Mangrove Forests

1. Mangrove Forests Worksheet (from supplemental reading in Nybakken)371-382 not 378-380 Text Reading 109-111 Video Questions “Creatures of the Mangrove” 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. 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, jd363@columbia.edu

5. 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, jd363@columbia.edu

6. 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, jd363@columbia.edu

7. 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

8. 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

9. 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, jd363@columbia.edu

10. 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

11. Root networks catch more sand, silt, and mangrove seeds. • This leads to dense patches. James A. Danoff-Burg, Columbia University, jd363@columbia.edu

12. 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

13. Salt is directed to a few leaves that yellow and die. James A. Danoff-Burg, Columbia University, jd363@columbia.edu

14. 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

15. 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

16. 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, jd363@columbia.edu

17. 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

18. 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

19. 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

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

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

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

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

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

25. 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