🌱Intro to Environmental Systems Unit 3 – Ecosystems and Biodiversity

Key Concepts and Definitions

• Ecosystem consists of a community of organisms interacting with each other and their physical environment
• Biodiversity refers to the variety of life forms within an ecosystem, including genetic diversity, species diversity, and ecosystem diversity
• Biotic factors are living components of an ecosystem, such as plants, animals, and microorganisms
• Abiotic factors are non-living components of an ecosystem, including temperature, water, sunlight, and soil
• Trophic levels represent the position of an organism in the food chain, such as producers (plants), primary consumers (herbivores), and secondary consumers (carnivores)
• Ecological niche describes the role and position of a species within an ecosystem, including its habitat, diet, and interactions with other species
• Keystone species have a disproportionately large impact on the ecosystem relative to their abundance (sea otters in kelp forests)
• Ecosystem services are benefits provided by ecosystems to humans, such as clean air, water purification, and pollination

Ecosystem Structure and Function

• Energy flow through ecosystems follows the laws of thermodynamics, with energy moving from producers to consumers and decomposers
• Food webs depict the complex feeding relationships among organisms in an ecosystem, showing the transfer of energy and nutrients
• Nutrient cycling involves the movement and exchange of essential elements (carbon, nitrogen, phosphorus) between biotic and abiotic components of an ecosystem
• Primary productivity refers to the rate at which energy is converted into organic compounds by photosynthetic organisms (phytoplankton in aquatic ecosystems)
• Decomposition is the breakdown of dead organic matter by decomposers, releasing nutrients back into the ecosystem
• Ecological succession describes the gradual and predictable changes in species composition over time, from pioneer species to climax communities
• Resilience is the ability of an ecosystem to recover from disturbances and maintain its structure and function
  • Resilient ecosystems have high biodiversity and redundancy, allowing them to adapt to changes more effectively

Types of Ecosystems

• Terrestrial ecosystems are land-based and include biomes such as forests, grasslands, deserts, and tundra
  • Forests are characterized by a dense canopy of trees and high biodiversity (Amazon rainforest)
  • Grasslands have grasses as the dominant vegetation and support grazing animals (African savanna)
• Aquatic ecosystems are water-based and include freshwater (lakes, rivers) and marine (oceans, coral reefs) habitats
  • Wetlands are transitional areas between terrestrial and aquatic ecosystems, providing crucial habitats for many species (Everglades)
• Estuaries are partially enclosed coastal bodies of water where freshwater and saltwater mix, supporting unique and productive ecosystems (Chesapeake Bay)
• Urban ecosystems are human-dominated environments that include cities and their surrounding areas, with a mix of natural and artificial elements
• Microbial ecosystems exist in diverse environments, from the human gut to deep-sea hydrothermal vents, and play crucial roles in nutrient cycling and symbiotic relationships
• Extreme ecosystems are found in harsh conditions, such as hot springs, deep-sea trenches, and polar regions, and host specialized organisms adapted to these environments

Biodiversity: Levels and Importance

• Genetic diversity refers to the variety of genes within a species, providing the basis for adaptation and evolution
• Species diversity is the number and abundance of different species within an ecosystem or region
  • Species richness is the total number of species present, while species evenness refers to the relative abundance of each species
• Ecosystem diversity encompasses the variety of habitats, communities, and ecological processes within a given area
• Biodiversity enhances ecosystem stability, resilience, and productivity by providing a range of ecological functions and services
• High biodiversity increases the chances of species survival during environmental changes or disturbances (redundancy)
• Biodiversity is essential for food security, as it provides a variety of crops, livestock, and wild food sources (agrobiodiversity)
• Biodiversity is a source of medicinal compounds and inspiration for biomimicry in technology and design (gecko-inspired adhesives)

