The wetland ecosystem & urban development

1. The wetland ecosystem& urban development GEOGRAPHY PROJECT producer: Tam Kit Ying 7A no.6

2. CONTENT • What are wetlands? • Importance of wetlands • Wetlands in Mei Po - Introduction - Biotic and abiotic components - Linkages of ecosystem - Effect of urban development - Conservation • Conclusion

3. What are wetlands? [1] • Transitional zone between permanently wet and generally dry environments • Support a large variety of plant and animal species • Can be found on the coasts and inland

4. What are wetlands? [2] • Definition in Ramsar Convention …areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt including areas of marine water, the depth of which at low tide does not exceed 6 m…

5. Importance of wetlands • As a winter ground • Support many Species • Improve water quality • Prevent flooding • Economic benefit • As an educational environment

6. Wetland in Mei Po

7. Introduction [1] • Location • One of the wetlands in Hong Kong • located at Deep Bay at the mouth of Zhujiang. • cover an area of 380 hectares • comprise shallow fish and shrimp ponds, dwarf mangroves and reed beds

8. Introduction [2] • Values • recognized as one of the 41 SSSI in HK • listed in the Sixth Schedule of the Wild Animals Protection Ordinance • access is restricted by the Agriculture, Fisheries and Conservation Department of the Hong Kong Government.

9. Introduction [3] • Land use • 24 Gei Wais • Mei Po Marshes Wildlife Education Centre and Nature Reserve • offers a wide range of educational opportunities for students, scientists, bird watchers, and the general public.

10. Biotic components: Plant 1.Mangroves • refer to groups of plants belong to several families which share a common habit and habitat. • soft depositing shores in tropical and subtropical regions

11. receive nutrients from both regular tidal flushing and freshwater streams and rivers • four common mangroves: Kandelia, Bruguiera, Aegiceras and Avicennia.

12. To overcome extreme conditions, develop: i) Droppers ii) Prop roots

13. iii) Pneumatophores iv) "Knees" of roots v) Salt glands

14. 2. REEDBEDS • one of the largest remaining stands in Guangdong Province • rich feeding habitat for migratory birds

15. Biotic components: Animals1. Shrimp • feed on the rich mangrove litter and accumulated detritus • protein rich food source for predators • Economical value: sold to market • increasing water pollution , reducing the productivity of the shrimp ponds and economic gain

16. 2. Fishes • enriched with nutrients from Shenzhen River • About 20 species of fishes occur in the Gei Wais. • fishes can grow very rapidly and are generally non-selective feeders

17. 3. Mammals • nocturnal and not easily seen during the daytime • include House Mouse, Brown Rat, Lesser Ricefield Rat, Large Bandicoot Rat, Chinese Common Otter, Civet cats • feed on plants and animals in the Marshes

18. a.Fiddler Crab • most distinctive species living in the mud banks of sluice channels • featured with prominent different sized chelae • one is for attack and defence, the other is for feeding • channels provide good shelter, protection and constant nutrient supply to the crabs that are abundant

19. b.Mudskippers • amphibious fish which has developed means for short period survival out of the sea • dark grey-brown or green coloring, several darker dots or oblique stripe across their bodies • feed on either insects or mud • prized as a delicacy and are caught and consumed locally in a considerable quantities

20. c. Reptiles and Amphibians • marshes provide a variety of habitats ranging from tidal mangroves to fully terrestrial areas • Gei Wais provide rich and permanent food supply to these animals • earth bunds between ponds are sufficiently dry and well vegetated to allow them shelter and breed • animals include snakes, Water snakes, chelonians, lizards, Gold-headed Terrapin, Reeves' terrapin, Redeared Terrapin, Chinese Soft-shelled Turtle, Steindachner's Turtle

21. d. Birds • Wetland acts as a refueling station and wintering site for thousands of migratory birds in their migration between the Arctic Russia and Australia. • More than 120,000 migratory birds stay in this area in a year • Some birds are globally threatened / endangered species, such as Black-faced Spoonbill (黑臉琵鷺), Saunders' Gull, Baikal Teal etc

22. Black-faced Spoonbill • one of the most endangered species of birds (only 700 left on Earth) • feeds on small fish and shrimp in wetlands • 25% of the world's Black-faced Spoonbills spend winter in and around the wetlands of the Mei Po

23. Abiotic components : Gei Wai[1] • Covers an area of 240 ha • Ponds are stocked by flushing in young shrimps from Deep Bay in autumn, and the shrimps feed on naturally occurring organic matter ,on the bottom of the pond. • So fishermen protected the stands of mangroves inside the pond as a source of food for the shrimps and fish.

24. Abiotic components : Gei Wai[2] • Gei wai are completely drained in turn for harvesting the remaining fish inside • Large areas of vegetation within the gei wai, principally mangroves, reedbeds and sedges

25. Abiotic components : Freshwater ponds (fish pond) • triangular pond at the back of the Mei Po Education Centre • aim to manage as a freshwater pond using rainwater to provide the freshwater • Problems: leaks in the bunds of the pond allowing brackish water in from adjacent ponds. • So, whole pond has had to be drained and the leaks plugged.

26. Linkage between biotic and abiotic components (Food Web) [1] • close inter-relationship • Mutualism: an association in which 2 species of organisms live together and both obtain benefits from each other • Non-mutualism: two organisms are not live together directly, but in close relation with each other.

