🪺Environmental Biology Unit 2 – Biodiversity and Conservation

What's Biodiversity Anyway?

• Biodiversity encompasses the variety of life on Earth at all levels, from genes to ecosystems
• Includes diversity within species (genetic diversity), between species (species diversity), and of ecosystems (ecosystem diversity)
• Genetic diversity provides the raw material for evolution and adaptation to changing environments
• Species diversity refers to the number and relative abundance of different species in a given area
  • Estimated 8.7 million eukaryotic species on Earth, with many more yet to be discovered
  • Prokaryotic diversity (bacteria and archaea) is even more extensive and less well-characterized
• Ecosystem diversity involves the variety of habitats, biological communities, and ecological processes
  • Ranges from tropical rainforests to deep-sea hydrothermal vents, each with unique species and interactions
• Biodiversity is not evenly distributed across the planet, with certain regions (biodiversity hotspots) harboring a disproportionate share of species richness

Earth's Ecosystems: A Quick Tour

• Terrestrial ecosystems cover approximately 30% of Earth's surface and include a wide range of habitats
  • Forests (boreal, temperate, and tropical) are dominated by trees and support diverse plant and animal communities
  • Grasslands (prairies, savannas, and steppes) are characterized by grasses and herbaceous vegetation
  • Deserts receive little precipitation and host specially adapted plants and animals
  • Tundra occurs in cold regions with low-growing vegetation and permafrost
• Aquatic ecosystems comprise both freshwater and marine habitats
  • Freshwater ecosystems include rivers, lakes, wetlands, and groundwater, supporting 10% of all known species
  • Marine ecosystems cover over 70% of Earth's surface and range from shallow coastal waters to the deep ocean
    • Coral reefs are biodiversity hotspots, harboring an estimated 25% of all marine species
    • Open ocean ecosystems, while less diverse, play crucial roles in global nutrient cycling and carbon sequestration
• Ecosystems are not isolated but interconnected through the movement of energy, matter, and organisms
  • Migratory species link distant ecosystems (birds, whales, and salmon)
  • Nutrient and water cycles transport materials across ecosystem boundaries

Why Biodiversity Matters

• Biodiversity provides numerous ecosystem services essential for human well-being
  • Provisioning services: food, fiber, fuel, and medicine derived from diverse species
  • Regulating services: climate regulation, water purification, pollination, and pest control
  • Cultural services: recreational, aesthetic, and spiritual benefits associated with nature
  • Supporting services: nutrient cycling, soil formation, and primary production that underpin other services
• Diverse ecosystems are more resilient to disturbances and can better adapt to changing conditions
  • Redundancy: multiple species performing similar functions provides insurance against species loss
  • Complementarity: species with different traits can respond differently to disturbances, enhancing overall stability
• Biodiversity is a source of inspiration and innovation for science, technology, and art
  • Biomimicry: designing materials and systems based on biological models (Velcro inspired by burdock seeds)
  • Bioprospecting: searching for new compounds and genes with medical or industrial applications
• Ethical arguments for biodiversity conservation emphasize the intrinsic value of all species and our moral responsibility as stewards of the planet

Threats to Biodiversity

• Habitat loss and fragmentation are the primary drivers of biodiversity loss
  • Conversion of natural habitats for agriculture, urbanization, and resource extraction
  • Fragmentation reduces habitat connectivity and isolates populations, increasing extinction risk
• Overexploitation of species through hunting, fishing, and collecting for trade
  • Unsustainable harvesting can lead to population declines and extinctions (passenger pigeon, Atlantic cod)
  • Illegal wildlife trade targets rare and endangered species for pets, traditional medicine, and luxury goods
• Invasive species, introduced intentionally or accidentally, can disrupt ecosystems and displace native species
  • Predation, competition, and disease transmission by invasive species (brown tree snake on Guam, chytrid fungus in amphibians)
  • Economic costs of invasive species management and control are substantial
• Pollution from agricultural runoff, industrial waste, and plastic debris affects both terrestrial and aquatic ecosystems
  • Nutrient pollution causes eutrophication and dead zones in aquatic systems
  • Persistent organic pollutants bioaccumulate in food webs, impacting top predators
  • Microplastics are ingested by marine organisms with largely unknown consequences
• Climate change, driven by anthropogenic greenhouse gas emissions, is an emerging threat to biodiversity
  • Shifting temperature and precipitation patterns alter species distributions and phenology
  • Ocean acidification, caused by increased CO2 absorption, impairs shell-forming organisms and coral reefs

