Hk mangrove ecosystem


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Introduce common plants and animals in mangrove

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Hk mangrove ecosystem

  1. 1. Mangrove ecosystem
  2. 2. What are mangroves? Mangroves consists of different kinds of plants living on protected soft shores
  3. 3. Northeast New Territories
  4. 4. Environment
  5. 5. Tidal zone
  6. 6. Soil in anaerobic condition
  7. 7. Distribution In tropical region between 20ºN and 20ºS where the annual temperature is above 20 degrees
  8. 8. Environment Highly unstable environment as sedimentation is active but the soil is not consolidated Waterlogged soil, so aeration is poor In high salinity environment
  9. 9. Plants Plants adapt to the soft sea shore where mud and sand are deposited Root buttresses and stilt roots develop
  10. 10. Mai Po Marsh
  11. 11. Common mangrove plants Kandelia candel Avicennia marina Lumnitzera Racemosa Bruguiera gymnorrhiza Heritiera littoralis Aegiceras corniculatum
  12. 12. Salt released on leaves
  13. 13. Avicennia marina
  14. 14. Lumnitzera Racemosa
  15. 15. PneumatophoresAvicennia marina
  16. 16. PneumatophoresAvicennia marina
  17. 17. Knee roots
  18. 18. Buttress roots
  19. 19. Derris trifoliata in Lai Chi Wo
  20. 20. Heritiera littoralis
  21. 21. Droppers
  22. 22. CerberaManghas
  23. 23. Animals Crabs - fiddler crabs and sesarmine crabs Oysters and barnacles Gastropods
  24. 24. Animals Mudskippers live between the high- tide and low-tide level. They can live without water for days Fish and shrimps larval
  25. 25. Mudskipper
  26. 26. Mudskipper
  27. 27. Mudskipper
  28. 28. Fiddler Crab (Uca borealis)
  29. 29. Crab
  30. 30. Crab
  31. 31. Fish
  32. 32. Egret
  33. 33. Energy flow Warm tropical climate provide a lot of solar energy for photosynthesis Mangrove litter dropped on the ground is consumed by crabs, shrimps and fish
  34. 34. Energy flow The small animals are then eaten by larger fish and then by resident and migrant birds (egrets and spoonbills) The litter that is not consumed is decomposed in the soil
  35. 35. Example The fish ponds and gei wais in South China The marsh provides shelter for juvenile and larval animals such as shrimps and fish Litters, small plants and animals provide food for these animals in the ponds The animal wastes and litter enrich the soil with nutrient
  36. 36. Nutrient cycling The sea and rivers carry nutrients to the shore The nutrients are absorbed by mangrove plants and seagrasses and algae. The nutrient is then transferred to the consumers such as crabs, fish and shrimps then transferred to human beings, birds and large fish
  37. 37. Nutrientcycling
  38. 38. Nutrient cycling The dead bodies and litter are decomposed by micro-organisms in the soil Nutrient is released to the soil and sea water
  39. 39. Utilization and threats Marsh lands have been dredged and vegetation removed to form fish ponds They have been developed into recreational grounds for fishing and barbecue This provides income and can make better use of mangrove resource.
  40. 40. Threats Increase in demand for land in coastal areas. – For industrial and residential development – Recreational use Environmental pollution around the wetland Other threats?
  41. 41. Tin Shui Wai
  42. 42. Yuen Long Industrial Estate