27. Food Web [2] Non-mutualism Competition: relationship in which 2 organisms (competitors) attempt to obtain the same requirement Predation: a relationship in which one species, the predator, kills and feeds on another species, the prey.

28. Food Web [3] Interdependence • commensalisms an association between 2 organisms of different species, in which commensal is benefited while the host is not affected. • Parasitism an association in which two species of organisms live together.parasites gain benefit from and impose harm to the hosts, which suffer from the loss of nutrients and other discomforts.

30. Effect of urban development • Hydrological alternation • Human activities: drainage, dredging, stream channelization, ditching, levees, deposition of fill material, stream diversion, ground water withdrawal,and impoundment. • Affect the soil chemistry and plant and animal community in the wetland • Reduce or increase the natural amount of water/the period of saturation and inundation  change ecosystem to an up land system / riverine or lacustrine system

31. Loss of habitat and fragmentation • Alters water diversion structures and impoundments • Change of water diversion structure can change the patterns of sedimentation • High sediment loads entering wetland can smother aquatic system shellfish beds and tidal flats, fill in riffles and pools, and contribute to turbidity. • Saltwater may be upstream and cause species change and mortality of salt-intolerant vegetation in both upstream and downstream

32. Impoundment alters the natural wetland's hydrology and decreases water circulation • Decreased circulation can cause an increase in water temperature, lower dissolved oxygen levels, and changes in salinity and pH • Prevent nutrient flow, increase in sedimentation. • Toxic substances may accumulate and contaminate wetland biota.

33. Urbanization • Reclamation and dumping reduce the area of wetland e.g Tin Shui Wai New Town • Loss of wildlife habitats and water-storage capability  loss of wildlife and flooding • Reduces the productivity of the land and their ecological value. • Degradation of wetland: caused by the change in water quality, quantity and flow rates, increases in pollutant inputs; and changes in species composition as a result of introduction of non-native species

34. Marinas / Boats • Intense boating activity increase the turbidity and degradation of wetlands • Dumping of wastes increase the amount of nutrients and organic matter  lead to eutrophication • Eutrophication: nutrient level in water is much higher than the demand  phytoplankton population explosion, massive death, and damage the ecosystem

35. Reclamation • New HK International Airport is built, dumping of soil and sludge raised the suspended solid level in water • High suspended solid blocks respiratory system of marine animal and plants that may cause death. • Industry • alter the wetland hydrology, increase water temperature, input of pollutants, change of pH value • pollutants can alter reproduction, growth, and behaviour of wetland organisms and result in mortality

36. Agriculture • Degrade wetlands, including harvesting food, fiber, or forest products, maintenance of drainage ditches, construction and maintenance of irrigation ditches, farms and roads, dams, dikes, and levees, direct and aerial application of damaging pesticides and groundwater withdrawals • Alter water hydrology, water quality and species composition. Excessive application of fertilizers and animal waste can cause eutrophication

37. Atmospheric Deposition • Air pollutants released from industrial and agricultural activities and from vehicles enter wetlands through atmospheric deposition and therefore affect the organisms in the wetlands. • Pollution Problems • new infrastructure and construction bring large amount of trash and solid waste to the new landfalls • Factories, farms and restaurants in N.T. dump out large amount of sewage or even untreated waste into the streams and the sea • severe damage is irreversible and the creatures in the sea are the direct victims of the capitalized city’s effort

38. Pollution

39. Victims: • nature reserve and birds in Mei Po Marsh threatened by the pig sewage flooding and the increased pollution from Shenzhen • bird forced to leave due to the government’s plan to build huge residential housing estates in the N.T • nature environment around Mei Po is changing – no longer a perfect heaven for the birds • flora and fauna ,human being are affected by ceaseless construction and large numbers of diesel vehicles have made for dangerous levels of particulate matter and nitrogen dioxide

40. Conservation • Designation as Ramsar Site – Mai Po • Sites of Special Scientific Interest (SSSI) • Sixth Schedule of the Wild Animals Protection Ordinance (Cap. 170) • Access permit required • Wetland management plan for Mai Po Marshes

42. Effective measures: • stop damaging the wetlands • Setting up some laws to avoid people doing something like deforestation, large amount of fishing and hunting in wetlands. • monitor the wetlands to see whether changes are happened. • construct more wetlands manually to increase the proportion of wetlands. (animals have more choices for them to live in) • Promoting the conservation of nature and natural resources to the publics does not be neglected (*children ) • Tours of Mai Po can let the people know more about the importance of wetlands.

43. Conclusion Wetlands: • home for many beautiful and rare species • protect many of our sources of drinking water • source of many commercially and recreationally valuable species of fish, shellfish and wildlife • retain flood waters and protect shorelines from erosion • Losing or degrading wetlands can lead to serious consequences • avoid these consequences by maintaining the valuable wetlands we have and restoring wetlands

44. Relevant websites Agriculture, Fisheries and Conservation Department (http://www.afcd.gov.hk/web/) World Wide Fund For Nature Hong Kong (http://www.wwf.org.hk/) The Ramsar Convention on Wetlands (http://www.ramsar.org/) National wildlife Federation (USA) (http://www.nwf.org/wetlands) Water, Soil, and Hydro-Environmental Decision Support system - Information on Wetlands (http://h2osparc.wq.ncsu.edu/info/wetlands/index.html) Convention on Conservation of Migratory Species of Wild Animals (Bonn Convention) (http://www.wcmc.org.uk/cms/) ~THE END~