Tropical wetlands

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Tropical wetlands

• Lowlands of Veracruz
• Daan Asscheman
• Jasper Ohm

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Tropical wetlands

• The term tropical wetlands is quite a broad
  concept
• If Ramsar-convention definition for wetland is
  used, at least 13 different habitats can be
  identified

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Tropical wetlands

• Threatened by drainage, logging, pollution and
  diverted water
• Services flood protection, storm prevention,
  waste absorption, recreation and forming an
  important habitat for numerous plant and animal
  species

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Veracruz lowland

• Landscape slopes down to coast from the Sierra
  Madre
• At coast, dunes are formed by strong northerly
  winds, preventing discharge by rivers ?
  floodplains, backswamps
• In between dunes marshy areas and shallow lakes

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Veracruz lowland
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Veracruz lowland

• Wet (june-sept) and dry (oct-march) season
• Seasonal flooding of backswamps

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Flora

• Highly influenced by flooding frequency, depth,
  duration and salt/brackish/fresh
• Backswamps
• Mangroves, salt tolerant grasses and tropical
  deciduous forests
• Inter-dunal wetlands
• Grasses, sedges and thickets in moist areas
• Phyto- and zooplankton and floating and flowering
  plants in lakes

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Fauna

• Veracruz lowland important bird migration
  corridor river of raptors

• 6 mln raptors and 8 mln passerines
• Also non-migratory bird species present
• Fishes, turtles, crocodiles

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Human use

• 2600 bc 300 AD
• Hunter gatherers, some cultivated cotton
• 300-700 AD
• population growth, backswamps used for
  agriculture by raised fields

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Human use

• Raised fields
• Soil from digging canals put on fields ? dryer
  pastures

• Very fertile land, muck from canals applied
  frequently

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Human use

• 700-1000 AD
• Population declined, fields abandoned
• Colonial times
• Marshes seen as sources of disease ? drained for
  agriculture and urban contructions
• Present
• Coffee plantations and cattle land (zebu)
• Expansion of urban areas is reducing wetland areas