IntroductionIntroductionThis information package will describe:

• What mangroves are;• Their geographic distribution;• How mangroves are unique;• The special adaptions they possess;• Why mangroves are important;• The different mangrove types presents in the Sian Ka’an

Biosphere; • Threats to mangroves;• Why mangroves need to be conserved; and• What work is currently being done to protect mangroves.

What are What are Mangroves?Mangroves?Mangroves are tree species which form valuable ecosystems along sheltered tropical and subtropical coastal environments.

Typical mangrove habitats are periodically subjected to tidal influences, including inundation by salt water. The first explorers described mangroves as “forests of the sea”.

Mangroves display amazing physiological, reproductive and structural features which enable them to live in these challenging conditions.

DistributionDistribution

Mangroves exist in four continents, covering an estimated 16,530,000 hectares (approximately 40 million acres). Caribbean and Latin American mangroves account for 35% or 5.8 million hectares.

The greatest expanse of mangroves, in the Americas, are found in Brazil with 2.5 million ha and in Mexico with 660,000 ha (this being nearly equivalent to the entire area of the Sian Ka’an Reserve).

Fuente: www.ramsar.org

• Mangroves are special because they can colonize and thrive in areas where most normal plants would die.

• Mangroves are tolerant of the high levels of salt found in coastal environments.

• Mangroves can tolerate flooding and water logged soils.

• Mangrove forests support extremely high biodiversity levels through the provision of nutrients and habitat.

• Mangroves are excellent coastal stabilizers and provide essential protection against extreme weather events.

Why are Mangroves Why are Mangroves Unique?Unique?

Salt Excretion and Salt Excretion and ExclusionExclusion

• Mangroves do not need salt to live, but unlike many other plants, they can tolerate living in salty environments.

• Mangroves have special physiological adaptations which enable them to minimize salt uptake and get rid of excess salt.

• Concentrated salt can be excreted through specialized pores in their leaves. Salt crystals are easily visible on the leaves of the Black Mangrove.

• Salt can also be stored in older leaves which can be dropped at a later stage. Similarly salt can be stored in bark and stems.

Pneumatophores Pneumatophores “Mangrove Snorkels”“Mangrove Snorkels”

• All plants require oxygen to “breathe”. Oxygen uptake through plant roots is an important part of cellular respiration.

• Normally this gas would be available to plants in the tiny spaces (interstitial spaces) which exist between soil particles underground. However, when soil is flooded or water logged, oxygen is no longer available .

• Pneumatophores are specialized roots which function as snorkels for mangroves. They grow upwards from underground cable roots, to appear above ground as pencil–like structures.

Both the Black (pictured above) and White mangroves have pneumatophores

Special AdaptationsSpecial AdaptationsStabilizing Root StructuresStabilizing Root Structures

• Mangroves are often subjected to flooding, water logged soils and wave action.

• Mangroves have developed extensive under and above ground root systems, made of dense wood, which help them to remain anchored and upright in these challenging conditions.

• The stilt roots of the Red Mangrove (left) are an example of this adaptation.

Special Adaptations - Special Adaptations - ViviparyVivipary

1.1. The Red Mangrove has white flowers which form in bright green The Red Mangrove has white flowers which form in bright green calyx. calyx.

2.2. Following pollination the seeds germinate while still on the tree to Following pollination the seeds germinate while still on the tree to form propagules. This process is known as vivipary. form propagules. This process is known as vivipary.

3.3. Developing propagules are bouyant which enables them to travel Developing propagules are bouyant which enables them to travel great distances.To begin with propagules float horizontally.great distances.To begin with propagules float horizontally.

4.4. While in the water propagules gradually absorb water, which While in the water propagules gradually absorb water, which alters the centre of gravity. The propagules begin to float alters the centre of gravity. The propagules begin to float vertically.vertically.

5.5. As soon as possible the propagule will attach to suitable As soon as possible the propagule will attach to suitable substrate.substrate.

6.6. Roots and leaves begin to develop.Roots and leaves begin to develop.7.7. If conditions are suitable the propagule will rapidly develop to If conditions are suitable the propagule will rapidly develop to

secure itself. secure itself. 8.8. Once one plant has established, additional plants can begin to Once one plant has established, additional plants can begin to

establish by using accumulated sediment. This is how islands can establish by using accumulated sediment. This is how islands can form.form.

