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Mangrove Forests

Mangrove Forests. Dr. James A. Danoff-Burg Columbia University. 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. Ecosystem Functions & Threats.

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Mangrove Forests

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  1. Mangrove Forests Dr. James A. Danoff-Burg Columbia University James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  2. 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, jd363@columbia.edu

  3. 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, jd363@columbia.edu

  4. 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, jd363@columbia.edu

  5. 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, jd363@columbia.edu

  6. Terminology • Mangal • Community of organisms in the mangrove habitat • Mangrove • Trees that flourish in the mangal • Pneumatophore • Vertical root structures for air exchange • Lenticels - tiny pores for air exchange • Aerenchyma – tissue for air storage James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  7. 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, jd363@columbia.edu

  8. 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, jd363@columbia.edu

  9. Mangrove Consequences of Adaptations • Greater root mass • Relative to rest of plant & relative to non-mangrove species • For water exchange & air exchange • Lower growth rates • Consequence of salt & air exchange • Tradeoff between salt tolerance & frequent inundation • Can adapt for one or other • Not both James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  10. 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, jd363@columbia.edu

  11. Mangrove Reproduction • Vivipary normal • Reproduction and growth while still attached to plant • Flowering • Fertilization • Propagule growth Mature propagule Young propagule a.k.a. Hypocotyl James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  12. 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, jd363@columbia.edu

  13. Mangal Habitat Types (from inland to oceanfront) • Riverine • Often found in river deltas • Constant influx of freshwater • Great changes in salinity levels • Basin Mangroves • Inland, behind coastal mangroves • Little change in tides, no wave action • Often higher salinity than others (evaporation) • Tide-Dominated • Coastal front habitats • Frequent sedimentation • Unstable morphology due to coastal erosion James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  14. Intraspecific Differences in Environmental Tolerances • Salinity variations and adaptations for excreting salt • Varies within and between species • Through growth stages • Tidal Inundation and adaptations for gas exchange • Pneumatophores and other aerial root extensions • Low soil stability, Shore morphology, and adaptations for rooting • Prop Roots • Sedimentationrates and types James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  15. All increase toward shore Salinity Bruguiera gymnorrhiza Rhizophora stylosa Inundation Decreasing Soil Stability Sedimentation Rate Mangrove Species Zonation Ceriops australis Avicennia marina James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  16. 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, jd363@columbia.edu

  17. Bark Identification James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  18. Tree Characters James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  19. Pneumatophores James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  20. Epiphytes James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  21. 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 James A. Danoff-Burg, Columbia University, jd363@columbia.edu

  22. Mangroves of Australia • The mangrove plants of Queensland (from http://www.aims.gov.au/pages/reflib/fg-mangroves/pages/fgm-qld-15.html) • Listed below are the true mangrove species that grow in Queensland. Hybrid plants are indicated by the use of an x in the scientific name (e.g. Lumnitzera x rosea). • AcanthaceaeAcanthus ebracteatus Acanthus ilicifolius • ArecaceaeNypa fruticans • AvicenniaceaeAvicennia marina • BignoniaceaeDolichandrone spathacea • BombaceaeCamptostemum schultzii • CaesalpiniaceaeCynometra iripa • CombretaceaeLumnitzera racemosa, Lumnitzera x rosea, Lumnitzera littorea • EbenaceaeDiospyros ferrea • EuphorbiaceaeExcoecaria agallocha • LythraceaePemphis acidula • MeliaceaeXylocarpus granatum • MyrsinaceaeXylocarpus mekongensis, Aegiceras corniculatum • MyrtaceaeOsbornia octodonta • PlumbaginaceaeAegialitis annulata • PteridaceaeAcrostichum speciosum • RhizophoraceaeBruguiera gymnorrhiza,Bruguiera sexangula, Bruguiera exaristata, Bruguiera parviflora, Bruguiera cylindrica, Ceriops australis, Ceriops decandra, Ceriops tagal, Rhizophora apiculata, Rhizophora x lamarckii, Rhizophora stylosa, Rhizophora mucronata • RubiaceaeScyphiphora hydrophyllacea • SonneratiaceaeSonneratia alba, Sonneratia x gulngai, Sonneratia caseolaris, Sonneratia lanceolata • SterculaceaeHeritiera littoralis James A. Danoff-Burg, Columbia University, jd363@columbia.edu

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