MANGROVES OR MANGAL

• “Rainforest by the Sea”• Associations of halophytic trees,

shrubs or other plants growing in brackish to saline water

• Found on tropical and subtropical coastlines

• Inundated daily with sea water but protected from heavy waves

• Limited by frost

ADAPTATIONS

• Salinity Control – salt exclusion or secretion

• Viviparous seedlings

• Prop roots and pneumatophores

SALINITY

• Facultative halophytes – found over a wide range of salinity; 10-60 ppt

• Competitive advantage over freshwater species

• Survive wide annual fluctuations

MANGROVE COMMUNITY TYPES

Fringe Mangroves

•Overwash island

•Shoreline

Rhizophora mangle Red Mangrove, Mangle Rojo

•Opposite, evergreen leaves & white flowers•Prop roots – grounded and ungrounded•Viviparous

Avicennia germinansBlack mangrove, Mangle negro

•Opposite, leathery leaves; yellowish to dark green above, downy beneath with salt glands •pneumatophores

Laguncularia racemosaWhite mangrove, Mangle blanco

•Leathery, opposite leaves with rounded tips and 2 salt glands on petiole

Conocarpus erectus Buttonwood, Mangle de botón

•Leaves alternate, elliptical, with a row of salt glands along the rachis

Rhizophora

mangle

Avicennia germ

inans

Laguncularia ra

cemosa

Conocarpus ere

ctus

MHW

ZONATION

SUCCESSION

• Peat accumulation balanced by tidal export, fire and hurricanes

• Advance and retreat of zones according to the fall or rise of sea level

• Stressed or youthful ecosystems– Slowed or arrested succession– Low diversity– Open nutrient cycles

FACTORS CONTROLLING PRIMARY PRODUCTIVITY

• Tides and water chemistry intertwined– Transport of oxygen to roots– Removal of toxins and salt from pore

water– Control of sediment accumulation– Regeneration of nutrients lost from root

zone

• Water chemistry alone– Pore water salinity– Concentration of nutrients

ORGANIC EXPORT

• 50% of productivity exported as detritus

• May supply as much as 52% of the fixed carbon available for secondary productivity

• Detritus primary food source to invertebrates and forage fish

• Roots provide nursery areas and solid substrate

• Proximity to and extent of exchange between coastal waters, especially coral reefs

• Presence or absence of algae• Tidal amplitude• Competitive interactions• Predation, particularly intraguild predation

ANIMALS ASSOCIATED WITH RED MANGROVE

PROP ROOTS

http://jrscience.wcp.muohio.edu/html/tropecoimages.html#Anchor-mangroves

GENERAL FAUNAL TYPES

• Adjacent to coral reefs, e.g. Carrie Bow Cay, Belize– Sponges, tunicates, hydroids,

anemones, polychaetes

• Isolated from reefs– Isopods, barnacles, molluscs,

algae, amphipods

Laguna Boca Paila

•Water very clear

• Bottom either covered with Halodule wrightii, Ruppia sp., or leaf litter, otherwise sand/shell

• Tree heights 10-22 ft.

• Protected embayment with only a small inlet to Caribbean

ABUNDANCES OF HIGHER TAXA

Bivalves3%

Polychaete1%

Amphipod86%

Tanaid4%

Isopod6%

DOMINANT SPECIES

•Isopods

Sphaeroma terebrans

•Amphipods

Hyale plumulosa

Ericthonius brasiliensis

Parhyale fascigera

•Algae

Polysiphonia sp.

Anotrichium tenue

Bostrychia montagnei

Batophora oerstiddi

EFFECTS OF ALGAE

TRENDS IN INVERTEBRATE DENSITY AND BIOMASS IN RELATION TO

ALGAL BIOMASS

-1012345

Invertebrate Density (ind./100cm2) in hundreds

Invertebrate Biomass (g/100cm2)

Algal Biomass (g/100cm2)

ALGAE-DOMINATED ROOT

Many small, motile invertebrates, especially amphipods•Low diversity•High abundance

BARE ROOTS

•Boring isopods & bivalves•Balanoid barnacles•Low diversity •Low abundance

Nematode

Sphyraena barracuda

Callinectes portunus

Eleotris pisonis

Sphoeroides testudinus

Lutjanus apodus

Palaemonetes vulgarisMacrobranchium acanthurus

Nodolittorina lineolata

Littoraria angulifera

Cassidinidea ovalis

Cyathura cubana

Copepods Ostracods

Bathygobius mystacium

Gobiosoma bosc

Mugil cephalus

Mytilopsis leucophaeata

Ischadium recurvum

Hyale plumulosa

Ericthonius brasiliensisNereis pelagica

Pachygrapsus gracilis

Detritus PhytoplanktonVaunthompsonia minor

Cyclaspis sp.

LAGUNA BOCA PAILA: PROPOSED FOOD WEB FOR R. MANGLE PROP ROOT COMMUNITY

Concrete relationship

Inferred relationship

Green algae Primary producer

Terminal carnivore

INTRAGUILD PREDATION

• Common in communities with many interference competitors

• Typical in mangrove prop root communities

• Defined as killing and eating of competitors

• Interference competitors at Laguna Boca Paila:– Lutjanus-Callinectes– Sphyraena-Lutjanus– Palaemonetes-Bathygobius

BIRDS

FISH

IMPORTANCE TO LOCAL COMMUNITIES

• Traditionally managed by local communities– Food, medicine, tannins, fuel

wood, construction materials– Sustainable, dependable, cultural

• Minimize property damage & deaths due to tropical weather

• Useful for treating effluent

CONSERVATION ISSUES

• Among the most threatened habitats in the world– Coastal development may result

in long-term exposure or flooding– Timber & charcoal industries– Expanding shrimp aquaculture

• Considered wastelands or useless swamps