Special Special AdaptationsAdaptations

ColonizationColonization• The Red Mangrove has the ability to both colonise new areas of land

and create new areas of land.

• Numerous large, bouyant propagules are produced and dispersed.

• Once the propagules become anchored they quickly establish.

• As the Red Mangrove’s intertwined root system develops it functions as a net, catching passing propagules.

• Once caught more trees develop, and so the process continues.

Mangroves are important for ecological, economic and cultural reasons, these include:

• The high level of productivity which forms the basis for a complex marine food web;

• Providing refuge, breeding and feeding grounds for both terrestrial and marine species;

• Protecting coral reefs from sedimentation and pollution;

• Providing valuable input into the Mexican economy through ecotourism and commercial and recreational fishing industries;

• Providing protection to coastal ecosystems and development against major storm events; and

• Mangroves remain culturally important to the Mayan people.

Why are Why are Mangroves Mangroves

Important?Important?

High BiodiversityHigh Biodiversity

• The word biodiversity is made up from the two words ‘biological’ and ‘diversity’.

• Biodiversity refers to all the species within and ecosystem and can therefore be used as a measure of the variety of life.

•The high level of productivity associated with mangrove ecosystems support complex plant habitats which in turn support a high number of terrestrial and aquatic animal species, including fish, mammals, reptiles and birds.

High High ProductivityProductivity

• Productivity is term used by scientists to describe the ecological value of a vegetation community.

• The productivity of mangrove communities is high in comparison to many other plant communities.

• It is the high productivity of mangrove communities which make them such an important part of the marine food web.

The Food WebThe Food Web•When mangrove leaves drop, they enter into a process of constant nutrient cycling.

•Microorganisms and bacteria begin to break down the organic matter.

•The tiny particles which are formed can then be consumed by small herbivorous marine animals.

•These animals are in turn consumed by larger animals such as fish and crustaceans.

Mangrove leaf litter

Eaten by carnivorous

and omnivorous

marine animals

Eaten by herbivorous

marine organisms

Protein rich organic debris

Microbial activity

•Mammals, reptiles and birds then prey on these animals, which may eventually be eaten by even larger predators such as crocodiles.

Which Animals Which Animals Live in the Live in the Mangroves?Mangroves?

A wide variety of animal species are dependent on the mangrove ecosystems of Sian Ka’an.

Reptiles, Mammals and Reptiles, Mammals and BirdsBirds

Sian Ka’an provides vital habitat and food resources for both local and migratory bird species. Cormorants, frigate birds, pelicans, herons and egrets are all commonly found in Sian Ka’an Biosphere Reserve.

Central American mangrove ecosystems are home to many different types of mammals including coatis, raccoons and bats.

Many species of reptiles, including iguanas, crocodiles and turtles , inhabitat coastal mangrove ecosystems.

FishFish

• Many fish, including commercially viable species, are dependent on mangrove ecosystems.

• The often submerged root systems of the mangroves provide essential shelter and food resources to many fish species, particularly during juvenile life stages.

• Species commonly found in the tidal zones during high tide inlcude barracudas, snappers and pipe fish.

InvertebratesInvertebrates

• Invertebrates are animals which do not have backbones. Instead they have tough external skeletons.

• invertebrate species constitute an integral part of the mangrove ecosystem, and are indeed dominant in the arboreal regions of the ecosystem.

• Examples of invertebrates found in the mangroves include crabs, molluscs, termites, ants and dragonflies.

Arboreal TermitesArboreal Termites• Arboreal (or tree dwelling) termites create large black or brown

nests which can be easily identified in the Sian Ka’an Reserve.

• The nests are made out of “carton” - wood which has been chewed by termites and cemented together. Worker termites are responsible for both construction and nest repairs.

• In addition to worker termites each nest has soldiers, which guard the nest. A king and queen are responsible for reproduction.

• Termites generally feed on rotting plant material and dead wood.

Relationships with Coral Relationships with Coral ReefsReefs

• Mangroves play a very important role in protecting the delicate coral reefs which surround the Yucatan Peninsular.

• The millions of tiny polyps which form coral reef are extremely sensitive to sediment loadings and pollution. Polyp dieback results in dramatic biodiversity reduction in reef communities.

• The complex root systems of mangroves communities act as large filters.

• Physically the roots are able to trap large volumes of sediment and silt which could potentially smother the reefs.

