APES 8.4 Human Impacts on Wetlands and Mangroves

Introduction to Human Disturbances in Wetlands and Mangroves

• Objective: Describe human activities impacting wetlands and mangroves.

• Skill Focus: Describing solutions to environmental problems.

Understanding Wetlands

• Definition: Areas where soil is submerged in water for all or part of the year.

• Emergent Vegetation: Plants with roots anchored in soil, parts extend above water.

  • Adaptations needed to survive in wet conditions.

  • Comparison to crops which can drown if roots are submerged.

Importance of Wetlands

• Ecosystem Services: Vital functions provided by wetlands.

  • Provisioning Services: Habitats for animals/plants; sources of food/raw materials.

  • Regulating Services: Groundwater recharge and filtration of pollutants.

    • Wetland plants trap and metabolize pollutants.

  • Carbon Sequestration: Storage of CO2 in woody plants, mitigating climate change.

  • Supporting Services: Water filtration and nutrient recycling through breakdown of organic matter.

  • Pest Control: Natural predators in wetlands help manage pest populations.

  • Cultural Services: Tourism, recreational activities, research opportunities, economic benefits.

Threats to Wetlands

• Pollution: Nutrient pollution along with sediment, pesticides, and motor oils impacting water quality.

• Development: Filling or draining wetlands for urbanization can destroy habitats and services.

• Water Diversion: Reduction of water levels through diversion for agriculture/drinking; affects ecosystems downstream.

  • Example: Everglades – historical vs. diverted water flow affecting habitats.

• Hydroelectric Power: Dams can trap sediment and vital nutrients behind barriers, altering soil fertility downstream.

• Overfishing: Disruption of food webs leading to instability in wetland ecosystems.

Mangrove Ecosystems

• Value of Mangroves: Estimated at $800 billion due to ecosystem services.

• Key Ecosystem Services:

  • Fuel Source: Sustainable harvesting opportunities in developing nations.

  • Coastal Protection: More effective than human-made barriers against storms and floods.

  • Water Filtration: Helps clean pollutants and recharge groundwater.

  • Tourism: Attracts visitors, providing economic opportunities.

  • Habitat for Biodiversity: Supports numerous fish and shellfish species.

  • Carbon Sequestration: Crucial for climate regulation.

Threats to Mangrove Ecosystems

• Deforestation: Clearing for development; beachfront property value leads to habitat loss.

• Aquaculture: Creating fish/shellfish farms results in mangrove destruction.

• Rice Paddies: Placement of agricultural fields in mangrove areas.

• Pollution: Sediments clogging roots and heavy metal toxicity degrading health of mangroves.

Solutions to Protect Wetlands and Mangroves

• Nutrient Reduction Strategies:

  • Cover Crops: Planting between main crops to prevent sediment/fertilizer runoff.

  • Animal Manure Management: Better containment and processing of manure.

• Riparian Buffers: Vegetation along waterways to filter and absorb runoff pollutants.

• Sewage Management:

  • Upgrade septic systems for efficient drainage and natural filtering.

  • Biological waste removal by microbes to reduce nutrient loading in water bodies.