangroves spread throughout the Caribbean Sea across an open seaway which once existed where Panama lies today.
Later, sea currents may have carried mangrove seeds to the western coast of Africa and as far south as New Zealand. This might explain why the mangroves of West Africa and the Americas contain fewer, but similar colonizing species, whereas those of Asia, India, and East Africa contain a much fuller range of mangrove species.
by Gilberto Cintron, US Fish & Wildlife Service
An ecotone is usually a transitional feature [without permanent “identity” (it is like a mixing zone)], whereas mangroves are stable entities (have a persistent identity) . Let’s say that when you see a mangrove ecosystem what you see is really a mosaic of features. Like elements in a picture, each little tile is part of the whole picture. If you focus your attention on a single tile you lose the whole picture. To see a mangrove as a whole you need to “step back” and see the whole, not the individual elements.
There are flows of materials between elements so that although they seem discrete they are tied to each other. In the case of mangroves, some of these elements can change their character and flip into other states, like the pixels on your computer screen. So the mosaic is dynamic, but the whole remains stable–it is still a mangrove ecosystem.
Really, the problem is in our need to fragment things. We cannot study an ecosystem broken into components. It cannot be assembled into a whole. I call this the Humpty Dumpty Effect –[Humpty Dumpty had a great fall. All the king’s horses and all the king’s men couldn’t put Humpty Dumpty together again”……… ] This nursery rhyme enfolds a very important management lesson. We cannot successfully manage ecosystems or landscapes in a fragmented way. Whereas scientists tend to like tearing things apart to see how they work, it is the manager’s role to do the opposite. Managers must learn to integrate. The problem is that in nature the parts in isolation behave in different ways than when they are part of a whole. So it is not an easy job to go from parts to whole.
One approach is to identify the larger whole and manage it to conserve all of its parts. This is called the First Rule of Tinkering….. Aldo Leopold said: “Instead of learning more and more about less and less, we must learn more and more about the whole biotic landcape [Round River 1953].
In the case of mangroves that whole is the tidal wetland that forms at the interface between the non-tidal upland to the lowest parts of the emergent sloping, tidally influenced platform. We call it mangrove, but that is because sometimes it has the woody trees we call mangroves. Other times the trees are missing and we call it a mud flat. If the trees are missing but the surface is covered by herbaceous vegetation we call it a salt marsh. If the herbaceous vegetation is missing there will probably be an algal mat that dries out periodically. We then call it a salt flat. But……it is always the same wetland. It is a natural engine to process sunlight and tidal energy and convert it into energy of higher quality (organic matter). Really, that platform is host to all those “types” of wetlands that exist on it in a latent form! Although the engines we know are mechanical, this tidal engine is adaptive, thus it adapts itself to local environmental conditions by changing its parts. Then we step in and confuse the issue by calling it different names!
by Gilberto Cintron, US Fish & Wildlife Service
Salinas, salt flats, coastal sabkhas, apicuns, and albinas are all names for the same geomorphic features. They are upper intertidal lands characterized by extreme flatness and salt levels. Where there are moisture deficits (arid areas) and lots of insulation (solar radiation), salt accumulates as the water evaporates. In more moist environments, salts would not accumulate and the areas are invaded by mangroves.
In some regions the mangrove/salina boundary shifts periodically due to decadal changes in moisture (such as El Niño events) and an 18-year tidal cycle, which is a normal tidal component. These two cycles can interact producing lower tidal flushing and limited freshwater inputs which favor salt accumulation and salt flat dominance over mangroves. When moist periods and greater tidal amplitudes return, these favor mangrove re-occupation. This is why in some of these landscapes you often see “forests” of dead mangroves on salt flats.
The IUCN Red List of Endangered Species lists most flora and fauna into seven categories ranging from “Least Concern” to “Extinct”. These categories are based on the current population of the species, the population trend (whether it is increasing or decreasing and how rapidly) and the threats faced by those species.
Hunting, habitat loss/degradation and climate change are the three biggest threats to the natural world and these problems are increasing the number of endangered species rapidly.
Below is a list of some of the species associated with Mangroves ranging from “Vulnerable” to “Critically Endangered”. The list covers fauna that rely on mangroves for either all or part of their lives as well as flora that are part of the Mangroves themselves. Many of these species are closely associated with each other and interlinking ecosystems, meaning the loss of one species can have devastating effects on another.
