Mangroves. Mangrove trees - a unique creation of nature Mangrove trees

Mangroves, mangroves (from the English mangrove), are tree and shrub plant communities that develop on periodically flooded areas of sea coasts and estuaries, protected from surf and storms by coral reefs or coastal islands. The Greek navigator Nearchus, who reached in 325 BC. northern border of the mangroves in the Persian Gulf, called them "forests growing in the sea."

Mangroves are distributed mainly in the humid tropics - on the coasts of East Africa, South Asia, Australia and Oceania. And on the western coasts of Africa and the tropical shores of America, they are practically not found. The most northerly distribution point of mangroves is about 32°N. in Florida and Bermuda, in the Red Sea (Gulf of Aqaba) and in southern Japan. In the Southern Hemisphere, mangroves move even further from the equator. On the east coast of Africa, they reach the vicinity of Durban (33 ° S), and in Eastern Australia - 38 ° S. The least extent of the mangrove range is on the Pacific coast of America, from Baja California to 3 ° 48 "S in South America - to the south, its distribution is limited by the cold Humboldt Current. In the Atlantic Ocean, mangroves reach 28 ° 20" in southern Brazil. On the coast of Africa, they are confined mainly to the estuaries of large rivers, and their spread to the south is stopped at about 9°S. dry, almost desert climate of the continent. Thus, from the point of view of zoogeography, mangrove biocenoses are considered intrazonal.

During low tide, the soil in the mangrove area dries up and the salt content in it increases several times. Mangrove trees have the ability to tolerate large fluctuations in the concentration of salts (mainly table salt) in the soil. Their roots absorb desalinated water through ultrafiltration. The fluid entering the vessels of mangrove plants contains only about 0.03% salt. Nevertheless, salt accumulates in tissues, especially strongly in old leaves due to prolonged transpiration. Mangrove leaves are juicy, but at the same time tough and leathery.

The tree species that make up the mangroves have strengthening stilted roots and rising from the ground (negative geotropism) respiratory roots-pneumatophores. Their fruits are usually supplied with air-bearing tissue and can float in water for a long time.

Mangroves usually consist of evergreen trees 10–15 m high. The tallest trees (up to 27–30 m) are found in the mangroves of the Eastern Hemisphere. Depending on the frequency and duration of flooding, the nature of the substrate (silty or sandy), the ratio of fresh and sea water (at river mouths), plants in mangroves are located in belts, each of which is dominated by one or two (sometimes several) species. The number of plant species that form mangrove thickets is relatively small - about 20 species belonging to the families of rhizophoraceae, verbena, myrisinaceae, sonnetariaceae and combretaceae. In the family of rhizophoraceae (Rhizophoraceae), representatives of 4 genera are best known: rhizophora (Rhizophora), brugiera (Bruguiera), ceriops (Ceriops) and candelia (Kandelia) - they form the bulk of mangroves.

Mangroves, forests flooded with water during sea tides - a symbol of tropical coasts. This mangrove tree belongs to the Rhizophora genus. Bako National Park, Sarawak. http://www.equator.ru/photo-forms/1999_borneo_sarawak/99gall15.htm Rhizophores, as a rule, are small trees or shrubs, but some of them can reach a height of 30–40 m. The root system of mangrove rhizophores is shallow, extended in the upper layers of the soil. Many species have the ability to form adventitious supporting (so-called stilted) roots on the lower part of the trunk and lower branches. Sometimes plank-shaped roots are also formed in rhizophores, which give stability to tall trees, since with their help the mass is evenly distributed over a large area of ​​\u200b\u200bsupport. Species of the rhizophora genus, as a rule, are pioneering mangroves growing from the seaward sides and taking on squalls of wind and wave blows. During high tide, sea water often floods them to the very crowns, and low tide exposes trunks and a dense plexus of roots. The trunks of such trees rarely stand upright, more often they are located obliquely or almost horizontally, relying only on stilted roots, which in representatives of this genus also appear on the lower branches. Upon reaching the soil, the stilted roots usually branch out, giving the trees additional stability during storms. The bark of trunks, branches, and adventitious roots is provided with lenticels connected with the intercellular spaces of internal tissues, and through these lenticels, as well as through stomata, gas exchange occurs during low tide.

Species of the genus Brugiera, on the contrary, gravitate towards drier, inland areas of mangrove thickets, where they form exceptionally dense straight-stemmed forests, under the canopy of which twilight constantly reigns. In brugiera, horizontal roots extending radially from the base of the trunk form high vertical knotty and clumsy cranked outgrowths sticking out of the ground. Their lower part, immersed in the soil, bears numerous nourishing roots, while the upper part grows in height over the years and is covered with a cork-like crust, through the pores of which oxygen is supplied to the tissues of the root system.

Rhizophore flowers are collected in small primrose inflorescences, sometimes solitary (in leaf axils), usually bisexual. The petals are dull, often white, yellowish or brownish. Pollination occurs mainly with the help of wind. But in Brugiera, the abundant nectar-producing flowers attract hawk moths and other insects, as well as nectary birds. Hard woody fruits of rhizophoraceae contain one seed. In unusual ecological conditions of growth, these plants developed a special property - live birth (viviparia), that is, the germination of a seed in a fruit still hanging on the mother plant. The rhizophoral embryo begins to develop immediately after fertilization. After 11–13 weeks, it breaks through the fetal wall and continues to grow vigorously. In rhizophora spiky, such hanging seedlings reach 1 m in length, which is why these plants are called "candle trees". The seedlings remain on the tree for 30–39 weeks, sometimes for a whole year, and then fall vertically down. If the soil under the tree is soft silt, the seedlings stick into it and due to this they are not immediately carried away by tidal currents. On denser soil, fallen seedlings remain on the surface and take root lying down, gradually rising. Often at the same time, some of them dry up in the sun, while the other part is carried away by water into the sea.

Carried away by a sea wave, rhizophoral seedlings can make long (up to a year) sea voyages, while maintaining viability. This is the main factor that ensures the wide distribution of rhizophorans on tropical sea coasts. In some places they cross the line of the tropics, where warm currents and climate favor the development of mangroves. Thanks to the mangrove rhizophora, islands arise, which first grow singly in shallow water, and then gradually merge.

The economic importance of rhizophora is small. Their wood serves as fuel, is used in construction, mainly for piles, sleepers, beams in underwater and underground structures. It is heavy, hard, durable, little affected by shellfish. The bark of mangrove rhizophora, containing up to 40% tannins, is used in leather production and for the production of dyes.

The verbena family (Verbenaceae) includes species of the genus Avicennia (Avicennia) - the most characteristic plants of mangroves in almost all tropical countries. At the same time, avicenna is more resistant to winter cold than other mangrove trees, and in the Southern Hemisphere (in New Zealand) it goes further south than other species. Like other mangroves, Avicenna has special respiratory roots - pneumatophores growing vertically upwards, protruding from the silt at low tide and supplying the underground parts of the plant with oxygen through a system of holes located at the ends, connected with the intercellular spaces of the root. Seed germination of Avicenna, as in rhizophora, begins already on the mother plant, and the falling one-seeded fruits bear a fully developed seedling. In nature, Avicenna species often replace mangrove rhizophora.