Conservation Strategies

• Protected areas, such as national parks and wildlife reserves, safeguard habitats and species
  • Globally, protected areas cover 15% of land and 7% of oceans, with targets to expand coverage
  • Effective management and enforcement are crucial for protected area success
  • Connectivity between protected areas facilitates species movement and gene flow
• Ecosystem restoration aims to recover degraded habitats and their associated biodiversity
  • Reforestation and afforestation efforts to restore forest cover and ecosystem services
  • Wetland and coral reef restoration to improve water quality, coastal protection, and fisheries
• Sustainable use of biodiversity involves managing species and ecosystems for long-term viability
  • Sustainable forestry practices, such as selective logging and reduced-impact logging
  • Fisheries management through quotas, gear restrictions, and marine protected areas
  • Sustainable agriculture, including agroforestry, crop diversification, and integrated pest management
• Ex-situ conservation maintains species outside their natural habitats, serving as a backup for wild populations
  • Zoos, aquariums, and botanical gardens maintain captive breeding programs for endangered species
  • Seed banks and gene banks store genetic diversity of crops and their wild relatives
• Community-based conservation engages local communities in biodiversity stewardship
  • Participatory approaches to natural resource management (community forests, wildlife conservancies)
  • Ecotourism generates income for communities while incentivizing conservation

Measuring and Monitoring Biodiversity

• Species richness is the simplest measure of biodiversity, counting the number of species in an area
  • Alpha diversity: species richness within a single habitat or community
  • Beta diversity: turnover of species between habitats or communities
  • Gamma diversity: total species richness across a landscape or region
• Evenness describes the relative abundance of species, with high evenness indicating similar abundances
  • Shannon and Simpson indices incorporate both richness and evenness
• Functional diversity considers the range of ecological roles and traits within a community
  • Functional groups: species with similar ecological functions (nitrogen fixers, seed dispersers)
  • Functional redundancy: multiple species performing similar functions, providing resilience
• Monitoring biodiversity over time is essential for assessing conservation effectiveness and detecting trends
  • Standardized survey methods, such as transects, quadrats, and point counts, enable comparisons across sites and years
  • Remote sensing techniques, including satellite imagery and aerial surveys, monitor habitat extent and quality
  • Citizen science engages the public in data collection, increasing the scale and scope of monitoring efforts
• Biodiversity indicators synthesize complex data into metrics for policy and decision-making
  • Living Planet Index tracks population trends of vertebrate species
  • Red List Index measures extinction risk for different taxonomic groups

Case Studies in Conservation

• African elephant conservation balances protecting a keystone species with human-wildlife conflict mitigation
  • Community-based conservation initiatives, such as the Namibian conservancy program, incentivize coexistence
  • Ivory trade bans and anti-poaching efforts aim to reduce illegal hunting pressure
• Coral reef conservation in the Great Barrier Reef showcases the challenges of managing a vast, diverse ecosystem
  • Marine protected areas, fishing regulations, and water quality improvement efforts aim to enhance reef resilience
  • Coral restoration projects, such as nurseries and transplantation, help to recover degraded reefs
• Yellowstone wolf reintroduction highlights the ecological benefits of restoring top predators
  • Wolves regulate elk populations, reducing overgrazing and promoting vegetation recovery
  • Trophic cascades extend to other species, such as beavers and songbirds, demonstrating the importance of species interactions
• Mangrove restoration in Southeast Asia provides multiple ecosystem services while supporting biodiversity
  • Mangroves protect coastlines from erosion and storm surges, filter pollutants, and sequester carbon
  • Restoration efforts involve local communities in planting and management, providing livelihood benefits

Future Challenges and Opportunities

• Integrating biodiversity conservation into land-use planning and decision-making across sectors
  • Incorporating biodiversity values into environmental impact assessments and strategic planning
  • Encouraging biodiversity-friendly practices in agriculture, forestry, and fisheries through incentives and regulations
• Addressing the underlying drivers of biodiversity loss, such as population growth and unsustainable consumption
  • Promoting education and awareness to shift attitudes and behaviors towards sustainability
  • Supporting family planning and women's empowerment to reduce population pressures on natural resources
• Harnessing technology and innovation for conservation science and practice
  • Applying genomics and biotechnology to species conservation and restoration (gene editing, synthetic biology)
  • Using artificial intelligence and big data to analyze patterns and predict conservation outcomes
• Mobilizing financial resources for biodiversity conservation from diverse sources
  • Scaling up public and private investments in conservation, including through biodiversity offsets and payments for ecosystem services
  • Exploring innovative financing mechanisms, such as conservation trust funds, green bonds, and impact investing
• Fostering collaboration and partnerships across sectors and scales for effective conservation action
  • Engaging indigenous and local communities as partners in conservation, respecting traditional knowledge and practices
  • Strengthening international cooperation and governance frameworks, such as the Convention on Biological Diversity and the Sustainable Development Goals