The loss of flora and fauna species and biodiversity is yet another reason why protecting mangrove habitat is so important. For more information please contact Mangrove Action Project at [email protected].
Range: Coastal and island waters between East Africa and Vanuatu (Islands west of Australia)
This large mammal is more closely related to the elephant than other sea mammals. It is the only fully marine mammal and is long lived and shy of humans. They are mostly herbivorous; sea grass being the main part of their diet, but have been known to eat jellyfish and squid.
The major threats to this animal come from habitat loss/degradation due to pollution and trawling, hunting for their meat and bones and fishing activities which either kill intentionally or sometimes accidentally.
Range: Only known on Isla Escudo de Veraguas, off the coast of Panama.
This is the smallest sloth in the world and it is only found in the red mangrove forests surrounding the tiny island it lives on. It is believed to only feed on mangrove leaves and it’s total population is estimated to be less than 500 individuals.
It’s main threat comes from loss of habitat because of indigenous peoples cutting the forest, but also from opportunistic hunters that visit the island.
This iconic species is found in tropical forests including Mangrove forests such as the Sunderbans. It’s population across its entire range is estimated at less than 2500. It’s diet mostly consists of large prey such as wild deer and pigs, but it will also prey on animals such as fish, elephants and primates.
The major threat to this species is poaching for its skin and of its body parts for “medicines”. It is also suffering heavily from habitat loss which is leading to a decline in prey for the animal.
Range: Papua New Guinea and coastal areas of Northern Territory and Queensland, Australia
There is little known about this small, nocturnal rodent. It is carnivorous and feeds mainly on mollusks and crabs found at low tide amongst mangrove roots. Its distribution is extremely patchy along its range and it is only found in mangroves and coastal wetland associated with them. The population of this species is unknown but it is declining.
The biggest threat for this animal is loss of mangrove habitat due to coastal development and aquaculture. Development inland of mangrove ecosystems is also a major threat.
Range: Endemic to Borneo, found in Brunei, Indonesia and Malaysia
This unique primate has a declining population of only a few thousand. It is found in coastal and riverine forest such as mangroves and is limited to these specific habitats, avoiding cleared land. It is easily identified by its huge nose, pot-belly and reddish fur. Its diet consists mainly of leaves and fruit but it will also eat flowers and seeds.
Because of its association with coastal habitat, the main threat to this animal is habitat destruction. Logging, forest fires and development are encroaching rapidly on the area this monkey occupies. Hunting for Chinese “medicines” and as bush meat are also problems as it is easily caught by hunters.
Range: Wide-spread across South and Southeast Asia
This animal is secretive and diurnal (active in the morning and evening) and is rarely seen in the wild. It can grow up to 65cm and is found in large rivers, lakes and mangrove estuaries. It builds dens along river banks and prefers habitat with cover available for hiding from predators. This mammal is an opportunistic hunter and mostly eats fish, but will also eat crustaceans, insects, amphibians, birds and small rodents.
This aquatic mammal faces many threats from humans: destruction of habitat for aquaculture and hydroelectric dams, pollution of waterways by pesticides, reduction in prey and indiscriminate killing because of competition with humans and finally trapping for the fur trade.
This primate has declining, fragmented populations along west Africa’s coast one of its 3 subspecies being listed as critically endangered. It uses a variety of forest habitats, including mangroves and is vegetarian. It is preyed on regularly by Chimpanzees.
This animal is rapidly losing its habitat due to logging and clearing land for plantations. It is also suffering from hunting as it is desired for “bush meat” in the country. The logging roads through its forests are giving more access to the interior of the forest where it was once safe.
This cat is about twice the size of a domestic cat and is found in wetland habitat such as swamps, marshland and mangroves. They are good swimmers and—as their name suggests—primarily prey on fish, although they are known to eat birds, insects and rodents as well.
The main threat to this feline is wetland destruction and degradation, due to its dependence on this type of habitat. Over-fishing these areas is another significant threat and persecution by fishermen is also seen. Though considered not as valuable as other wild cats, its fur is still sold through illegal trade.
Status: Vulnerable, some populations classed as endangered
Range: Fragmented populations across South Asia, Southeast Asia and China
This large deer can reach up to 350 kg in weight, is highly adaptable and is the dominant species of deer in Tropical Asia. It’s habitat varies widely from savannah to mangroves and it is indiscriminate with its herbivorous diet, eating many types of course vegetation.