The Myrsinaceae family includes the genus Aegiceras, one of the representatives of which, A. corniculatum, is one of the common plants protected from the surf by mangrove forests on the muddy coasts of the Indian and Pacific Oceans, from India and Sri Lanka. Lanka to South China and Northeast Australia. Another species of the genus, flowering aegitseras (A.floridum), is found only in Melanesia.

Aegicerases are shrubs or small trees no more than 8 m high, with respiratory pneumatophore roots that supply the plant with oxygen, with leathery leaves, often covered with salt crystals secreted by special salt glands. Aegiceras grow mainly in swamps along the banks of rivers and estuaries and are confined to the inner zone of mangroves, where the influence of salt water is less felt. As in rhizophora and avicenna, the only large elongated seed of Aegiceras germinates without a dormant period, still in the fruit hanging on the tree. But the seedling breaks through the shell of the fruit only after it has fallen off. The fruits of these plants are carried sea ​​water. In addition to Aegiceras, other myrsine species are also found in mangrove thickets - elliptical erdisia (Ardisia elliptica), umbrella rapanea (Rapanea umbellulata), etc.

The Sonneratiaceae family includes 5 species of the genus Sonneratia, which grow in mangroves on the sea coasts of East Africa and Madagascar, Tropical Asia to the islands of Hainan and Ryukyu, Micronesia, the Greater and Lesser Sunda Islands, Northern Australia, and New Guinea , Solomon Islands and New Caledonia. The most widespread are white sonneria (S. alba) and cheese sonneria (S. caseolaris). Sonnerathiaceae are evergreen trees 15–20 m high, sometimes more. On their long horizontal roots, numerous vertical outgrowths sticking out above the soil surface are formed, covered with loose bark with abundant intercellular spaces and bearing many small feeding roots, which are formed anew in the upper part as silt and sand accumulate. This is the main function of the vertical outgrowths that form in the soil flooded by the tides - the constant removal of the feeding roots to the upper fertile layers.
The flowers of the sonnerathiaceae are quite large, bisexual, arranged in 1-3 or in small inflorescences-scutes. Petals in some species are absent or inconspicuous. Flowering is night, short-term, at dawn the petals and stamens fall off. The flowers emit an unpleasant odor, secrete abundant nectar and are visited in the evening and at dawn by nectary birds, and at night by nectar-eating bats.
The fruits of sonnetratiaceae are berries that quickly rot on the surface of the soil. The seeds are then dispersed by water and germinate on beaches and coral terraces. The wood of the sonnerathiaceae is brown-black, heavy, and quite strong. Locals sometimes use it in the construction of houses and for the manufacture of boats.

The upright conocarpus (Conocarpus erectus) belongs to the Combretaceae family (Combretaceae), a small evergreen tree found on the coasts of the Atlantic Ocean. Conocarpus gravitate toward the interior of the mangroves. As the soil washed by the tides grows, this plant forms adventitious roots in the lower part of the trunk.

Mangrove forest in Australia. So little light penetrates inside the mangrove forest that the lower tiers of vegetation are practically absent. This is also prevented by significant fluctuations in the water level and semi-liquid soil. But at the top, on the branches of the mangroves, epiphytic plants, such as Louisiana moss, or Tillandsia usneoides, a flowering plant similar to the lichen, from the bromeliad family, can settle. Tillandsia is an epiphyte from the group of so-called "atmospheric" bromeliads, it receives everything it needs from the air. Its root system is completely absent (with the exception of seedlings), the plant absorbs moisture directly from the air, and mineral salts from rainwater and airborne dust. The branchy shoots of Tillandsia usneiform reach 8 m.

Mangroves are characterized by high productivity. At the same time, in places where they grow on the coasts of tropical seas, in bays and estuaries of rivers, silt and sand are deposited. In the inner parts of the mangrove, real soil is already forming - as a result of mixing sea silt with the remains of leaves, branches and trunks of mangrove trees, humus is formed here, and sometimes even layers of peat. The rich detritus produced by decaying leaves and wood provides the basis for new food chains that parallel or intertwine with normal food systems that begin with phytoplankton. The creation of physical habitats, especially the vast network of protected waterways, is of great importance for many small animals on the shallow continental shelf. Among the inhabitants of the mangroves, crabs are numerous. Oyster species and other bivalve species are also abundant in the lower, flooded areas, and a variety of gastropods attach themselves to trees above the intertidal zone, holding tighter in areas completely flooded with water. In open spaces among the roots of trees and above, in their crowns, various spiders weave their webs, sometimes reaching almost 2 m in diameter.

Fish from the family of mudskippers (Periophthalmidae) can be considered very characteristic inhabitants of mangroves. This family includes 3 genera and 10–12 species of small (with a body length of 10–27 cm) fish distributed in the tropical regions of the eastern Atlantic and Indian and western Indian Oceans. Mudskippers have a valky body and a large, round-browed head with retractable, bulging eyes. The bases of the pectoral fins of these fish are muscular, and the fins themselves are long and wide. Mudskippers live in the littoral, most often near the mouths of rivers, in calm bays and lagoons with a muddy bottom. They spend a significant part of their lives out of the water, staying on the shore at low tide. In addition to breathing through the gills, these fish are able to absorb oxygen directly from atmospheric air through the skin. The peculiar structure of the pectoral fins allows jumpers to move on land with fast jumps. They can also jump on the surface of the water without sinking to a depth, while the movement of the fish resembles a thrown pebble jumping on the water.

At low tide, mudskippers either sit quietly in water holes with their heads and pectoral fins out into the air, or actively hunt for small crabs and aerial insects. At the same time, they often climb onto snags and mangrove tops protruding from the water - clasping a thin branch with their pectoral fins and resting their tail, these fish can crawl to a rather large height (above human height). The ventral sucker allows jumpers to hold on to almost vertical tree trunks and rocks.

Mangrove crowns are often inhabited by typically terrestrial animals - parrots, monkeys, etc.

The formation of mangroves significantly affects the living conditions of bottom dwellers. Due to the abundance of organic residues in the soil here, already a few millimeters from the surface, there is no free oxygen. Where the parent rock is not formed by calcareous deposits, but consists of weathering products of volcanic rocks, a large volume of hard-to-destroy wood fibers leads to the formation of humus, humic acids and even peat in the silty soil. The consequence of this is the high acidity of soil water, and sometimes the water in the channels that cut through the mangroves. Since sea water is alkaline, water with a pH of 6 to 7 is a very unusual environment for marine animals. For example, for mollusks, this means difficulties in the formation of a calcareous shell.

