Lecture 12 Sustaining Ecosystems II

Midterm exam is scheduled for the next class, covering material discussed today.
Students should bring a blue or black pen (non-erasable).

Over 50% of mature tropical forests have been lost since 1950.
In 2021, about 14 football fields of tropical forest were lost every minute.
Deforestation Facts:
- 90% of global deforestation occurs in tropical regions.
- Tropical forests house at least 80% of the world’s known terrestrial species.
- Implications of Tropical Forest Loss: Loss of biodiversity, disruptions in ecosystem services, and potential climate change impacts.
Causes of Tropical Deforestation:
- Population growth pressures.
- Government subsidies for large-scale logging and cattle ranching.
- Geographic variations in deforestation drivers:
  - South America: Cattle grazing and crop land.
  - Indonesia/Southeast Asia: Oil palm plantations.
  - Africa: Firewood and farming.

Implement selective cutting or strip cutting in forests.
Phase out subsidies and tax breaks favoring deforestation; implement full-cost pricing for consumers.
Encourage tree planting programs and protect diverse forest areas.
Offer economic incentives for sustainable forestry (e.g., FSC certification).
Fire Management Strategies:
- Use prescribed burns to eliminate small trees and underbrush.
- Allow natural fires under controlled conditions that do not threaten human life.
- Thin trees around homes to protect against wildfires.
Wood Consumption and Waste:
- 60% of the wood consumed in the U.S. is wasted.
- Alternatives: Use non-tree fibers such as kenaf and hemp to reduce tree dependence.
- Promote reusable products over single-use paper products to minimize waste.

Grasslands include rangelands and pastures and are the second most widely used ecosystem after forests.
Definitions:
- Rangelands: Unfenced grasslands that offer forage for grazing.
- Pastures: Managed grasslands usually planted with domesticated grasses.
Overgrazing Impacts:
- Harms grass roots and reduces grass cover.
- Leads to soil erosion and compaction, diminishing water retention and promoting invasive, non-palatable species.
Sustainable Rangeland Management:
- Control grazing animal numbers and grazing durations.
- Use rotational grazing techniques.
- Protect riparian zones by fence-enforced recovery zones around natural water sources.

Establish and protect wilderness areas, parks, and nature reserves.
Identify and prioritize biodiversity hotspots for conservation efforts.
Strategies to sustain biodiversity include:
- Protecting species from extinction.
- Avoiding the destruction of critical habitats.
- Rehabilitating damaged ecosystems and maintaining protected areas.
- Conducting basic research to identify critical conservation areas.

Definition of Wilderness: Areas undisturbed by humans, protected by federal law.
Wilderness Act (1964): Established protection for undeveloped public lands; only 5% of U.S. land is protected as wilderness.
U.S. national parks system includes 63 major national parks, but many are too small to support large species.
Challenges faced by parks include:
- Introduced species threatening native populations.
- Visitor impacts degrading natural features.
- Pollution from surrounding industrial activities affecting natural vistas.

In the 1800s, gray wolves thrived in America but were nearly exterminated by the 1900s.
Reintroduction efforts in 1996 aimed to restore ecological balance in Yellowstone.
- Wolves control populations of several large herbivores, impacting overall ecosystem health.
- Initial fears of cattle ranchers were mitigated as coyote populations decreased.

The design of reserves and size is crucial for successful biodiversity conservation.
Habitat corridors: Allow migration and movement of various species between reserves.
Establishing buffer zones enables sustainable resource use by local communities while protecting inner reserves.
Example: Costa Rica leading in creating a global network of bioreserves.

Map and inventory ecosystems and their services.
Identify resilient ecosystems needing protection.
Prioritize conservation of endangered ecosystems and species.
Restore severely degraded ecosystems.
Offer financial and technical assistance for biodiversity-friendly development initiatives.

Restoration Techniques:
- Direct restoration to original conditions: replanting forests, reintroducing native species.
- Rehabilitation: Improve functionality without returning to original state (e.g., removing pollutants).
- Replacement: Introduce alternative ecosystems (e.g., pasture instead of forest).
- Artificial ecosystems can fulfill specific ecological functions (e.g., created wetlands).
Reconciling Human Development with Conservation:
- Promote sustainable ecotourism.
- Educate local populations on the importance of protecting ecosystems.

Human activities have severely impacted coastal, ocean, and freshwater ecosystems.
Major threats include:
- Sea-bottom habitat destruction from dredging and trawling.
- Ocean acidification from increased CO2 levels.
- Habitat degradation from invasive species.
Strategies for protecting aquatic biodiversity:
- Establish marine protected areas (MPAs) and sanctuaries.
- Sustainably manage coastal development and reduce pollution.

The economic value of ecosystem services far exceeds the value of raw materials.
Biodiversity can be sustained through focused conservation efforts and responsible management of ecosystems, both terrestrial and aquatic, to strengthen ecosystem services.