lecture 16 - mangals. mangal: a tropical shoreline community in which various species of mangrove...
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Lecture 16 -MANGALS
Mangal: a tropical shoreline community in which various species of MANGROVE are the dominant plant species
Conditions for Mangal Formation
1. Protection from strong wave action
2. Availability and accumulation of sediment
3. Periodic flooding by salt water
Mangal = Tropical Salt Marsh
Mangals - Tropical Salt Marshes
World Distribution
Mangrove Succession
Mangrove Succession -Red Mangrove - Rhizophora mangle
Tolerating Anaerobic Mud
Lenticels
Aerobic mud
Anaerobic mud
lenticel
O2
O2
To proproot
O2
Concentration
time
apply grease to root
48 h
Red Mangrove - basis of community
1. Provide substrate for growth of other species
Red Mangrove - basis of community
2. Trap sediment and stabilize shore
Black Mangrove (Avicenna) - second stage of succession
Aerobic mud
Anaerobic mud
Pneumatophores(air root)
Radial rootAnchor root
Structure of the Black Mangrove
Pneumatophores
Pneumatophores
Coping with salt
Salt secreting glands on leaf
Final Successional Stage - White Mangrove - Laguncularia racemosa
-least tolerant of salt and aerobic muds
Mangrove Succession and Zonation
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
1. Plant succession due to land building
- plant zonation - a successional sequence
But do mangroves cause different patterns of sediment deposition orjust respond to deposition?
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
2. Geomorphological influences
-mangroves response to changes in geomorphology but don’t cause them
Patterns depend on abiotic patterns of sediment deposition
1. Land building
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
3. Physico- Chemical Gradients
Two hypotheses
1. Land building2. Geomorphology
Gradient
Different optima for each species leads to zonation
a. Distinct preference
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
3. Physico- Chemical Gradients
Two hypotheses
1. Land building2. Geomorphology
b. No preference
Gradient
a. Distinct preference
Optimum range for all species
Zonation is determined by other factors (competition, predation)
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
3. Physico- Chemical Gradients
1. Land building2. Geomorphology
e.g. Tidal inundation
<10 ppt
35 ppt
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
3. Physico- Chemical Gradients
1. Land building2. Geomorphology
SeedlingSurvival (%)
100
50
0
Salinity
0 20 30 40 50 60 70 80
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
3. Physico- Chemical Gradients
1. Land building2. Geomorphology
Salinity
0 20 30 40 50 60 70 80
Ceriops tagal
Ceriops australis
Optimum salinity for germination - 15 ppt
(lab)
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
1. Land building2. Geomorphology3. Physico-chemical
4. Propagule dispersion
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
1. Land building2. Geomorphology3. Physico-chemical4. Propagule dispersion
5. Propagule predation
Grapsid crabs
Dominance 1/predation
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
1. Land building2. Geomorphology3. Physico-chemical4. Propagule dispersion
5. Propagule predation
Avicennia marina
Normal distribution
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
1. Land building2. Geomorphology3. Physico-chemical4. Propagule dispersion
5. Propagule predation
Normal distribution
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
1. Land building2. Geomorphology3. Physico-chemical4. Propagule dispersion
5. Propagule predation
Normal distribution
MANGROVE ZONATION PATTERNS
HYPOTHESES FOR ZONATION
1. Land building2. Geomorphology3. Physico-chemical4. Propagule dispersion5. Propagule predation
6. Competition
?
MANGROVE ZONATION PATTERNS
Structure of Mangroves
MANGROVES AS NURSERIESLutjanus griseus(Gray snapper)
Spawn on ocean side of
reef
Postlarva moves to Thalassia beds
Juveniles live in mangroves & move to Thalassia at night
to feed
Mangrove Reproduction - Red Mangrove
Wind Pollinated
Mangrove Reproduction - Black Mangrove
Wind Pollinated
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
prawn
Particulate organic matter
Small fish
Small crustacea
detritus
protozoa
bacteria
algae
Absorbed by sediment
Eaten by mud whelks
Dissolved organic substances
MANGROVE LEAF
algae
Hurricanes and Mangroves
Hurricanes and Mangroves
Hurricanes and Mangroves
Hurricanes and Mangroves
Hurricanes and Mangroves
Costanza et al, 2008. AMBIO 37(4):241-248.