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 germinans
Black mangrove, Mangle negro
•Opposite, leathery leaves; yellowish to
dark green above, downy beneath with
salt glands
•pneumatophores
Laguncularia racemosa
White 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
ZONATION
MHW
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
ANIMALS ASSOCIATED
WITH RED MANGROVE
PROP ROOTS
• 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
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
Isopod
6%
Tanaid
4%
Amphipod
86% Bivalves
3%
Polychaete
1%
DOMINANT SPECIES
•Amphipods
Hyale plumulosa
Ericthonius brasiliensis
Parhyale fascigera
•Isopods
Sphaeroma terebrans
•Algae
Polysiphonia sp.
Anotrichium tenue
Bostrychia montagnei
Batophora oerstiddi
EFFECTS OF ALGAE
TRENDS IN INVERTEBRATE DENSITY
AND BIOMASS IN RELATION TO
ALGAL BIOMASS
5
4
3
2
1
0
-1
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
LAGUNA BOCA PAILA: PROPOSED FOOD WEB FOR R. MANGLE PROP ROOT COMMUNITY
Detritus Green algae Vaunthompsonia minor Phytoplankton Primary producer
Cyclaspis sp.
Mugil cephalus
Pachygrapsus gracilis Hyale plumulosa
Nereis pelagica Mytilopsis leucophaeata
Ericthonius brasiliensis
Ischadium recurvum
Nodolittorina lineolata Cassidinidea ovalis Copepods Ostracods Nematode
Littoraria angulifera Cyathura cubana
Macrobranchium Palaemonetes vulgaris Bathygobius mystacium
acanthurus Gobiosoma bosc
Lutjanus apodus Callinectes portunus
Concrete relationship
Sphoeroides testudinus
Inferred relationship
Eleotris pisonis
Sphyraena barracuda 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