Physiologically mangroves are able to take up large quantities of nutrients and pollutants, thereby reducing the impact of these on ocean water quality and reef ecosystems.

EcotourismEcotourism

• The unique mangrove ecosystems, such as those found in Sian Ka’an are visited by tourists from all over the world.

• Each year the increasing number of visitors increases employment opportunities and brings valuable tourism dollars to the Yucatan area.

The Commercial The Commercial Fishing IndustryFishing Industry

• As previously mentioned mangrove ecosystems provide vital breeding grounds and refuge for many fish species. Many of these fish species are important food sources for people. Caught fish is both exported and consumed in Mexico.

• Commercially viable marine species which are dependent on magrove ecosystems include snapper and mahi mahi.

• Recreational fishing is also important economically as it is a major tourist attraction.

Coastal Stabilization Coastal Stabilization and Protectionand Protection

• Mangroves are the best natural defence we have against storm events and hurricanes.

• Their complex interlinked root sytems protect shorelines and coastal development from coastal erosion by reducing the impacts of currents, waves and wind.

• This function is important both ecological and economically.

Mangroves Mangroves in Sian Ka’anin Sian Ka’an

In the Sian Ka’an Biosphere Reserve there are four species of mangrove:

•The Red Mangrove (Rizophora mangle)

•The Black Mangrove (Avicennia germinans)

•The White Mangrove (Laguncularia racemosa)

•The Gray Mangrove o Botoncillo (Conocarpus erectus )

Mangrove ZonationMangrove Zonation• Mangrove communities are often

naturally sorted into zones which run approximately parallel to the coast.

• Each zone is likely to be dominated by the species of tree best adapted to the particular conditions of that area.

• Factors which influence where a particular species dominates include the concentration of salt, the frequency of inundation, the intensity of wave action, the level of seed predation by animals such as crabs and propagule and seed characteristics.

• The diagram illustrates the zonation pattern found in Sian Ka’an.

The Red The Red MangroveMangrove

•Scientific name: Rizophora mangle•Mayan name: Xtapche’

Red mangroves are easily recognized by the downward arching prop roots which originate from the trunk and lower branches.

These stilt or prop roots enable these trees to secure themselves in tidal regions which are often subjected to wave action and flooding. The roots also function in gas exchange.

Rhizophora species are able to actively reduce salt uptake by their roots. Salt which is absorbed is stored in leaves until they can be dropped.

The large viviparous propagules of the Red Mangrove enable this species to reproduce and colonize new areas despite challenging conditions.

Why is the Why is the Water Red?Water Red?

Have you ever noticed that the water in mangrove areas has a reddish colour, particularly after rains?

Beh-Ha (Water Road) at the Sian Ka’an Biosphere Reserve.

The Black The Black MangroveMangrove

Scientific name: Avicennia germinans.Mayan name: Taabche’

•The flowers of the black mangrove are yellow and have a scent similar to honey, which attracts insects. Like many other plants, Avicennia sp. are dependent upon insects to pollinate their flowers for reproduction. This type of relationship is called symbiotic mutualism, where each species involved benefits the other.

•Avicennia species concenrate salt which is taken up by the root system, then secrete it from their leaves. Salt crystals may be visible on both sides of the leaves.

•The Black Mangrove has many pnuematophores which assist the tree with cellular respiration when soil is water logged or flooded.

•The black coloured bark at the base of the leaves gives this mangrove its common name

The Gray The Gray Mangrove Mangrove

o Botoncilloo BotoncilloScientific name: Conocarpus erectus Mayan name: Kanche’

•This is the only species of mangrove i n the Sian Ka’an reserve which does not have aerial roots of any kind. It is possible that this adaptation is not necessary, as this species is generally found the furthest inland of the four species.

•Seeds are produced in small bunches or ‘botoncillos”, this accounting for the alternative common name which translates to Buttonwood.

•The leaves can be easily distinguished from those of other mangroves by the two glands present on the stem at the base of the leaf.

•On the underside of the leaf along the central vein are pairs of small pores called “Domacios”.

•While the exact function of these pores is unknown, it is thought that they originate from a type of symbiotic relationship between the tree and algae and bacteria.

The White The White MangroveMangrove

Scientific name: Laguncularia racemosa. Mayan name: Sak-olhom

•The White Mangrove uses many pneumatophores for the purpose of aerial respiration. These pneumatophores are generally shorter than those of the Black Mangrove.