The ecological group of decomposers of wood of mangrove trees includes the mollusk shipworm (teredo) and boring crustaceans (Sphaeroma) from the order of isopods. They begin the mangrove destruction cycle, which ends with marine fungi and bacteria. Without the activity of decomposers, the banks would be littered with a huge number of dead trees. Sometimes shipworms and crustaceans attack live mangrove trees. This promotes natural thinning of the thicket, keeps the waterways open within them, provides continuous access to nutrients, and prevents excessive accumulation of rotten trees.

Bulldozer - Apr 22nd, 2015

Amazing plant communities called mangrove forests have formed on the sea coasts of tropical and equatorial latitudes. The plants that form them, united by the common name mangroves, have adapted to life in the intertidal zone. The name most likely comes from the Malay "mangle", which translates as "trees growing in the sea."

Periodically flooded with water, mangroves raise only their crowns above its surface. Cold currents are considered one of the most important restrictions on the spread of mangroves to higher latitudes from the equator. These communities can be found in varying numbers on the coasts of New Zealand and Australia, and on the western coast of the South American continent, and on the African coasts.

Photo: mangrove forest
A large number of species (up to 30) are distinguished by eastern mangroves (the coast of the Indian and Pacific Oceans). Less rich (up to 4 species) in this regard are considered western mangroves (the coasts of the Atlantic and Pacific oceans).

Photo: heart-shaped mangrove lake in New Caledonia.
Plants growing in mangroves have adapted to unique habitat conditions. First of all, they are able to withstand high levels of salinity. And they are salt-tolerant plants. In the mangroves themselves, zoning of species distribution can be observed, since. some can tolerate the most severe salinity (such as the genus Avicennia), while others can grow in conditions whose salinity is not higher than that of sea water.

A few more photos of mangroves.

Helps plants and the presence of stilted or aerial roots. Mangrams have a special type of reproduction - viviparia or live birth. The essence of this method is the germination of seeds on the mother plant in not yet ripe fruits. A sprout with a root germ appears from the fruit. Upon reaching a length of 50-70 cm, the seedlings fall off and immediately attach to the muddy seabed.

Video: mangroves.

Mangrove forest Chanthaburi Thailand

Thailand - Krabi Longtail Trip. Wild monkeys in the mangroves

In the mangroves with a crocodile swiming with a crocodile

Normal trees grow on the ground and go down with their roots. At some point, the mangroves mixed everything up, and grow in the water, and the roots confidently run up to take a breath of air. In normal trees, the ecosystem is built around, because there are a lot of fallen leaves and soil nearby. Mangroves are spaceships for almost the entire biome- for example, the fauna tries to live in them, and not outside them. Therefore, there is no soil outside the tree and it is somehow wet.

And these very mangroves make the islands fertile.

But let's start with cloning coconuts. Or not, even since the appearance of the island as such. Or why it is more interesting for rain to flow on the islands, but not nearby.

And then in the middle of Lent, a branch of mangrove will sail to the island, and everything will spin.

How the island appears

I say right away - I am not a biologist or a geologist, so the whole story will be very simplified further. But then I ate a geologist with a biological education. So, the Philippines is the place where the edge of the tectonic plate falls. Everything boils and explodes. On the time scale of geology, of course. In practice, this means increased volcanic activity and many, many volcanic islands. As a rule, one or two or three volcanoes come out on the site of the future island, something spits out of them - and all this may seem above the water. The scale is millennia.

If it seemed - it turns out harvesting a tropical island - because there is no soil there. There is nothing to grow and nothing.

Further on the island begins to rain. Because due to small temperature inversions, it is more interesting for rain to fall on our workpiece than just into the ocean. At the same time, sand is washed in, so there is a lot of shallow water around the stone blocks - sand accumulates along the currents.

In total, thousands of such blanks appeared in the Philippines, and there are a few kilometers between them.

Then coconut travelers suddenly stumble upon the island. These devils regularly slide into the water and swim at their pleasure. Therefore, in Micronesia and Oceania, one can observe someone's head in the surf - these are not people overboard, but coconuts. Psychedelic sometimes add pop-up flip-flops and rubber duckies. The fact is that an incredible amount of garbage comes here (it seems from China), and there are even entire garbage clusters in the ocean. Plus, there is a story that somewhere in the northern seas a cargo ship with several containers of bath ducks capsized a long time ago, and now they swim all over the world. In general, sailors have many reasons to go crazy on a "dog" watch.

Coconuts hit the shore and begin to germinate in any dense substrate. They do it quickly, and can even grow right into a bunch of their fellow tribesmen who turned out to be less fortunate. As a result, the first palm tree with coconut is formed on the island.

Actually, a coconut needs to have a dad and a mom, like all normal plants. But when there is only one palm tree on the island, there is nothing to do - you have to multiply with what you have. Therefore, as a result of the combination of "female" and "male" inflorescences, a clone of the original palm tree is obtained. UPD: Meklon corrects that it turns out not a clone, but a child of two twins (there will be more or less recessive genes). Plus minor mutations from background radiation and replication errors. Pretty soon, the island looks like an army from Star Wars, plus a couple more traveling nuts sail up for a change. By the way, they are popular with the opposite sex.

Coconuts provide the soil and strengthen it, fix it. But this is not enough, because the island is still open to all winds. At this point, mangroves are involved in the case. As a rule, when the island is already planted with cloned palm trees, a piece of mangrove is washed ashore. Immediately with woodworms and other biome features that were imported using the "Shift-Del, Shift-Ins" method along with the tree.

At the time of arrival of the branch, it turns out something like this (this is far from a fresh island, but you can see from it both the part with the volcano, and the parts where there is where to strengthen, and the parts where the soil is washed off). By the way, when piloting a drone, one must remember that the islands are interesting for rain, in particular, because they slow down the wind. This means that flying over the “screen” from the rocks is an immediate chance to catch a big stream.

mangrove

Mangrove is very important to have salty, but not very salty and not very fresh water. Usual. No, there are mangroves that grow in salt water with concentrations higher than in the sea, but our Filipino friends prefer a stream and intertidal cocktail.

Those rains that poured onto the island from above formed puddles or lakes there, and then streams. These streams serve as mangrove sources fresh water.

Mangroves - these green "heaps" in the water and near the shore

Mangroves reproduce quite quickly (actually, there are a whole bunch of stages - there are special perimeter plants, there are internal ones, and so on, and it's better to read about this in some brutal biology textbook, since the biome is well studied) - skipping a long process. In the final, a grove is formed, which closes the island from two or three sides. As a rule, on the other sides there are impregnable rocks, where water simply does not drain. This is no accident because the mangroves fix the soil and shape the island to the end. That is, just as the island determines where the mangroves will grow, so the mangroves determine where there will be more soil and sand will be better fixed.

Mangrove house in Puerto Princesa

View from his veranda at night

And here fishermen hide from storms: the bay inside the island of Calabanbanyang is covered with mangroves:

The fact is that they protect against waves. Any strong wave enters the mangrove forest and starts to get confused. As a result of certain actions of worms and the movement of fresh water flows, mangroves naturally sit down in such a way that the waves begin to break into small ones, and then interfere with each other and cancel out.

