mangrove forests
DESCRIPTION
Mangrove Forests. Worksheet (from supplemental reading in Nybakken)371-382 not 378-380 Text Reading 109-111 Video Questions “Creatures of the Mangrove”. Mangrove Forests. Found in coastal areas all over the tropics Primarily in brackish water salty and fresh mix - PowerPoint PPT PresentationTRANSCRIPT
James A. Danoff-Burg, Columbia University, [email protected]
Mangrove Forests
Worksheet (from supplemental reading in Nybakken)371-382 not 378-380Text Reading 109-111Video Questions “Creatures of the Mangrove”
James A. Danoff-Burg, Columbia University, [email protected]
Mangrove Forests
• Found in coastal areas all over the tropics
• Primarily in brackish water– salty and fresh mix
• Cover approximately 22 million hectares in tropical and subtropical coasts
James A. Danoff-Burg, Columbia University, [email protected]
Ecosystem Functions & Threats
• Serve as an important buffer between sea and land– Lessen impact of intense storms– Reduce erosion and increase sedimentation– Important coastal pioneer species– Act as basis for a complex, biologically diverse,
and productive ecosystem
• Increasingly threatened– Human development is most intense along
coasts
James A. Danoff-Burg, Columbia University, [email protected]
• Lives in/on salt water.
• Prop-roots provide air for the plant and shelter for small fish and other marine animals.
James A. Danoff-Burg, Columbia University, [email protected]
• Sand and silt causes the swamp to become more firm.
• This growth can continue until the island is big enough for people to take interest in it.
James A. Danoff-Burg, Columbia University, [email protected]
• Mangroves get cut down to allow for sandy beaches and waterfront real estate.
• This destroys habitats and is severely detrimental to fisheries.
• Little Palm Island and resort replaces its beaches yearly with imported sand to make up for erosion caused by replacing its mangroves with palm trees but is still getting smaller.
James A. Danoff-Burg, Columbia University, [email protected]
Mangroves
• Not a natural taxonomic group– Convergence among several groups
• Possibly 16 convergent events
– Based on physiological attributes– 54 species total world-wide
• 16 Families– Principally: Avicenniaceae & Rhizophoraceae– These two families include 25 spp.
• 20 Genera
James A. Danoff-Burg, Columbia University, [email protected]
Mangrove Location
• Found in tropical areas only– Within the 20ºC isocline– More southern on East side of continents
• Due to southward moving warm Equatorial currents there
James A. Danoff-Burg, Columbia University, [email protected]
Terminology(you have this from your reading so you
don’t have to write this)
• Mangal– Community of organisms in the mangrove
habitat
• Mangrove– Trees that flourish in the mangal
• Pneumatophore– Vertical root structures for air exchange
James A. Danoff-Burg, Columbia University, [email protected]
Characteristics of Mangal
• Inundation with tides• Increasing salinity towards ocean• Sandy clay soil
– Nutrient poor
• Nitrogen & Phosphorus are limiting– Limiting mangrove growth only
• Organic nutrients deposited via siltation– Fresh water streams & down-shore currents– Most all are of terrestrial origin
• In sum: Mangal is a harsh place to live
James A. Danoff-Burg, Columbia University, [email protected]
• Root networks catch more sand, silt, and mangrove seeds.
• This leads to dense patches.
James A. Danoff-Burg, Columbia University, [email protected]
Mangrove Adaptations
• Salt tolerance – Sequester in tissue (bark, stem, root)– Secrete through leaves– Exclusion by negative hydrostatic pressure
• Frequent inundation– Aerenchyma tissue & aerial roots
• Tolerant of soils low in oxygen– Hypoxic or anoxic
James A. Danoff-Burg, Columbia University, [email protected]
• Salt is directed to a few leaves that yellow and die.
James A. Danoff-Burg, Columbia University, [email protected]
Mangrove Pollination
• Pollination method varies by species– Wind (Rhizophora)– bat or hawk moth (Sonneratia)– birds and butterflies (Bruguiera)– bees (Acanthus, Aegiceras, Avicennia,
Excoecaria, Xylocarpus)– fruit flies (Nypa)– other small insects (Ceriops, Kandelia)
James A. Danoff-Burg, Columbia University, [email protected]
Mangrove Reproduction
• Vivipary normal– Reproduction and growth while still attached to
plant• Flowering• Fertilization• Propagule growth
Young propagule a.k.a. HypocotylHypocotyl
Mature propagule
James A. Danoff-Burg, Columbia University, [email protected]
• Seeds sprout while still on the trees.
• They are transported by currents and tides to other suitable locations.
• This allows them to start growing as soon as they hit a shallow spot.
James A. Danoff-Burg, Columbia University, [email protected]
Mangrove Dispersal
• Maturity -> Drop off maternal plant• Float horizontally initially
– Dispersal to novel environments ideally
• Float vertically with appropriate environmental conditions
• Rooting and growth
James A. Danoff-Burg, Columbia University, [email protected]
Mangrove Species Zonation
Bruguiera gymnorrhiza
Ceriops australis
Avicennia marina
Rhizophora stylosa
SalinitySalinityInundationInundation
Decreasing Soil StabilityDecreasing Soil StabilitySedimentation RateSedimentation Rate
All increase toward shoreAll increase toward shore
James A. Danoff-Burg, Columbia University, [email protected]
Most Common Species
• Red Mangrove (Rhizophora mangle)
• Black Mangrove (Avicennia germinans)
• White Mangrove(Laguncularia racemosa)
– All are found throughout tropics
James A. Danoff-Burg, Columbia University, [email protected]
Bark Identification
James A. Danoff-Burg, Columbia University, [email protected]
Tree Characters
James A. Danoff-Burg, Columbia University, [email protected]
Pneumatophores
James A. Danoff-Burg, Columbia University, [email protected]
Epiphytes
James A. Danoff-Burg, Columbia University, [email protected]
James A. Danoff-Burg, Columbia University, [email protected]
For more information
• Go to http://www.earthisland.org/map/mngec.htm and read the ecology link
• A clearinghouse on information on mangrove ecology is available at http://www.ncl.ac.uk/tcmweb/tcm/mglinks.htm