Lecture 15 - The Importance of Plants in Ecosystems and to Human Welfare

Importance of Plants in Ecosystems and to Human Welfare

Overview

• Focus questions to understand:

  1. How are plants important in ecosystems?

  2. What life-supporting ecosystem services do plants provide for human welfare?

  3. How are human activities influencing plant abundance and species diversity?

Importance of Plants in Ecosystems

Plants as Keystone Species

• Keystone Species: Essential species that significantly influence community structure.

• Biodiversity Support: Promote the abundance of other taxa, enhancing overall biodiversity.

• Energy Conversion:

  • Convert solar energy into chemical energy stored in biomass.

  • Make energy and nutrients available to primary consumers.

Energy and Nutrient Flow

• Energy Flow: Movement of energy through the ecosystem, primarily in the form of carbohydrates, such as glucose.

• Nutrient Flow: Direct influence on the cycling of nutrients, such as nitrogen and phosphorus.

Habitat Provision

• Ecosystem Engineers: Plants modify their environment, creating habitats for numerous organisms.

Impacts on Human Welfare

Source of Food

• Direct Consumption: Humans directly eat plants, which are crucial for nutrition.

• Indirect Consumption: Humans rely on animals that consume plants, reflecting their foundational role in food webs.

Building Materials and Fuel

• Construction Materials: Wood products for houses, furniture, etc.

• Fuels: Biomass, fossil fuels, and plants used for biofuels like ethanol and biodiesel.

Medicinal Value

• Plant-Derived Medicines: Many pharmaceuticals originate from plant compounds, emphasizing their role in healthcare.

• Defense Mechanisms: Plants produce compounds for defense against herbivores, some of which have therapeutic effects for humans.

Life-Supporting Attributes of the Biosphere

• Oxygen Production: Plants are responsible for generating oxygen through photosynthesis.

• Water Regulation:

  • Influence on local and global water cycles through uptake and transpiration, regulating climate and temperature.

Climate Change Mitigation

• Greenhouse Gas Uptake: Plants absorb CO2 during photosynthesis, counteracting climate change impacts.

• Temperature Regulation: Maintained through transpiration and surface cover.

Soil Quality Enhancement

• Nutrient Addition: Decomposition of plant matter enriches soil fertility.

• Water Retention: Roots and organic matter boost soil's ability to retain nutrients and moisture.

Water Pollution Mitigation

• Erosion Control: Plant roots stabilize soil, reducing nutrient runoff into water bodies.

• Sediment Filtration: Help maintain clean aquatic ecosystems by limiting sediment and nutrient influx.

Human Impacts on Plants

Declines in Plant Abundance and Diversity

• Causes:

  • Ecosystem Conversion: Natural ecosystems transformed for agriculture or urban development.

  • Overharvesting: Unsustainable extraction of plant resources.

  • Climate Change: Alters habitats and growth conditions, threatening plant species.

Concluding Thoughts

• Understanding the multifaceted roles of plants is crucial to addressing ecosystem degradation and informing conservation efforts.