Among other things, mangroves cannot grow too close due to air and light restrictions - at the level of the forest canopy it is already completely dark and scary.

Now pneumatophores. These are snorkels that rise vertically from the underground root. Plants use them to take in oxygen from environment. Avicennia (a type of mangrove in my photographs) can grow pneumatophores up to 30 centimeters in height - this is not enough, there are trees with breathing tubes of a couple of meters. But for one "my" adult mangrove of this particular species, there are up to 10 thousand such processes. "Brushes" at the bottom of the mangrove - this is it. The second way to breathe when you're in the intertidal zone is to let out roots on branches. Straight into the air.

Naturally, pneumatophores are not only found in mangroves.

On Puerto Princesa, 5 cm worms are eaten. I’m not sure about the locals, but they definitely sell “a super exotic dish that you must try” to tourists. I didn't risk it. At the beginning of the expedition, it is better to eat a friend. Yes, and I have already lived for several weeks in China, so I was definitely not surprised.

The locals boil the bark and tan the skin in the decoction. More small shoots go to beer.

Everything that is found in swamps also lives in mangroves. For example, snakes and mosquitoes (malarial mosquitoes, in particular). There is no vaccination against malaria, and the pathogen can also hide for many years in your liver, so when choosing a mangrove forest for an excursion, you should look at one where malaria cases have not been recorded for several years. When a mangrove dies, it is merrily decomposed by shellfish, and then by bacteria and fungi. A bunch of these mushrooms are compatible with humans. So if you're collecting samples (like we are), gloves are a must. Although, of course, all this does not prevent the locals from cutting down thickets. Ah, yes! Mangroves are very sensitive to the purity of water, so if you see thickets, know that there is most likely good ecology nearby. Not the fact that not seeking to kill you, but good.

Orchids of course

Extremely vicious ants

Another notable thing inside this whole brew is labyrinth fish. Labyrinth fish are, of course, cute dumb animals, but what is interesting for us is that they are presented in a wide range of types of respiratory systems. A journey through the wondrous world of the struggle for oxygen should begin with an article on Wiki about the labyrinth organ. In short, a crutch was attached to the fish, which allows you to go without water for several hours or days. But now she has to come up from time to time, because just in the water she can also suffocate.

But mudskippers are fish with elbows. Able to fall into suspended animation and climb walls on suction cups. Like the mangroves themselves, they got it mixed up somewhere.

Of course, monkeys. They sometimes even on small islands.

The journey through the links is worth starting, again, with Wiki, there is an excellent analysis. And yes, I have just told you in general terms only one specific type of mangrove forest that is found in the Philippines, and I have not gone through the whole variety of mangrove groves. And they are crazy cool.

UPD: Gorynych23 left a big one here

Such a restless sea greatly increases the tides.

Now imagine that the waves of a restless sea regularly crash on the vegetation growing on the shore, and it will become clear to us why many tree species cannot withstand the enormous pressure of salt water and cannot live near the sea. But in the process of evolution, a whole group tropical woody plants, which not only successfully withstand the pressure of giant waves, but also adapted to regular and prolonged flooding by the sea during high tide, have adapted to a kind of alternating existence either in sea salt water or in the air atmosphere during the period when the tidal wave recedes from low gently sloping coast. These amphibian trees are unusual both in appearance and in biological features that help them survive, survive in the coastal strip near the seas and oceans. The strongest, the most adapted survive such an existence.

An interesting group of woody plants that live along the gently sloping and muddy shores of the seas and form dense plantations here received the combined name - mangrove species, and the forests formed from these species began to be called mangrove forests, or simply mangroves, mangroves. Typically, such forests stretch in the tropical zone in a narrow coastal strip on the low, silty shores of bays, in lagoons, and in estuaries, where silt and sand are deposited. The mangrove group includes 24 species of tropical woody plants from 8 families.

Mangrove forests have a very peculiar appearance when they are flooded by the sea at high tide. If you look at them at this time from the sea, they look like a floating dense green mass. When the sea recedes from the coast, stunted and tall trees begin to stand out from the total mass with numerous curved aerial roots exposed after the water subsides. These are respiratory roots, which also serve as a support on unsteady, silty soil, which has poor aeration and is very poor in oxygen. Interestingly, adventitious respiratory (or, as they are called, "stilted") roots hang not only from the trunk, but also from the lower and even from the upper branches, and often the roots branch out, which makes the trees especially resistant to storms.

Being regularly and for quite a long time in salty sea water, mangroves not only successfully resist the force of waves and winds, but also fight against oversaturation of the plant organism with salts (mainly table salt). They also fight to increase the supply of oxygen, which is necessary for the roots, but difficult to obtain in the muddy soil.

Mangroves have a number of special adaptations for such a fight. It is for a better supply of oxygen to the plant that they have formed adventitious respiratory roots. These roots consist of loose tissue that supplies oxygen well to the root system. Such roots are different types have their own characteristics: in xylocarpus, the respiratory roots are creeping, in brugiera they have a very original cranked structure: horizontal roots first depart from the base of the trunk, on which high vertical knotty and clumsy cranked outgrowths are formed, sticking out of the ground. The lower part of such outgrowths immersed in the soil has many nutritious roots. Top part annually grows in height and is covered with a cork-like crust with numerous pores through which the roots are supplied with oxygen. Avicenna and synergy have a completely different structure of the root system - they have straight roots growing upwards.
The respiration of mangrove plants is also enhanced due to numerous respiratory slits - the so-called "lentils", which are clearly visible in the form of dashes in the bark of trunks, branches and adventitious roots. The intercellular space of "lentils" is in contact with the intercellular cavities of the internal tissues of wood, which allows, like the mechanism of leaf stomata, to carry out gas exchange in the plant.

Particularly interesting in mangroves are special adaptations for survival in salty sea water. Some species, such as Avicenna, have glands in the leaves that remove excess salts from the plant, while other species have a kind of salt filtration system in the roots, which ensures that already desalinated water is absorbed into the plant.

Available interesting features and in the structure of leaves: mangrove leaves are xeromorphic - they have special stomata on the lower surface of the leaf to release excess salts and increased osmotic pressure (more than 3 MPa). This allows mangroves to exist in an aquatic environment that is 10 times more salty than ordinary water. And mangrove forests have another amazing property: they successfully tolerate large fluctuations in the concentration of salts in the soil, caused by the fact that at low tide in the soil quickly drying out in the sun, the salt concentration rises sharply.