Ecosystem Services and Human Impact

• Provisioning services include the production of food, water, timber, and other resources that humans rely on
• Regulating services help maintain the balance of natural processes, such as climate regulation, water purification, and pest control
  • Forests absorb carbon dioxide and regulate the Earth's climate, while wetlands filter water and reduce the impact of floods
• Cultural services provide non-material benefits, such as recreation, education, and spiritual values (national parks, sacred groves)
• Supporting services are necessary for the production of all other ecosystem services, including nutrient cycling, soil formation, and primary production
• Human activities, such as habitat destruction, pollution, and overexploitation, are the main drivers of biodiversity loss and ecosystem degradation
• Land-use change, particularly deforestation and urbanization, fragments habitats and disrupts ecological processes (palm oil plantations in Southeast Asia)
• Climate change, caused by anthropogenic greenhouse gas emissions, alters temperature and precipitation patterns, affecting species distributions and ecosystem functioning
• Invasive species, often introduced by human activities, can outcompete native species and disrupt ecosystem balance (kudzu in the southeastern United States)

Conservation and Management Strategies

• Protected areas, such as national parks, wildlife reserves, and marine protected areas, aim to conserve biodiversity and ecosystems by limiting human activities
• Habitat restoration involves the active recovery of degraded or destroyed ecosystems to their natural state (wetland restoration projects)
• Ecosystem-based management considers the entire ecosystem, including humans, in decision-making and resource management
• Sustainable resource use practices, such as sustainable forestry and fishing, aim to balance human needs with the long-term health of ecosystems
• Ex-situ conservation involves the preservation of species outside their natural habitats, such as in zoos, botanical gardens, and seed banks (Svalbard Global Seed Vault)
• In-situ conservation focuses on protecting species and ecosystems in their natural environments, often through the establishment of protected areas and conservation easements
• Community-based conservation engages local communities in the management and protection of their natural resources, promoting sustainable livelihoods and cultural values
• International agreements, such as the Convention on Biological Diversity and the Paris Agreement, provide frameworks for global cooperation in biodiversity conservation and climate change mitigation

Case Studies and Real-World Examples

• The Yellowstone Wolf Reintroduction (1995) demonstrated the importance of keystone species in shaping ecosystem dynamics and trophic cascades
• The Great Barrier Reef, the world's largest coral reef system, is under threat from climate change, ocean acidification, and coastal development
• The Mangroves for the Future initiative promotes the conservation and sustainable use of mangrove ecosystems in the Indian Ocean region, recognizing their importance for coastal protection and livelihoods
• The Sustainable Amazon Network brings together researchers, policymakers, and local communities to develop strategies for reconciling economic development with biodiversity conservation in the Amazon rainforest
• The Serengeti Ecosystem in East Africa is a prime example of a complex and dynamic savanna ecosystem, with iconic species such as wildebeest, zebras, and lions
• The Oostvaardersplassen in the Netherlands is a unique example of rewilding, where large herbivores (Heck cattle, Konik horses) were introduced to create a self-sustaining ecosystem on reclaimed land
• The Loess Plateau Watershed Rehabilitation Project in China demonstrates the successful restoration of a degraded ecosystem through soil conservation, afforestation, and sustainable land management practices

Emerging Trends and Future Challenges

• Ecosystem-based adaptation strategies use biodiversity and ecosystem services to help communities adapt to the impacts of climate change (mangrove restoration for coastal protection)
• Nature-based solutions harness the power of ecosystems to address societal challenges, such as climate change mitigation, water security, and disaster risk reduction
• Green infrastructure incorporates natural elements into urban planning and design to provide ecosystem services and enhance biodiversity (green roofs, urban wetlands)
• Ecological restoration is increasingly recognized as a critical tool for reversing ecosystem degradation and supporting biodiversity recovery (Bonn Challenge for forest landscape restoration)
• Biodiversity offsetting is a controversial approach that aims to compensate for the unavoidable impacts of development projects on biodiversity by creating or restoring habitats elsewhere
• The integration of traditional ecological knowledge with modern science can lead to more effective and culturally sensitive conservation strategies (Indigenous-led conservation initiatives)
• The development of new technologies, such as remote sensing, eDNA analysis, and artificial intelligence, is transforming the way we monitor and manage ecosystems and biodiversity
• The COVID-19 pandemic has highlighted the urgent need to address the root causes of zoonotic disease emergence, such as habitat destruction and wildlife trade, and to promote a One Health approach that recognizes the interconnectedness of human, animal, and ecosystem health