Despite it’s adaptability, populations outside protected areas are at a very high risk with some having faced up to 50% declines over the last 3 generations. Hunting is the most serious threat to the animal: its antlers are used as “medicine” and it is killed for its meat . The demand for bush meat is a rapidly growing industry and for this deer the market is based in South-East Asia and China. Hunting has head to localised extinction in Vietnam, India, Thailand and Laos (amongst others), seen by a lack of this species in otherwise suitable habitat.
Trapping for the caged bird trade is the biggest threat to this bird. It is valued at around $400 per bird. Habitat loss, hunting, changing weather and introduced predators are also adding to the decline of this species.
More information: http://www.iucnredlist.org/details/106001403/0
Mangrove Finch, Camarhynchus heliobates
Status: Critically Endangered
Range: Restricted to the Galapagos Islands
This bird is thought to only have a maximum of 200 mature individuals left in the wild, restricted to the North-West coast of Isabela Island. It inhabits dense mangrove swamps and has a diet of insects, larvae, spiders and some vegetable matter.
The biggest threat to this bird is predation and disease from invasive species such as the common rat (Rattus rattus).
More information: http://www.iucnredlist.org/details/106009612/0
Madagascar Teal, Anas bernieri
Range: Endemic to western coast of Madagascar
This bird has a total population of 1500-2500 individuals but this is decreasing. The species prefers coastal mangroves usually, but only breeds in seasonally flooded, non-tidal areas dominated by Black Mangrove Avicennia marina. It feeds mainly on aquatic and terrestrial insects and vegetation.
Habitat loss and disturbance by agriculture and development are threatening this species and isolating its populations. Hunting and trapping are also a problem as it is considered a delicacy.
More information: http://www.iucnredlist.org/details/100600449/0
Mangrove Hummingbird, Amazilia boucardi
Range: Endemic to the Pacific coast of Costa Rica
A maximum of 7000 mature individuals are found spaced along the stretch of coast but numbers are decreasing. It has very a specific habitat and feeds mostly on the flowers of the mangrove species Pelliciera rhizophorae.
The biggest threat is habitat loss due to construction of shrimp ponds and salt farms, but pollution and road construction (destroying hydrology) are also threats.
More information: http://www.iucnredlist.org/details/106001941/0
Illidge’s Ant Blue Butterfly, Acrodipsas illidgei
Range: Endemic to Australia
This rare insect is a classic example of the interlinking web mangrove ecosystems maintain. The female butterfly lays her eggs in the stubs of Grey Mangrove (Avicennia marina) where there are colonies of Crematogastor ants. It has a symbiotic relationship with the ants: the ants carry the larvae into their nests and feed on the excrement and the larvae feed on developing ants.
Loss of habitat is the biggest threat to this insect as it is only found in mangroves.
Range: Very localised in China, Hong Kong and Japan
This species is a marine dragon fly, restricted to coastal habitats and can only be found either in mangrove forests or on the mud flats near them. The males are territorial and the females will visit in mornings and evenings.
Coastal development and aquaculture are the biggest threats to this insect, resulting in habitat loss and degradation.
Range: Tropical and subtropical waters of the Atlantic, Indian and Pacific oceans
This animal is migratory and occupies many different habitats during its lifetime. Mangroves are an essential habitat for older juveniles and adults, offering protection and food. One sub-population in Central America nests and lives in mangrove estuaries all year round. Hawksbills are long-lived animals which can take between 20-40 years to reach maturity. There has been an 80% decrease in the number of turtles over the last 3 generations and the population is still decreasing.
The major threats to this species are the Tortoiseshell trade, egg collection, destruction of nesting and foraging habitat, hunting for meat and entanglement in fishing equipment.
Although this species is widespread, it is not common in any of the areas it occurs. It is venomous and can reach almost 6m in length. It can be found in mangrove forests but has a range of habitats. It’s diet consists mostly of other snakes but it will also eat birds, rodents and lizards.
Deforestation and agriculture development are leading to habitat loss which is the biggest threat. However this reptile is also hunted for its skin and body parts for traditional Chinese medicine.
Range: Atlantic coast of South and Central America up to Florida and Pacific Coast of Mexico to Peru
This reptile is the most widespread of the New World Crocodiles. They are mostly found in coastal habitats such as lagoons and mangroves but also inhabit freshwater. Their main prey is fish but adults have been known to hunt animals as large as cattle. A male adult can grow to nearly 4.5m long. Over the last 75 years the population has declined by 30%.