Mangroves also have amazing adaptations for reproduction in specific living conditions: their seeds are equipped with air cavities and can float in water for a long time, retaining the ability to germinate when they get into favorable conditions for this. Very common mangroves from the rhizophora family have hard, woody, single-seeded mangroves, and in some genera, for example, rhizophora, the ability to live birth (viviparia), i.e., to germinate a seed in a fruit still hanging on a tree, has appeared. It is interesting to observe the development of the rhizophora embryo: an elongated large embryo, having no dormant period, develops continuously and after 11-13 weeks of growth breaks the fetal wall and continues its further development outside the genital membrane. The mother trees of the rhizophora spiky have a very original appearance, when green spindle-shaped seedlings up to 1 m long hang in abundance on its branches. It is interesting that in some mangroves, for example, in species from the rhizophoraceae family, not only in leaves and roots, but also in seed tissues, there are special adaptations to reduce the salt concentration in the water entering the seed and reduce the osmotic pressure of solutions. The appearance of this ability in the seeds is due to the fact that during a long stay in sea water saturated with salts, despite the filtration of salts by the roots, their excess gradually accumulates in the plant tissues, and the process of desalination of the incoming water that occurs in the seed provides the seedlings with almost fresh water.

But let us continue our observations of the development of rhizophoral seedlings. The seedlings that escaped from the fruit shell remain on the tree for 30-39 weeks, and sometimes for a whole year. Then, breaking away from the fruit, the club-shaped seedlings fall and, under the influence of gravity, the thickened lower part sticks almost vertically into the silty soft soil. Once in moist soil, they continue to grow, developing the root system and trunk. If, on the other hand, the seedlings fall on dense dried soil, they can lie on its surface for a long time, and even after strong drying in the sun they do not lose their viability when favorable conditions appear, i.e., after watering. They describe a striking case when seedlings from the family Rhizophoraceae, which spent 52 days in the herbarium, that is, completely dried, after planting in moist soil, swelled and took root.

And another amazing feature of rhizophoral seedlings: carried away by sea waves, they can travel through the seas and oceans for up to a year, and they retain the ability to root when they enter moist soil. It is believed that this is why representatives of the rhizophora family are widely distributed on the sea coasts of many countries in the tropics and are one of the main components of mangrove forests.

Rhizophores and many other mangrove species are of comparatively little economic importance, although their wood is used for fuel and for the construction of piles, underwater and underground structures. Finds application and their bark, containing up to 40% tannins. However, the main value of mangrove species is not in their economic use as raw materials, but in the ability to grow on the sea low muddy coast and strengthen the shores of the seas. Thanks to mangroves, not only the coasts are preserved, but often there is an increase in the areas of coastal forests that appear on the soil prepared by mangrove species. Sometimes, after felling mangrove forests, people create rice plantations in their place.

What species are most characteristic of mangrove forests and what do they look like? The main educator of mangrove thickets, which determines their appearance, are representatives of the family Rhizophoraceae already familiar to us. Of this family, the most common and known are species from four genera: rhizophora, brugiera, ceriops and candelia. It is the species of these four genera that form the bulk of mangrove forests, although their species composition on the coasts of many countries is different.

Among the Rhizophore family there are not only stunted, but also tall trees, reaching 27-30 m. Tall species are found mainly in the mangrove forests of the Eastern Hemisphere. High-stemmed species include brugiera bare-root and hexagonal, as well as spiky rhizophora. Most of the species of the rhizophora genus, which gave the name to the family, are represented mainly by low trees. They usually grow on the sea side of mangrove forests and are the first to take on the blows of the sea waves and the pressure of the winds. They can be called pioneers in the settlement of the silty gently sloping coasts of the seas, since these plants are among the first to settle here and further than other species move towards the sea.
In addition to rhizophora, some types of avicenna (manawa, maori) from the verbena family are found as an admixture in mangrove thickets. In places of especially strong tides, the roots of Avicenna raise the trunks to a height of up to 5 m and form, as it were, a second tier, and in lower tier the smallest are located - canocarpuses, which grow in places completely flooded by the sea tide.

Where can we see mangrove forests? They grow in a narrow intermittent strip along the coast of the seas in the tropical zone, forming dense thickets on muddy gentle banks, in estuaries and lagoons in America and Africa, in Southeast Asia and Australia, on many islands, including Cuba and island of Madagascar, Philippines, Indonesia.

In Australia, mangrove forests are common along the northern coast, especially along the shores of the shallow Gulf of Carpentaria. Having sailed to the northern coast of Australia at low tide, you can clearly see Avicenna officinalis in the mangrove forests, towering on its stilted roots, and next to it you can find some types of rhizophora, ceriops, brugiera, exocarias. In some places, there are fragrant pandanus, nipa water palm and undersized horsetail casaurin, which the Australians call "coastal oak".

In India, mangrove forests grow in the floodplains and deltas of the Ganges, Brahmaputra, Godavari, but they are also found in the tidal zone of some gentle coasts. In Bangladesh, mangrove forests cover 0.5 million hectares and are typical of the coast of the Bay of Bengal and river deltas. In Sri Lanka and Burma, mangroves stretch in a strip along low-lying, muddy shores. In these and other countries of Southeast Asia, representatives of the same genera grow in mangrove forests mainly as in Australia, although there are differences in the species composition. In marshy places of the coast and estuaries, mangrove forests form Avicenna, Ceriops, Rhizophores, Brugiera. The nipa water palm tends to grow along the coast-facing edge of the mangroves; in drier places, date palms, exocarias, sinneration, and in some places geritiera, valued for its colorful, very hard and durable wood, are found.

In Vietnam, mangroves spread along the southern sea coast on an area of ​​​​about 300 thousand hectares, and more than 15 tree species can be found in them. Among them there are also avicennas, representatives of the rhizophoraceae family - brugiers and rhizophores (several species), the nipa water palm and other palms grow, including the prickly date palm. In Malaysia, as part of the mangrove forests, all the same representatives of the already listed genera, and it should only be noted that usually thickets of casaurin, low terminalia of catappa and calaphyllum stretch behind a strip of palm trees.

In Africa, groves of coconut palms are common along the sea coast, and mangrove forests grow along the silty gently sloping shores along the Atlantic Ocean, in which rhizophora is widely represented, forming either pure stands or mixed with Avicenna and Canocarpus.

In Brazil, mangroves are also characteristic of the Atlantic coast and are found at the mouth of the Amazon. They are characterized by kars mangrove - rhizophora, black mangrove - avicenna and the smallest white mangrove - canocarpus.

The composition of mangrove forests in all the countries that we mentally visited is almost similar. There are differences only in species and in the characteristics of their growth, which is determined by local specific growing conditions.

Acquaintance with the most interesting mangrove forests, consisting of amazing tree species - amphibian trees, whose trunks are either in sea salt water or in the air above the surface of muddy, salt-saturated soil, expanded our knowledge of the inexhaustible variety of adaptive features of plant organisms, with the help of which plants are able to both desalinate water and withstand, not bend or break under the pressure of heavy winds and mighty waves, and give viable offspring in extreme environmental conditions. At the same time, when we got acquainted with mangrove species, we realized that these plants are true allies of man, helping him to fight the sea elements that destroy the shores, and the swamping of the muddy shores. Mangroves are extremely interesting both for their morphological and biological features and the results of its activities on the coasts of the seas and oceans.