•El mangle blanco, además de las raíces convencionales, tiene en el tronco y las ramas unas pequeñas raíces aéreas especializadas similares a “hongos leñosos”.

•The Mayan people traditionally use the White Mangrove for medicinal purposes. The bark has astringent properties and ....

•En la medicina tradicional (herbolaria maya) se usa en casos de disentería y fiebre. La corteza tiene propiedades astringentes.

EpiphytesEpiphytes• Epiphytes are plants which are dependent on another

plant, usually a tree, for growing space and support.

• Water necessary for the plants survival is actually collected from the humidity in the air.

• Epiphytes do not parasitize their host. They collect their own nutrients from tiny pieces of debris in the air. Eventually plant material, dust and soil accumulate at the base of the epiphyte, and the plant can become rooted.

• This type of biological relationship is known as commensalism. It is an excellent example of relationships which exist between organisms within an ecosystem.

• Epiphytic species of plants are most common in cloud and wet forest systems where fresh water is plentiful. It is for this reason that the species found in the Sian Ka’an Biosphere Reserve are unusual, they have adapted to life in an area where fresh water is not always readily available.

EpiphytesEpiphytes BromeliadsBromeliads

• Bromeliads are also known as plants of the pineapple family.

• Water and dissolved organic compounds are absorbed through the bromeliads leaves.

• The sheathing shape of the leaves enables rain and organic debris to accumulate at the base of the plant where it can be absorbed.

• These tiny freshwater pools often form a microenvironment used by other plants and animals.

EpiphytesEpiphytes CactusCactus

Cacti are well known as plants capable of withstanding long periods of drought.

Their fleshy stems serve as important water reservoirs when freshwater is scarce.

The epidermis (skin) of the cactus is tough and thick, so water loss though evapotranspiration can be reduced.

The spines on the stem of the cactus can help to promote the formation of dew.

EpiphyteEpiphytess

OrchidsOrchidsOrchids are capable of nutrient and water absorption through aerial roots.

Epiphytic orchids have a bulbous stem, thickened at the base, which is capable of storing water.

Threats to Threats to Mangrove EcosystemsMangrove Ecosystems

• Unfortunately mangrove ecosystems all over the world have been negatively impacted by coastal development.

• Vast tracts of mangrove ecosystems have been cleared or reclaimed to facilitate developments such as hotels, marinas and residential estates.

• Additionally mangroves continue to be impacted by pollutants such as sewage, industrial and agricultural chemicals, rubbish and sediment.

Why Should we Why Should we Conserve Mangroves?Conserve Mangroves?

It should now be clear that mangrove ecosystems are a very important part of the coastal environment. They are productive systems with extremely high levels of biodiviersity, upon which many plant and animal species are dependent.

Mangroves are also very important for Mexico in terms of ecotourism, commercial fishing and mayan culture.

It is essential that our mangroves ecosystems are protected for future generations to experience and enjoy.

What is Being Done?What is Being Done?Sian Ka’an Biosphere ReserveSian Ka’an Biosphere Reserve

• In January, 1986 Sian Ka’an became a dedicated biosphere reserve and in 1997 was declared a UNESCO World Heritage Site.

• Conservation, environmental education, ecological research, and ecotourism are the main priorities of the reserve.

• The reserve continues to work with local people to reduce the negative impacts associated with non sustainable fishing and forestry industries.

• Financial backing and support is dependent on non-government organizations and donations.

• If you would like to learn more about the amazing mangrove ecosystems found in the Yucatan Pennisular please contact........

Do you want to know Do you want to know more?more?

·Instituto Nacional de Ecologíawww.ine.gob.mx/

•Comisión nacional para el conocimiento y uso de la biodiversidadwww.conabio.gob.mx

•Atlas of Florida Vascular Plantswww.plantatlas.usf.edu/main.asp?plantID=3926

·USDA: Plants Profile.plants.usda.gov/cgi_bin/plant_profile.cgi?symbol=RHMA2#wetland

Ramsar convention for the international protection of the wetlandswww.ramsar.com

Los humedales, un mundo olvidado.Juan José Morales.Amigos de Sian Ka’an

http://www3.cibnor.mx/conserv/mangrove/emang.htmlCentro de Investigaciones Biológicas del Noroeste SC.