Coastal development is leading to a loss of nesting ground and loss of mangrove habitat for this species. Despite a ban, illegal hunting for this crocodile’s skin is an on-going threat. This species is also hybridizing with other Crocodylus spp. but it is unclear yet whether this will have a long-term detrimental affect on the population.
Found in tidal areas of estuaries, this turtle lays its eggs in riverbanks and sandbars. This animal is listed under CITED appendix I which is meant to be the highest level of protection from trade, yet it’s population is declining rapidly and has become extinct in 4 countries over the last 15 years.
The biggest threat comes from illegal trade of the animal, especially in China.
Found in tropical waters including coral reefs and mangrove estuaries, this fish dwells on the bottom of the ocean and has a limited movement range. It feeds on bony fish and can grow up to 3m as an adult but its threat to humans is relatively low.
The major threat to this fish is habitat loss through coral reef destruction by pollution and dynamite fishing, along with deforestation of mangroves throughout Southeast Asia. It is very susceptible to heavy localized fishing and has become extinct in local areas in Thailand and India because of this.
Range: Western-central Pacific: Malaysia, Brunei, Singapore and Indonesia.
Little is really known about this stingray an its population size is unknown. It mainly occupies mangrove estuaries and coastal areas in very shallow waters. It has a very restricted range and habitat and dwells on the sea bed.
The rapid destruction of mangroves for aquaculture is a serious threat for this animal. It is also exploited by for its shallow water habitat and over-fishing are the main threats to this animal.
These fish are found in coral reefs, seagrass beds and mangroves. They are nocturnal and are ambush predators, eating anything small enough to swallow from tiny invertebrates to fish fry. It uses its tail to grasp onto coral, sponge and sea grass and its habitat is very localized. These seahorse mate for life and it is the male that gives birth rather than the female.
They are under threat for use in traditional “medicines” and the aquarium trade. It is also affected through by-catch and habitat degradation from fishing techniques and development. The unique behavior of fidelity towards a partner means the sea horse may never reproduce is one partner is lost.
Range: Only in 2 mangrove streams leading to the Panama Canal, Gulf of Panama
This little fish—up to 7.2cm—is endemic to this part of Panama and is incredibly rare. It depends on the mangrove forests it lives in and is only found in their shallow, fresh waters. It is carnivorous and feeds on invertebrates found on the bottom of the sea, such as mollusks, crabs and worms.
The biggest threat to this fish is habitat loss due to coastal development in Panama.
Range: Caribbean coast of Central and South America
This rare mangrove species has 5 small and separate populations along its range. It is restricted in its distribution and these populations are declining. It is a relatively small tree that has specific salinity needs and is the main habitat for the endangered Mangrove hummingbird.
The main threat to this mangrove is deforestation. Due to its localized populations, it is also at risk from unpredictable storms. Rise in sea level is also a threat.
Range: Eastern Tropical Pacific from Mexico to Columbia
This species population has declined by around 30% over the last 30 years. It is a canopy tree reaching up to 15m and can withstand relatively high salinity levels compared to other mangrove species.
The major threat to this species is cattle grazing: either the land is cleared or the cattle graze under the mangroves and damage/destroy the undergrowth and any potential regeneration. It is also under threat from aquaculture and urban development.
There are estimate to be less than 1200 mature species across its range in a restricted and patchy distribution with this number decreasing. It is found on the edge of mangrove forests along tidal creeks.
Fish and shrimp aquaculture is a severe threat to this species, especially in the Philippines. It is targeted locally as a source of wood for various uses and pollution is also a problem.
Range: From the Sundarbans in India spreading down the coast to Northern Malaysia
This species can be common in local populations but has a limited overall distribution. The population in India and Bangladesh is rapidly declining. It prefers fresh water and can grow rapidly in such conditions, up to 25m tall.
This species is quickly disappearing in many parts of its range due to coastal development (urban, agricultural and industrial), disease, typhoons, aquaculture and selective cutting for charcoal.
All images used are for non-profit, educational purposes only. They are sourced from multiple websites. I have cited the owner wherever possible and have provided links to the website I sourced them from when details are not available.
If the owner of any image used feels that there is any violation in copyright law then please contact [email protected]
Pygmy Three-toed Sloth: http://news.mongabay.com/2010/0316-hance_fs_pygmythree.html
Source: Photos courtesy of Bryson Voirin