Having become acquainted with tropical plants that are not afraid of the seas and oceans, we will now try to find tree species that are not afraid of river water and exist in direct contact with rivers. Such species also feel good during the “high water” period, when the rivers overflow, and are able to settle in muddy estuaries and on swampy gently sloping river banks.
Tree species in the neighborhood of rivers grow in all countries where mighty and small rivers flow. Depending on the climate, the set of species that are not afraid of rivers changes, but the main properties characteristic of all these plants remain the same - successfully resist large spring floods, river floods, carrying fragments of ice floes in the water element, beating against trees growing in their path. Many of the species adjacent to rivers have the ability to establish themselves well in sandy or silty soil of gently sloping banks, swelling from excess water, with poor aeration and often supersaturated with nitrogenous substances. These conditions are somewhat similar to those of mangrove species, although they are in even more difficult conditions of growth in salt water.

What tree species successfully grow in the peculiar conditions created along the banks and in the mouths of rivers by continuous water flows? These species include mainly some representatives of three genera - poplar, alder and willow.

Have you ever sailed in a boat in early spring on the water surface above the floodplain flooded by the overflowing river?

Once we had to swim several kilometers in such water near Volgograd. The water was high from the spill, and our boat could hardly make its way among the green tops of the flooded trees: old willows - willows and poplars - sedges. We floated in some fantastic garden on the water. Here and there, in the silvery foliage, the tops of willows, or white willow, were visible, interspersed with the tops of osocor or poplar, and singly, trees of another type of willow stuck out - belotala, or three-stamen willow, with branches covered with young leaves.
The leaves of the willows gave off the foam that dripped on those who sailed in the boat. Foamed juice formed at the site of insect injections. Such a “weeping” of willow leaves is apparently associated with increased pressure in the vessels. Repulsive water rats dived among the thin white rootlets emerging in bunches from the thick willow trunks. Then, when the water subsides, these roots dry up and form a kind of dry “beards” that cover the trunks high above the ground, to the level of the rise of the spring overflowing waters of the river.

Trees struggling with the water element look pitiful. However, the willow tolerates the spring flood well and lives for many years. The willow, which forms adventitious roots in the form of “bearded moss” during the floods of the river, is called the “moss” willow by the locals. It is the ability of trees growing in floodplains to endure floods and form roots in any part of the stem that helps them live in peculiar, dramatically changing environmental conditions. The riverine strip with the coastal rampart is often completely occupied by willows, consisting of different types of willows. Willow thickets often reach a width of fifty meters and very well protect the banks from destruction, and floodplain meadows from sand drifts.

When you come every year to the same place in the river, it may seem that the thickets of willows near the river do not change much. However, it is not. They go through a cycle of development from a young thicket to full bloom and, finally, decrepitude and a new renewal after the ice drift. Somewhere in a quiet place on a sandbank rich in washed-out silt particles, pubescent willow seeds stick and germinate. This usually happens at the beginning of summer, as willow seeds ripen very quickly. In the same year, a continuous brush of seedlings appears about 30 cm high with a deepening of the central root in wet sand by 20-25 cm. Such seedlings of willow can be counted per 1 km of the river up to 50 thousand. . From the seedlings, dense young growths will grow in subsequent years, and when they are broken by an icebreaker or when cut into a rod, a continuous shoot appears.

This is how impenetrable thickets of willows appear. Riverside willows often grow in the form of bushes, but sometimes trees up to 5 m high are also formed. Usually such trees do not show off for long - they are broken by ice floes passing in the spring. And new growths grow from the stump, and the former appearance of willow thickets is restored.

On the banks of rivers and streams, in addition to willows, you can also find another tree species - alder. Its most common species - gray alder and black alder - are constant companions of large and small reservoirs.

Alder gray is very common in the central region of the European part of the Soviet Union. It is frost-resistant and unpretentious and goes to the tundra zone, and in the south - to the forest-steppe. In high places, it reaches a height of 15 m, and a diameter of 30 cm, but more often grows in the form of bushes along the banks of lakes, rivers, streams, forming dense thickets here. The seeds born in fruit cones in autumn fall into the water and are carried by water to new places along the banks of the rivers, and having got to high places with the help of birds, they successfully grow there.

The sister of gray alder - black alder - is a typical hygrophilous and, in addition, it is demanding on the richness of the soil. The whole nature of this plant is associated with a humid environment. Black alder grows along the banks of rivers and reservoirs, in marshy lowlands on watersheds, in narrow mountain valleys. It subtly reacts to various conditions of low places, but everywhere it requires flowing groundwater rich in salts and oxygen.

At present, the range of black alder resembles strongly branched narrow tentacles, stretching along a whole system of large and small rivers and streams, compressed by the vegetation of upland areas. These tentacles from the Baltic extend north to the Onega Sea and the upper reaches of the Kama River. In the east, alder barely reaches the Urals, but some of its islands are found in Siberia. However, the main massifs of black briers are concentrated in the Baltic lowland - in Russia, and in Poland, and in Germany. There are many of them in Belarus, especially in Polesie. Fast-growing black alder is found along the rivers in the Bryansk and Smolensk regions.

A large array of black alder can be found in a swampy area between two rivers - the Resseta, which flows from west to east and flows through a system of other rivers into the Oksky water basin of the Volga system, and the Snezhet river, which flows from east to west and flows into the Desna River of the Dnieper system . In some places, these two rivers flow at a distance of no more than 20 km, but although their path diverges in different directions, you can get from one river to another. by water along streams and canals. It is in this swampy area saturated with water channels that highly productive plantations of black alder grow.

An eighty-year-old alder forest here seems to consist of black columnar trunks with a diameter of up to 35 cm and a height equal to a nine-story house, amazingly straight, with sharp forks of black branches carried upwards, covered with dark green shiny foliage. The rays of the sun, reflected from their surface, create some kind of elusive play of light and shadows in this forest of slender giants. Only occasionally here you can see a modest birch or a lone spruce, and bushes of bird cherry, black currant and viburnum grow along the edges. They, like a variety of green screens, cover the bases of tall black alder trees. In places in the gaps sheltered curtains of willows, mainly a five-starred willow, and an ashy willow, hung with garlands of hops.

I would also like to tell you about one beautiful woody plant - bird cherry. It very generously frames many rivers and streams, forming pure thickets of seed or vegetative origin; occurs in the undergrowth of floodplain oak forests and forms on Southern Urals single trees up to 10 m high or their clumps. Cherry blossoms profusely in spring, and in autumn generously endows people with a rich harvest of black astringent, but nevertheless tasty juicy berries. Very thick bird cherry trees, planted in the middle of the 19th century by the writer A.K. Tolstoy, grow in an old park in the Bryansk region.

Thickets of bird cherry of predominantly vegetative origin can usually be found below the bank ridge, in depressions, and here they are especially dense and often go deep into the forest along the bank of the stream. Thickets of bird cherry can be formed from layering, stumps, and partly from thick roots. Bird cherry has an extraordinary rooting ability. Bird cherry branches lying on the ground are often covered with a layer of silt in the spring, and over time, growth appears in the form of young slender bird cherry trees from such underground outlets.

