8.4 Human Impacts on Mangroves and Wetlands

Wetlands

Definition

  • Wetlands are defined as areas where soil is submerged or saturated in water for at least part of the year. They must be shallow enough to support emergent plants.

Characteristics of Wetlands

  • Wetland plants have adapted to living in water, with examples including:

    • Cattails

    • Lily Pads

    • Reeds

Ecosystem Services of Wetlands

Wetlands provide a variety of ecosystem services, which can be categorized into several types:

Provisioning Services

  • Provisioning services refer to the resources that wetlands provide, such as:

    • Habitat for animals

    • Raw materials for various human uses

Regulating Services

  • Wetlands serve to regulate environmental conditions, including:

    • Groundwater recharge

    • Groundwater absorption

    • Water filtration

    • CO₂ sequestration

Supporting Services

  • Supporting services enhance the conditions for life and include:

    • Pollinator habitats

    • Nutrient cycling

    • Pest control

Cultural Services

  • Cultural services encompass the benefits obtained from wetlands that enrich people's lives including:

    • Recreational activities (e.g., fishing, camping)

    • Educational research opportunities

Threats to Wetlands

Wetlands face several threats that reduce their sustainability and ecosystem services:

Pollution

  • Major pollutants affecting wetlands include:

    • Nutrients (nitrogen (N) and phosphorus (P))

    • Sediment

    • Motor oil

    • Pesticides

Development Pressure

  • Wetlands can be filled in or drained for:

    • Agricultural land

    • Housing developments

    • Parking lots

    • Infrastructure projects (e.g., roads)

Water Diversion

  • Water diversion upstream can lead to:

    • Reduced water flow into wetlands

    • Drying up of wetlands (example: Everglades)

Dam Construction

  • Construction of dams can contribute to:

    • Altered water flow patterns

    • Reduced habitat for wetland species

Overfishing

  • Overfishing impacts wetland food webs by:

    • Decreasing populations of fish and predatory species

    • Reducing overall biodiversity

Conclusion

  • Wetlands are crucial for maintaining ecological balance and providing services that benefit both wildlife and human communities, but they are facing significant threats from pollution, development, and other human activities.

Human activities threatening wetlands, like mangrove ecosystems, include:

  • Pollution: Introduction of harmful substances such as chemicals, heavy metals, and plastics.

  • Coastal Development: Construction of housing, resorts, and infrastructure leading to habitat loss.

  • Agricultural Expansion: Conversion of mangrove areas into agricultural land through clearing and drainage.

  • Overfishing: Unsustainable fishing practices diminishing fish populations that rely on mangrove habitats.

  • Climate Change: Rising sea levels affecting the coastal ecosystems and increasing salinity in wetlands.