Tropical Shoreline Plants
Open BeachesDunesRocky ShoresMangrove Communities
Coccoloba uvifera
• Sandy seashores
• Grows 2m to 8m
• Small white flowers
Coccoloba uvifera
• up to 50 fruits on a single cluster
• gives appearance of a bunch of grapes
• “sea grape”
• edible pulp (jelly)
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Cocos nucifera
• Sandy seashores
• Grows to 30m
• Up to 100 years
• 1 - 2kg fruit
Cocos nucifera
• drupe • light and buoyant
• floats long distances in water • viable for a long time
• contains one seed• solid & liquid endosperm
Problems
• Salt water• Salt spray• High temperatures• Dryness
Adaptations
• Succulence - water storage• Thick cuticle - prevent water loss• Sunken stomata - prevent water loss• CAM metabolism - prevent water loss• Osmolytes - balance osmotic potential• Filtration - exclude salt• Salt glands - remove salt
Mangal
tropical shoreline community in which various species of MANGROVE are the dominant plant species
Mangals - Tropical Salt Marshes
•Mangal
• 80 + mostly unrelated plant species
• 23 - 28 C
• 60 - 70% of tropical shores
• high productivity - 900g C/m2/year• 50% exported to coastal zone
• Habitats support 1300 species of animalsHabitats support 1300 species of animals• 628 are mammals, birds, reptiles, fish and amphibians628 are mammals, birds, reptiles, fish and amphibians
World Mangrove Distribution
• planet has lost 33-50% of its mangrove planet has lost 33-50% of its mangrove forests over the last fifty yearsforests over the last fifty years
• urbanization, exploitation and sea level riseurbanization, exploitation and sea level rise
• The rate of loss of mangroves each year The rate of loss of mangroves each year tops the loss of the rainforest at 2.1%tops the loss of the rainforest at 2.1%
• At current rate of destruction, all the At current rate of destruction, all the world’s mangroves will disappear in 50 world’s mangroves will disappear in 50 yearsyears
Different tolerances to salt & flooding
Zonation & succession
Mangrove Succession - Red Mangrove - Rhizophora mangle
Red Mangrove - basis of community
1. Provide substrate for growth of other species
Red Mangrove - Tolerating Anaerobic Mud
Lenticels
Aerobic mud
Anaerobic mud
prop roots
lenticel
O2
O2
To proproot
[O2]
time
apply grease to root
48 h
Red Mangrove - Tolerating Anaerobic Mud
Red Mangrove - dealing with salt
• lacks glandular secretory structures
• salt in xylem sap 100 times less concentrated than in seawater
• excludes salt from entering the roots
• ultrafiltration in the cell membranes of roots
Red Mangrove - basis of community
2. Trap sediment and stabilize shore
Red Mangrove - basis of community
2. Trap sediment and stabilize shore
Black Mangrove (Avicenna) - second stage of succession
Aerobic
Anaerobic
Pneumatophores(air root)
Radial rootAnchor root
Structure of the Black Mangrove
Black Mangrove pneumatophores
Black Mangrove - Coping with salt
Salt secreting glands on leaf
(Final) Successional Stage - White Mangrove - Laguncularia racemosa
-least tolerant of salt and anaerobic muds - grows to 18m
Buttonwood - Conocarpus erectus
• 4 - 12m
• intolerant of salt
• used for charcoal
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Mangrove Succession and Zonation
Mangrove Reproduction - Red Mangrove
Wind Pollinated - viviparous - germinates on parent plant
propagule
Mangrove Reproduction - Black Mangrove
Wind Pollinated
propagule
Mangrove Reproduction - White Mangrove
Insect Pollinated
Mangrove Food Chain
Direct grazing by crabs
Leaf particles colonized by bacteria and fungi
Bacterial and fungal recolonization
fish
shrimp
Particulate organic matter
Small fish
Small crustacea
detritus
protozoa
bacteria
algae
Absorbed by sediment
Eaten by mud whelks
Dissolved organic substances
MANGROVE LEAF
algae