Solid thickets of bird cherry occupy large areas on the floodplains of rivers and streams. Sometimes it is possible to find in these thickets a highly located, but bent branch, forming an air layer - a “stilts”, covered with shoots directed upwards.

Before us are typical thickets of bird cherry, adapted to the peculiar conditions of the flooded floodplain of the river. L. N. Tolstoy wrote about the bird-cherry stooped branches-arcs, figuratively calling this phenomenon “this is how trees walk”. There are very interesting specimens of bird cherry, in which rooted branches thicken, when growing in the shade, they lose their leaves and the ability to bloom, and begin to serve as a support for a tilted trunk. Such supporting branches can be compared with the stilted roots of tree species of tropical and mangrove forests. There, supporting roots, or supporting roots, in the form of stilts or plank-shaped flat formations, are useful for plants, strengthening them with a variable water level and a superficial location of the main root system. These roots give stability to tropical trees, as do the supporting branches-stems of bird cherry.

This is how plants adapt to different environmental conditions in different ways. The arboreal mangrove species of the tropics have adapted well to life near the sea, opposing its elements and changing salt water levels, while other species grow well near freshwater rivers, withstanding their spring floods and increased soil moisture of river floodplains and swampy watersheds.

mangroves

View above and below the water at the edge of the mangroves.

Mangroves(or mangroves) - trees or shrubs that grow in coastal habitats or in mangroves (Hogarth, 1999), to which the term is also applied mangrove swamp. Mangrove plants inhabit coastal sedimentary environments where fine sediments, often high in organic matter, accumulate in areas protected from wave energy.

General information

Mangrove plants are a group of diverse plants that have been able to adapt to their habitat (littoral) because they have been able to develop a set of physiological adaptations to deal with the problems of poor oxygen content, salinity and frequent tidal flooding. Each species has its own capabilities and ways of dealing with these problems; this may be the main reason why, on some coasts, mangrove species exhibit distinct zoning due to differences in the range of ecological conditions in the intertidal zone. Because of this, the species composition at any point within the intertidal zone is partly determined by the stability certain types physical conditions such as tidal flooding and salinity, although other factors such as crabs predating their seedlings can also affect it.

Once established, the roots of mangrove plants create a habitat for oysters and help slow down the flow of water, thereby increasing sedimentation in areas where it is already occurring. As a rule, fine, oxygen-poor sediments under mangroves act as reservoirs for a wide variety of heavy metals (traces of metals) that are captured from sea water by colloidal particles in sediments. In parts of the world where mangroves have been destroyed by development, the disruption of these sediments is causing the problem of heavy metal contamination of seawater and local flora and fauna.

It is often claimed that mangroves are of significant value in the coastal zone, acting as a buffer against erosion, the onslaught of storms and tsunamis. Although there is a certain decrease in wave height and energy as sea water passes through mangroves, it must be recognized that mangroves usually grow in those areas. coastline, where low wave energy is the norm. Therefore, their ability to withstand the powerful onslaught of storms and tsunamis is limited. Their long-term impact on erosion rates is also likely to be limited. The many river channels meandering through the mangroves actively erode the mangroves on the outside of all the bends in the river, just as new mangroves appear on the inside of the same bends where the deposition takes place.

They also form a habitat for wildlife, including a number of commercially important fish and crustaceans, and, at least in some cases, mangrove carbon exports have importance in the coastal food web. In Vietnam, Thailand, the Philippines, and India, mangroves are cultivated in coastal areas for the benefits they provide to coastal fisheries and other uses. Despite ongoing mangrove programs, more than half of the world's mangroves have already been lost.

Biology of mangroves

red mangroves, Rhizophora sp..

Mangroves are a type of mangrove habitat. These are exclusively subtropics and tropics, where there are ebbs and flows, which means soil or sedimentary deposits supersaturated with water and saline or water of variable salinity. Mangrove areas include river estuaries and coastal areas. Mangrove habitat contains a wide variety of plant species, but "true" mangroves (which are almost exclusively found in mangrove habitat and rarely elsewhere) are about 54 species in 20 genera belonging to 16 families (Hogarth, 1999). Evolutionary convergence has led many species of these plants to find similar ways to deal with the problems of changing water salinity, tide levels (flooding), anaerobic soils and strong sunlight- Consequences of being in the tropics.

Low oxygen adaptation

Red mangroves, which live in the most flooded areas, raise themselves above the water level with stilted roots, and then can absorb air through pores in the bark (lentils). Black mangroves grow taller and produce many respiratory roots - pneumatophores (special root-like formations that stick up from the soil like breathing straws) covered with lentils. These respiratory roots reach a height of up to 30 cm, although in some species they are more than 3 meters long. There are 4 types of pneumatophores - supporting or stilted, breathing or tubular, cranked and tape or board-shaped. Articulated and banded pneumatophores can be combined with supporting roots at the base of the tree. To facilitate the transport of oxygen within the plant, the roots also contain loose parenchymal tissue (aerenchyma).

Salt restriction

Red mangroves prevent salt from entering through rather impenetrable roots that are heavily corked, acting as a super-filtration mechanism to keep sodium salts out of the plant. The water inside the plant shows that 90%, and in some cases of high salt content - up to 97%, salt has been eliminated by the roots. Any salt that accumulates in the shoots accumulates in the old leaves, which are then shed, as well as in the cell vesicles, where it cannot do any harm. White (or gray) mangroves can excrete salt directly due to the presence of two salt glands at the base of each leaf (hence their name - they are covered with white salt crystals).

Limiting moisture loss

Due to the lack of fresh water in the saline soils of the intertidal zone, mangroves have developed ways to limit the loss of moisture through the leaves. They can restrict the opening of their stomata (small pores on the leaf surface through which carbon dioxide and water vapor are exchanged during photosynthesis) and are also able to change the orientation of their leaves. By turning the leaves to avoid the harsh rays of the midday sun, mangroves reduce evaporation from the leaf surface.

Absorption of nutrients

The biggest problem for mangroves is nutrient uptake. Since the soil under mangroves is always saturated with water, there is little free oxygen in it. At these low oxygen levels, anaerobic bacteria release nitrogen gas, soluble iron, inorganic phosphates, sulfides, and methane, which contribute to mangroves' particularly strong odor and make the soil unfavorable for most plant development. Since the soil is poor in nutrients, mangroves have adapted to it by changing their roots. The stilted root system allows mangroves to obtain gaseous substances directly from the atmosphere, and various other nutrients, such as iron, from the soil. Quite often, they store gaseous substances directly in the roots so that they can be processed even when the roots are under water at high tide.

