tropical shoreline plants open beaches dunes rocky shores mangrove communities

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