8.4 - Human Impacts On Wetlands And Mangroves

Question 1

Wetlands

Answer 1

• An area with soil and submerged/saturated in water for at least part of the year, but shallow enough for emergent plants
  - wetland plants have adapted to living wil the roots submerged in standing water

Ecosystem services of wetlands
- Provisioning: habitat for animal and plant foods
- regulating: groundwater recharge abrobption of floodwater, CO2 sequestrian
- Supporting: H2O filtration, pollinator habitats, nutrient cycling, pest control
- Cultural: tourism revenue, fishing license, camping fees, ed/med research

Question 2

Threats to Wetlands

Answer 2

• Pollutants - nutrients, sediment, motor oil, pesticides, endocrine disruptors
• Development - wetlands can be filled in or drained to be developed into homes, parking lots, stores, or agricultural land
• Water diversion upstream for flood control, agriculture, or drinking water can reduce water flow and dry up wetlands
  - dam construction for flood control/hydroelectric reduces water and sediment flow to wetlands
• Overfishing - disrupts food web of wetlands (decrease in fish predators, increase in prey)

Question 3

Benefits of and Threats to Mangroves

Answer 3

Threats:
- mangrove loss: 35% between 1980 and 2000, the equivalent of losing almost $150,000 annually, and 4x higher than overall global forest loss
- Climate change: air temperature and rainfall regimes influence global mangrove distribution, abrupt changes in sea level are a primary cause of local and regional extinctions
- Coastal development: urbanization drives mangrove loss and degradation density in coastal regions, 3x higher than global average
- Pollution: mangroves aerial roots, through which they obtain oxygen, can easily be smothered and clogged by sediment, soil waste and oil
- aquaculture: causes more than half of mangrove loses globally mostly due to shrimp culture
- Agriculture: conversion to rice paddies responsible for 88% of mangrove loss in Myanmar
- Logging: can cause altered species composition, fragmentation and total clearance of mangrove forest

Benefits:
- Wood: its density makes mangrove wood a valued source of timber and fuel
- livelihoods: 120 million people living near mangroves
- Mangrove ecosystem services: worth US$ 33,000-57,000 per hectare per year, up to 800 million per years
- climate regulation:CARBON STORAGE POTENTIAL OF MANGROVES IS 3-5X HIGHER THAN THAT OF TROPICAL UPLAND FOREST DUE TO STRONG CARBON STORAGE IN THE SOIL, CO2 RELEASED BY GLIOBAL MANGROVE LOSS ANNUALLY COULD BE AS HIGH AS THE ANNUAL EMMISIONS OF AUSTRAILIA
- Fisheries: more than 3000 fish species are found in mangrove ecosystems
- Tourism: there are over 2000 mangrove-related attractions globally
- Water filtration: 25 hectares of mangroves May treated the effluents of 1 hectare of aquaculture
- Coastal protection: restoring mangroves for coastal defense up to 5x more cost-effective than grey infrastructure such as breakwaters