Increasing offspring survival

In such a harsh environment, mangroves have developed a special mechanism that helps their offspring survive. All mangroves have floating seeds adapted to disperse through water. Unlike most plants, whose seeds germinate in the soil, many mangroves (eg red mangrove) are "viviparous", that is, their seeds germinate before detaching from the tree. After germination, the seedling grows either inside the fruit (e.g., Aegialitis, Acanthus, Avicennia, aegiceras (Aegiceras)), or through the fetus to the outside (for example, rhizophora (Rhizophora), ceriops (Ceriops), bruguiera (Bruguiera), nypa), producing a seedling (seedling ready to separate) that can feed on its own through photosynthesis. After the seedling matures, it falls into the water, which can carry it over long distances. Seedlings are able to tolerate desiccation and remain dormant for weeks, months, or even more than a year until they reach a favorable environment. When the seedling is ready to take root, it changes its density in such a way that its elongated form now floats in the water not horizontally, but vertically. In this position, it is more likely that it will get stuck in the mud and take root. If the seedling does not take root, then it can change its density so that it sails away again in search of more favorable conditions.

mangrove ecosystems

Mangroves support unique ecosystems, especially on their complex root systems. In areas of permanent root submergence, mangroves can harbor a vast array of organisms, including algae, barnacles, oysters, sponges, and bryozoans, all of which require a solid substrate to which they attach when filtering food. Mangroves are a perfect buffer between a rough ocean and a vulnerable coast, especially during hurricanes that bring powerful storms to shores. The powerful root system of mangroves is quite effective in discharging wave energy. The same root system also prevents bank erosion. As tidal waters pass through the root system, they slow down so significantly that sedimentation occurs at rising tide, and the return current slows at low tide, preventing the smaller particles from being resuspended. As a result, mangroves are able to shape their own environment.

Types of mangroves

The following list (adapted from: Tomlinson, 1986 and modified) gives the number of mangrove species in each listed genus and plant family.

Main Components

Family	Genus, number of species
Acanthaceae (Acanthaceae)(syn. avicenniaceae (Avicenniaceae) or verbena (Verbenaceae))	Avicennia (Avicennia), 9
Combretaceae (Combretaceae)	Laguncularia (Laguncularia), 11; Lumnitzera (Lumnitzera), 2
Palms (Arecaceae)	bushy nipa (Nypa fruticans), 1
Rhizophoraceae (Rhizophoraceae)	Bruguiera (Bruguiera), 6; Ceriops (Ceriops), 2; Candelia (Kandelia), 1; Rhizophora (Rhizophora), 8
Sonneratiaceae (Sonneratiaceae)	Sonneratia (Sonneratia), 5

Less significant components

Family	Genus, number of species
Acanthaceae	Acanthus, 1; Bravaisia, 2
Bombacaceae	Camptostemon, 2
Cyperaceae	Fimbristylis, 1
Euphorbiaceae	Excoecaria, 2
Lythraceae	Pemphis, 1
Meliaceae	Xylocarpus, 2
Myrsinaceae (Myrsinaceae)	Aegiceras (Aegiceras), 2
Myrtle (Myrtaceae)	Osbornia, 1
Pellicieraceae	Pelliciera (Pelliciera), 1
Plumbaginaceae	Aegialitis, 2
Pteridaceae	Acrostichum, 3
rubiaceae	Scyphiphora, 1
Sterculiaceae	Heritiera, 3

Mangroves in the USA

Due to their sensitivity to sub-freezing temperatures, mangroves in the continental United States are confined to the coast of the Florida peninsula from Cape Canaveral in the east around small islands to Tampa Bay in the west. The mangroves of the Banana rivers are significant ( Banana) and Indian ( Indian) Brevard County ( Brevard County), as well as within the Center for Space Research. Kennedy.

Around the entrance to Port Everglades ( Port Everglades) and in Fort Lauderdale ( Fort Lauderdale) are several clusters of thickets of formerly much denser mangrove forest. Biscayne Bay ( Biscayne Bay) in Miami Dade County ( Miami Dade County) was previously densely framed by mangroves. From most of them, only separate thickets remained, however, on the Oleta River ( Oleta River), an estuary in northern Miami Dade County, has survived a fairly large patch of mangrove that is now a state recreation area. Extensive fringing mangroves survive in southern Biscayne Bay and Card Sound ( card sound), as well as downwind of most of the Florida Keys.

The southern tip of the Florida peninsula is flanked by the largest remaining mangrove in the continental United States. They cover the entire southern part of the Everglades National Park. This biotope extends from Card Sound in the west through southern Miami Dade County to Monroe Counties ( Monroe) and Collier ( Collier), including the Cape Sable area ( Cape Sable) and the Thousand Islands region to the west. This community also includes a number of almost exclusively mangrove-inhabited islets dotted across Florida Bay ( Florida Bay).

The mangrove community of small islands and the Everglades plays an important role as a breeding ground for the commercially important island shrimp. Other important species that feed or spend part of their life cycle in this habitat: tarpon, snook (robalo), sharptooth (yellow) shark, baleen nurse shark, snapper, spiny lobster, trout and elops. It is also the exclusive habitat of the American crocodile.

The west coast of Florida has several scattered mangroves in the estuaries of the Calusahachee River ( Calusahatchee) and Charlotte Harbor ( Charlotte Harbor). As well as on the east coast, they used to be much more extensive, but have become a victim of development. Significant accumulations of mangroves also occur in Sarasota Bay ( Sarasota Bay), Lemon Bay ( lemon bay), Anna Maria Bay ( Anna Maria Bay) and in the estuary of the Manati River ( Manatee River). The mangroves of Tampa Bay have also been reduced to small isolated stands.

Type of mangroves sonneracy, many pneumatophores are visible on the shore-facing edge of the reef surface on Yap Island.

Mangroves in other geographic regions

Mangroves are found in many places around the world, including the west coast of Costa Rica, the southern coast of Pakistan, many Caribbean islands, and interspersed with Madagascan dry deciduous forests. Mangroves grow in Iran - in the waters of the Persian Gulf near the coast of Hormozgan province, in the Ras Mohammed and Nabq nature reserves of Egypt.

Mangroves in a different environment

• Mangroves were used as a symbol in an essay by Annie Dillard Sojourner due to its importance as a self-sustaining biocenosis.

see also

• List of mangrove ecoregions
• mangrove crab

Literature

• Hogarth, P.J., 1999: The Biology of Mangroves, Oxford University Press (ISBN 0-19-850222-2).
• Thanikaimoni, G., 1986: Mangrove Palynology, UNDP/UNESCO and the French Institute of Pondicherry, 0073-8336 (E).
• Tomlinson, P.B., 1986: The Botany of Mangroves, Cambridge University Press.
• Jayatissa, L. P., Dahdouh-Guebas, F. & Koedam, N. (2002). A review of the floral composition and distribution of mangroves in Sri Lanka. Botanical Journal of the Linnean Society 138: 29-43.

Links

• Forests growing in the sea (features of mangrove biocenosis)
• History of the UNESCO Mangrove Program language
• Mapping coastal wetlands and coastline change at Pichavaram on the southeast coast of India using satellite data language
• Condition of India's Mangroves: Pollution Status of Pichawarama Mangroves, South East Coast of India language
• Mangrove Action Project language (Community Group for the Conservation, Restoration and Sustainable Management of Mangroves and Associated Coastal Ecosystems)